Index: head/sys/kern/kern_umtx.c
===================================================================
--- head/sys/kern/kern_umtx.c (revision 347354)
+++ head/sys/kern/kern_umtx.c (revision 347355)
@@ -1,4568 +1,4572 @@
/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2015, 2016 The FreeBSD Foundation
* Copyright (c) 2004, David Xu <davidxu@freebsd.org>
* Copyright (c) 2002, Jeffrey Roberson <jeff@freebsd.org>
* All rights reserved.
*
* Portions of this software were developed by Konstantin Belousov
* under sponsorship from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_umtx_profiling.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mman.h>
#include <sys/mutex.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/resource.h>
#include <sys/resourcevar.h>
#include <sys/rwlock.h>
#include <sys/sbuf.h>
#include <sys/sched.h>
#include <sys/smp.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/syscallsubr.h>
#include <sys/taskqueue.h>
#include <sys/time.h>
#include <sys/eventhandler.h>
#include <sys/umtx.h>
#include <security/mac/mac_framework.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <machine/atomic.h>
#include <machine/cpu.h>
#ifdef COMPAT_FREEBSD32
#include <compat/freebsd32/freebsd32_proto.h>
#endif
#define _UMUTEX_TRY 1
#define _UMUTEX_WAIT 2
#ifdef UMTX_PROFILING
#define UPROF_PERC_BIGGER(w, f, sw, sf) \
(((w) > (sw)) || ((w) == (sw) && (f) > (sf)))
#endif
/* Priority inheritance mutex info. */
struct umtx_pi {
/* Owner thread */
struct thread *pi_owner;
/* Reference count */
int pi_refcount;
/* List entry to link umtx holding by thread */
TAILQ_ENTRY(umtx_pi) pi_link;
/* List entry in hash */
TAILQ_ENTRY(umtx_pi) pi_hashlink;
/* List for waiters */
TAILQ_HEAD(,umtx_q) pi_blocked;
/* Identify a userland lock object */
struct umtx_key pi_key;
};
/* A userland synchronous object user. */
struct umtx_q {
/* Linked list for the hash. */
TAILQ_ENTRY(umtx_q) uq_link;
/* Umtx key. */
struct umtx_key uq_key;
/* Umtx flags. */
int uq_flags;
#define UQF_UMTXQ 0x0001
/* The thread waits on. */
struct thread *uq_thread;
/*
* Blocked on PI mutex. read can use chain lock
* or umtx_lock, write must have both chain lock and
* umtx_lock being hold.
*/
struct umtx_pi *uq_pi_blocked;
/* On blocked list */
TAILQ_ENTRY(umtx_q) uq_lockq;
/* Thread contending with us */
TAILQ_HEAD(,umtx_pi) uq_pi_contested;
/* Inherited priority from PP mutex */
u_char uq_inherited_pri;
/* Spare queue ready to be reused */
struct umtxq_queue *uq_spare_queue;
/* The queue we on */
struct umtxq_queue *uq_cur_queue;
};
TAILQ_HEAD(umtxq_head, umtx_q);
/* Per-key wait-queue */
struct umtxq_queue {
struct umtxq_head head;
struct umtx_key key;
LIST_ENTRY(umtxq_queue) link;
int length;
};
LIST_HEAD(umtxq_list, umtxq_queue);
/* Userland lock object's wait-queue chain */
struct umtxq_chain {
/* Lock for this chain. */
struct mtx uc_lock;
/* List of sleep queues. */
struct umtxq_list uc_queue[2];
#define UMTX_SHARED_QUEUE 0
#define UMTX_EXCLUSIVE_QUEUE 1
LIST_HEAD(, umtxq_queue) uc_spare_queue;
/* Busy flag */
char uc_busy;
/* Chain lock waiters */
int uc_waiters;
/* All PI in the list */
TAILQ_HEAD(,umtx_pi) uc_pi_list;
#ifdef UMTX_PROFILING
u_int length;
u_int max_length;
#endif
};
#define UMTXQ_LOCKED_ASSERT(uc) mtx_assert(&(uc)->uc_lock, MA_OWNED)
/*
* Don't propagate time-sharing priority, there is a security reason,
* a user can simply introduce PI-mutex, let thread A lock the mutex,
* and let another thread B block on the mutex, because B is
* sleeping, its priority will be boosted, this causes A's priority to
* be boosted via priority propagating too and will never be lowered even
* if it is using 100%CPU, this is unfair to other processes.
*/
#define UPRI(td) (((td)->td_user_pri >= PRI_MIN_TIMESHARE &&\
(td)->td_user_pri <= PRI_MAX_TIMESHARE) ?\
PRI_MAX_TIMESHARE : (td)->td_user_pri)
#define GOLDEN_RATIO_PRIME 2654404609U
#ifndef UMTX_CHAINS
#define UMTX_CHAINS 512
#endif
#define UMTX_SHIFTS (__WORD_BIT - 9)
#define GET_SHARE(flags) \
(((flags) & USYNC_PROCESS_SHARED) == 0 ? THREAD_SHARE : PROCESS_SHARE)
#define BUSY_SPINS 200
struct abs_timeout {
int clockid;
bool is_abs_real; /* TIMER_ABSTIME && CLOCK_REALTIME* */
struct timespec cur;
struct timespec end;
};
#ifdef COMPAT_FREEBSD32
struct umutex32 {
volatile __lwpid_t m_owner; /* Owner of the mutex */
__uint32_t m_flags; /* Flags of the mutex */
__uint32_t m_ceilings[2]; /* Priority protect ceiling */
__uint32_t m_rb_lnk; /* Robust linkage */
__uint32_t m_pad;
__uint32_t m_spare[2];
};
_Static_assert(sizeof(struct umutex) == sizeof(struct umutex32), "umutex32");
_Static_assert(__offsetof(struct umutex, m_spare[0]) ==
__offsetof(struct umutex32, m_spare[0]), "m_spare32");
#endif
int umtx_shm_vnobj_persistent = 0;
SYSCTL_INT(_kern_ipc, OID_AUTO, umtx_vnode_persistent, CTLFLAG_RWTUN,
&umtx_shm_vnobj_persistent, 0,
"False forces destruction of umtx attached to file, on last close");
static int umtx_max_rb = 1000;
SYSCTL_INT(_kern_ipc, OID_AUTO, umtx_max_robust, CTLFLAG_RWTUN,
&umtx_max_rb, 0,
"");
static uma_zone_t umtx_pi_zone;
static struct umtxq_chain umtxq_chains[2][UMTX_CHAINS];
static MALLOC_DEFINE(M_UMTX, "umtx", "UMTX queue memory");
static int umtx_pi_allocated;
static SYSCTL_NODE(_debug, OID_AUTO, umtx, CTLFLAG_RW, 0, "umtx debug");
SYSCTL_INT(_debug_umtx, OID_AUTO, umtx_pi_allocated, CTLFLAG_RD,
&umtx_pi_allocated, 0, "Allocated umtx_pi");
static int umtx_verbose_rb = 1;
SYSCTL_INT(_debug_umtx, OID_AUTO, robust_faults_verbose, CTLFLAG_RWTUN,
&umtx_verbose_rb, 0,
"");
#ifdef UMTX_PROFILING
static long max_length;
SYSCTL_LONG(_debug_umtx, OID_AUTO, max_length, CTLFLAG_RD, &max_length, 0, "max_length");
static SYSCTL_NODE(_debug_umtx, OID_AUTO, chains, CTLFLAG_RD, 0, "umtx chain stats");
#endif
static void abs_timeout_update(struct abs_timeout *timo);
static void umtx_shm_init(void);
static void umtxq_sysinit(void *);
static void umtxq_hash(struct umtx_key *key);
static struct umtxq_chain *umtxq_getchain(struct umtx_key *key);
static void umtxq_lock(struct umtx_key *key);
static void umtxq_unlock(struct umtx_key *key);
static void umtxq_busy(struct umtx_key *key);
static void umtxq_unbusy(struct umtx_key *key);
static void umtxq_insert_queue(struct umtx_q *uq, int q);
static void umtxq_remove_queue(struct umtx_q *uq, int q);
static int umtxq_sleep(struct umtx_q *uq, const char *wmesg, struct abs_timeout *);
static int umtxq_count(struct umtx_key *key);
static struct umtx_pi *umtx_pi_alloc(int);
static void umtx_pi_free(struct umtx_pi *pi);
static int do_unlock_pp(struct thread *td, struct umutex *m, uint32_t flags,
bool rb);
static void umtx_thread_cleanup(struct thread *td);
static void umtx_exec_hook(void *arg __unused, struct proc *p __unused,
struct image_params *imgp __unused);
SYSINIT(umtx, SI_SUB_EVENTHANDLER+1, SI_ORDER_MIDDLE, umtxq_sysinit, NULL);
#define umtxq_signal(key, nwake) umtxq_signal_queue((key), (nwake), UMTX_SHARED_QUEUE)
#define umtxq_insert(uq) umtxq_insert_queue((uq), UMTX_SHARED_QUEUE)
#define umtxq_remove(uq) umtxq_remove_queue((uq), UMTX_SHARED_QUEUE)
static struct mtx umtx_lock;
#ifdef UMTX_PROFILING
static void
umtx_init_profiling(void)
{
struct sysctl_oid *chain_oid;
char chain_name[10];
int i;
for (i = 0; i < UMTX_CHAINS; ++i) {
snprintf(chain_name, sizeof(chain_name), "%d", i);
chain_oid = SYSCTL_ADD_NODE(NULL,
SYSCTL_STATIC_CHILDREN(_debug_umtx_chains), OID_AUTO,
chain_name, CTLFLAG_RD, NULL, "umtx hash stats");
SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
"max_length0", CTLFLAG_RD, &umtxq_chains[0][i].max_length, 0, NULL);
SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
"max_length1", CTLFLAG_RD, &umtxq_chains[1][i].max_length, 0, NULL);
}
}
static int
sysctl_debug_umtx_chains_peaks(SYSCTL_HANDLER_ARGS)
{
char buf[512];
struct sbuf sb;
struct umtxq_chain *uc;
u_int fract, i, j, tot, whole;
u_int sf0, sf1, sf2, sf3, sf4;
u_int si0, si1, si2, si3, si4;
u_int sw0, sw1, sw2, sw3, sw4;
sbuf_new(&sb, buf, sizeof(buf), SBUF_FIXEDLEN);
for (i = 0; i < 2; i++) {
tot = 0;
for (j = 0; j < UMTX_CHAINS; ++j) {
uc = &umtxq_chains[i][j];
mtx_lock(&uc->uc_lock);
tot += uc->max_length;
mtx_unlock(&uc->uc_lock);
}
if (tot == 0)
sbuf_printf(&sb, "%u) Empty ", i);
else {
sf0 = sf1 = sf2 = sf3 = sf4 = 0;
si0 = si1 = si2 = si3 = si4 = 0;
sw0 = sw1 = sw2 = sw3 = sw4 = 0;
for (j = 0; j < UMTX_CHAINS; j++) {
uc = &umtxq_chains[i][j];
mtx_lock(&uc->uc_lock);
whole = uc->max_length * 100;
mtx_unlock(&uc->uc_lock);
fract = (whole % tot) * 100;
if (UPROF_PERC_BIGGER(whole, fract, sw0, sf0)) {
sf0 = fract;
si0 = j;
sw0 = whole;
} else if (UPROF_PERC_BIGGER(whole, fract, sw1,
sf1)) {
sf1 = fract;
si1 = j;
sw1 = whole;
} else if (UPROF_PERC_BIGGER(whole, fract, sw2,
sf2)) {
sf2 = fract;
si2 = j;
sw2 = whole;
} else if (UPROF_PERC_BIGGER(whole, fract, sw3,
sf3)) {
sf3 = fract;
si3 = j;
sw3 = whole;
} else if (UPROF_PERC_BIGGER(whole, fract, sw4,
sf4)) {
sf4 = fract;
si4 = j;
sw4 = whole;
}
}
sbuf_printf(&sb, "queue %u:\n", i);
sbuf_printf(&sb, "1st: %u.%u%% idx: %u\n", sw0 / tot,
sf0 / tot, si0);
sbuf_printf(&sb, "2nd: %u.%u%% idx: %u\n", sw1 / tot,
sf1 / tot, si1);
sbuf_printf(&sb, "3rd: %u.%u%% idx: %u\n", sw2 / tot,
sf2 / tot, si2);
sbuf_printf(&sb, "4th: %u.%u%% idx: %u\n", sw3 / tot,
sf3 / tot, si3);
sbuf_printf(&sb, "5th: %u.%u%% idx: %u\n", sw4 / tot,
sf4 / tot, si4);
}
}
sbuf_trim(&sb);
sbuf_finish(&sb);
sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req);
sbuf_delete(&sb);
return (0);
}
static int
sysctl_debug_umtx_chains_clear(SYSCTL_HANDLER_ARGS)
{
struct umtxq_chain *uc;
u_int i, j;
int clear, error;
clear = 0;
error = sysctl_handle_int(oidp, &clear, 0, req);
if (error != 0 || req->newptr == NULL)
return (error);
if (clear != 0) {
for (i = 0; i < 2; ++i) {
for (j = 0; j < UMTX_CHAINS; ++j) {
uc = &umtxq_chains[i][j];
mtx_lock(&uc->uc_lock);
uc->length = 0;
uc->max_length = 0;
mtx_unlock(&uc->uc_lock);
}
}
}
return (0);
}
SYSCTL_PROC(_debug_umtx_chains, OID_AUTO, clear,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 0,
sysctl_debug_umtx_chains_clear, "I", "Clear umtx chains statistics");
SYSCTL_PROC(_debug_umtx_chains, OID_AUTO, peaks,
CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
sysctl_debug_umtx_chains_peaks, "A", "Highest peaks in chains max length");
#endif
static void
umtxq_sysinit(void *arg __unused)
{
int i, j;
umtx_pi_zone = uma_zcreate("umtx pi", sizeof(struct umtx_pi),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
for (i = 0; i < 2; ++i) {
for (j = 0; j < UMTX_CHAINS; ++j) {
mtx_init(&umtxq_chains[i][j].uc_lock, "umtxql", NULL,
MTX_DEF | MTX_DUPOK);
LIST_INIT(&umtxq_chains[i][j].uc_queue[0]);
LIST_INIT(&umtxq_chains[i][j].uc_queue[1]);
LIST_INIT(&umtxq_chains[i][j].uc_spare_queue);
TAILQ_INIT(&umtxq_chains[i][j].uc_pi_list);
umtxq_chains[i][j].uc_busy = 0;
umtxq_chains[i][j].uc_waiters = 0;
#ifdef UMTX_PROFILING
umtxq_chains[i][j].length = 0;
umtxq_chains[i][j].max_length = 0;
#endif
}
}
#ifdef UMTX_PROFILING
umtx_init_profiling();
#endif
mtx_init(&umtx_lock, "umtx lock", NULL, MTX_DEF);
EVENTHANDLER_REGISTER(process_exec, umtx_exec_hook, NULL,
EVENTHANDLER_PRI_ANY);
umtx_shm_init();
}
struct umtx_q *
umtxq_alloc(void)
{
struct umtx_q *uq;
uq = malloc(sizeof(struct umtx_q), M_UMTX, M_WAITOK | M_ZERO);
uq->uq_spare_queue = malloc(sizeof(struct umtxq_queue), M_UMTX,
M_WAITOK | M_ZERO);
TAILQ_INIT(&uq->uq_spare_queue->head);
TAILQ_INIT(&uq->uq_pi_contested);
uq->uq_inherited_pri = PRI_MAX;
return (uq);
}
void
umtxq_free(struct umtx_q *uq)
{
MPASS(uq->uq_spare_queue != NULL);
free(uq->uq_spare_queue, M_UMTX);
free(uq, M_UMTX);
}
static inline void
umtxq_hash(struct umtx_key *key)
{
unsigned n;
n = (uintptr_t)key->info.both.a + key->info.both.b;
key->hash = ((n * GOLDEN_RATIO_PRIME) >> UMTX_SHIFTS) % UMTX_CHAINS;
}
static inline struct umtxq_chain *
umtxq_getchain(struct umtx_key *key)
{
if (key->type <= TYPE_SEM)
return (&umtxq_chains[1][key->hash]);
return (&umtxq_chains[0][key->hash]);
}
/*
* Lock a chain.
*/
static inline void
umtxq_lock(struct umtx_key *key)
{
struct umtxq_chain *uc;
uc = umtxq_getchain(key);
mtx_lock(&uc->uc_lock);
}
/*
* Unlock a chain.
*/
static inline void
umtxq_unlock(struct umtx_key *key)
{
struct umtxq_chain *uc;
uc = umtxq_getchain(key);
mtx_unlock(&uc->uc_lock);
}
/*
* Set chain to busy state when following operation
* may be blocked (kernel mutex can not be used).
*/
static inline void
umtxq_busy(struct umtx_key *key)
{
struct umtxq_chain *uc;
uc = umtxq_getchain(key);
mtx_assert(&uc->uc_lock, MA_OWNED);
if (uc->uc_busy) {
#ifdef SMP
if (smp_cpus > 1) {
int count = BUSY_SPINS;
if (count > 0) {
umtxq_unlock(key);
while (uc->uc_busy && --count > 0)
cpu_spinwait();
umtxq_lock(key);
}
}
#endif
while (uc->uc_busy) {
uc->uc_waiters++;
msleep(uc, &uc->uc_lock, 0, "umtxqb", 0);
uc->uc_waiters--;
}
}
uc->uc_busy = 1;
}
/*
* Unbusy a chain.
*/
static inline void
umtxq_unbusy(struct umtx_key *key)
{
struct umtxq_chain *uc;
uc = umtxq_getchain(key);
mtx_assert(&uc->uc_lock, MA_OWNED);
KASSERT(uc->uc_busy != 0, ("not busy"));
uc->uc_busy = 0;
if (uc->uc_waiters)
wakeup_one(uc);
}
static inline void
umtxq_unbusy_unlocked(struct umtx_key *key)
{
umtxq_lock(key);
umtxq_unbusy(key);
umtxq_unlock(key);
}
static struct umtxq_queue *
umtxq_queue_lookup(struct umtx_key *key, int q)
{
struct umtxq_queue *uh;
struct umtxq_chain *uc;
uc = umtxq_getchain(key);
UMTXQ_LOCKED_ASSERT(uc);
LIST_FOREACH(uh, &uc->uc_queue[q], link) {
if (umtx_key_match(&uh->key, key))
return (uh);
}
return (NULL);
}
static inline void
umtxq_insert_queue(struct umtx_q *uq, int q)
{
struct umtxq_queue *uh;
struct umtxq_chain *uc;
uc = umtxq_getchain(&uq->uq_key);
UMTXQ_LOCKED_ASSERT(uc);
KASSERT((uq->uq_flags & UQF_UMTXQ) == 0, ("umtx_q is already on queue"));
uh = umtxq_queue_lookup(&uq->uq_key, q);
if (uh != NULL) {
LIST_INSERT_HEAD(&uc->uc_spare_queue, uq->uq_spare_queue, link);
} else {
uh = uq->uq_spare_queue;
uh->key = uq->uq_key;
LIST_INSERT_HEAD(&uc->uc_queue[q], uh, link);
#ifdef UMTX_PROFILING
uc->length++;
if (uc->length > uc->max_length) {
uc->max_length = uc->length;
if (uc->max_length > max_length)
max_length = uc->max_length;
}
#endif
}
uq->uq_spare_queue = NULL;
TAILQ_INSERT_TAIL(&uh->head, uq, uq_link);
uh->length++;
uq->uq_flags |= UQF_UMTXQ;
uq->uq_cur_queue = uh;
return;
}
static inline void
umtxq_remove_queue(struct umtx_q *uq, int q)
{
struct umtxq_chain *uc;
struct umtxq_queue *uh;
uc = umtxq_getchain(&uq->uq_key);
UMTXQ_LOCKED_ASSERT(uc);
if (uq->uq_flags & UQF_UMTXQ) {
uh = uq->uq_cur_queue;
TAILQ_REMOVE(&uh->head, uq, uq_link);
uh->length--;
uq->uq_flags &= ~UQF_UMTXQ;
if (TAILQ_EMPTY(&uh->head)) {
KASSERT(uh->length == 0,
("inconsistent umtxq_queue length"));
#ifdef UMTX_PROFILING
uc->length--;
#endif
LIST_REMOVE(uh, link);
} else {
uh = LIST_FIRST(&uc->uc_spare_queue);
KASSERT(uh != NULL, ("uc_spare_queue is empty"));
LIST_REMOVE(uh, link);
}
uq->uq_spare_queue = uh;
uq->uq_cur_queue = NULL;
}
}
/*
* Check if there are multiple waiters
*/
static int
umtxq_count(struct umtx_key *key)
{
struct umtxq_queue *uh;
UMTXQ_LOCKED_ASSERT(umtxq_getchain(key));
uh = umtxq_queue_lookup(key, UMTX_SHARED_QUEUE);
if (uh != NULL)
return (uh->length);
return (0);
}
/*
* Check if there are multiple PI waiters and returns first
* waiter.
*/
static int
umtxq_count_pi(struct umtx_key *key, struct umtx_q **first)
{
struct umtxq_queue *uh;
*first = NULL;
UMTXQ_LOCKED_ASSERT(umtxq_getchain(key));
uh = umtxq_queue_lookup(key, UMTX_SHARED_QUEUE);
if (uh != NULL) {
*first = TAILQ_FIRST(&uh->head);
return (uh->length);
}
return (0);
}
static int
umtxq_check_susp(struct thread *td)
{
struct proc *p;
int error;
/*
* The check for TDF_NEEDSUSPCHK is racy, but it is enough to
* eventually break the lockstep loop.
*/
if ((td->td_flags & TDF_NEEDSUSPCHK) == 0)
return (0);
error = 0;
p = td->td_proc;
PROC_LOCK(p);
if (P_SHOULDSTOP(p) ||
((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_SUSPEND))) {
if (p->p_flag & P_SINGLE_EXIT)
error = EINTR;
else
error = ERESTART;
}
PROC_UNLOCK(p);
return (error);
}
/*
* Wake up threads waiting on an userland object.
*/
static int
umtxq_signal_queue(struct umtx_key *key, int n_wake, int q)
{
struct umtxq_queue *uh;
struct umtx_q *uq;
int ret;
ret = 0;
UMTXQ_LOCKED_ASSERT(umtxq_getchain(key));
uh = umtxq_queue_lookup(key, q);
if (uh != NULL) {
while ((uq = TAILQ_FIRST(&uh->head)) != NULL) {
umtxq_remove_queue(uq, q);
wakeup(uq);
if (++ret >= n_wake)
return (ret);
}
}
return (ret);
}
/*
* Wake up specified thread.
*/
static inline void
umtxq_signal_thread(struct umtx_q *uq)
{
UMTXQ_LOCKED_ASSERT(umtxq_getchain(&uq->uq_key));
umtxq_remove(uq);
wakeup(uq);
}
static inline int
tstohz(const struct timespec *tsp)
{
struct timeval tv;
TIMESPEC_TO_TIMEVAL(&tv, tsp);
return tvtohz(&tv);
}
static void
abs_timeout_init(struct abs_timeout *timo, int clockid, int absolute,
const struct timespec *timeout)
{
timo->clockid = clockid;
if (!absolute) {
timo->is_abs_real = false;
abs_timeout_update(timo);
timespecadd(&timo->cur, timeout, &timo->end);
} else {
timo->end = *timeout;
timo->is_abs_real = clockid == CLOCK_REALTIME ||
clockid == CLOCK_REALTIME_FAST ||
clockid == CLOCK_REALTIME_PRECISE;
/*
* If is_abs_real, umtxq_sleep will read the clock
* after setting td_rtcgen; otherwise, read it here.
*/
if (!timo->is_abs_real) {
abs_timeout_update(timo);
}
}
}
static void
abs_timeout_init2(struct abs_timeout *timo, const struct _umtx_time *umtxtime)
{
abs_timeout_init(timo, umtxtime->_clockid,
(umtxtime->_flags & UMTX_ABSTIME) != 0, &umtxtime->_timeout);
}
static inline void
abs_timeout_update(struct abs_timeout *timo)
{
kern_clock_gettime(curthread, timo->clockid, &timo->cur);
}
static int
abs_timeout_gethz(struct abs_timeout *timo)
{
struct timespec tts;
if (timespeccmp(&timo->end, &timo->cur, <=))
return (-1);
timespecsub(&timo->end, &timo->cur, &tts);
return (tstohz(&tts));
}
static uint32_t
umtx_unlock_val(uint32_t flags, bool rb)
{
if (rb)
return (UMUTEX_RB_OWNERDEAD);
else if ((flags & UMUTEX_NONCONSISTENT) != 0)
return (UMUTEX_RB_NOTRECOV);
else
return (UMUTEX_UNOWNED);
}
/*
* Put thread into sleep state, before sleeping, check if
* thread was removed from umtx queue.
*/
static inline int
umtxq_sleep(struct umtx_q *uq, const char *wmesg, struct abs_timeout *abstime)
{
struct umtxq_chain *uc;
int error, timo;
if (abstime != NULL && abstime->is_abs_real) {
curthread->td_rtcgen = atomic_load_acq_int(&rtc_generation);
abs_timeout_update(abstime);
}
uc = umtxq_getchain(&uq->uq_key);
UMTXQ_LOCKED_ASSERT(uc);
for (;;) {
if (!(uq->uq_flags & UQF_UMTXQ)) {
error = 0;
break;
}
if (abstime != NULL) {
timo = abs_timeout_gethz(abstime);
if (timo < 0) {
error = ETIMEDOUT;
break;
}
} else
timo = 0;
error = msleep(uq, &uc->uc_lock, PCATCH | PDROP, wmesg, timo);
if (error == EINTR || error == ERESTART) {
umtxq_lock(&uq->uq_key);
break;
}
if (abstime != NULL) {
if (abstime->is_abs_real)
curthread->td_rtcgen =
atomic_load_acq_int(&rtc_generation);
abs_timeout_update(abstime);
}
umtxq_lock(&uq->uq_key);
}
curthread->td_rtcgen = 0;
return (error);
}
/*
* Convert userspace address into unique logical address.
*/
int
umtx_key_get(const void *addr, int type, int share, struct umtx_key *key)
{
struct thread *td = curthread;
vm_map_t map;
vm_map_entry_t entry;
vm_pindex_t pindex;
vm_prot_t prot;
boolean_t wired;
key->type = type;
if (share == THREAD_SHARE) {
key->shared = 0;
key->info.private.vs = td->td_proc->p_vmspace;
key->info.private.addr = (uintptr_t)addr;
} else {
MPASS(share == PROCESS_SHARE || share == AUTO_SHARE);
map = &td->td_proc->p_vmspace->vm_map;
if (vm_map_lookup(&map, (vm_offset_t)addr, VM_PROT_WRITE,
&entry, &key->info.shared.object, &pindex, &prot,
&wired) != KERN_SUCCESS) {
return (EFAULT);
}
if ((share == PROCESS_SHARE) ||
(share == AUTO_SHARE &&
VM_INHERIT_SHARE == entry->inheritance)) {
key->shared = 1;
key->info.shared.offset = (vm_offset_t)addr -
entry->start + entry->offset;
vm_object_reference(key->info.shared.object);
} else {
key->shared = 0;
key->info.private.vs = td->td_proc->p_vmspace;
key->info.private.addr = (uintptr_t)addr;
}
vm_map_lookup_done(map, entry);
}
umtxq_hash(key);
return (0);
}
/*
* Release key.
*/
void
umtx_key_release(struct umtx_key *key)
{
if (key->shared)
vm_object_deallocate(key->info.shared.object);
}
/*
* Fetch and compare value, sleep on the address if value is not changed.
*/
static int
do_wait(struct thread *td, void *addr, u_long id,
struct _umtx_time *timeout, int compat32, int is_private)
{
struct abs_timeout timo;
struct umtx_q *uq;
u_long tmp;
uint32_t tmp32;
int error = 0;
uq = td->td_umtxq;
if ((error = umtx_key_get(addr, TYPE_SIMPLE_WAIT,
is_private ? THREAD_SHARE : AUTO_SHARE, &uq->uq_key)) != 0)
return (error);
if (timeout != NULL)
abs_timeout_init2(&timo, timeout);
umtxq_lock(&uq->uq_key);
umtxq_insert(uq);
umtxq_unlock(&uq->uq_key);
if (compat32 == 0) {
error = fueword(addr, &tmp);
if (error != 0)
error = EFAULT;
} else {
error = fueword32(addr, &tmp32);
if (error == 0)
tmp = tmp32;
else
error = EFAULT;
}
umtxq_lock(&uq->uq_key);
if (error == 0) {
if (tmp == id)
error = umtxq_sleep(uq, "uwait", timeout == NULL ?
NULL : &timo);
if ((uq->uq_flags & UQF_UMTXQ) == 0)
error = 0;
else
umtxq_remove(uq);
} else if ((uq->uq_flags & UQF_UMTXQ) != 0) {
umtxq_remove(uq);
}
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
if (error == ERESTART)
error = EINTR;
return (error);
}
/*
* Wake up threads sleeping on the specified address.
*/
int
kern_umtx_wake(struct thread *td, void *uaddr, int n_wake, int is_private)
{
struct umtx_key key;
int ret;
if ((ret = umtx_key_get(uaddr, TYPE_SIMPLE_WAIT,
is_private ? THREAD_SHARE : AUTO_SHARE, &key)) != 0)
return (ret);
umtxq_lock(&key);
umtxq_signal(&key, n_wake);
umtxq_unlock(&key);
umtx_key_release(&key);
return (0);
}
/*
* Lock PTHREAD_PRIO_NONE protocol POSIX mutex.
*/
static int
do_lock_normal(struct thread *td, struct umutex *m, uint32_t flags,
struct _umtx_time *timeout, int mode)
{
struct abs_timeout timo;
struct umtx_q *uq;
uint32_t owner, old, id;
int error, rv;
id = td->td_tid;
uq = td->td_umtxq;
error = 0;
if (timeout != NULL)
abs_timeout_init2(&timo, timeout);
/*
* Care must be exercised when dealing with umtx structure. It
* can fault on any access.
*/
for (;;) {
rv = fueword32(&m->m_owner, &owner);
if (rv == -1)
return (EFAULT);
if (mode == _UMUTEX_WAIT) {
if (owner == UMUTEX_UNOWNED ||
owner == UMUTEX_CONTESTED ||
owner == UMUTEX_RB_OWNERDEAD ||
owner == UMUTEX_RB_NOTRECOV)
return (0);
} else {
/*
* Robust mutex terminated. Kernel duty is to
* return EOWNERDEAD to the userspace. The
* umutex.m_flags UMUTEX_NONCONSISTENT is set
* by the common userspace code.
*/
if (owner == UMUTEX_RB_OWNERDEAD) {
rv = casueword32(&m->m_owner,
UMUTEX_RB_OWNERDEAD, &owner,
id | UMUTEX_CONTESTED);
if (rv == -1)
return (EFAULT);
if (owner == UMUTEX_RB_OWNERDEAD)
return (EOWNERDEAD); /* success */
rv = umtxq_check_susp(td);
if (rv != 0)
return (rv);
continue;
}
if (owner == UMUTEX_RB_NOTRECOV)
return (ENOTRECOVERABLE);
/*
* Try the uncontested case. This should be
* done in userland.
*/
rv = casueword32(&m->m_owner, UMUTEX_UNOWNED,
&owner, id);
/* The address was invalid. */
if (rv == -1)
return (EFAULT);
/* The acquire succeeded. */
if (owner == UMUTEX_UNOWNED)
return (0);
/*
* If no one owns it but it is contested try
* to acquire it.
*/
if (owner == UMUTEX_CONTESTED) {
rv = casueword32(&m->m_owner,
UMUTEX_CONTESTED, &owner,
id | UMUTEX_CONTESTED);
/* The address was invalid. */
if (rv == -1)
return (EFAULT);
if (owner == UMUTEX_CONTESTED)
return (0);
rv = umtxq_check_susp(td);
if (rv != 0)
return (rv);
/*
* If this failed the lock has
* changed, restart.
*/
continue;
}
}
if (mode == _UMUTEX_TRY)
return (EBUSY);
/*
* If we caught a signal, we have retried and now
* exit immediately.
*/
if (error != 0)
return (error);
if ((error = umtx_key_get(m, TYPE_NORMAL_UMUTEX,
GET_SHARE(flags), &uq->uq_key)) != 0)
return (error);
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
umtxq_insert(uq);
umtxq_unlock(&uq->uq_key);
/*
* Set the contested bit so that a release in user space
* knows to use the system call for unlock. If this fails
* either some one else has acquired the lock or it has been
* released.
*/
rv = casueword32(&m->m_owner, owner, &old,
owner | UMUTEX_CONTESTED);
/* The address was invalid. */
if (rv == -1) {
umtxq_lock(&uq->uq_key);
umtxq_remove(uq);
umtxq_unbusy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
return (EFAULT);
}
/*
* We set the contested bit, sleep. Otherwise the lock changed
* and we need to retry or we lost a race to the thread
* unlocking the umtx.
*/
umtxq_lock(&uq->uq_key);
umtxq_unbusy(&uq->uq_key);
if (old == owner)
error = umtxq_sleep(uq, "umtxn", timeout == NULL ?
NULL : &timo);
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
if (error == 0)
error = umtxq_check_susp(td);
}
return (0);
}
/*
* Unlock PTHREAD_PRIO_NONE protocol POSIX mutex.
*/
static int
do_unlock_normal(struct thread *td, struct umutex *m, uint32_t flags, bool rb)
{
struct umtx_key key;
uint32_t owner, old, id, newlock;
int error, count;
id = td->td_tid;
/*
* Make sure we own this mtx.
*/
error = fueword32(&m->m_owner, &owner);
if (error == -1)
return (EFAULT);
if ((owner & ~UMUTEX_CONTESTED) != id)
return (EPERM);
newlock = umtx_unlock_val(flags, rb);
if ((owner & UMUTEX_CONTESTED) == 0) {
error = casueword32(&m->m_owner, owner, &old, newlock);
if (error == -1)
return (EFAULT);
if (old == owner)
return (0);
owner = old;
}
/* We should only ever be in here for contested locks */
if ((error = umtx_key_get(m, TYPE_NORMAL_UMUTEX, GET_SHARE(flags),
&key)) != 0)
return (error);
umtxq_lock(&key);
umtxq_busy(&key);
count = umtxq_count(&key);
umtxq_unlock(&key);
/*
* When unlocking the umtx, it must be marked as unowned if
* there is zero or one thread only waiting for it.
* Otherwise, it must be marked as contested.
*/
if (count > 1)
newlock |= UMUTEX_CONTESTED;
error = casueword32(&m->m_owner, owner, &old, newlock);
umtxq_lock(&key);
umtxq_signal(&key, 1);
umtxq_unbusy(&key);
umtxq_unlock(&key);
umtx_key_release(&key);
if (error == -1)
return (EFAULT);
if (old != owner)
return (EINVAL);
return (0);
}
/*
* Check if the mutex is available and wake up a waiter,
* only for simple mutex.
*/
static int
do_wake_umutex(struct thread *td, struct umutex *m)
{
struct umtx_key key;
uint32_t owner;
uint32_t flags;
int error;
int count;
error = fueword32(&m->m_owner, &owner);
if (error == -1)
return (EFAULT);
if ((owner & ~UMUTEX_CONTESTED) != 0 && owner != UMUTEX_RB_OWNERDEAD &&
owner != UMUTEX_RB_NOTRECOV)
return (0);
error = fueword32(&m->m_flags, &flags);
if (error == -1)
return (EFAULT);
/* We should only ever be in here for contested locks */
if ((error = umtx_key_get(m, TYPE_NORMAL_UMUTEX, GET_SHARE(flags),
&key)) != 0)
return (error);
umtxq_lock(&key);
umtxq_busy(&key);
count = umtxq_count(&key);
umtxq_unlock(&key);
if (count <= 1 && owner != UMUTEX_RB_OWNERDEAD &&
owner != UMUTEX_RB_NOTRECOV) {
error = casueword32(&m->m_owner, UMUTEX_CONTESTED, &owner,
UMUTEX_UNOWNED);
if (error == -1)
error = EFAULT;
}
umtxq_lock(&key);
if (error == 0 && count != 0 && ((owner & ~UMUTEX_CONTESTED) == 0 ||
owner == UMUTEX_RB_OWNERDEAD || owner == UMUTEX_RB_NOTRECOV))
umtxq_signal(&key, 1);
umtxq_unbusy(&key);
umtxq_unlock(&key);
umtx_key_release(&key);
return (error);
}
/*
* Check if the mutex has waiters and tries to fix contention bit.
*/
static int
do_wake2_umutex(struct thread *td, struct umutex *m, uint32_t flags)
{
struct umtx_key key;
uint32_t owner, old;
int type;
int error;
int count;
switch (flags & (UMUTEX_PRIO_INHERIT | UMUTEX_PRIO_PROTECT |
UMUTEX_ROBUST)) {
case 0:
case UMUTEX_ROBUST:
type = TYPE_NORMAL_UMUTEX;
break;
case UMUTEX_PRIO_INHERIT:
type = TYPE_PI_UMUTEX;
break;
case (UMUTEX_PRIO_INHERIT | UMUTEX_ROBUST):
type = TYPE_PI_ROBUST_UMUTEX;
break;
case UMUTEX_PRIO_PROTECT:
type = TYPE_PP_UMUTEX;
break;
case (UMUTEX_PRIO_PROTECT | UMUTEX_ROBUST):
type = TYPE_PP_ROBUST_UMUTEX;
break;
default:
return (EINVAL);
}
if ((error = umtx_key_get(m, type, GET_SHARE(flags), &key)) != 0)
return (error);
owner = 0;
umtxq_lock(&key);
umtxq_busy(&key);
count = umtxq_count(&key);
umtxq_unlock(&key);
/*
* Only repair contention bit if there is a waiter, this means the mutex
* is still being referenced by userland code, otherwise don't update
* any memory.
*/
if (count > 1) {
error = fueword32(&m->m_owner, &owner);
if (error == -1)
error = EFAULT;
while (error == 0 && (owner & UMUTEX_CONTESTED) == 0) {
error = casueword32(&m->m_owner, owner, &old,
owner | UMUTEX_CONTESTED);
if (error == -1) {
error = EFAULT;
break;
}
if (old == owner)
break;
owner = old;
error = umtxq_check_susp(td);
if (error != 0)
break;
}
} else if (count == 1) {
error = fueword32(&m->m_owner, &owner);
if (error == -1)
error = EFAULT;
while (error == 0 && (owner & ~UMUTEX_CONTESTED) != 0 &&
(owner & UMUTEX_CONTESTED) == 0) {
error = casueword32(&m->m_owner, owner, &old,
owner | UMUTEX_CONTESTED);
if (error == -1) {
error = EFAULT;
break;
}
if (old == owner)
break;
owner = old;
error = umtxq_check_susp(td);
if (error != 0)
break;
}
}
umtxq_lock(&key);
if (error == EFAULT) {
umtxq_signal(&key, INT_MAX);
} else if (count != 0 && ((owner & ~UMUTEX_CONTESTED) == 0 ||
owner == UMUTEX_RB_OWNERDEAD || owner == UMUTEX_RB_NOTRECOV))
umtxq_signal(&key, 1);
umtxq_unbusy(&key);
umtxq_unlock(&key);
umtx_key_release(&key);
return (error);
}
static inline struct umtx_pi *
umtx_pi_alloc(int flags)
{
struct umtx_pi *pi;
pi = uma_zalloc(umtx_pi_zone, M_ZERO | flags);
TAILQ_INIT(&pi->pi_blocked);
atomic_add_int(&umtx_pi_allocated, 1);
return (pi);
}
static inline void
umtx_pi_free(struct umtx_pi *pi)
{
uma_zfree(umtx_pi_zone, pi);
atomic_add_int(&umtx_pi_allocated, -1);
}
/*
* Adjust the thread's position on a pi_state after its priority has been
* changed.
*/
static int
umtx_pi_adjust_thread(struct umtx_pi *pi, struct thread *td)
{
struct umtx_q *uq, *uq1, *uq2;
struct thread *td1;
mtx_assert(&umtx_lock, MA_OWNED);
if (pi == NULL)
return (0);
uq = td->td_umtxq;
/*
* Check if the thread needs to be moved on the blocked chain.
* It needs to be moved if either its priority is lower than
* the previous thread or higher than the next thread.
*/
uq1 = TAILQ_PREV(uq, umtxq_head, uq_lockq);
uq2 = TAILQ_NEXT(uq, uq_lockq);
if ((uq1 != NULL && UPRI(td) < UPRI(uq1->uq_thread)) ||
(uq2 != NULL && UPRI(td) > UPRI(uq2->uq_thread))) {
/*
* Remove thread from blocked chain and determine where
* it should be moved to.
*/
TAILQ_REMOVE(&pi->pi_blocked, uq, uq_lockq);
TAILQ_FOREACH(uq1, &pi->pi_blocked, uq_lockq) {
td1 = uq1->uq_thread;
MPASS(td1->td_proc->p_magic == P_MAGIC);
if (UPRI(td1) > UPRI(td))
break;
}
if (uq1 == NULL)
TAILQ_INSERT_TAIL(&pi->pi_blocked, uq, uq_lockq);
else
TAILQ_INSERT_BEFORE(uq1, uq, uq_lockq);
}
return (1);
}
static struct umtx_pi *
umtx_pi_next(struct umtx_pi *pi)
{
struct umtx_q *uq_owner;
if (pi->pi_owner == NULL)
return (NULL);
uq_owner = pi->pi_owner->td_umtxq;
if (uq_owner == NULL)
return (NULL);
return (uq_owner->uq_pi_blocked);
}
/*
* Floyd's Cycle-Finding Algorithm.
*/
static bool
umtx_pi_check_loop(struct umtx_pi *pi)
{
struct umtx_pi *pi1; /* fast iterator */
mtx_assert(&umtx_lock, MA_OWNED);
if (pi == NULL)
return (false);
pi1 = pi;
for (;;) {
pi = umtx_pi_next(pi);
if (pi == NULL)
break;
pi1 = umtx_pi_next(pi1);
if (pi1 == NULL)
break;
pi1 = umtx_pi_next(pi1);
if (pi1 == NULL)
break;
if (pi == pi1)
return (true);
}
return (false);
}
/*
* Propagate priority when a thread is blocked on POSIX
* PI mutex.
*/
static void
umtx_propagate_priority(struct thread *td)
{
struct umtx_q *uq;
struct umtx_pi *pi;
int pri;
mtx_assert(&umtx_lock, MA_OWNED);
pri = UPRI(td);
uq = td->td_umtxq;
pi = uq->uq_pi_blocked;
if (pi == NULL)
return;
if (umtx_pi_check_loop(pi))
return;
for (;;) {
td = pi->pi_owner;
if (td == NULL || td == curthread)
return;
MPASS(td->td_proc != NULL);
MPASS(td->td_proc->p_magic == P_MAGIC);
thread_lock(td);
if (td->td_lend_user_pri > pri)
sched_lend_user_prio(td, pri);
else {
thread_unlock(td);
break;
}
thread_unlock(td);
/*
* Pick up the lock that td is blocked on.
*/
uq = td->td_umtxq;
pi = uq->uq_pi_blocked;
if (pi == NULL)
break;
/* Resort td on the list if needed. */
umtx_pi_adjust_thread(pi, td);
}
}
/*
* Unpropagate priority for a PI mutex when a thread blocked on
* it is interrupted by signal or resumed by others.
*/
static void
umtx_repropagate_priority(struct umtx_pi *pi)
{
struct umtx_q *uq, *uq_owner;
struct umtx_pi *pi2;
int pri;
mtx_assert(&umtx_lock, MA_OWNED);
if (umtx_pi_check_loop(pi))
return;
while (pi != NULL && pi->pi_owner != NULL) {
pri = PRI_MAX;
uq_owner = pi->pi_owner->td_umtxq;
TAILQ_FOREACH(pi2, &uq_owner->uq_pi_contested, pi_link) {
uq = TAILQ_FIRST(&pi2->pi_blocked);
if (uq != NULL) {
if (pri > UPRI(uq->uq_thread))
pri = UPRI(uq->uq_thread);
}
}
if (pri > uq_owner->uq_inherited_pri)
pri = uq_owner->uq_inherited_pri;
thread_lock(pi->pi_owner);
sched_lend_user_prio(pi->pi_owner, pri);
thread_unlock(pi->pi_owner);
if ((pi = uq_owner->uq_pi_blocked) != NULL)
umtx_pi_adjust_thread(pi, uq_owner->uq_thread);
}
}
/*
* Insert a PI mutex into owned list.
*/
static void
umtx_pi_setowner(struct umtx_pi *pi, struct thread *owner)
{
struct umtx_q *uq_owner;
uq_owner = owner->td_umtxq;
mtx_assert(&umtx_lock, MA_OWNED);
MPASS(pi->pi_owner == NULL);
pi->pi_owner = owner;
TAILQ_INSERT_TAIL(&uq_owner->uq_pi_contested, pi, pi_link);
}
/*
* Disown a PI mutex, and remove it from the owned list.
*/
static void
umtx_pi_disown(struct umtx_pi *pi)
{
mtx_assert(&umtx_lock, MA_OWNED);
TAILQ_REMOVE(&pi->pi_owner->td_umtxq->uq_pi_contested, pi, pi_link);
pi->pi_owner = NULL;
}
/*
* Claim ownership of a PI mutex.
*/
static int
umtx_pi_claim(struct umtx_pi *pi, struct thread *owner)
{
struct umtx_q *uq;
int pri;
mtx_lock(&umtx_lock);
if (pi->pi_owner == owner) {
mtx_unlock(&umtx_lock);
return (0);
}
if (pi->pi_owner != NULL) {
/*
* userland may have already messed the mutex, sigh.
*/
mtx_unlock(&umtx_lock);
return (EPERM);
}
umtx_pi_setowner(pi, owner);
uq = TAILQ_FIRST(&pi->pi_blocked);
if (uq != NULL) {
pri = UPRI(uq->uq_thread);
thread_lock(owner);
if (pri < UPRI(owner))
sched_lend_user_prio(owner, pri);
thread_unlock(owner);
}
mtx_unlock(&umtx_lock);
return (0);
}
/*
* Adjust a thread's order position in its blocked PI mutex,
* this may result new priority propagating process.
*/
void
umtx_pi_adjust(struct thread *td, u_char oldpri)
{
struct umtx_q *uq;
struct umtx_pi *pi;
uq = td->td_umtxq;
mtx_lock(&umtx_lock);
/*
* Pick up the lock that td is blocked on.
*/
pi = uq->uq_pi_blocked;
if (pi != NULL) {
umtx_pi_adjust_thread(pi, td);
umtx_repropagate_priority(pi);
}
mtx_unlock(&umtx_lock);
}
/*
* Sleep on a PI mutex.
*/
static int
umtxq_sleep_pi(struct umtx_q *uq, struct umtx_pi *pi, uint32_t owner,
const char *wmesg, struct abs_timeout *timo, bool shared)
{
struct thread *td, *td1;
struct umtx_q *uq1;
int error, pri;
#ifdef INVARIANTS
struct umtxq_chain *uc;
uc = umtxq_getchain(&pi->pi_key);
#endif
error = 0;
td = uq->uq_thread;
KASSERT(td == curthread, ("inconsistent uq_thread"));
UMTXQ_LOCKED_ASSERT(umtxq_getchain(&uq->uq_key));
KASSERT(uc->uc_busy != 0, ("umtx chain is not busy"));
umtxq_insert(uq);
mtx_lock(&umtx_lock);
if (pi->pi_owner == NULL) {
mtx_unlock(&umtx_lock);
td1 = tdfind(owner, shared ? -1 : td->td_proc->p_pid);
mtx_lock(&umtx_lock);
if (td1 != NULL) {
if (pi->pi_owner == NULL)
umtx_pi_setowner(pi, td1);
PROC_UNLOCK(td1->td_proc);
}
}
TAILQ_FOREACH(uq1, &pi->pi_blocked, uq_lockq) {
pri = UPRI(uq1->uq_thread);
if (pri > UPRI(td))
break;
}
if (uq1 != NULL)
TAILQ_INSERT_BEFORE(uq1, uq, uq_lockq);
else
TAILQ_INSERT_TAIL(&pi->pi_blocked, uq, uq_lockq);
uq->uq_pi_blocked = pi;
thread_lock(td);
td->td_flags |= TDF_UPIBLOCKED;
thread_unlock(td);
umtx_propagate_priority(td);
mtx_unlock(&umtx_lock);
umtxq_unbusy(&uq->uq_key);
error = umtxq_sleep(uq, wmesg, timo);
umtxq_remove(uq);
mtx_lock(&umtx_lock);
uq->uq_pi_blocked = NULL;
thread_lock(td);
td->td_flags &= ~TDF_UPIBLOCKED;
thread_unlock(td);
TAILQ_REMOVE(&pi->pi_blocked, uq, uq_lockq);
umtx_repropagate_priority(pi);
mtx_unlock(&umtx_lock);
umtxq_unlock(&uq->uq_key);
return (error);
}
/*
* Add reference count for a PI mutex.
*/
static void
umtx_pi_ref(struct umtx_pi *pi)
{
UMTXQ_LOCKED_ASSERT(umtxq_getchain(&pi->pi_key));
pi->pi_refcount++;
}
/*
* Decrease reference count for a PI mutex, if the counter
* is decreased to zero, its memory space is freed.
*/
static void
umtx_pi_unref(struct umtx_pi *pi)
{
struct umtxq_chain *uc;
uc = umtxq_getchain(&pi->pi_key);
UMTXQ_LOCKED_ASSERT(uc);
KASSERT(pi->pi_refcount > 0, ("invalid reference count"));
if (--pi->pi_refcount == 0) {
mtx_lock(&umtx_lock);
if (pi->pi_owner != NULL)
umtx_pi_disown(pi);
KASSERT(TAILQ_EMPTY(&pi->pi_blocked),
("blocked queue not empty"));
mtx_unlock(&umtx_lock);
TAILQ_REMOVE(&uc->uc_pi_list, pi, pi_hashlink);
umtx_pi_free(pi);
}
}
/*
* Find a PI mutex in hash table.
*/
static struct umtx_pi *
umtx_pi_lookup(struct umtx_key *key)
{
struct umtxq_chain *uc;
struct umtx_pi *pi;
uc = umtxq_getchain(key);
UMTXQ_LOCKED_ASSERT(uc);
TAILQ_FOREACH(pi, &uc->uc_pi_list, pi_hashlink) {
if (umtx_key_match(&pi->pi_key, key)) {
return (pi);
}
}
return (NULL);
}
/*
* Insert a PI mutex into hash table.
*/
static inline void
umtx_pi_insert(struct umtx_pi *pi)
{
struct umtxq_chain *uc;
uc = umtxq_getchain(&pi->pi_key);
UMTXQ_LOCKED_ASSERT(uc);
TAILQ_INSERT_TAIL(&uc->uc_pi_list, pi, pi_hashlink);
}
/*
* Lock a PI mutex.
*/
static int
do_lock_pi(struct thread *td, struct umutex *m, uint32_t flags,
struct _umtx_time *timeout, int try)
{
struct abs_timeout timo;
struct umtx_q *uq;
struct umtx_pi *pi, *new_pi;
uint32_t id, old_owner, owner, old;
int error, rv;
id = td->td_tid;
uq = td->td_umtxq;
if ((error = umtx_key_get(m, (flags & UMUTEX_ROBUST) != 0 ?
TYPE_PI_ROBUST_UMUTEX : TYPE_PI_UMUTEX, GET_SHARE(flags),
&uq->uq_key)) != 0)
return (error);
if (timeout != NULL)
abs_timeout_init2(&timo, timeout);
umtxq_lock(&uq->uq_key);
pi = umtx_pi_lookup(&uq->uq_key);
if (pi == NULL) {
new_pi = umtx_pi_alloc(M_NOWAIT);
if (new_pi == NULL) {
umtxq_unlock(&uq->uq_key);
new_pi = umtx_pi_alloc(M_WAITOK);
umtxq_lock(&uq->uq_key);
pi = umtx_pi_lookup(&uq->uq_key);
if (pi != NULL) {
umtx_pi_free(new_pi);
new_pi = NULL;
}
}
if (new_pi != NULL) {
new_pi->pi_key = uq->uq_key;
umtx_pi_insert(new_pi);
pi = new_pi;
}
}
umtx_pi_ref(pi);
umtxq_unlock(&uq->uq_key);
/*
* Care must be exercised when dealing with umtx structure. It
* can fault on any access.
*/
for (;;) {
/*
* Try the uncontested case. This should be done in userland.
*/
rv = casueword32(&m->m_owner, UMUTEX_UNOWNED, &owner, id);
/* The address was invalid. */
if (rv == -1) {
error = EFAULT;
break;
}
/* The acquire succeeded. */
if (owner == UMUTEX_UNOWNED) {
error = 0;
break;
}
if (owner == UMUTEX_RB_NOTRECOV) {
error = ENOTRECOVERABLE;
break;
}
/* If no one owns it but it is contested try to acquire it. */
if (owner == UMUTEX_CONTESTED || owner == UMUTEX_RB_OWNERDEAD) {
old_owner = owner;
rv = casueword32(&m->m_owner, owner, &owner,
id | UMUTEX_CONTESTED);
/* The address was invalid. */
if (rv == -1) {
error = EFAULT;
break;
}
if (owner == old_owner) {
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
error = umtx_pi_claim(pi, td);
umtxq_unbusy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
if (error != 0) {
/*
* Since we're going to return an
* error, restore the m_owner to its
* previous, unowned state to avoid
* compounding the problem.
*/
(void)casuword32(&m->m_owner,
id | UMUTEX_CONTESTED,
old_owner);
}
if (error == 0 &&
old_owner == UMUTEX_RB_OWNERDEAD)
error = EOWNERDEAD;
break;
}
error = umtxq_check_susp(td);
if (error != 0)
break;
/* If this failed the lock has changed, restart. */
continue;
}
if ((owner & ~UMUTEX_CONTESTED) == id) {
error = EDEADLK;
break;
}
if (try != 0) {
error = EBUSY;
break;
}
/*
* If we caught a signal, we have retried and now
* exit immediately.
*/
if (error != 0)
break;
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
/*
* Set the contested bit so that a release in user space
* knows to use the system call for unlock. If this fails
* either some one else has acquired the lock or it has been
* released.
*/
rv = casueword32(&m->m_owner, owner, &old, owner |
UMUTEX_CONTESTED);
/* The address was invalid. */
if (rv == -1) {
umtxq_unbusy_unlocked(&uq->uq_key);
error = EFAULT;
break;
}
umtxq_lock(&uq->uq_key);
/*
* We set the contested bit, sleep. Otherwise the lock changed
* and we need to retry or we lost a race to the thread
* unlocking the umtx. Note that the UMUTEX_RB_OWNERDEAD
* value for owner is impossible there.
*/
if (old == owner) {
error = umtxq_sleep_pi(uq, pi,
owner & ~UMUTEX_CONTESTED,
"umtxpi", timeout == NULL ? NULL : &timo,
(flags & USYNC_PROCESS_SHARED) != 0);
if (error != 0)
continue;
} else {
umtxq_unbusy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
}
error = umtxq_check_susp(td);
if (error != 0)
break;
}
umtxq_lock(&uq->uq_key);
umtx_pi_unref(pi);
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
return (error);
}
/*
* Unlock a PI mutex.
*/
static int
do_unlock_pi(struct thread *td, struct umutex *m, uint32_t flags, bool rb)
{
struct umtx_key key;
struct umtx_q *uq_first, *uq_first2, *uq_me;
struct umtx_pi *pi, *pi2;
uint32_t id, new_owner, old, owner;
int count, error, pri;
id = td->td_tid;
/*
* Make sure we own this mtx.
*/
error = fueword32(&m->m_owner, &owner);
if (error == -1)
return (EFAULT);
if ((owner & ~UMUTEX_CONTESTED) != id)
return (EPERM);
new_owner = umtx_unlock_val(flags, rb);
/* This should be done in userland */
if ((owner & UMUTEX_CONTESTED) == 0) {
error = casueword32(&m->m_owner, owner, &old, new_owner);
if (error == -1)
return (EFAULT);
if (old == owner)
return (0);
owner = old;
}
/* We should only ever be in here for contested locks */
if ((error = umtx_key_get(m, (flags & UMUTEX_ROBUST) != 0 ?
TYPE_PI_ROBUST_UMUTEX : TYPE_PI_UMUTEX, GET_SHARE(flags),
&key)) != 0)
return (error);
umtxq_lock(&key);
umtxq_busy(&key);
count = umtxq_count_pi(&key, &uq_first);
if (uq_first != NULL) {
mtx_lock(&umtx_lock);
pi = uq_first->uq_pi_blocked;
KASSERT(pi != NULL, ("pi == NULL?"));
if (pi->pi_owner != td && !(rb && pi->pi_owner == NULL)) {
mtx_unlock(&umtx_lock);
umtxq_unbusy(&key);
umtxq_unlock(&key);
umtx_key_release(&key);
/* userland messed the mutex */
return (EPERM);
}
uq_me = td->td_umtxq;
if (pi->pi_owner == td)
umtx_pi_disown(pi);
/* get highest priority thread which is still sleeping. */
uq_first = TAILQ_FIRST(&pi->pi_blocked);
while (uq_first != NULL &&
(uq_first->uq_flags & UQF_UMTXQ) == 0) {
uq_first = TAILQ_NEXT(uq_first, uq_lockq);
}
pri = PRI_MAX;
TAILQ_FOREACH(pi2, &uq_me->uq_pi_contested, pi_link) {
uq_first2 = TAILQ_FIRST(&pi2->pi_blocked);
if (uq_first2 != NULL) {
if (pri > UPRI(uq_first2->uq_thread))
pri = UPRI(uq_first2->uq_thread);
}
}
thread_lock(td);
sched_lend_user_prio(td, pri);
thread_unlock(td);
mtx_unlock(&umtx_lock);
if (uq_first)
umtxq_signal_thread(uq_first);
} else {
pi = umtx_pi_lookup(&key);
/*
* A umtx_pi can exist if a signal or timeout removed the
* last waiter from the umtxq, but there is still
* a thread in do_lock_pi() holding the umtx_pi.
*/
if (pi != NULL) {
/*
* The umtx_pi can be unowned, such as when a thread
* has just entered do_lock_pi(), allocated the
* umtx_pi, and unlocked the umtxq.
* If the current thread owns it, it must disown it.
*/
mtx_lock(&umtx_lock);
if (pi->pi_owner == td)
umtx_pi_disown(pi);
mtx_unlock(&umtx_lock);
}
}
umtxq_unlock(&key);
/*
* When unlocking the umtx, it must be marked as unowned if
* there is zero or one thread only waiting for it.
* Otherwise, it must be marked as contested.
*/
if (count > 1)
new_owner |= UMUTEX_CONTESTED;
error = casueword32(&m->m_owner, owner, &old, new_owner);
umtxq_unbusy_unlocked(&key);
umtx_key_release(&key);
if (error == -1)
return (EFAULT);
if (old != owner)
return (EINVAL);
return (0);
}
/*
* Lock a PP mutex.
*/
static int
do_lock_pp(struct thread *td, struct umutex *m, uint32_t flags,
struct _umtx_time *timeout, int try)
{
struct abs_timeout timo;
struct umtx_q *uq, *uq2;
struct umtx_pi *pi;
uint32_t ceiling;
uint32_t owner, id;
int error, pri, old_inherited_pri, su, rv;
id = td->td_tid;
uq = td->td_umtxq;
if ((error = umtx_key_get(m, (flags & UMUTEX_ROBUST) != 0 ?
TYPE_PP_ROBUST_UMUTEX : TYPE_PP_UMUTEX, GET_SHARE(flags),
&uq->uq_key)) != 0)
return (error);
if (timeout != NULL)
abs_timeout_init2(&timo, timeout);
su = (priv_check(td, PRIV_SCHED_RTPRIO) == 0);
for (;;) {
old_inherited_pri = uq->uq_inherited_pri;
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
rv = fueword32(&m->m_ceilings[0], &ceiling);
if (rv == -1) {
error = EFAULT;
goto out;
}
ceiling = RTP_PRIO_MAX - ceiling;
if (ceiling > RTP_PRIO_MAX) {
error = EINVAL;
goto out;
}
mtx_lock(&umtx_lock);
if (UPRI(td) < PRI_MIN_REALTIME + ceiling) {
mtx_unlock(&umtx_lock);
error = EINVAL;
goto out;
}
if (su && PRI_MIN_REALTIME + ceiling < uq->uq_inherited_pri) {
uq->uq_inherited_pri = PRI_MIN_REALTIME + ceiling;
thread_lock(td);
if (uq->uq_inherited_pri < UPRI(td))
sched_lend_user_prio(td, uq->uq_inherited_pri);
thread_unlock(td);
}
mtx_unlock(&umtx_lock);
rv = casueword32(&m->m_owner, UMUTEX_CONTESTED, &owner,
id | UMUTEX_CONTESTED);
/* The address was invalid. */
if (rv == -1) {
error = EFAULT;
break;
}
if (owner == UMUTEX_CONTESTED) {
error = 0;
break;
} else if (owner == UMUTEX_RB_OWNERDEAD) {
rv = casueword32(&m->m_owner, UMUTEX_RB_OWNERDEAD,
&owner, id | UMUTEX_CONTESTED);
if (rv == -1) {
error = EFAULT;
break;
}
if (owner == UMUTEX_RB_OWNERDEAD) {
error = EOWNERDEAD; /* success */
break;
}
error = 0;
} else if (owner == UMUTEX_RB_NOTRECOV) {
error = ENOTRECOVERABLE;
break;
}
if (try != 0) {
error = EBUSY;
break;
}
/*
* If we caught a signal, we have retried and now
* exit immediately.
*/
if (error != 0)
break;
umtxq_lock(&uq->uq_key);
umtxq_insert(uq);
umtxq_unbusy(&uq->uq_key);
error = umtxq_sleep(uq, "umtxpp", timeout == NULL ?
NULL : &timo);
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
mtx_lock(&umtx_lock);
uq->uq_inherited_pri = old_inherited_pri;
pri = PRI_MAX;
TAILQ_FOREACH(pi, &uq->uq_pi_contested, pi_link) {
uq2 = TAILQ_FIRST(&pi->pi_blocked);
if (uq2 != NULL) {
if (pri > UPRI(uq2->uq_thread))
pri = UPRI(uq2->uq_thread);
}
}
if (pri > uq->uq_inherited_pri)
pri = uq->uq_inherited_pri;
thread_lock(td);
sched_lend_user_prio(td, pri);
thread_unlock(td);
mtx_unlock(&umtx_lock);
}
if (error != 0 && error != EOWNERDEAD) {
mtx_lock(&umtx_lock);
uq->uq_inherited_pri = old_inherited_pri;
pri = PRI_MAX;
TAILQ_FOREACH(pi, &uq->uq_pi_contested, pi_link) {
uq2 = TAILQ_FIRST(&pi->pi_blocked);
if (uq2 != NULL) {
if (pri > UPRI(uq2->uq_thread))
pri = UPRI(uq2->uq_thread);
}
}
if (pri > uq->uq_inherited_pri)
pri = uq->uq_inherited_pri;
thread_lock(td);
sched_lend_user_prio(td, pri);
thread_unlock(td);
mtx_unlock(&umtx_lock);
}
out:
umtxq_unbusy_unlocked(&uq->uq_key);
umtx_key_release(&uq->uq_key);
return (error);
}
/*
* Unlock a PP mutex.
*/
static int
do_unlock_pp(struct thread *td, struct umutex *m, uint32_t flags, bool rb)
{
struct umtx_key key;
struct umtx_q *uq, *uq2;
struct umtx_pi *pi;
uint32_t id, owner, rceiling;
int error, pri, new_inherited_pri, su;
id = td->td_tid;
uq = td->td_umtxq;
su = (priv_check(td, PRIV_SCHED_RTPRIO) == 0);
/*
* Make sure we own this mtx.
*/
error = fueword32(&m->m_owner, &owner);
if (error == -1)
return (EFAULT);
if ((owner & ~UMUTEX_CONTESTED) != id)
return (EPERM);
error = copyin(&m->m_ceilings[1], &rceiling, sizeof(uint32_t));
if (error != 0)
return (error);
if (rceiling == -1)
new_inherited_pri = PRI_MAX;
else {
rceiling = RTP_PRIO_MAX - rceiling;
if (rceiling > RTP_PRIO_MAX)
return (EINVAL);
new_inherited_pri = PRI_MIN_REALTIME + rceiling;
}
if ((error = umtx_key_get(m, (flags & UMUTEX_ROBUST) != 0 ?
TYPE_PP_ROBUST_UMUTEX : TYPE_PP_UMUTEX, GET_SHARE(flags),
&key)) != 0)
return (error);
umtxq_lock(&key);
umtxq_busy(&key);
umtxq_unlock(&key);
/*
* For priority protected mutex, always set unlocked state
* to UMUTEX_CONTESTED, so that userland always enters kernel
* to lock the mutex, it is necessary because thread priority
* has to be adjusted for such mutex.
*/
error = suword32(&m->m_owner, umtx_unlock_val(flags, rb) |
UMUTEX_CONTESTED);
umtxq_lock(&key);
if (error == 0)
umtxq_signal(&key, 1);
umtxq_unbusy(&key);
umtxq_unlock(&key);
if (error == -1)
error = EFAULT;
else {
mtx_lock(&umtx_lock);
if (su != 0)
uq->uq_inherited_pri = new_inherited_pri;
pri = PRI_MAX;
TAILQ_FOREACH(pi, &uq->uq_pi_contested, pi_link) {
uq2 = TAILQ_FIRST(&pi->pi_blocked);
if (uq2 != NULL) {
if (pri > UPRI(uq2->uq_thread))
pri = UPRI(uq2->uq_thread);
}
}
if (pri > uq->uq_inherited_pri)
pri = uq->uq_inherited_pri;
thread_lock(td);
sched_lend_user_prio(td, pri);
thread_unlock(td);
mtx_unlock(&umtx_lock);
}
umtx_key_release(&key);
return (error);
}
static int
do_set_ceiling(struct thread *td, struct umutex *m, uint32_t ceiling,
uint32_t *old_ceiling)
{
struct umtx_q *uq;
uint32_t flags, id, owner, save_ceiling;
int error, rv, rv1;
error = fueword32(&m->m_flags, &flags);
if (error == -1)
return (EFAULT);
if ((flags & UMUTEX_PRIO_PROTECT) == 0)
return (EINVAL);
if (ceiling > RTP_PRIO_MAX)
return (EINVAL);
id = td->td_tid;
uq = td->td_umtxq;
if ((error = umtx_key_get(m, (flags & UMUTEX_ROBUST) != 0 ?
TYPE_PP_ROBUST_UMUTEX : TYPE_PP_UMUTEX, GET_SHARE(flags),
&uq->uq_key)) != 0)
return (error);
for (;;) {
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
rv = fueword32(&m->m_ceilings[0], &save_ceiling);
if (rv == -1) {
error = EFAULT;
break;
}
rv = casueword32(&m->m_owner, UMUTEX_CONTESTED, &owner,
id | UMUTEX_CONTESTED);
if (rv == -1) {
error = EFAULT;
break;
}
if (owner == UMUTEX_CONTESTED) {
rv = suword32(&m->m_ceilings[0], ceiling);
rv1 = suword32(&m->m_owner, UMUTEX_CONTESTED);
error = (rv == 0 && rv1 == 0) ? 0: EFAULT;
break;
}
if ((owner & ~UMUTEX_CONTESTED) == id) {
rv = suword32(&m->m_ceilings[0], ceiling);
error = rv == 0 ? 0 : EFAULT;
break;
}
if (owner == UMUTEX_RB_OWNERDEAD) {
error = EOWNERDEAD;
break;
} else if (owner == UMUTEX_RB_NOTRECOV) {
error = ENOTRECOVERABLE;
break;
}
/*
* If we caught a signal, we have retried and now
* exit immediately.
*/
if (error != 0)
break;
/*
* We set the contested bit, sleep. Otherwise the lock changed
* and we need to retry or we lost a race to the thread
* unlocking the umtx.
*/
umtxq_lock(&uq->uq_key);
umtxq_insert(uq);
umtxq_unbusy(&uq->uq_key);
error = umtxq_sleep(uq, "umtxpp", NULL);
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
}
umtxq_lock(&uq->uq_key);
if (error == 0)
umtxq_signal(&uq->uq_key, INT_MAX);
umtxq_unbusy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
if (error == 0 && old_ceiling != NULL) {
rv = suword32(old_ceiling, save_ceiling);
error = rv == 0 ? 0 : EFAULT;
}
return (error);
}
/*
* Lock a userland POSIX mutex.
*/
static int
do_lock_umutex(struct thread *td, struct umutex *m,
struct _umtx_time *timeout, int mode)
{
uint32_t flags;
int error;
error = fueword32(&m->m_flags, &flags);
if (error == -1)
return (EFAULT);
switch (flags & (UMUTEX_PRIO_INHERIT | UMUTEX_PRIO_PROTECT)) {
case 0:
error = do_lock_normal(td, m, flags, timeout, mode);
break;
case UMUTEX_PRIO_INHERIT:
error = do_lock_pi(td, m, flags, timeout, mode);
break;
case UMUTEX_PRIO_PROTECT:
error = do_lock_pp(td, m, flags, timeout, mode);
break;
default:
return (EINVAL);
}
if (timeout == NULL) {
if (error == EINTR && mode != _UMUTEX_WAIT)
error = ERESTART;
} else {
/* Timed-locking is not restarted. */
if (error == ERESTART)
error = EINTR;
}
return (error);
}
/*
* Unlock a userland POSIX mutex.
*/
static int
do_unlock_umutex(struct thread *td, struct umutex *m, bool rb)
{
uint32_t flags;
int error;
error = fueword32(&m->m_flags, &flags);
if (error == -1)
return (EFAULT);
switch (flags & (UMUTEX_PRIO_INHERIT | UMUTEX_PRIO_PROTECT)) {
case 0:
return (do_unlock_normal(td, m, flags, rb));
case UMUTEX_PRIO_INHERIT:
return (do_unlock_pi(td, m, flags, rb));
case UMUTEX_PRIO_PROTECT:
return (do_unlock_pp(td, m, flags, rb));
}
return (EINVAL);
}
static int
do_cv_wait(struct thread *td, struct ucond *cv, struct umutex *m,
struct timespec *timeout, u_long wflags)
{
struct abs_timeout timo;
struct umtx_q *uq;
uint32_t flags, clockid, hasw;
int error;
uq = td->td_umtxq;
error = fueword32(&cv->c_flags, &flags);
if (error == -1)
return (EFAULT);
error = umtx_key_get(cv, TYPE_CV, GET_SHARE(flags), &uq->uq_key);
if (error != 0)
return (error);
if ((wflags & CVWAIT_CLOCKID) != 0) {
error = fueword32(&cv->c_clockid, &clockid);
if (error == -1) {
umtx_key_release(&uq->uq_key);
return (EFAULT);
}
if (clockid < CLOCK_REALTIME ||
clockid >= CLOCK_THREAD_CPUTIME_ID) {
/* hmm, only HW clock id will work. */
umtx_key_release(&uq->uq_key);
return (EINVAL);
}
} else {
clockid = CLOCK_REALTIME;
}
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
umtxq_insert(uq);
umtxq_unlock(&uq->uq_key);
/*
* Set c_has_waiters to 1 before releasing user mutex, also
* don't modify cache line when unnecessary.
*/
error = fueword32(&cv->c_has_waiters, &hasw);
if (error == 0 && hasw == 0)
suword32(&cv->c_has_waiters, 1);
umtxq_unbusy_unlocked(&uq->uq_key);
error = do_unlock_umutex(td, m, false);
if (timeout != NULL)
abs_timeout_init(&timo, clockid, (wflags & CVWAIT_ABSTIME) != 0,
timeout);
umtxq_lock(&uq->uq_key);
if (error == 0) {
error = umtxq_sleep(uq, "ucond", timeout == NULL ?
NULL : &timo);
}
if ((uq->uq_flags & UQF_UMTXQ) == 0)
error = 0;
else {
/*
* This must be timeout,interrupted by signal or
* surprious wakeup, clear c_has_waiter flag when
* necessary.
*/
umtxq_busy(&uq->uq_key);
if ((uq->uq_flags & UQF_UMTXQ) != 0) {
int oldlen = uq->uq_cur_queue->length;
umtxq_remove(uq);
if (oldlen == 1) {
umtxq_unlock(&uq->uq_key);
suword32(&cv->c_has_waiters, 0);
umtxq_lock(&uq->uq_key);
}
}
umtxq_unbusy(&uq->uq_key);
if (error == ERESTART)
error = EINTR;
}
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
return (error);
}
/*
* Signal a userland condition variable.
*/
static int
do_cv_signal(struct thread *td, struct ucond *cv)
{
struct umtx_key key;
int error, cnt, nwake;
uint32_t flags;
error = fueword32(&cv->c_flags, &flags);
if (error == -1)
return (EFAULT);
if ((error = umtx_key_get(cv, TYPE_CV, GET_SHARE(flags), &key)) != 0)
return (error);
umtxq_lock(&key);
umtxq_busy(&key);
cnt = umtxq_count(&key);
nwake = umtxq_signal(&key, 1);
if (cnt <= nwake) {
umtxq_unlock(&key);
error = suword32(&cv->c_has_waiters, 0);
if (error == -1)
error = EFAULT;
umtxq_lock(&key);
}
umtxq_unbusy(&key);
umtxq_unlock(&key);
umtx_key_release(&key);
return (error);
}
static int
do_cv_broadcast(struct thread *td, struct ucond *cv)
{
struct umtx_key key;
int error;
uint32_t flags;
error = fueword32(&cv->c_flags, &flags);
if (error == -1)
return (EFAULT);
if ((error = umtx_key_get(cv, TYPE_CV, GET_SHARE(flags), &key)) != 0)
return (error);
umtxq_lock(&key);
umtxq_busy(&key);
umtxq_signal(&key, INT_MAX);
umtxq_unlock(&key);
error = suword32(&cv->c_has_waiters, 0);
if (error == -1)
error = EFAULT;
umtxq_unbusy_unlocked(&key);
umtx_key_release(&key);
return (error);
}
static int
do_rw_rdlock(struct thread *td, struct urwlock *rwlock, long fflag, struct _umtx_time *timeout)
{
struct abs_timeout timo;
struct umtx_q *uq;
uint32_t flags, wrflags;
int32_t state, oldstate;
int32_t blocked_readers;
int error, error1, rv;
uq = td->td_umtxq;
error = fueword32(&rwlock->rw_flags, &flags);
if (error == -1)
return (EFAULT);
error = umtx_key_get(rwlock, TYPE_RWLOCK, GET_SHARE(flags), &uq->uq_key);
if (error != 0)
return (error);
if (timeout != NULL)
abs_timeout_init2(&timo, timeout);
wrflags = URWLOCK_WRITE_OWNER;
if (!(fflag & URWLOCK_PREFER_READER) && !(flags & URWLOCK_PREFER_READER))
wrflags |= URWLOCK_WRITE_WAITERS;
for (;;) {
rv = fueword32(&rwlock->rw_state, &state);
if (rv == -1) {
umtx_key_release(&uq->uq_key);
return (EFAULT);
}
/* try to lock it */
while (!(state & wrflags)) {
if (__predict_false(URWLOCK_READER_COUNT(state) == URWLOCK_MAX_READERS)) {
umtx_key_release(&uq->uq_key);
return (EAGAIN);
}
rv = casueword32(&rwlock->rw_state, state,
&oldstate, state + 1);
if (rv == -1) {
umtx_key_release(&uq->uq_key);
return (EFAULT);
}
if (oldstate == state) {
umtx_key_release(&uq->uq_key);
return (0);
}
error = umtxq_check_susp(td);
if (error != 0)
break;
state = oldstate;
}
if (error)
break;
/* grab monitor lock */
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
/*
* re-read the state, in case it changed between the try-lock above
* and the check below
*/
rv = fueword32(&rwlock->rw_state, &state);
if (rv == -1)
error = EFAULT;
/* set read contention bit */
while (error == 0 && (state & wrflags) &&
!(state & URWLOCK_READ_WAITERS)) {
rv = casueword32(&rwlock->rw_state, state,
&oldstate, state | URWLOCK_READ_WAITERS);
if (rv == -1) {
error = EFAULT;
break;
}
if (oldstate == state)
goto sleep;
state = oldstate;
error = umtxq_check_susp(td);
if (error != 0)
break;
}
if (error != 0) {
umtxq_unbusy_unlocked(&uq->uq_key);
break;
}
/* state is changed while setting flags, restart */
if (!(state & wrflags)) {
umtxq_unbusy_unlocked(&uq->uq_key);
error = umtxq_check_susp(td);
if (error != 0)
break;
continue;
}
sleep:
/* contention bit is set, before sleeping, increase read waiter count */
rv = fueword32(&rwlock->rw_blocked_readers,
&blocked_readers);
if (rv == -1) {
umtxq_unbusy_unlocked(&uq->uq_key);
error = EFAULT;
break;
}
suword32(&rwlock->rw_blocked_readers, blocked_readers+1);
while (state & wrflags) {
umtxq_lock(&uq->uq_key);
umtxq_insert(uq);
umtxq_unbusy(&uq->uq_key);
error = umtxq_sleep(uq, "urdlck", timeout == NULL ?
NULL : &timo);
umtxq_busy(&uq->uq_key);
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
if (error)
break;
rv = fueword32(&rwlock->rw_state, &state);
if (rv == -1) {
error = EFAULT;
break;
}
}
/* decrease read waiter count, and may clear read contention bit */
rv = fueword32(&rwlock->rw_blocked_readers,
&blocked_readers);
if (rv == -1) {
umtxq_unbusy_unlocked(&uq->uq_key);
error = EFAULT;
break;
}
suword32(&rwlock->rw_blocked_readers, blocked_readers-1);
if (blocked_readers == 1) {
rv = fueword32(&rwlock->rw_state, &state);
if (rv == -1) {
umtxq_unbusy_unlocked(&uq->uq_key);
error = EFAULT;
break;
}
for (;;) {
rv = casueword32(&rwlock->rw_state, state,
&oldstate, state & ~URWLOCK_READ_WAITERS);
if (rv == -1) {
error = EFAULT;
break;
}
if (oldstate == state)
break;
state = oldstate;
error1 = umtxq_check_susp(td);
if (error1 != 0) {
if (error == 0)
error = error1;
break;
}
}
}
umtxq_unbusy_unlocked(&uq->uq_key);
if (error != 0)
break;
}
umtx_key_release(&uq->uq_key);
if (error == ERESTART)
error = EINTR;
return (error);
}
static int
do_rw_wrlock(struct thread *td, struct urwlock *rwlock, struct _umtx_time *timeout)
{
struct abs_timeout timo;
struct umtx_q *uq;
uint32_t flags;
int32_t state, oldstate;
int32_t blocked_writers;
int32_t blocked_readers;
int error, error1, rv;
uq = td->td_umtxq;
error = fueword32(&rwlock->rw_flags, &flags);
if (error == -1)
return (EFAULT);
error = umtx_key_get(rwlock, TYPE_RWLOCK, GET_SHARE(flags), &uq->uq_key);
if (error != 0)
return (error);
if (timeout != NULL)
abs_timeout_init2(&timo, timeout);
blocked_readers = 0;
for (;;) {
rv = fueword32(&rwlock->rw_state, &state);
if (rv == -1) {
umtx_key_release(&uq->uq_key);
return (EFAULT);
}
while (!(state & URWLOCK_WRITE_OWNER) && URWLOCK_READER_COUNT(state) == 0) {
rv = casueword32(&rwlock->rw_state, state,
&oldstate, state | URWLOCK_WRITE_OWNER);
if (rv == -1) {
umtx_key_release(&uq->uq_key);
return (EFAULT);
}
if (oldstate == state) {
umtx_key_release(&uq->uq_key);
return (0);
}
state = oldstate;
error = umtxq_check_susp(td);
if (error != 0)
break;
}
if (error) {
if (!(state & (URWLOCK_WRITE_OWNER|URWLOCK_WRITE_WAITERS)) &&
blocked_readers != 0) {
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
umtxq_signal_queue(&uq->uq_key, INT_MAX, UMTX_SHARED_QUEUE);
umtxq_unbusy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
}
break;
}
/* grab monitor lock */
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
/*
* re-read the state, in case it changed between the try-lock above
* and the check below
*/
rv = fueword32(&rwlock->rw_state, &state);
if (rv == -1)
error = EFAULT;
while (error == 0 && ((state & URWLOCK_WRITE_OWNER) ||
URWLOCK_READER_COUNT(state) != 0) &&
(state & URWLOCK_WRITE_WAITERS) == 0) {
rv = casueword32(&rwlock->rw_state, state,
&oldstate, state | URWLOCK_WRITE_WAITERS);
if (rv == -1) {
error = EFAULT;
break;
}
if (oldstate == state)
goto sleep;
state = oldstate;
error = umtxq_check_susp(td);
if (error != 0)
break;
}
if (error != 0) {
umtxq_unbusy_unlocked(&uq->uq_key);
break;
}
if (!(state & URWLOCK_WRITE_OWNER) && URWLOCK_READER_COUNT(state) == 0) {
umtxq_unbusy_unlocked(&uq->uq_key);
error = umtxq_check_susp(td);
if (error != 0)
break;
continue;
}
sleep:
rv = fueword32(&rwlock->rw_blocked_writers,
&blocked_writers);
if (rv == -1) {
umtxq_unbusy_unlocked(&uq->uq_key);
error = EFAULT;
break;
}
suword32(&rwlock->rw_blocked_writers, blocked_writers+1);
while ((state & URWLOCK_WRITE_OWNER) || URWLOCK_READER_COUNT(state) != 0) {
umtxq_lock(&uq->uq_key);
umtxq_insert_queue(uq, UMTX_EXCLUSIVE_QUEUE);
umtxq_unbusy(&uq->uq_key);
error = umtxq_sleep(uq, "uwrlck", timeout == NULL ?
NULL : &timo);
umtxq_busy(&uq->uq_key);
umtxq_remove_queue(uq, UMTX_EXCLUSIVE_QUEUE);
umtxq_unlock(&uq->uq_key);
if (error)
break;
rv = fueword32(&rwlock->rw_state, &state);
if (rv == -1) {
error = EFAULT;
break;
}
}
rv = fueword32(&rwlock->rw_blocked_writers,
&blocked_writers);
if (rv == -1) {
umtxq_unbusy_unlocked(&uq->uq_key);
error = EFAULT;
break;
}
suword32(&rwlock->rw_blocked_writers, blocked_writers-1);
if (blocked_writers == 1) {
rv = fueword32(&rwlock->rw_state, &state);
if (rv == -1) {
umtxq_unbusy_unlocked(&uq->uq_key);
error = EFAULT;
break;
}
for (;;) {
rv = casueword32(&rwlock->rw_state, state,
&oldstate, state & ~URWLOCK_WRITE_WAITERS);
if (rv == -1) {
error = EFAULT;
break;
}
if (oldstate == state)
break;
state = oldstate;
error1 = umtxq_check_susp(td);
/*
* We are leaving the URWLOCK_WRITE_WAITERS
* behind, but this should not harm the
* correctness.
*/
if (error1 != 0) {
if (error == 0)
error = error1;
break;
}
}
rv = fueword32(&rwlock->rw_blocked_readers,
&blocked_readers);
if (rv == -1) {
umtxq_unbusy_unlocked(&uq->uq_key);
error = EFAULT;
break;
}
} else
blocked_readers = 0;
umtxq_unbusy_unlocked(&uq->uq_key);
}
umtx_key_release(&uq->uq_key);
if (error == ERESTART)
error = EINTR;
return (error);
}
static int
do_rw_unlock(struct thread *td, struct urwlock *rwlock)
{
struct umtx_q *uq;
uint32_t flags;
int32_t state, oldstate;
int error, rv, q, count;
uq = td->td_umtxq;
error = fueword32(&rwlock->rw_flags, &flags);
if (error == -1)
return (EFAULT);
error = umtx_key_get(rwlock, TYPE_RWLOCK, GET_SHARE(flags), &uq->uq_key);
if (error != 0)
return (error);
error = fueword32(&rwlock->rw_state, &state);
if (error == -1) {
error = EFAULT;
goto out;
}
if (state & URWLOCK_WRITE_OWNER) {
for (;;) {
rv = casueword32(&rwlock->rw_state, state,
&oldstate, state & ~URWLOCK_WRITE_OWNER);
if (rv == -1) {
error = EFAULT;
goto out;
}
if (oldstate != state) {
state = oldstate;
if (!(oldstate & URWLOCK_WRITE_OWNER)) {
error = EPERM;
goto out;
}
error = umtxq_check_susp(td);
if (error != 0)
goto out;
} else
break;
}
} else if (URWLOCK_READER_COUNT(state) != 0) {
for (;;) {
rv = casueword32(&rwlock->rw_state, state,
&oldstate, state - 1);
if (rv == -1) {
error = EFAULT;
goto out;
}
if (oldstate != state) {
state = oldstate;
if (URWLOCK_READER_COUNT(oldstate) == 0) {
error = EPERM;
goto out;
}
error = umtxq_check_susp(td);
if (error != 0)
goto out;
} else
break;
}
} else {
error = EPERM;
goto out;
}
count = 0;
if (!(flags & URWLOCK_PREFER_READER)) {
if (state & URWLOCK_WRITE_WAITERS) {
count = 1;
q = UMTX_EXCLUSIVE_QUEUE;
} else if (state & URWLOCK_READ_WAITERS) {
count = INT_MAX;
q = UMTX_SHARED_QUEUE;
}
} else {
if (state & URWLOCK_READ_WAITERS) {
count = INT_MAX;
q = UMTX_SHARED_QUEUE;
} else if (state & URWLOCK_WRITE_WAITERS) {
count = 1;
q = UMTX_EXCLUSIVE_QUEUE;
}
}
if (count) {
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
umtxq_signal_queue(&uq->uq_key, count, q);
umtxq_unbusy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
}
out:
umtx_key_release(&uq->uq_key);
return (error);
}
#if defined(COMPAT_FREEBSD9) || defined(COMPAT_FREEBSD10)
static int
do_sem_wait(struct thread *td, struct _usem *sem, struct _umtx_time *timeout)
{
struct abs_timeout timo;
struct umtx_q *uq;
uint32_t flags, count, count1;
int error, rv;
uq = td->td_umtxq;
error = fueword32(&sem->_flags, &flags);
if (error == -1)
return (EFAULT);
error = umtx_key_get(sem, TYPE_SEM, GET_SHARE(flags), &uq->uq_key);
if (error != 0)
return (error);
if (timeout != NULL)
abs_timeout_init2(&timo, timeout);
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
umtxq_insert(uq);
umtxq_unlock(&uq->uq_key);
rv = casueword32(&sem->_has_waiters, 0, &count1, 1);
if (rv == 0)
rv = fueword32(&sem->_count, &count);
if (rv == -1 || count != 0) {
umtxq_lock(&uq->uq_key);
umtxq_unbusy(&uq->uq_key);
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
return (rv == -1 ? EFAULT : 0);
}
umtxq_lock(&uq->uq_key);
umtxq_unbusy(&uq->uq_key);
error = umtxq_sleep(uq, "usem", timeout == NULL ? NULL : &timo);
if ((uq->uq_flags & UQF_UMTXQ) == 0)
error = 0;
else {
umtxq_remove(uq);
/* A relative timeout cannot be restarted. */
if (error == ERESTART && timeout != NULL &&
(timeout->_flags & UMTX_ABSTIME) == 0)
error = EINTR;
}
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
return (error);
}
/*
* Signal a userland semaphore.
*/
static int
do_sem_wake(struct thread *td, struct _usem *sem)
{
struct umtx_key key;
int error, cnt;
uint32_t flags;
error = fueword32(&sem->_flags, &flags);
if (error == -1)
return (EFAULT);
if ((error = umtx_key_get(sem, TYPE_SEM, GET_SHARE(flags), &key)) != 0)
return (error);
umtxq_lock(&key);
umtxq_busy(&key);
cnt = umtxq_count(&key);
if (cnt > 0) {
/*
* Check if count is greater than 0, this means the memory is
* still being referenced by user code, so we can safely
* update _has_waiters flag.
*/
if (cnt == 1) {
umtxq_unlock(&key);
error = suword32(&sem->_has_waiters, 0);
umtxq_lock(&key);
if (error == -1)
error = EFAULT;
}
umtxq_signal(&key, 1);
}
umtxq_unbusy(&key);
umtxq_unlock(&key);
umtx_key_release(&key);
return (error);
}
#endif
static int
do_sem2_wait(struct thread *td, struct _usem2 *sem, struct _umtx_time *timeout)
{
struct abs_timeout timo;
struct umtx_q *uq;
uint32_t count, flags;
int error, rv;
uq = td->td_umtxq;
flags = fuword32(&sem->_flags);
error = umtx_key_get(sem, TYPE_SEM, GET_SHARE(flags), &uq->uq_key);
if (error != 0)
return (error);
if (timeout != NULL)
abs_timeout_init2(&timo, timeout);
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
umtxq_insert(uq);
umtxq_unlock(&uq->uq_key);
rv = fueword32(&sem->_count, &count);
if (rv == -1) {
umtxq_lock(&uq->uq_key);
umtxq_unbusy(&uq->uq_key);
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
return (EFAULT);
}
for (;;) {
if (USEM_COUNT(count) != 0) {
umtxq_lock(&uq->uq_key);
umtxq_unbusy(&uq->uq_key);
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
return (0);
}
if (count == USEM_HAS_WAITERS)
break;
rv = casueword32(&sem->_count, 0, &count, USEM_HAS_WAITERS);
if (rv == -1) {
umtxq_lock(&uq->uq_key);
umtxq_unbusy(&uq->uq_key);
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
return (EFAULT);
}
if (count == 0)
break;
}
umtxq_lock(&uq->uq_key);
umtxq_unbusy(&uq->uq_key);
error = umtxq_sleep(uq, "usem", timeout == NULL ? NULL : &timo);
if ((uq->uq_flags & UQF_UMTXQ) == 0)
error = 0;
else {
umtxq_remove(uq);
if (timeout != NULL && (timeout->_flags & UMTX_ABSTIME) == 0) {
/* A relative timeout cannot be restarted. */
if (error == ERESTART)
error = EINTR;
if (error == EINTR) {
abs_timeout_update(&timo);
timespecsub(&timo.end, &timo.cur,
&timeout->_timeout);
}
}
}
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
return (error);
}
/*
* Signal a userland semaphore.
*/
static int
do_sem2_wake(struct thread *td, struct _usem2 *sem)
{
struct umtx_key key;
int error, cnt, rv;
uint32_t count, flags;
rv = fueword32(&sem->_flags, &flags);
if (rv == -1)
return (EFAULT);
if ((error = umtx_key_get(sem, TYPE_SEM, GET_SHARE(flags), &key)) != 0)
return (error);
umtxq_lock(&key);
umtxq_busy(&key);
cnt = umtxq_count(&key);
if (cnt > 0) {
/*
* If this was the last sleeping thread, clear the waiters
* flag in _count.
*/
if (cnt == 1) {
umtxq_unlock(&key);
rv = fueword32(&sem->_count, &count);
while (rv != -1 && count & USEM_HAS_WAITERS)
rv = casueword32(&sem->_count, count, &count,
count & ~USEM_HAS_WAITERS);
if (rv == -1)
error = EFAULT;
umtxq_lock(&key);
}
umtxq_signal(&key, 1);
}
umtxq_unbusy(&key);
umtxq_unlock(&key);
umtx_key_release(&key);
return (error);
}
inline int
umtx_copyin_timeout(const void *addr, struct timespec *tsp)
{
int error;
error = copyin(addr, tsp, sizeof(struct timespec));
if (error == 0) {
if (tsp->tv_sec < 0 ||
tsp->tv_nsec >= 1000000000 ||
tsp->tv_nsec < 0)
error = EINVAL;
}
return (error);
}
static inline int
umtx_copyin_umtx_time(const void *addr, size_t size, struct _umtx_time *tp)
{
int error;
if (size <= sizeof(struct timespec)) {
tp->_clockid = CLOCK_REALTIME;
tp->_flags = 0;
error = copyin(addr, &tp->_timeout, sizeof(struct timespec));
} else
error = copyin(addr, tp, sizeof(struct _umtx_time));
if (error != 0)
return (error);
if (tp->_timeout.tv_sec < 0 ||
tp->_timeout.tv_nsec >= 1000000000 || tp->_timeout.tv_nsec < 0)
return (EINVAL);
return (0);
}
static int
__umtx_op_unimpl(struct thread *td, struct _umtx_op_args *uap)
{
return (EOPNOTSUPP);
}
static int
__umtx_op_wait(struct thread *td, struct _umtx_op_args *uap)
{
struct _umtx_time timeout, *tm_p;
int error;
if (uap->uaddr2 == NULL)
tm_p = NULL;
else {
error = umtx_copyin_umtx_time(
uap->uaddr2, (size_t)uap->uaddr1, &timeout);
if (error != 0)
return (error);
tm_p = &timeout;
}
return (do_wait(td, uap->obj, uap->val, tm_p, 0, 0));
}
static int
__umtx_op_wait_uint(struct thread *td, struct _umtx_op_args *uap)
{
struct _umtx_time timeout, *tm_p;
int error;
if (uap->uaddr2 == NULL)
tm_p = NULL;
else {
error = umtx_copyin_umtx_time(
uap->uaddr2, (size_t)uap->uaddr1, &timeout);
if (error != 0)
return (error);
tm_p = &timeout;
}
return (do_wait(td, uap->obj, uap->val, tm_p, 1, 0));
}
static int
__umtx_op_wait_uint_private(struct thread *td, struct _umtx_op_args *uap)
{
struct _umtx_time *tm_p, timeout;
int error;
if (uap->uaddr2 == NULL)
tm_p = NULL;
else {
error = umtx_copyin_umtx_time(
uap->uaddr2, (size_t)uap->uaddr1, &timeout);
if (error != 0)
return (error);
tm_p = &timeout;
}
return (do_wait(td, uap->obj, uap->val, tm_p, 1, 1));
}
static int
__umtx_op_wake(struct thread *td, struct _umtx_op_args *uap)
{
return (kern_umtx_wake(td, uap->obj, uap->val, 0));
}
#define BATCH_SIZE 128
static int
__umtx_op_nwake_private(struct thread *td, struct _umtx_op_args *uap)
{
char *uaddrs[BATCH_SIZE], **upp;
int count, error, i, pos, tocopy;
upp = (char **)uap->obj;
error = 0;
for (count = uap->val, pos = 0; count > 0; count -= tocopy,
pos += tocopy) {
tocopy = MIN(count, BATCH_SIZE);
error = copyin(upp + pos, uaddrs, tocopy * sizeof(char *));
if (error != 0)
break;
for (i = 0; i < tocopy; ++i)
kern_umtx_wake(td, uaddrs[i], INT_MAX, 1);
maybe_yield();
}
return (error);
}
static int
__umtx_op_wake_private(struct thread *td, struct _umtx_op_args *uap)
{
return (kern_umtx_wake(td, uap->obj, uap->val, 1));
}
static int
__umtx_op_lock_umutex(struct thread *td, struct _umtx_op_args *uap)
{
struct _umtx_time *tm_p, timeout;
int error;
/* Allow a null timespec (wait forever). */
if (uap->uaddr2 == NULL)
tm_p = NULL;
else {
error = umtx_copyin_umtx_time(
uap->uaddr2, (size_t)uap->uaddr1, &timeout);
if (error != 0)
return (error);
tm_p = &timeout;
}
return (do_lock_umutex(td, uap->obj, tm_p, 0));
}
static int
__umtx_op_trylock_umutex(struct thread *td, struct _umtx_op_args *uap)
{
return (do_lock_umutex(td, uap->obj, NULL, _UMUTEX_TRY));
}
static int
__umtx_op_wait_umutex(struct thread *td, struct _umtx_op_args *uap)
{
struct _umtx_time *tm_p, timeout;
int error;
/* Allow a null timespec (wait forever). */
if (uap->uaddr2 == NULL)
tm_p = NULL;
else {
error = umtx_copyin_umtx_time(
uap->uaddr2, (size_t)uap->uaddr1, &timeout);
if (error != 0)
return (error);
tm_p = &timeout;
}
return (do_lock_umutex(td, uap->obj, tm_p, _UMUTEX_WAIT));
}
static int
__umtx_op_wake_umutex(struct thread *td, struct _umtx_op_args *uap)
{
return (do_wake_umutex(td, uap->obj));
}
static int
__umtx_op_unlock_umutex(struct thread *td, struct _umtx_op_args *uap)
{
return (do_unlock_umutex(td, uap->obj, false));
}
static int
__umtx_op_set_ceiling(struct thread *td, struct _umtx_op_args *uap)
{
return (do_set_ceiling(td, uap->obj, uap->val, uap->uaddr1));
}
static int
__umtx_op_cv_wait(struct thread *td, struct _umtx_op_args *uap)
{
struct timespec *ts, timeout;
int error;
/* Allow a null timespec (wait forever). */
if (uap->uaddr2 == NULL)
ts = NULL;
else {
error = umtx_copyin_timeout(uap->uaddr2, &timeout);
if (error != 0)
return (error);
ts = &timeout;
}
return (do_cv_wait(td, uap->obj, uap->uaddr1, ts, uap->val));
}
static int
__umtx_op_cv_signal(struct thread *td, struct _umtx_op_args *uap)
{
return (do_cv_signal(td, uap->obj));
}
static int
__umtx_op_cv_broadcast(struct thread *td, struct _umtx_op_args *uap)
{
return (do_cv_broadcast(td, uap->obj));
}
static int
__umtx_op_rw_rdlock(struct thread *td, struct _umtx_op_args *uap)
{
struct _umtx_time timeout;
int error;
/* Allow a null timespec (wait forever). */
if (uap->uaddr2 == NULL) {
error = do_rw_rdlock(td, uap->obj, uap->val, 0);
} else {
error = umtx_copyin_umtx_time(uap->uaddr2,
(size_t)uap->uaddr1, &timeout);
if (error != 0)
return (error);
error = do_rw_rdlock(td, uap->obj, uap->val, &timeout);
}
return (error);
}
static int
__umtx_op_rw_wrlock(struct thread *td, struct _umtx_op_args *uap)
{
struct _umtx_time timeout;
int error;
/* Allow a null timespec (wait forever). */
if (uap->uaddr2 == NULL) {
error = do_rw_wrlock(td, uap->obj, 0);
} else {
error = umtx_copyin_umtx_time(uap->uaddr2,
(size_t)uap->uaddr1, &timeout);
if (error != 0)
return (error);
error = do_rw_wrlock(td, uap->obj, &timeout);
}
return (error);
}
static int
__umtx_op_rw_unlock(struct thread *td, struct _umtx_op_args *uap)
{
return (do_rw_unlock(td, uap->obj));
}
#if defined(COMPAT_FREEBSD9) || defined(COMPAT_FREEBSD10)
static int
__umtx_op_sem_wait(struct thread *td, struct _umtx_op_args *uap)
{
struct _umtx_time *tm_p, timeout;
int error;
/* Allow a null timespec (wait forever). */
if (uap->uaddr2 == NULL)
tm_p = NULL;
else {
error = umtx_copyin_umtx_time(
uap->uaddr2, (size_t)uap->uaddr1, &timeout);
if (error != 0)
return (error);
tm_p = &timeout;
}
return (do_sem_wait(td, uap->obj, tm_p));
}
static int
__umtx_op_sem_wake(struct thread *td, struct _umtx_op_args *uap)
{
return (do_sem_wake(td, uap->obj));
}
#endif
static int
__umtx_op_wake2_umutex(struct thread *td, struct _umtx_op_args *uap)
{
return (do_wake2_umutex(td, uap->obj, uap->val));
}
static int
__umtx_op_sem2_wait(struct thread *td, struct _umtx_op_args *uap)
{
struct _umtx_time *tm_p, timeout;
size_t uasize;
int error;
/* Allow a null timespec (wait forever). */
if (uap->uaddr2 == NULL) {
uasize = 0;
tm_p = NULL;
} else {
uasize = (size_t)uap->uaddr1;
error = umtx_copyin_umtx_time(uap->uaddr2, uasize, &timeout);
if (error != 0)
return (error);
tm_p = &timeout;
}
error = do_sem2_wait(td, uap->obj, tm_p);
if (error == EINTR && uap->uaddr2 != NULL &&
(timeout._flags & UMTX_ABSTIME) == 0 &&
uasize >= sizeof(struct _umtx_time) + sizeof(struct timespec)) {
error = copyout(&timeout._timeout,
(struct _umtx_time *)uap->uaddr2 + 1,
sizeof(struct timespec));
if (error == 0) {
error = EINTR;
}
}
return (error);
}
static int
__umtx_op_sem2_wake(struct thread *td, struct _umtx_op_args *uap)
{
return (do_sem2_wake(td, uap->obj));
}
#define USHM_OBJ_UMTX(o) \
((struct umtx_shm_obj_list *)(&(o)->umtx_data))
#define USHMF_REG_LINKED 0x0001
#define USHMF_OBJ_LINKED 0x0002
struct umtx_shm_reg {
TAILQ_ENTRY(umtx_shm_reg) ushm_reg_link;
LIST_ENTRY(umtx_shm_reg) ushm_obj_link;
struct umtx_key ushm_key;
struct ucred *ushm_cred;
struct shmfd *ushm_obj;
u_int ushm_refcnt;
u_int ushm_flags;
};
LIST_HEAD(umtx_shm_obj_list, umtx_shm_reg);
TAILQ_HEAD(umtx_shm_reg_head, umtx_shm_reg);
static uma_zone_t umtx_shm_reg_zone;
static struct umtx_shm_reg_head umtx_shm_registry[UMTX_CHAINS];
static struct mtx umtx_shm_lock;
static struct umtx_shm_reg_head umtx_shm_reg_delfree =
TAILQ_HEAD_INITIALIZER(umtx_shm_reg_delfree);
static void umtx_shm_free_reg(struct umtx_shm_reg *reg);
static void
umtx_shm_reg_delfree_tq(void *context __unused, int pending __unused)
{
struct umtx_shm_reg_head d;
struct umtx_shm_reg *reg, *reg1;
TAILQ_INIT(&d);
mtx_lock(&umtx_shm_lock);
TAILQ_CONCAT(&d, &umtx_shm_reg_delfree, ushm_reg_link);
mtx_unlock(&umtx_shm_lock);
TAILQ_FOREACH_SAFE(reg, &d, ushm_reg_link, reg1) {
TAILQ_REMOVE(&d, reg, ushm_reg_link);
umtx_shm_free_reg(reg);
}
}
static struct task umtx_shm_reg_delfree_task =
TASK_INITIALIZER(0, umtx_shm_reg_delfree_tq, NULL);
static struct umtx_shm_reg *
umtx_shm_find_reg_locked(const struct umtx_key *key)
{
struct umtx_shm_reg *reg;
struct umtx_shm_reg_head *reg_head;
KASSERT(key->shared, ("umtx_p_find_rg: private key"));
mtx_assert(&umtx_shm_lock, MA_OWNED);
reg_head = &umtx_shm_registry[key->hash];
TAILQ_FOREACH(reg, reg_head, ushm_reg_link) {
KASSERT(reg->ushm_key.shared,
("non-shared key on reg %p %d", reg, reg->ushm_key.shared));
if (reg->ushm_key.info.shared.object ==
key->info.shared.object &&
reg->ushm_key.info.shared.offset ==
key->info.shared.offset) {
KASSERT(reg->ushm_key.type == TYPE_SHM, ("TYPE_USHM"));
KASSERT(reg->ushm_refcnt > 0,
("reg %p refcnt 0 onlist", reg));
KASSERT((reg->ushm_flags & USHMF_REG_LINKED) != 0,
("reg %p not linked", reg));
reg->ushm_refcnt++;
return (reg);
}
}
return (NULL);
}
static struct umtx_shm_reg *
umtx_shm_find_reg(const struct umtx_key *key)
{
struct umtx_shm_reg *reg;
mtx_lock(&umtx_shm_lock);
reg = umtx_shm_find_reg_locked(key);
mtx_unlock(&umtx_shm_lock);
return (reg);
}
static void
umtx_shm_free_reg(struct umtx_shm_reg *reg)
{
chgumtxcnt(reg->ushm_cred->cr_ruidinfo, -1, 0);
crfree(reg->ushm_cred);
shm_drop(reg->ushm_obj);
uma_zfree(umtx_shm_reg_zone, reg);
}
static bool
umtx_shm_unref_reg_locked(struct umtx_shm_reg *reg, bool force)
{
bool res;
mtx_assert(&umtx_shm_lock, MA_OWNED);
KASSERT(reg->ushm_refcnt > 0, ("ushm_reg %p refcnt 0", reg));
reg->ushm_refcnt--;
res = reg->ushm_refcnt == 0;
if (res || force) {
if ((reg->ushm_flags & USHMF_REG_LINKED) != 0) {
TAILQ_REMOVE(&umtx_shm_registry[reg->ushm_key.hash],
reg, ushm_reg_link);
reg->ushm_flags &= ~USHMF_REG_LINKED;
}
if ((reg->ushm_flags & USHMF_OBJ_LINKED) != 0) {
LIST_REMOVE(reg, ushm_obj_link);
reg->ushm_flags &= ~USHMF_OBJ_LINKED;
}
}
return (res);
}
static void
umtx_shm_unref_reg(struct umtx_shm_reg *reg, bool force)
{
vm_object_t object;
bool dofree;
if (force) {
object = reg->ushm_obj->shm_object;
VM_OBJECT_WLOCK(object);
object->flags |= OBJ_UMTXDEAD;
VM_OBJECT_WUNLOCK(object);
}
mtx_lock(&umtx_shm_lock);
dofree = umtx_shm_unref_reg_locked(reg, force);
mtx_unlock(&umtx_shm_lock);
if (dofree)
umtx_shm_free_reg(reg);
}
void
umtx_shm_object_init(vm_object_t object)
{
LIST_INIT(USHM_OBJ_UMTX(object));
}
void
umtx_shm_object_terminated(vm_object_t object)
{
struct umtx_shm_reg *reg, *reg1;
bool dofree;
if (LIST_EMPTY(USHM_OBJ_UMTX(object)))
return;
dofree = false;
mtx_lock(&umtx_shm_lock);
LIST_FOREACH_SAFE(reg, USHM_OBJ_UMTX(object), ushm_obj_link, reg1) {
if (umtx_shm_unref_reg_locked(reg, true)) {
TAILQ_INSERT_TAIL(&umtx_shm_reg_delfree, reg,
ushm_reg_link);
dofree = true;
}
}
mtx_unlock(&umtx_shm_lock);
if (dofree)
taskqueue_enqueue(taskqueue_thread, &umtx_shm_reg_delfree_task);
}
static int
umtx_shm_create_reg(struct thread *td, const struct umtx_key *key,
struct umtx_shm_reg **res)
{
struct umtx_shm_reg *reg, *reg1;
struct ucred *cred;
int error;
reg = umtx_shm_find_reg(key);
if (reg != NULL) {
*res = reg;
return (0);
}
cred = td->td_ucred;
if (!chgumtxcnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_UMTXP)))
return (ENOMEM);
reg = uma_zalloc(umtx_shm_reg_zone, M_WAITOK | M_ZERO);
reg->ushm_refcnt = 1;
bcopy(key, ®->ushm_key, sizeof(*key));
reg->ushm_obj = shm_alloc(td->td_ucred, O_RDWR);
reg->ushm_cred = crhold(cred);
error = shm_dotruncate(reg->ushm_obj, PAGE_SIZE);
if (error != 0) {
umtx_shm_free_reg(reg);
return (error);
}
mtx_lock(&umtx_shm_lock);
reg1 = umtx_shm_find_reg_locked(key);
if (reg1 != NULL) {
mtx_unlock(&umtx_shm_lock);
umtx_shm_free_reg(reg);
*res = reg1;
return (0);
}
reg->ushm_refcnt++;
TAILQ_INSERT_TAIL(&umtx_shm_registry[key->hash], reg, ushm_reg_link);
LIST_INSERT_HEAD(USHM_OBJ_UMTX(key->info.shared.object), reg,
ushm_obj_link);
reg->ushm_flags = USHMF_REG_LINKED | USHMF_OBJ_LINKED;
mtx_unlock(&umtx_shm_lock);
*res = reg;
return (0);
}
static int
umtx_shm_alive(struct thread *td, void *addr)
{
vm_map_t map;
vm_map_entry_t entry;
vm_object_t object;
vm_pindex_t pindex;
vm_prot_t prot;
int res, ret;
boolean_t wired;
map = &td->td_proc->p_vmspace->vm_map;
res = vm_map_lookup(&map, (uintptr_t)addr, VM_PROT_READ, &entry,
&object, &pindex, &prot, &wired);
if (res != KERN_SUCCESS)
return (EFAULT);
if (object == NULL)
ret = EINVAL;
else
ret = (object->flags & OBJ_UMTXDEAD) != 0 ? ENOTTY : 0;
vm_map_lookup_done(map, entry);
return (ret);
}
static void
umtx_shm_init(void)
{
int i;
umtx_shm_reg_zone = uma_zcreate("umtx_shm", sizeof(struct umtx_shm_reg),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
mtx_init(&umtx_shm_lock, "umtxshm", NULL, MTX_DEF);
for (i = 0; i < nitems(umtx_shm_registry); i++)
TAILQ_INIT(&umtx_shm_registry[i]);
}
static int
umtx_shm(struct thread *td, void *addr, u_int flags)
{
struct umtx_key key;
struct umtx_shm_reg *reg;
struct file *fp;
int error, fd;
if (__bitcount(flags & (UMTX_SHM_CREAT | UMTX_SHM_LOOKUP |
UMTX_SHM_DESTROY| UMTX_SHM_ALIVE)) != 1)
return (EINVAL);
if ((flags & UMTX_SHM_ALIVE) != 0)
return (umtx_shm_alive(td, addr));
error = umtx_key_get(addr, TYPE_SHM, PROCESS_SHARE, &key);
if (error != 0)
return (error);
KASSERT(key.shared == 1, ("non-shared key"));
if ((flags & UMTX_SHM_CREAT) != 0) {
error = umtx_shm_create_reg(td, &key, ®);
} else {
reg = umtx_shm_find_reg(&key);
if (reg == NULL)
error = ESRCH;
}
umtx_key_release(&key);
if (error != 0)
return (error);
KASSERT(reg != NULL, ("no reg"));
if ((flags & UMTX_SHM_DESTROY) != 0) {
umtx_shm_unref_reg(reg, true);
} else {
#if 0
#ifdef MAC
error = mac_posixshm_check_open(td->td_ucred,
reg->ushm_obj, FFLAGS(O_RDWR));
if (error == 0)
#endif
error = shm_access(reg->ushm_obj, td->td_ucred,
FFLAGS(O_RDWR));
if (error == 0)
#endif
error = falloc_caps(td, &fp, &fd, O_CLOEXEC, NULL);
if (error == 0) {
shm_hold(reg->ushm_obj);
finit(fp, FFLAGS(O_RDWR), DTYPE_SHM, reg->ushm_obj,
&shm_ops);
td->td_retval[0] = fd;
fdrop(fp, td);
}
}
umtx_shm_unref_reg(reg, false);
return (error);
}
static int
__umtx_op_shm(struct thread *td, struct _umtx_op_args *uap)
{
return (umtx_shm(td, uap->uaddr1, uap->val));
}
static int
umtx_robust_lists(struct thread *td, struct umtx_robust_lists_params *rbp)
{
td->td_rb_list = rbp->robust_list_offset;
td->td_rbp_list = rbp->robust_priv_list_offset;
td->td_rb_inact = rbp->robust_inact_offset;
return (0);
}
static int
__umtx_op_robust_lists(struct thread *td, struct _umtx_op_args *uap)
{
struct umtx_robust_lists_params rb;
int error;
if (uap->val > sizeof(rb))
return (EINVAL);
bzero(&rb, sizeof(rb));
error = copyin(uap->uaddr1, &rb, uap->val);
if (error != 0)
return (error);
return (umtx_robust_lists(td, &rb));
}
typedef int (*_umtx_op_func)(struct thread *td, struct _umtx_op_args *uap);
static const _umtx_op_func op_table[] = {
[UMTX_OP_RESERVED0] = __umtx_op_unimpl,
[UMTX_OP_RESERVED1] = __umtx_op_unimpl,
[UMTX_OP_WAIT] = __umtx_op_wait,
[UMTX_OP_WAKE] = __umtx_op_wake,
[UMTX_OP_MUTEX_TRYLOCK] = __umtx_op_trylock_umutex,
[UMTX_OP_MUTEX_LOCK] = __umtx_op_lock_umutex,
[UMTX_OP_MUTEX_UNLOCK] = __umtx_op_unlock_umutex,
[UMTX_OP_SET_CEILING] = __umtx_op_set_ceiling,
[UMTX_OP_CV_WAIT] = __umtx_op_cv_wait,
[UMTX_OP_CV_SIGNAL] = __umtx_op_cv_signal,
[UMTX_OP_CV_BROADCAST] = __umtx_op_cv_broadcast,
[UMTX_OP_WAIT_UINT] = __umtx_op_wait_uint,
[UMTX_OP_RW_RDLOCK] = __umtx_op_rw_rdlock,
[UMTX_OP_RW_WRLOCK] = __umtx_op_rw_wrlock,
[UMTX_OP_RW_UNLOCK] = __umtx_op_rw_unlock,
[UMTX_OP_WAIT_UINT_PRIVATE] = __umtx_op_wait_uint_private,
[UMTX_OP_WAKE_PRIVATE] = __umtx_op_wake_private,
[UMTX_OP_MUTEX_WAIT] = __umtx_op_wait_umutex,
[UMTX_OP_MUTEX_WAKE] = __umtx_op_wake_umutex,
#if defined(COMPAT_FREEBSD9) || defined(COMPAT_FREEBSD10)
[UMTX_OP_SEM_WAIT] = __umtx_op_sem_wait,
[UMTX_OP_SEM_WAKE] = __umtx_op_sem_wake,
#else
[UMTX_OP_SEM_WAIT] = __umtx_op_unimpl,
[UMTX_OP_SEM_WAKE] = __umtx_op_unimpl,
#endif
[UMTX_OP_NWAKE_PRIVATE] = __umtx_op_nwake_private,
[UMTX_OP_MUTEX_WAKE2] = __umtx_op_wake2_umutex,
[UMTX_OP_SEM2_WAIT] = __umtx_op_sem2_wait,
[UMTX_OP_SEM2_WAKE] = __umtx_op_sem2_wake,
[UMTX_OP_SHM] = __umtx_op_shm,
[UMTX_OP_ROBUST_LISTS] = __umtx_op_robust_lists,
};
int
sys__umtx_op(struct thread *td, struct _umtx_op_args *uap)
{
if ((unsigned)uap->op < nitems(op_table))
return (*op_table[uap->op])(td, uap);
return (EINVAL);
}
#ifdef COMPAT_FREEBSD32
struct timespec32 {
int32_t tv_sec;
int32_t tv_nsec;
};
struct umtx_time32 {
struct timespec32 timeout;
uint32_t flags;
uint32_t clockid;
};
static inline int
umtx_copyin_timeout32(void *addr, struct timespec *tsp)
{
struct timespec32 ts32;
int error;
error = copyin(addr, &ts32, sizeof(struct timespec32));
if (error == 0) {
if (ts32.tv_sec < 0 ||
ts32.tv_nsec >= 1000000000 ||
ts32.tv_nsec < 0)
error = EINVAL;
else {
tsp->tv_sec = ts32.tv_sec;
tsp->tv_nsec = ts32.tv_nsec;
}
}
return (error);
}
static inline int
umtx_copyin_umtx_time32(const void *addr, size_t size, struct _umtx_time *tp)
{
struct umtx_time32 t32;
int error;
t32.clockid = CLOCK_REALTIME;
t32.flags = 0;
if (size <= sizeof(struct timespec32))
error = copyin(addr, &t32.timeout, sizeof(struct timespec32));
else
error = copyin(addr, &t32, sizeof(struct umtx_time32));
if (error != 0)
return (error);
if (t32.timeout.tv_sec < 0 ||
t32.timeout.tv_nsec >= 1000000000 || t32.timeout.tv_nsec < 0)
return (EINVAL);
tp->_timeout.tv_sec = t32.timeout.tv_sec;
tp->_timeout.tv_nsec = t32.timeout.tv_nsec;
tp->_flags = t32.flags;
tp->_clockid = t32.clockid;
return (0);
}
static int
__umtx_op_wait_compat32(struct thread *td, struct _umtx_op_args *uap)
{
struct _umtx_time *tm_p, timeout;
int error;
if (uap->uaddr2 == NULL)
tm_p = NULL;
else {
error = umtx_copyin_umtx_time32(uap->uaddr2,
(size_t)uap->uaddr1, &timeout);
if (error != 0)
return (error);
tm_p = &timeout;
}
return (do_wait(td, uap->obj, uap->val, tm_p, 1, 0));
}
static int
__umtx_op_lock_umutex_compat32(struct thread *td, struct _umtx_op_args *uap)
{
struct _umtx_time *tm_p, timeout;
int error;
/* Allow a null timespec (wait forever). */
if (uap->uaddr2 == NULL)
tm_p = NULL;
else {
error = umtx_copyin_umtx_time32(uap->uaddr2,
(size_t)uap->uaddr1, &timeout);
if (error != 0)
return (error);
tm_p = &timeout;
}
return (do_lock_umutex(td, uap->obj, tm_p, 0));
}
static int
__umtx_op_wait_umutex_compat32(struct thread *td, struct _umtx_op_args *uap)
{
struct _umtx_time *tm_p, timeout;
int error;
/* Allow a null timespec (wait forever). */
if (uap->uaddr2 == NULL)
tm_p = NULL;
else {
error = umtx_copyin_umtx_time32(uap->uaddr2,
(size_t)uap->uaddr1, &timeout);
if (error != 0)
return (error);
tm_p = &timeout;
}
return (do_lock_umutex(td, uap->obj, tm_p, _UMUTEX_WAIT));
}
static int
__umtx_op_cv_wait_compat32(struct thread *td, struct _umtx_op_args *uap)
{
struct timespec *ts, timeout;
int error;
/* Allow a null timespec (wait forever). */
if (uap->uaddr2 == NULL)
ts = NULL;
else {
error = umtx_copyin_timeout32(uap->uaddr2, &timeout);
if (error != 0)
return (error);
ts = &timeout;
}
return (do_cv_wait(td, uap->obj, uap->uaddr1, ts, uap->val));
}
static int
__umtx_op_rw_rdlock_compat32(struct thread *td, struct _umtx_op_args *uap)
{
struct _umtx_time timeout;
int error;
/* Allow a null timespec (wait forever). */
if (uap->uaddr2 == NULL) {
error = do_rw_rdlock(td, uap->obj, uap->val, 0);
} else {
error = umtx_copyin_umtx_time32(uap->uaddr2,
(size_t)uap->uaddr1, &timeout);
if (error != 0)
return (error);
error = do_rw_rdlock(td, uap->obj, uap->val, &timeout);
}
return (error);
}
static int
__umtx_op_rw_wrlock_compat32(struct thread *td, struct _umtx_op_args *uap)
{
struct _umtx_time timeout;
int error;
/* Allow a null timespec (wait forever). */
if (uap->uaddr2 == NULL) {
error = do_rw_wrlock(td, uap->obj, 0);
} else {
error = umtx_copyin_umtx_time32(uap->uaddr2,
(size_t)uap->uaddr1, &timeout);
if (error != 0)
return (error);
error = do_rw_wrlock(td, uap->obj, &timeout);
}
return (error);
}
static int
__umtx_op_wait_uint_private_compat32(struct thread *td, struct _umtx_op_args *uap)
{
struct _umtx_time *tm_p, timeout;
int error;
if (uap->uaddr2 == NULL)
tm_p = NULL;
else {
error = umtx_copyin_umtx_time32(
uap->uaddr2, (size_t)uap->uaddr1,&timeout);
if (error != 0)
return (error);
tm_p = &timeout;
}
return (do_wait(td, uap->obj, uap->val, tm_p, 1, 1));
}
#if defined(COMPAT_FREEBSD9) || defined(COMPAT_FREEBSD10)
static int
__umtx_op_sem_wait_compat32(struct thread *td, struct _umtx_op_args *uap)
{
struct _umtx_time *tm_p, timeout;
int error;
/* Allow a null timespec (wait forever). */
if (uap->uaddr2 == NULL)
tm_p = NULL;
else {
error = umtx_copyin_umtx_time32(uap->uaddr2,
(size_t)uap->uaddr1, &timeout);
if (error != 0)
return (error);
tm_p = &timeout;
}
return (do_sem_wait(td, uap->obj, tm_p));
}
#endif
static int
__umtx_op_sem2_wait_compat32(struct thread *td, struct _umtx_op_args *uap)
{
struct _umtx_time *tm_p, timeout;
size_t uasize;
int error;
/* Allow a null timespec (wait forever). */
if (uap->uaddr2 == NULL) {
uasize = 0;
tm_p = NULL;
} else {
uasize = (size_t)uap->uaddr1;
error = umtx_copyin_umtx_time32(uap->uaddr2, uasize, &timeout);
if (error != 0)
return (error);
tm_p = &timeout;
}
error = do_sem2_wait(td, uap->obj, tm_p);
if (error == EINTR && uap->uaddr2 != NULL &&
(timeout._flags & UMTX_ABSTIME) == 0 &&
uasize >= sizeof(struct umtx_time32) + sizeof(struct timespec32)) {
struct timespec32 remain32 = {
.tv_sec = timeout._timeout.tv_sec,
.tv_nsec = timeout._timeout.tv_nsec
};
error = copyout(&remain32,
(struct umtx_time32 *)uap->uaddr2 + 1,
sizeof(struct timespec32));
if (error == 0) {
error = EINTR;
}
}
return (error);
}
static int
__umtx_op_nwake_private32(struct thread *td, struct _umtx_op_args *uap)
{
uint32_t uaddrs[BATCH_SIZE], **upp;
int count, error, i, pos, tocopy;
upp = (uint32_t **)uap->obj;
error = 0;
for (count = uap->val, pos = 0; count > 0; count -= tocopy,
pos += tocopy) {
tocopy = MIN(count, BATCH_SIZE);
error = copyin(upp + pos, uaddrs, tocopy * sizeof(uint32_t));
if (error != 0)
break;
for (i = 0; i < tocopy; ++i)
kern_umtx_wake(td, (void *)(intptr_t)uaddrs[i],
INT_MAX, 1);
maybe_yield();
}
return (error);
}
struct umtx_robust_lists_params_compat32 {
uint32_t robust_list_offset;
uint32_t robust_priv_list_offset;
uint32_t robust_inact_offset;
};
static int
__umtx_op_robust_lists_compat32(struct thread *td, struct _umtx_op_args *uap)
{
struct umtx_robust_lists_params rb;
struct umtx_robust_lists_params_compat32 rb32;
int error;
if (uap->val > sizeof(rb32))
return (EINVAL);
bzero(&rb, sizeof(rb));
bzero(&rb32, sizeof(rb32));
error = copyin(uap->uaddr1, &rb32, uap->val);
if (error != 0)
return (error);
rb.robust_list_offset = rb32.robust_list_offset;
rb.robust_priv_list_offset = rb32.robust_priv_list_offset;
rb.robust_inact_offset = rb32.robust_inact_offset;
return (umtx_robust_lists(td, &rb));
}
static const _umtx_op_func op_table_compat32[] = {
[UMTX_OP_RESERVED0] = __umtx_op_unimpl,
[UMTX_OP_RESERVED1] = __umtx_op_unimpl,
[UMTX_OP_WAIT] = __umtx_op_wait_compat32,
[UMTX_OP_WAKE] = __umtx_op_wake,
[UMTX_OP_MUTEX_TRYLOCK] = __umtx_op_trylock_umutex,
[UMTX_OP_MUTEX_LOCK] = __umtx_op_lock_umutex_compat32,
[UMTX_OP_MUTEX_UNLOCK] = __umtx_op_unlock_umutex,
[UMTX_OP_SET_CEILING] = __umtx_op_set_ceiling,
[UMTX_OP_CV_WAIT] = __umtx_op_cv_wait_compat32,
[UMTX_OP_CV_SIGNAL] = __umtx_op_cv_signal,
[UMTX_OP_CV_BROADCAST] = __umtx_op_cv_broadcast,
[UMTX_OP_WAIT_UINT] = __umtx_op_wait_compat32,
[UMTX_OP_RW_RDLOCK] = __umtx_op_rw_rdlock_compat32,
[UMTX_OP_RW_WRLOCK] = __umtx_op_rw_wrlock_compat32,
[UMTX_OP_RW_UNLOCK] = __umtx_op_rw_unlock,
[UMTX_OP_WAIT_UINT_PRIVATE] = __umtx_op_wait_uint_private_compat32,
[UMTX_OP_WAKE_PRIVATE] = __umtx_op_wake_private,
[UMTX_OP_MUTEX_WAIT] = __umtx_op_wait_umutex_compat32,
[UMTX_OP_MUTEX_WAKE] = __umtx_op_wake_umutex,
#if defined(COMPAT_FREEBSD9) || defined(COMPAT_FREEBSD10)
[UMTX_OP_SEM_WAIT] = __umtx_op_sem_wait_compat32,
[UMTX_OP_SEM_WAKE] = __umtx_op_sem_wake,
#else
[UMTX_OP_SEM_WAIT] = __umtx_op_unimpl,
[UMTX_OP_SEM_WAKE] = __umtx_op_unimpl,
#endif
[UMTX_OP_NWAKE_PRIVATE] = __umtx_op_nwake_private32,
[UMTX_OP_MUTEX_WAKE2] = __umtx_op_wake2_umutex,
[UMTX_OP_SEM2_WAIT] = __umtx_op_sem2_wait_compat32,
[UMTX_OP_SEM2_WAKE] = __umtx_op_sem2_wake,
[UMTX_OP_SHM] = __umtx_op_shm,
[UMTX_OP_ROBUST_LISTS] = __umtx_op_robust_lists_compat32,
};
int
freebsd32__umtx_op(struct thread *td, struct freebsd32__umtx_op_args *uap)
{
if ((unsigned)uap->op < nitems(op_table_compat32)) {
return (*op_table_compat32[uap->op])(td,
(struct _umtx_op_args *)uap);
}
return (EINVAL);
}
#endif
void
umtx_thread_init(struct thread *td)
{
td->td_umtxq = umtxq_alloc();
td->td_umtxq->uq_thread = td;
}
void
umtx_thread_fini(struct thread *td)
{
umtxq_free(td->td_umtxq);
}
/*
* It will be called when new thread is created, e.g fork().
*/
void
umtx_thread_alloc(struct thread *td)
{
struct umtx_q *uq;
uq = td->td_umtxq;
uq->uq_inherited_pri = PRI_MAX;
KASSERT(uq->uq_flags == 0, ("uq_flags != 0"));
KASSERT(uq->uq_thread == td, ("uq_thread != td"));
KASSERT(uq->uq_pi_blocked == NULL, ("uq_pi_blocked != NULL"));
KASSERT(TAILQ_EMPTY(&uq->uq_pi_contested), ("uq_pi_contested is not empty"));
}
/*
* exec() hook.
*
* Clear robust lists for all process' threads, not delaying the
* cleanup to thread_exit hook, since the relevant address space is
* destroyed right now.
*/
static void
umtx_exec_hook(void *arg __unused, struct proc *p,
struct image_params *imgp __unused)
{
struct thread *td;
KASSERT(p == curproc, ("need curproc"));
- PROC_LOCK(p);
KASSERT((p->p_flag & P_HADTHREADS) == 0 ||
(p->p_flag & P_STOPPED_SINGLE) != 0,
("curproc must be single-threaded"));
+ /*
+ * There is no need to lock the list as only this thread can be
+ * running.
+ */
FOREACH_THREAD_IN_PROC(p, td) {
KASSERT(td == curthread ||
((td->td_flags & TDF_BOUNDARY) != 0 && TD_IS_SUSPENDED(td)),
("running thread %p %p", p, td));
- PROC_UNLOCK(p);
umtx_thread_cleanup(td);
- PROC_LOCK(p);
td->td_rb_list = td->td_rbp_list = td->td_rb_inact = 0;
}
- PROC_UNLOCK(p);
}
/*
* thread_exit() hook.
*/
void
umtx_thread_exit(struct thread *td)
{
umtx_thread_cleanup(td);
}
static int
umtx_read_uptr(struct thread *td, uintptr_t ptr, uintptr_t *res)
{
u_long res1;
#ifdef COMPAT_FREEBSD32
uint32_t res32;
#endif
int error;
#ifdef COMPAT_FREEBSD32
if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) {
error = fueword32((void *)ptr, &res32);
if (error == 0)
res1 = res32;
} else
#endif
{
error = fueword((void *)ptr, &res1);
}
if (error == 0)
*res = res1;
else
error = EFAULT;
return (error);
}
static void
umtx_read_rb_list(struct thread *td, struct umutex *m, uintptr_t *rb_list)
{
#ifdef COMPAT_FREEBSD32
struct umutex32 m32;
if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) {
memcpy(&m32, m, sizeof(m32));
*rb_list = m32.m_rb_lnk;
} else
#endif
*rb_list = m->m_rb_lnk;
}
static int
umtx_handle_rb(struct thread *td, uintptr_t rbp, uintptr_t *rb_list, bool inact)
{
struct umutex m;
int error;
KASSERT(td->td_proc == curproc, ("need current vmspace"));
error = copyin((void *)rbp, &m, sizeof(m));
if (error != 0)
return (error);
if (rb_list != NULL)
umtx_read_rb_list(td, &m, rb_list);
if ((m.m_flags & UMUTEX_ROBUST) == 0)
return (EINVAL);
if ((m.m_owner & ~UMUTEX_CONTESTED) != td->td_tid)
/* inact is cleared after unlock, allow the inconsistency */
return (inact ? 0 : EINVAL);
return (do_unlock_umutex(td, (struct umutex *)rbp, true));
}
static void
umtx_cleanup_rb_list(struct thread *td, uintptr_t rb_list, uintptr_t *rb_inact,
const char *name)
{
int error, i;
uintptr_t rbp;
bool inact;
if (rb_list == 0)
return;
error = umtx_read_uptr(td, rb_list, &rbp);
for (i = 0; error == 0 && rbp != 0 && i < umtx_max_rb; i++) {
if (rbp == *rb_inact) {
inact = true;
*rb_inact = 0;
} else
inact = false;
error = umtx_handle_rb(td, rbp, &rbp, inact);
}
if (i == umtx_max_rb && umtx_verbose_rb) {
uprintf("comm %s pid %d: reached umtx %smax rb %d\n",
td->td_proc->p_comm, td->td_proc->p_pid, name, umtx_max_rb);
}
if (error != 0 && umtx_verbose_rb) {
uprintf("comm %s pid %d: handling %srb error %d\n",
td->td_proc->p_comm, td->td_proc->p_pid, name, error);
}
}
/*
* Clean up umtx data.
*/
static void
umtx_thread_cleanup(struct thread *td)
{
struct umtx_q *uq;
struct umtx_pi *pi;
uintptr_t rb_inact;
/*
* Disown pi mutexes.
*/
uq = td->td_umtxq;
if (uq != NULL) {
- mtx_lock(&umtx_lock);
- uq->uq_inherited_pri = PRI_MAX;
- while ((pi = TAILQ_FIRST(&uq->uq_pi_contested)) != NULL) {
- pi->pi_owner = NULL;
- TAILQ_REMOVE(&uq->uq_pi_contested, pi, pi_link);
+ if (uq->uq_inherited_pri != PRI_MAX ||
+ !TAILQ_EMPTY(&uq->uq_pi_contested)) {
+ mtx_lock(&umtx_lock);
+ uq->uq_inherited_pri = PRI_MAX;
+ while ((pi = TAILQ_FIRST(&uq->uq_pi_contested)) != NULL) {
+ pi->pi_owner = NULL;
+ TAILQ_REMOVE(&uq->uq_pi_contested, pi, pi_link);
+ }
+ mtx_unlock(&umtx_lock);
}
- mtx_unlock(&umtx_lock);
- thread_lock(td);
- sched_lend_user_prio(td, PRI_MAX);
- thread_unlock(td);
+ sched_lend_user_prio_cond(td, PRI_MAX);
}
+
+ if (td->td_rb_inact == 0 && td->td_rb_list == 0 && td->td_rbp_list == 0)
+ return;
/*
* Handle terminated robust mutexes. Must be done after
* robust pi disown, otherwise unlock could see unowned
* entries.
*/
rb_inact = td->td_rb_inact;
if (rb_inact != 0)
(void)umtx_read_uptr(td, rb_inact, &rb_inact);
umtx_cleanup_rb_list(td, td->td_rb_list, &rb_inact, "");
umtx_cleanup_rb_list(td, td->td_rbp_list, &rb_inact, "priv ");
if (rb_inact != 0)
(void)umtx_handle_rb(td, rb_inact, NULL, true);
}
Index: head/sys/kern/sched_4bsd.c
===================================================================
--- head/sys/kern/sched_4bsd.c (revision 347354)
+++ head/sys/kern/sched_4bsd.c (revision 347355)
@@ -1,1768 +1,1789 @@
/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1982, 1986, 1990, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_hwpmc_hooks.h"
#include "opt_sched.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/cpuset.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/kthread.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/sdt.h>
#include <sys/smp.h>
#include <sys/sysctl.h>
#include <sys/sx.h>
#include <sys/turnstile.h>
#include <sys/umtx.h>
#include <machine/pcb.h>
#include <machine/smp.h>
#ifdef HWPMC_HOOKS
#include <sys/pmckern.h>
#endif
#ifdef KDTRACE_HOOKS
#include <sys/dtrace_bsd.h>
int dtrace_vtime_active;
dtrace_vtime_switch_func_t dtrace_vtime_switch_func;
#endif
/*
* INVERSE_ESTCPU_WEIGHT is only suitable for statclock() frequencies in
* the range 100-256 Hz (approximately).
*/
#define ESTCPULIM(e) \
min((e), INVERSE_ESTCPU_WEIGHT * (NICE_WEIGHT * (PRIO_MAX - PRIO_MIN) - \
RQ_PPQ) + INVERSE_ESTCPU_WEIGHT - 1)
#ifdef SMP
#define INVERSE_ESTCPU_WEIGHT (8 * smp_cpus)
#else
#define INVERSE_ESTCPU_WEIGHT 8 /* 1 / (priorities per estcpu level). */
#endif
#define NICE_WEIGHT 1 /* Priorities per nice level. */
#define TS_NAME_LEN (MAXCOMLEN + sizeof(" td ") + sizeof(__XSTRING(UINT_MAX)))
/*
* The schedulable entity that runs a context.
* This is an extension to the thread structure and is tailored to
* the requirements of this scheduler.
* All fields are protected by the scheduler lock.
*/
struct td_sched {
fixpt_t ts_pctcpu; /* %cpu during p_swtime. */
u_int ts_estcpu; /* Estimated cpu utilization. */
int ts_cpticks; /* Ticks of cpu time. */
int ts_slptime; /* Seconds !RUNNING. */
int ts_slice; /* Remaining part of time slice. */
int ts_flags;
struct runq *ts_runq; /* runq the thread is currently on */
#ifdef KTR
char ts_name[TS_NAME_LEN];
#endif
};
/* flags kept in td_flags */
#define TDF_DIDRUN TDF_SCHED0 /* thread actually ran. */
#define TDF_BOUND TDF_SCHED1 /* Bound to one CPU. */
#define TDF_SLICEEND TDF_SCHED2 /* Thread time slice is over. */
/* flags kept in ts_flags */
#define TSF_AFFINITY 0x0001 /* Has a non-"full" CPU set. */
#define SKE_RUNQ_PCPU(ts) \
((ts)->ts_runq != 0 && (ts)->ts_runq != &runq)
#define THREAD_CAN_SCHED(td, cpu) \
CPU_ISSET((cpu), &(td)->td_cpuset->cs_mask)
_Static_assert(sizeof(struct thread) + sizeof(struct td_sched) <=
sizeof(struct thread0_storage),
"increase struct thread0_storage.t0st_sched size");
static struct mtx sched_lock;
static int realstathz = 127; /* stathz is sometimes 0 and run off of hz. */
static int sched_tdcnt; /* Total runnable threads in the system. */
static int sched_slice = 12; /* Thread run time before rescheduling. */
static void setup_runqs(void);
static void schedcpu(void);
static void schedcpu_thread(void);
static void sched_priority(struct thread *td, u_char prio);
static void sched_setup(void *dummy);
static void maybe_resched(struct thread *td);
static void updatepri(struct thread *td);
static void resetpriority(struct thread *td);
static void resetpriority_thread(struct thread *td);
#ifdef SMP
static int sched_pickcpu(struct thread *td);
static int forward_wakeup(int cpunum);
static void kick_other_cpu(int pri, int cpuid);
#endif
static struct kproc_desc sched_kp = {
"schedcpu",
schedcpu_thread,
NULL
};
SYSINIT(schedcpu, SI_SUB_LAST, SI_ORDER_FIRST, kproc_start,
&sched_kp);
SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL);
static void sched_initticks(void *dummy);
SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks,
NULL);
/*
* Global run queue.
*/
static struct runq runq;
#ifdef SMP
/*
* Per-CPU run queues
*/
static struct runq runq_pcpu[MAXCPU];
long runq_length[MAXCPU];
static cpuset_t idle_cpus_mask;
#endif
struct pcpuidlestat {
u_int idlecalls;
u_int oldidlecalls;
};
DPCPU_DEFINE_STATIC(struct pcpuidlestat, idlestat);
static void
setup_runqs(void)
{
#ifdef SMP
int i;
for (i = 0; i < MAXCPU; ++i)
runq_init(&runq_pcpu[i]);
#endif
runq_init(&runq);
}
static int
sysctl_kern_quantum(SYSCTL_HANDLER_ARGS)
{
int error, new_val, period;
period = 1000000 / realstathz;
new_val = period * sched_slice;
error = sysctl_handle_int(oidp, &new_val, 0, req);
if (error != 0 || req->newptr == NULL)
return (error);
if (new_val <= 0)
return (EINVAL);
sched_slice = imax(1, (new_val + period / 2) / period);
hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) /
realstathz);
return (0);
}
SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RD, 0, "Scheduler");
SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "4BSD", 0,
"Scheduler name");
SYSCTL_PROC(_kern_sched, OID_AUTO, quantum, CTLTYPE_INT | CTLFLAG_RW,
NULL, 0, sysctl_kern_quantum, "I",
"Quantum for timeshare threads in microseconds");
SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0,
"Quantum for timeshare threads in stathz ticks");
#ifdef SMP
/* Enable forwarding of wakeups to all other cpus */
static SYSCTL_NODE(_kern_sched, OID_AUTO, ipiwakeup, CTLFLAG_RD, NULL,
"Kernel SMP");
static int runq_fuzz = 1;
SYSCTL_INT(_kern_sched, OID_AUTO, runq_fuzz, CTLFLAG_RW, &runq_fuzz, 0, "");
static int forward_wakeup_enabled = 1;
SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, enabled, CTLFLAG_RW,
&forward_wakeup_enabled, 0,
"Forwarding of wakeup to idle CPUs");
static int forward_wakeups_requested = 0;
SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, requested, CTLFLAG_RD,
&forward_wakeups_requested, 0,
"Requests for Forwarding of wakeup to idle CPUs");
static int forward_wakeups_delivered = 0;
SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, delivered, CTLFLAG_RD,
&forward_wakeups_delivered, 0,
"Completed Forwarding of wakeup to idle CPUs");
static int forward_wakeup_use_mask = 1;
SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, usemask, CTLFLAG_RW,
&forward_wakeup_use_mask, 0,
"Use the mask of idle cpus");
static int forward_wakeup_use_loop = 0;
SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, useloop, CTLFLAG_RW,
&forward_wakeup_use_loop, 0,
"Use a loop to find idle cpus");
#endif
#if 0
static int sched_followon = 0;
SYSCTL_INT(_kern_sched, OID_AUTO, followon, CTLFLAG_RW,
&sched_followon, 0,
"allow threads to share a quantum");
#endif
SDT_PROVIDER_DEFINE(sched);
SDT_PROBE_DEFINE3(sched, , , change__pri, "struct thread *",
"struct proc *", "uint8_t");
SDT_PROBE_DEFINE3(sched, , , dequeue, "struct thread *",
"struct proc *", "void *");
SDT_PROBE_DEFINE4(sched, , , enqueue, "struct thread *",
"struct proc *", "void *", "int");
SDT_PROBE_DEFINE4(sched, , , lend__pri, "struct thread *",
"struct proc *", "uint8_t", "struct thread *");
SDT_PROBE_DEFINE2(sched, , , load__change, "int", "int");
SDT_PROBE_DEFINE2(sched, , , off__cpu, "struct thread *",
"struct proc *");
SDT_PROBE_DEFINE(sched, , , on__cpu);
SDT_PROBE_DEFINE(sched, , , remain__cpu);
SDT_PROBE_DEFINE2(sched, , , surrender, "struct thread *",
"struct proc *");
static __inline void
sched_load_add(void)
{
sched_tdcnt++;
KTR_COUNTER0(KTR_SCHED, "load", "global load", sched_tdcnt);
SDT_PROBE2(sched, , , load__change, NOCPU, sched_tdcnt);
}
static __inline void
sched_load_rem(void)
{
sched_tdcnt--;
KTR_COUNTER0(KTR_SCHED, "load", "global load", sched_tdcnt);
SDT_PROBE2(sched, , , load__change, NOCPU, sched_tdcnt);
}
/*
* Arrange to reschedule if necessary, taking the priorities and
* schedulers into account.
*/
static void
maybe_resched(struct thread *td)
{
THREAD_LOCK_ASSERT(td, MA_OWNED);
if (td->td_priority < curthread->td_priority)
curthread->td_flags |= TDF_NEEDRESCHED;
}
/*
* This function is called when a thread is about to be put on run queue
* because it has been made runnable or its priority has been adjusted. It
* determines if the new thread should preempt the current thread. If so,
* it sets td_owepreempt to request a preemption.
*/
int
maybe_preempt(struct thread *td)
{
#ifdef PREEMPTION
struct thread *ctd;
int cpri, pri;
/*
* The new thread should not preempt the current thread if any of the
* following conditions are true:
*
* - The kernel is in the throes of crashing (panicstr).
* - The current thread has a higher (numerically lower) or
* equivalent priority. Note that this prevents curthread from
* trying to preempt to itself.
* - The current thread has an inhibitor set or is in the process of
* exiting. In this case, the current thread is about to switch
* out anyways, so there's no point in preempting. If we did,
* the current thread would not be properly resumed as well, so
* just avoid that whole landmine.
* - If the new thread's priority is not a realtime priority and
* the current thread's priority is not an idle priority and
* FULL_PREEMPTION is disabled.
*
* If all of these conditions are false, but the current thread is in
* a nested critical section, then we have to defer the preemption
* until we exit the critical section. Otherwise, switch immediately
* to the new thread.
*/
ctd = curthread;
THREAD_LOCK_ASSERT(td, MA_OWNED);
KASSERT((td->td_inhibitors == 0),
("maybe_preempt: trying to run inhibited thread"));
pri = td->td_priority;
cpri = ctd->td_priority;
if (panicstr != NULL || pri >= cpri /* || dumping */ ||
TD_IS_INHIBITED(ctd))
return (0);
#ifndef FULL_PREEMPTION
if (pri > PRI_MAX_ITHD && cpri < PRI_MIN_IDLE)
return (0);
#endif
CTR0(KTR_PROC, "maybe_preempt: scheduling preemption");
ctd->td_owepreempt = 1;
return (1);
#else
return (0);
#endif
}
/*
* Constants for digital decay and forget:
* 90% of (ts_estcpu) usage in 5 * loadav time
* 95% of (ts_pctcpu) usage in 60 seconds (load insensitive)
* Note that, as ps(1) mentions, this can let percentages
* total over 100% (I've seen 137.9% for 3 processes).
*
* Note that schedclock() updates ts_estcpu and p_cpticks asynchronously.
*
* We wish to decay away 90% of ts_estcpu in (5 * loadavg) seconds.
* That is, the system wants to compute a value of decay such
* that the following for loop:
* for (i = 0; i < (5 * loadavg); i++)
* ts_estcpu *= decay;
* will compute
* ts_estcpu *= 0.1;
* for all values of loadavg:
*
* Mathematically this loop can be expressed by saying:
* decay ** (5 * loadavg) ~= .1
*
* The system computes decay as:
* decay = (2 * loadavg) / (2 * loadavg + 1)
*
* We wish to prove that the system's computation of decay
* will always fulfill the equation:
* decay ** (5 * loadavg) ~= .1
*
* If we compute b as:
* b = 2 * loadavg
* then
* decay = b / (b + 1)
*
* We now need to prove two things:
* 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1)
* 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg)
*
* Facts:
* For x close to zero, exp(x) =~ 1 + x, since
* exp(x) = 0! + x**1/1! + x**2/2! + ... .
* therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b.
* For x close to zero, ln(1+x) =~ x, since
* ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1
* therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1).
* ln(.1) =~ -2.30
*
* Proof of (1):
* Solve (factor)**(power) =~ .1 given power (5*loadav):
* solving for factor,
* ln(factor) =~ (-2.30/5*loadav), or
* factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) =
* exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED
*
* Proof of (2):
* Solve (factor)**(power) =~ .1 given factor == (b/(b+1)):
* solving for power,
* power*ln(b/(b+1)) =~ -2.30, or
* power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED
*
* Actual power values for the implemented algorithm are as follows:
* loadav: 1 2 3 4
* power: 5.68 10.32 14.94 19.55
*/
/* calculations for digital decay to forget 90% of usage in 5*loadav sec */
#define loadfactor(loadav) (2 * (loadav))
#define decay_cpu(loadfac, cpu) (((loadfac) * (cpu)) / ((loadfac) + FSCALE))
/* decay 95% of `ts_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */
static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */
SYSCTL_UINT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
/*
* If `ccpu' is not equal to `exp(-1/20)' and you still want to use the
* faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below
* and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT).
*
* To estimate CCPU_SHIFT for exp(-1/20), the following formula was used:
* 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits).
*
* If you don't want to bother with the faster/more-accurate formula, you
* can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate
* (more general) method of calculating the %age of CPU used by a process.
*/
#define CCPU_SHIFT 11
/*
* Recompute process priorities, every hz ticks.
* MP-safe, called without the Giant mutex.
*/
/* ARGSUSED */
static void
schedcpu(void)
{
fixpt_t loadfac = loadfactor(averunnable.ldavg[0]);
struct thread *td;
struct proc *p;
struct td_sched *ts;
int awake;
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
PROC_LOCK(p);
if (p->p_state == PRS_NEW) {
PROC_UNLOCK(p);
continue;
}
FOREACH_THREAD_IN_PROC(p, td) {
awake = 0;
ts = td_get_sched(td);
thread_lock(td);
/*
* Increment sleep time (if sleeping). We
* ignore overflow, as above.
*/
/*
* The td_sched slptimes are not touched in wakeup
* because the thread may not HAVE everything in
* memory? XXX I think this is out of date.
*/
if (TD_ON_RUNQ(td)) {
awake = 1;
td->td_flags &= ~TDF_DIDRUN;
} else if (TD_IS_RUNNING(td)) {
awake = 1;
/* Do not clear TDF_DIDRUN */
} else if (td->td_flags & TDF_DIDRUN) {
awake = 1;
td->td_flags &= ~TDF_DIDRUN;
}
/*
* ts_pctcpu is only for ps and ttyinfo().
*/
ts->ts_pctcpu = (ts->ts_pctcpu * ccpu) >> FSHIFT;
/*
* If the td_sched has been idle the entire second,
* stop recalculating its priority until
* it wakes up.
*/
if (ts->ts_cpticks != 0) {
#if (FSHIFT >= CCPU_SHIFT)
ts->ts_pctcpu += (realstathz == 100)
? ((fixpt_t) ts->ts_cpticks) <<
(FSHIFT - CCPU_SHIFT) :
100 * (((fixpt_t) ts->ts_cpticks)
<< (FSHIFT - CCPU_SHIFT)) / realstathz;
#else
ts->ts_pctcpu += ((FSCALE - ccpu) *
(ts->ts_cpticks *
FSCALE / realstathz)) >> FSHIFT;
#endif
ts->ts_cpticks = 0;
}
/*
* If there are ANY running threads in this process,
* then don't count it as sleeping.
* XXX: this is broken.
*/
if (awake) {
if (ts->ts_slptime > 1) {
/*
* In an ideal world, this should not
* happen, because whoever woke us
* up from the long sleep should have
* unwound the slptime and reset our
* priority before we run at the stale
* priority. Should KASSERT at some
* point when all the cases are fixed.
*/
updatepri(td);
}
ts->ts_slptime = 0;
} else
ts->ts_slptime++;
if (ts->ts_slptime > 1) {
thread_unlock(td);
continue;
}
ts->ts_estcpu = decay_cpu(loadfac, ts->ts_estcpu);
resetpriority(td);
resetpriority_thread(td);
thread_unlock(td);
}
PROC_UNLOCK(p);
}
sx_sunlock(&allproc_lock);
}
/*
* Main loop for a kthread that executes schedcpu once a second.
*/
static void
schedcpu_thread(void)
{
for (;;) {
schedcpu();
pause("-", hz);
}
}
/*
* Recalculate the priority of a process after it has slept for a while.
* For all load averages >= 1 and max ts_estcpu of 255, sleeping for at
* least six times the loadfactor will decay ts_estcpu to zero.
*/
static void
updatepri(struct thread *td)
{
struct td_sched *ts;
fixpt_t loadfac;
unsigned int newcpu;
ts = td_get_sched(td);
loadfac = loadfactor(averunnable.ldavg[0]);
if (ts->ts_slptime > 5 * loadfac)
ts->ts_estcpu = 0;
else {
newcpu = ts->ts_estcpu;
ts->ts_slptime--; /* was incremented in schedcpu() */
while (newcpu && --ts->ts_slptime)
newcpu = decay_cpu(loadfac, newcpu);
ts->ts_estcpu = newcpu;
}
}
/*
* Compute the priority of a process when running in user mode.
* Arrange to reschedule if the resulting priority is better
* than that of the current process.
*/
static void
resetpriority(struct thread *td)
{
u_int newpriority;
if (td->td_pri_class != PRI_TIMESHARE)
return;
newpriority = PUSER +
td_get_sched(td)->ts_estcpu / INVERSE_ESTCPU_WEIGHT +
NICE_WEIGHT * (td->td_proc->p_nice - PRIO_MIN);
newpriority = min(max(newpriority, PRI_MIN_TIMESHARE),
PRI_MAX_TIMESHARE);
sched_user_prio(td, newpriority);
}
/*
* Update the thread's priority when the associated process's user
* priority changes.
*/
static void
resetpriority_thread(struct thread *td)
{
/* Only change threads with a time sharing user priority. */
if (td->td_priority < PRI_MIN_TIMESHARE ||
td->td_priority > PRI_MAX_TIMESHARE)
return;
/* XXX the whole needresched thing is broken, but not silly. */
maybe_resched(td);
sched_prio(td, td->td_user_pri);
}
/* ARGSUSED */
static void
sched_setup(void *dummy)
{
setup_runqs();
/* Account for thread0. */
sched_load_add();
}
/*
* This routine determines time constants after stathz and hz are setup.
*/
static void
sched_initticks(void *dummy)
{
realstathz = stathz ? stathz : hz;
sched_slice = realstathz / 10; /* ~100ms */
hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) /
realstathz);
}
/* External interfaces start here */
/*
* Very early in the boot some setup of scheduler-specific
* parts of proc0 and of some scheduler resources needs to be done.
* Called from:
* proc0_init()
*/
void
schedinit(void)
{
/*
* Set up the scheduler specific parts of thread0.
*/
thread0.td_lock = &sched_lock;
td_get_sched(&thread0)->ts_slice = sched_slice;
mtx_init(&sched_lock, "sched lock", NULL, MTX_SPIN | MTX_RECURSE);
}
int
sched_runnable(void)
{
#ifdef SMP
return runq_check(&runq) + runq_check(&runq_pcpu[PCPU_GET(cpuid)]);
#else
return runq_check(&runq);
#endif
}
int
sched_rr_interval(void)
{
/* Convert sched_slice from stathz to hz. */
return (imax(1, (sched_slice * hz + realstathz / 2) / realstathz));
}
/*
* We adjust the priority of the current process. The priority of a
* process gets worse as it accumulates CPU time. The cpu usage
* estimator (ts_estcpu) is increased here. resetpriority() will
* compute a different priority each time ts_estcpu increases by
* INVERSE_ESTCPU_WEIGHT (until PRI_MAX_TIMESHARE is reached). The
* cpu usage estimator ramps up quite quickly when the process is
* running (linearly), and decays away exponentially, at a rate which
* is proportionally slower when the system is busy. The basic
* principle is that the system will 90% forget that the process used
* a lot of CPU time in 5 * loadav seconds. This causes the system to
* favor processes which haven't run much recently, and to round-robin
* among other processes.
*/
void
sched_clock(struct thread *td)
{
struct pcpuidlestat *stat;
struct td_sched *ts;
THREAD_LOCK_ASSERT(td, MA_OWNED);
ts = td_get_sched(td);
ts->ts_cpticks++;
ts->ts_estcpu = ESTCPULIM(ts->ts_estcpu + 1);
if ((ts->ts_estcpu % INVERSE_ESTCPU_WEIGHT) == 0) {
resetpriority(td);
resetpriority_thread(td);
}
/*
* Force a context switch if the current thread has used up a full
* time slice (default is 100ms).
*/
if (!TD_IS_IDLETHREAD(td) && --ts->ts_slice <= 0) {
ts->ts_slice = sched_slice;
td->td_flags |= TDF_NEEDRESCHED | TDF_SLICEEND;
}
stat = DPCPU_PTR(idlestat);
stat->oldidlecalls = stat->idlecalls;
stat->idlecalls = 0;
}
/*
* Charge child's scheduling CPU usage to parent.
*/
void
sched_exit(struct proc *p, struct thread *td)
{
KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "proc exit",
"prio:%d", td->td_priority);
PROC_LOCK_ASSERT(p, MA_OWNED);
sched_exit_thread(FIRST_THREAD_IN_PROC(p), td);
}
void
sched_exit_thread(struct thread *td, struct thread *child)
{
KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "exit",
"prio:%d", child->td_priority);
thread_lock(td);
td_get_sched(td)->ts_estcpu = ESTCPULIM(td_get_sched(td)->ts_estcpu +
td_get_sched(child)->ts_estcpu);
thread_unlock(td);
thread_lock(child);
if ((child->td_flags & TDF_NOLOAD) == 0)
sched_load_rem();
thread_unlock(child);
}
void
sched_fork(struct thread *td, struct thread *childtd)
{
sched_fork_thread(td, childtd);
}
void
sched_fork_thread(struct thread *td, struct thread *childtd)
{
struct td_sched *ts, *tsc;
childtd->td_oncpu = NOCPU;
childtd->td_lastcpu = NOCPU;
childtd->td_lock = &sched_lock;
childtd->td_cpuset = cpuset_ref(td->td_cpuset);
childtd->td_domain.dr_policy = td->td_cpuset->cs_domain;
childtd->td_priority = childtd->td_base_pri;
ts = td_get_sched(childtd);
bzero(ts, sizeof(*ts));
tsc = td_get_sched(td);
ts->ts_estcpu = tsc->ts_estcpu;
ts->ts_flags |= (tsc->ts_flags & TSF_AFFINITY);
ts->ts_slice = 1;
}
void
sched_nice(struct proc *p, int nice)
{
struct thread *td;
PROC_LOCK_ASSERT(p, MA_OWNED);
p->p_nice = nice;
FOREACH_THREAD_IN_PROC(p, td) {
thread_lock(td);
resetpriority(td);
resetpriority_thread(td);
thread_unlock(td);
}
}
void
sched_class(struct thread *td, int class)
{
THREAD_LOCK_ASSERT(td, MA_OWNED);
td->td_pri_class = class;
}
/*
* Adjust the priority of a thread.
*/
static void
sched_priority(struct thread *td, u_char prio)
{
KTR_POINT3(KTR_SCHED, "thread", sched_tdname(td), "priority change",
"prio:%d", td->td_priority, "new prio:%d", prio, KTR_ATTR_LINKED,
sched_tdname(curthread));
SDT_PROBE3(sched, , , change__pri, td, td->td_proc, prio);
if (td != curthread && prio > td->td_priority) {
KTR_POINT3(KTR_SCHED, "thread", sched_tdname(curthread),
"lend prio", "prio:%d", td->td_priority, "new prio:%d",
prio, KTR_ATTR_LINKED, sched_tdname(td));
SDT_PROBE4(sched, , , lend__pri, td, td->td_proc, prio,
curthread);
}
THREAD_LOCK_ASSERT(td, MA_OWNED);
if (td->td_priority == prio)
return;
td->td_priority = prio;
if (TD_ON_RUNQ(td) && td->td_rqindex != (prio / RQ_PPQ)) {
sched_rem(td);
sched_add(td, SRQ_BORING);
}
}
/*
* Update a thread's priority when it is lent another thread's
* priority.
*/
void
sched_lend_prio(struct thread *td, u_char prio)
{
td->td_flags |= TDF_BORROWING;
sched_priority(td, prio);
}
/*
* Restore a thread's priority when priority propagation is
* over. The prio argument is the minimum priority the thread
* needs to have to satisfy other possible priority lending
* requests. If the thread's regulary priority is less
* important than prio the thread will keep a priority boost
* of prio.
*/
void
sched_unlend_prio(struct thread *td, u_char prio)
{
u_char base_pri;
if (td->td_base_pri >= PRI_MIN_TIMESHARE &&
td->td_base_pri <= PRI_MAX_TIMESHARE)
base_pri = td->td_user_pri;
else
base_pri = td->td_base_pri;
if (prio >= base_pri) {
td->td_flags &= ~TDF_BORROWING;
sched_prio(td, base_pri);
} else
sched_lend_prio(td, prio);
}
void
sched_prio(struct thread *td, u_char prio)
{
u_char oldprio;
/* First, update the base priority. */
td->td_base_pri = prio;
/*
* If the thread is borrowing another thread's priority, don't ever
* lower the priority.
*/
if (td->td_flags & TDF_BORROWING && td->td_priority < prio)
return;
/* Change the real priority. */
oldprio = td->td_priority;
sched_priority(td, prio);
/*
* If the thread is on a turnstile, then let the turnstile update
* its state.
*/
if (TD_ON_LOCK(td) && oldprio != prio)
turnstile_adjust(td, oldprio);
}
void
sched_user_prio(struct thread *td, u_char prio)
{
THREAD_LOCK_ASSERT(td, MA_OWNED);
td->td_base_user_pri = prio;
if (td->td_lend_user_pri <= prio)
return;
td->td_user_pri = prio;
}
void
sched_lend_user_prio(struct thread *td, u_char prio)
{
THREAD_LOCK_ASSERT(td, MA_OWNED);
td->td_lend_user_pri = prio;
td->td_user_pri = min(prio, td->td_base_user_pri);
if (td->td_priority > td->td_user_pri)
sched_prio(td, td->td_user_pri);
else if (td->td_priority != td->td_user_pri)
td->td_flags |= TDF_NEEDRESCHED;
}
+/*
+ * Like the above but first check if there is anything to do.
+ */
+void
+sched_lend_user_prio_cond(struct thread *td, u_char prio)
+{
+
+ if (td->td_lend_user_pri != prio)
+ goto lend;
+ if (td->td_user_pri != min(prio, td->td_base_user_pri))
+ goto lend;
+ if (td->td_priority >= td->td_user_pri)
+ goto lend;
+ return;
+
+lend:
+ thread_lock(td);
+ sched_lend_user_prio(td, prio);
+ thread_unlock(td);
+}
+
void
sched_sleep(struct thread *td, int pri)
{
THREAD_LOCK_ASSERT(td, MA_OWNED);
td->td_slptick = ticks;
td_get_sched(td)->ts_slptime = 0;
if (pri != 0 && PRI_BASE(td->td_pri_class) == PRI_TIMESHARE)
sched_prio(td, pri);
if (TD_IS_SUSPENDED(td) || pri >= PSOCK)
td->td_flags |= TDF_CANSWAP;
}
void
sched_switch(struct thread *td, struct thread *newtd, int flags)
{
struct mtx *tmtx;
struct td_sched *ts;
struct proc *p;
int preempted;
tmtx = NULL;
ts = td_get_sched(td);
p = td->td_proc;
THREAD_LOCK_ASSERT(td, MA_OWNED);
/*
* Switch to the sched lock to fix things up and pick
* a new thread.
* Block the td_lock in order to avoid breaking the critical path.
*/
if (td->td_lock != &sched_lock) {
mtx_lock_spin(&sched_lock);
tmtx = thread_lock_block(td);
}
if ((td->td_flags & TDF_NOLOAD) == 0)
sched_load_rem();
td->td_lastcpu = td->td_oncpu;
preempted = (td->td_flags & TDF_SLICEEND) == 0 &&
(flags & SW_PREEMPT) != 0;
td->td_flags &= ~(TDF_NEEDRESCHED | TDF_SLICEEND);
td->td_owepreempt = 0;
td->td_oncpu = NOCPU;
/*
* At the last moment, if this thread is still marked RUNNING,
* then put it back on the run queue as it has not been suspended
* or stopped or any thing else similar. We never put the idle
* threads on the run queue, however.
*/
if (td->td_flags & TDF_IDLETD) {
TD_SET_CAN_RUN(td);
#ifdef SMP
CPU_CLR(PCPU_GET(cpuid), &idle_cpus_mask);
#endif
} else {
if (TD_IS_RUNNING(td)) {
/* Put us back on the run queue. */
sched_add(td, preempted ?
SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED :
SRQ_OURSELF|SRQ_YIELDING);
}
}
if (newtd) {
/*
* The thread we are about to run needs to be counted
* as if it had been added to the run queue and selected.
* It came from:
* * A preemption
* * An upcall
* * A followon
*/
KASSERT((newtd->td_inhibitors == 0),
("trying to run inhibited thread"));
newtd->td_flags |= TDF_DIDRUN;
TD_SET_RUNNING(newtd);
if ((newtd->td_flags & TDF_NOLOAD) == 0)
sched_load_add();
} else {
newtd = choosethread();
MPASS(newtd->td_lock == &sched_lock);
}
#if (KTR_COMPILE & KTR_SCHED) != 0
if (TD_IS_IDLETHREAD(td))
KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "idle",
"prio:%d", td->td_priority);
else
KTR_STATE3(KTR_SCHED, "thread", sched_tdname(td), KTDSTATE(td),
"prio:%d", td->td_priority, "wmesg:\"%s\"", td->td_wmesg,
"lockname:\"%s\"", td->td_lockname);
#endif
if (td != newtd) {
#ifdef HWPMC_HOOKS
if (PMC_PROC_IS_USING_PMCS(td->td_proc))
PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
#endif
SDT_PROBE2(sched, , , off__cpu, newtd, newtd->td_proc);
/* I feel sleepy */
lock_profile_release_lock(&sched_lock.lock_object);
#ifdef KDTRACE_HOOKS
/*
* If DTrace has set the active vtime enum to anything
* other than INACTIVE (0), then it should have set the
* function to call.
*/
if (dtrace_vtime_active)
(*dtrace_vtime_switch_func)(newtd);
#endif
cpu_switch(td, newtd, tmtx != NULL ? tmtx : td->td_lock);
lock_profile_obtain_lock_success(&sched_lock.lock_object,
0, 0, __FILE__, __LINE__);
/*
* Where am I? What year is it?
* We are in the same thread that went to sleep above,
* but any amount of time may have passed. All our context
* will still be available as will local variables.
* PCPU values however may have changed as we may have
* changed CPU so don't trust cached values of them.
* New threads will go to fork_exit() instead of here
* so if you change things here you may need to change
* things there too.
*
* If the thread above was exiting it will never wake
* up again here, so either it has saved everything it
* needed to, or the thread_wait() or wait() will
* need to reap it.
*/
SDT_PROBE0(sched, , , on__cpu);
#ifdef HWPMC_HOOKS
if (PMC_PROC_IS_USING_PMCS(td->td_proc))
PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN);
#endif
} else
SDT_PROBE0(sched, , , remain__cpu);
KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "running",
"prio:%d", td->td_priority);
#ifdef SMP
if (td->td_flags & TDF_IDLETD)
CPU_SET(PCPU_GET(cpuid), &idle_cpus_mask);
#endif
sched_lock.mtx_lock = (uintptr_t)td;
td->td_oncpu = PCPU_GET(cpuid);
MPASS(td->td_lock == &sched_lock);
}
void
sched_wakeup(struct thread *td)
{
struct td_sched *ts;
THREAD_LOCK_ASSERT(td, MA_OWNED);
ts = td_get_sched(td);
td->td_flags &= ~TDF_CANSWAP;
if (ts->ts_slptime > 1) {
updatepri(td);
resetpriority(td);
}
td->td_slptick = 0;
ts->ts_slptime = 0;
ts->ts_slice = sched_slice;
sched_add(td, SRQ_BORING);
}
#ifdef SMP
static int
forward_wakeup(int cpunum)
{
struct pcpu *pc;
cpuset_t dontuse, map, map2;
u_int id, me;
int iscpuset;
mtx_assert(&sched_lock, MA_OWNED);
CTR0(KTR_RUNQ, "forward_wakeup()");
if ((!forward_wakeup_enabled) ||
(forward_wakeup_use_mask == 0 && forward_wakeup_use_loop == 0))
return (0);
if (!smp_started || panicstr)
return (0);
forward_wakeups_requested++;
/*
* Check the idle mask we received against what we calculated
* before in the old version.
*/
me = PCPU_GET(cpuid);
/* Don't bother if we should be doing it ourself. */
if (CPU_ISSET(me, &idle_cpus_mask) &&
(cpunum == NOCPU || me == cpunum))
return (0);
CPU_SETOF(me, &dontuse);
CPU_OR(&dontuse, &stopped_cpus);
CPU_OR(&dontuse, &hlt_cpus_mask);
CPU_ZERO(&map2);
if (forward_wakeup_use_loop) {
STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
id = pc->pc_cpuid;
if (!CPU_ISSET(id, &dontuse) &&
pc->pc_curthread == pc->pc_idlethread) {
CPU_SET(id, &map2);
}
}
}
if (forward_wakeup_use_mask) {
map = idle_cpus_mask;
CPU_NAND(&map, &dontuse);
/* If they are both on, compare and use loop if different. */
if (forward_wakeup_use_loop) {
if (CPU_CMP(&map, &map2)) {
printf("map != map2, loop method preferred\n");
map = map2;
}
}
} else {
map = map2;
}
/* If we only allow a specific CPU, then mask off all the others. */
if (cpunum != NOCPU) {
KASSERT((cpunum <= mp_maxcpus),("forward_wakeup: bad cpunum."));
iscpuset = CPU_ISSET(cpunum, &map);
if (iscpuset == 0)
CPU_ZERO(&map);
else
CPU_SETOF(cpunum, &map);
}
if (!CPU_EMPTY(&map)) {
forward_wakeups_delivered++;
STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
id = pc->pc_cpuid;
if (!CPU_ISSET(id, &map))
continue;
if (cpu_idle_wakeup(pc->pc_cpuid))
CPU_CLR(id, &map);
}
if (!CPU_EMPTY(&map))
ipi_selected(map, IPI_AST);
return (1);
}
if (cpunum == NOCPU)
printf("forward_wakeup: Idle processor not found\n");
return (0);
}
static void
kick_other_cpu(int pri, int cpuid)
{
struct pcpu *pcpu;
int cpri;
pcpu = pcpu_find(cpuid);
if (CPU_ISSET(cpuid, &idle_cpus_mask)) {
forward_wakeups_delivered++;
if (!cpu_idle_wakeup(cpuid))
ipi_cpu(cpuid, IPI_AST);
return;
}
cpri = pcpu->pc_curthread->td_priority;
if (pri >= cpri)
return;
#if defined(IPI_PREEMPTION) && defined(PREEMPTION)
#if !defined(FULL_PREEMPTION)
if (pri <= PRI_MAX_ITHD)
#endif /* ! FULL_PREEMPTION */
{
ipi_cpu(cpuid, IPI_PREEMPT);
return;
}
#endif /* defined(IPI_PREEMPTION) && defined(PREEMPTION) */
pcpu->pc_curthread->td_flags |= TDF_NEEDRESCHED;
ipi_cpu(cpuid, IPI_AST);
return;
}
#endif /* SMP */
#ifdef SMP
static int
sched_pickcpu(struct thread *td)
{
int best, cpu;
mtx_assert(&sched_lock, MA_OWNED);
if (td->td_lastcpu != NOCPU && THREAD_CAN_SCHED(td, td->td_lastcpu))
best = td->td_lastcpu;
else
best = NOCPU;
CPU_FOREACH(cpu) {
if (!THREAD_CAN_SCHED(td, cpu))
continue;
if (best == NOCPU)
best = cpu;
else if (runq_length[cpu] < runq_length[best])
best = cpu;
}
KASSERT(best != NOCPU, ("no valid CPUs"));
return (best);
}
#endif
void
sched_add(struct thread *td, int flags)
#ifdef SMP
{
cpuset_t tidlemsk;
struct td_sched *ts;
u_int cpu, cpuid;
int forwarded = 0;
int single_cpu = 0;
ts = td_get_sched(td);
THREAD_LOCK_ASSERT(td, MA_OWNED);
KASSERT((td->td_inhibitors == 0),
("sched_add: trying to run inhibited thread"));
KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)),
("sched_add: bad thread state"));
KASSERT(td->td_flags & TDF_INMEM,
("sched_add: thread swapped out"));
KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add",
"prio:%d", td->td_priority, KTR_ATTR_LINKED,
sched_tdname(curthread));
KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup",
KTR_ATTR_LINKED, sched_tdname(td));
SDT_PROBE4(sched, , , enqueue, td, td->td_proc, NULL,
flags & SRQ_PREEMPTED);
/*
* Now that the thread is moving to the run-queue, set the lock
* to the scheduler's lock.
*/
if (td->td_lock != &sched_lock) {
mtx_lock_spin(&sched_lock);
thread_lock_set(td, &sched_lock);
}
TD_SET_RUNQ(td);
/*
* If SMP is started and the thread is pinned or otherwise limited to
* a specific set of CPUs, queue the thread to a per-CPU run queue.
* Otherwise, queue the thread to the global run queue.
*
* If SMP has not yet been started we must use the global run queue
* as per-CPU state may not be initialized yet and we may crash if we
* try to access the per-CPU run queues.
*/
if (smp_started && (td->td_pinned != 0 || td->td_flags & TDF_BOUND ||
ts->ts_flags & TSF_AFFINITY)) {
if (td->td_pinned != 0)
cpu = td->td_lastcpu;
else if (td->td_flags & TDF_BOUND) {
/* Find CPU from bound runq. */
KASSERT(SKE_RUNQ_PCPU(ts),
("sched_add: bound td_sched not on cpu runq"));
cpu = ts->ts_runq - &runq_pcpu[0];
} else
/* Find a valid CPU for our cpuset */
cpu = sched_pickcpu(td);
ts->ts_runq = &runq_pcpu[cpu];
single_cpu = 1;
CTR3(KTR_RUNQ,
"sched_add: Put td_sched:%p(td:%p) on cpu%d runq", ts, td,
cpu);
} else {
CTR2(KTR_RUNQ,
"sched_add: adding td_sched:%p (td:%p) to gbl runq", ts,
td);
cpu = NOCPU;
ts->ts_runq = &runq;
}
if ((td->td_flags & TDF_NOLOAD) == 0)
sched_load_add();
runq_add(ts->ts_runq, td, flags);
if (cpu != NOCPU)
runq_length[cpu]++;
cpuid = PCPU_GET(cpuid);
if (single_cpu && cpu != cpuid) {
kick_other_cpu(td->td_priority, cpu);
} else {
if (!single_cpu) {
tidlemsk = idle_cpus_mask;
CPU_NAND(&tidlemsk, &hlt_cpus_mask);
CPU_CLR(cpuid, &tidlemsk);
if (!CPU_ISSET(cpuid, &idle_cpus_mask) &&
((flags & SRQ_INTR) == 0) &&
!CPU_EMPTY(&tidlemsk))
forwarded = forward_wakeup(cpu);
}
if (!forwarded) {
if (!maybe_preempt(td))
maybe_resched(td);
}
}
}
#else /* SMP */
{
struct td_sched *ts;
ts = td_get_sched(td);
THREAD_LOCK_ASSERT(td, MA_OWNED);
KASSERT((td->td_inhibitors == 0),
("sched_add: trying to run inhibited thread"));
KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)),
("sched_add: bad thread state"));
KASSERT(td->td_flags & TDF_INMEM,
("sched_add: thread swapped out"));
KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add",
"prio:%d", td->td_priority, KTR_ATTR_LINKED,
sched_tdname(curthread));
KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup",
KTR_ATTR_LINKED, sched_tdname(td));
SDT_PROBE4(sched, , , enqueue, td, td->td_proc, NULL,
flags & SRQ_PREEMPTED);
/*
* Now that the thread is moving to the run-queue, set the lock
* to the scheduler's lock.
*/
if (td->td_lock != &sched_lock) {
mtx_lock_spin(&sched_lock);
thread_lock_set(td, &sched_lock);
}
TD_SET_RUNQ(td);
CTR2(KTR_RUNQ, "sched_add: adding td_sched:%p (td:%p) to runq", ts, td);
ts->ts_runq = &runq;
if ((td->td_flags & TDF_NOLOAD) == 0)
sched_load_add();
runq_add(ts->ts_runq, td, flags);
if (!maybe_preempt(td))
maybe_resched(td);
}
#endif /* SMP */
void
sched_rem(struct thread *td)
{
struct td_sched *ts;
ts = td_get_sched(td);
KASSERT(td->td_flags & TDF_INMEM,
("sched_rem: thread swapped out"));
KASSERT(TD_ON_RUNQ(td),
("sched_rem: thread not on run queue"));
mtx_assert(&sched_lock, MA_OWNED);
KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq rem",
"prio:%d", td->td_priority, KTR_ATTR_LINKED,
sched_tdname(curthread));
SDT_PROBE3(sched, , , dequeue, td, td->td_proc, NULL);
if ((td->td_flags & TDF_NOLOAD) == 0)
sched_load_rem();
#ifdef SMP
if (ts->ts_runq != &runq)
runq_length[ts->ts_runq - runq_pcpu]--;
#endif
runq_remove(ts->ts_runq, td);
TD_SET_CAN_RUN(td);
}
/*
* Select threads to run. Note that running threads still consume a
* slot.
*/
struct thread *
sched_choose(void)
{
struct thread *td;
struct runq *rq;
mtx_assert(&sched_lock, MA_OWNED);
#ifdef SMP
struct thread *tdcpu;
rq = &runq;
td = runq_choose_fuzz(&runq, runq_fuzz);
tdcpu = runq_choose(&runq_pcpu[PCPU_GET(cpuid)]);
if (td == NULL ||
(tdcpu != NULL &&
tdcpu->td_priority < td->td_priority)) {
CTR2(KTR_RUNQ, "choosing td %p from pcpu runq %d", tdcpu,
PCPU_GET(cpuid));
td = tdcpu;
rq = &runq_pcpu[PCPU_GET(cpuid)];
} else {
CTR1(KTR_RUNQ, "choosing td_sched %p from main runq", td);
}
#else
rq = &runq;
td = runq_choose(&runq);
#endif
if (td) {
#ifdef SMP
if (td == tdcpu)
runq_length[PCPU_GET(cpuid)]--;
#endif
runq_remove(rq, td);
td->td_flags |= TDF_DIDRUN;
KASSERT(td->td_flags & TDF_INMEM,
("sched_choose: thread swapped out"));
return (td);
}
return (PCPU_GET(idlethread));
}
void
sched_preempt(struct thread *td)
{
SDT_PROBE2(sched, , , surrender, td, td->td_proc);
thread_lock(td);
if (td->td_critnest > 1)
td->td_owepreempt = 1;
else
mi_switch(SW_INVOL | SW_PREEMPT | SWT_PREEMPT, NULL);
thread_unlock(td);
}
void
sched_userret_slowpath(struct thread *td)
{
thread_lock(td);
td->td_priority = td->td_user_pri;
td->td_base_pri = td->td_user_pri;
thread_unlock(td);
}
void
sched_bind(struct thread *td, int cpu)
{
struct td_sched *ts;
THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED);
KASSERT(td == curthread, ("sched_bind: can only bind curthread"));
ts = td_get_sched(td);
td->td_flags |= TDF_BOUND;
#ifdef SMP
ts->ts_runq = &runq_pcpu[cpu];
if (PCPU_GET(cpuid) == cpu)
return;
mi_switch(SW_VOL, NULL);
#endif
}
void
sched_unbind(struct thread* td)
{
THREAD_LOCK_ASSERT(td, MA_OWNED);
KASSERT(td == curthread, ("sched_unbind: can only bind curthread"));
td->td_flags &= ~TDF_BOUND;
}
int
sched_is_bound(struct thread *td)
{
THREAD_LOCK_ASSERT(td, MA_OWNED);
return (td->td_flags & TDF_BOUND);
}
void
sched_relinquish(struct thread *td)
{
thread_lock(td);
mi_switch(SW_VOL | SWT_RELINQUISH, NULL);
thread_unlock(td);
}
int
sched_load(void)
{
return (sched_tdcnt);
}
int
sched_sizeof_proc(void)
{
return (sizeof(struct proc));
}
int
sched_sizeof_thread(void)
{
return (sizeof(struct thread) + sizeof(struct td_sched));
}
fixpt_t
sched_pctcpu(struct thread *td)
{
struct td_sched *ts;
THREAD_LOCK_ASSERT(td, MA_OWNED);
ts = td_get_sched(td);
return (ts->ts_pctcpu);
}
#ifdef RACCT
/*
* Calculates the contribution to the thread cpu usage for the latest
* (unfinished) second.
*/
fixpt_t
sched_pctcpu_delta(struct thread *td)
{
struct td_sched *ts;
fixpt_t delta;
int realstathz;
THREAD_LOCK_ASSERT(td, MA_OWNED);
ts = td_get_sched(td);
delta = 0;
realstathz = stathz ? stathz : hz;
if (ts->ts_cpticks != 0) {
#if (FSHIFT >= CCPU_SHIFT)
delta = (realstathz == 100)
? ((fixpt_t) ts->ts_cpticks) <<
(FSHIFT - CCPU_SHIFT) :
100 * (((fixpt_t) ts->ts_cpticks)
<< (FSHIFT - CCPU_SHIFT)) / realstathz;
#else
delta = ((FSCALE - ccpu) *
(ts->ts_cpticks *
FSCALE / realstathz)) >> FSHIFT;
#endif
}
return (delta);
}
#endif
u_int
sched_estcpu(struct thread *td)
{
return (td_get_sched(td)->ts_estcpu);
}
/*
* The actual idle process.
*/
void
sched_idletd(void *dummy)
{
struct pcpuidlestat *stat;
THREAD_NO_SLEEPING();
stat = DPCPU_PTR(idlestat);
for (;;) {
mtx_assert(&Giant, MA_NOTOWNED);
while (sched_runnable() == 0) {
cpu_idle(stat->idlecalls + stat->oldidlecalls > 64);
stat->idlecalls++;
}
mtx_lock_spin(&sched_lock);
mi_switch(SW_VOL | SWT_IDLE, NULL);
mtx_unlock_spin(&sched_lock);
}
}
/*
* A CPU is entering for the first time or a thread is exiting.
*/
void
sched_throw(struct thread *td)
{
/*
* Correct spinlock nesting. The idle thread context that we are
* borrowing was created so that it would start out with a single
* spin lock (sched_lock) held in fork_trampoline(). Since we've
* explicitly acquired locks in this function, the nesting count
* is now 2 rather than 1. Since we are nested, calling
* spinlock_exit() will simply adjust the counts without allowing
* spin lock using code to interrupt us.
*/
if (td == NULL) {
mtx_lock_spin(&sched_lock);
spinlock_exit();
PCPU_SET(switchtime, cpu_ticks());
PCPU_SET(switchticks, ticks);
} else {
lock_profile_release_lock(&sched_lock.lock_object);
MPASS(td->td_lock == &sched_lock);
td->td_lastcpu = td->td_oncpu;
td->td_oncpu = NOCPU;
}
mtx_assert(&sched_lock, MA_OWNED);
KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count"));
cpu_throw(td, choosethread()); /* doesn't return */
}
void
sched_fork_exit(struct thread *td)
{
/*
* Finish setting up thread glue so that it begins execution in a
* non-nested critical section with sched_lock held but not recursed.
*/
td->td_oncpu = PCPU_GET(cpuid);
sched_lock.mtx_lock = (uintptr_t)td;
lock_profile_obtain_lock_success(&sched_lock.lock_object,
0, 0, __FILE__, __LINE__);
THREAD_LOCK_ASSERT(td, MA_OWNED | MA_NOTRECURSED);
KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "running",
"prio:%d", td->td_priority);
SDT_PROBE0(sched, , , on__cpu);
}
char *
sched_tdname(struct thread *td)
{
#ifdef KTR
struct td_sched *ts;
ts = td_get_sched(td);
if (ts->ts_name[0] == '\0')
snprintf(ts->ts_name, sizeof(ts->ts_name),
"%s tid %d", td->td_name, td->td_tid);
return (ts->ts_name);
#else
return (td->td_name);
#endif
}
#ifdef KTR
void
sched_clear_tdname(struct thread *td)
{
struct td_sched *ts;
ts = td_get_sched(td);
ts->ts_name[0] = '\0';
}
#endif
void
sched_affinity(struct thread *td)
{
#ifdef SMP
struct td_sched *ts;
int cpu;
THREAD_LOCK_ASSERT(td, MA_OWNED);
/*
* Set the TSF_AFFINITY flag if there is at least one CPU this
* thread can't run on.
*/
ts = td_get_sched(td);
ts->ts_flags &= ~TSF_AFFINITY;
CPU_FOREACH(cpu) {
if (!THREAD_CAN_SCHED(td, cpu)) {
ts->ts_flags |= TSF_AFFINITY;
break;
}
}
/*
* If this thread can run on all CPUs, nothing else to do.
*/
if (!(ts->ts_flags & TSF_AFFINITY))
return;
/* Pinned threads and bound threads should be left alone. */
if (td->td_pinned != 0 || td->td_flags & TDF_BOUND)
return;
switch (td->td_state) {
case TDS_RUNQ:
/*
* If we are on a per-CPU runqueue that is in the set,
* then nothing needs to be done.
*/
if (ts->ts_runq != &runq &&
THREAD_CAN_SCHED(td, ts->ts_runq - runq_pcpu))
return;
/* Put this thread on a valid per-CPU runqueue. */
sched_rem(td);
sched_add(td, SRQ_BORING);
break;
case TDS_RUNNING:
/*
* See if our current CPU is in the set. If not, force a
* context switch.
*/
if (THREAD_CAN_SCHED(td, td->td_oncpu))
return;
td->td_flags |= TDF_NEEDRESCHED;
if (td != curthread)
ipi_cpu(cpu, IPI_AST);
break;
default:
break;
}
#endif
}
Index: head/sys/kern/sched_ule.c
===================================================================
--- head/sys/kern/sched_ule.c (revision 347354)
+++ head/sys/kern/sched_ule.c (revision 347355)
@@ -1,3074 +1,3095 @@
/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2002-2007, Jeffrey Roberson <jeff@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* This file implements the ULE scheduler. ULE supports independent CPU
* run queues and fine grain locking. It has superior interactive
* performance under load even on uni-processor systems.
*
* etymology:
* ULE is the last three letters in schedule. It owes its name to a
* generic user created for a scheduling system by Paul Mikesell at
* Isilon Systems and a general lack of creativity on the part of the author.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_hwpmc_hooks.h"
#include "opt_sched.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resource.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/sdt.h>
#include <sys/smp.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/sysproto.h>
#include <sys/turnstile.h>
#include <sys/umtx.h>
#include <sys/vmmeter.h>
#include <sys/cpuset.h>
#include <sys/sbuf.h>
#ifdef HWPMC_HOOKS
#include <sys/pmckern.h>
#endif
#ifdef KDTRACE_HOOKS
#include <sys/dtrace_bsd.h>
int dtrace_vtime_active;
dtrace_vtime_switch_func_t dtrace_vtime_switch_func;
#endif
#include <machine/cpu.h>
#include <machine/smp.h>
#define KTR_ULE 0
#define TS_NAME_LEN (MAXCOMLEN + sizeof(" td ") + sizeof(__XSTRING(UINT_MAX)))
#define TDQ_NAME_LEN (sizeof("sched lock ") + sizeof(__XSTRING(MAXCPU)))
#define TDQ_LOADNAME_LEN (sizeof("CPU ") + sizeof(__XSTRING(MAXCPU)) - 1 + sizeof(" load"))
/*
* Thread scheduler specific section. All fields are protected
* by the thread lock.
*/
struct td_sched {
struct runq *ts_runq; /* Run-queue we're queued on. */
short ts_flags; /* TSF_* flags. */
int ts_cpu; /* CPU that we have affinity for. */
int ts_rltick; /* Real last tick, for affinity. */
int ts_slice; /* Ticks of slice remaining. */
u_int ts_slptime; /* Number of ticks we vol. slept */
u_int ts_runtime; /* Number of ticks we were running */
int ts_ltick; /* Last tick that we were running on */
int ts_ftick; /* First tick that we were running on */
int ts_ticks; /* Tick count */
#ifdef KTR
char ts_name[TS_NAME_LEN];
#endif
};
/* flags kept in ts_flags */
#define TSF_BOUND 0x0001 /* Thread can not migrate. */
#define TSF_XFERABLE 0x0002 /* Thread was added as transferable. */
#define THREAD_CAN_MIGRATE(td) ((td)->td_pinned == 0)
#define THREAD_CAN_SCHED(td, cpu) \
CPU_ISSET((cpu), &(td)->td_cpuset->cs_mask)
_Static_assert(sizeof(struct thread) + sizeof(struct td_sched) <=
sizeof(struct thread0_storage),
"increase struct thread0_storage.t0st_sched size");
/*
* Priority ranges used for interactive and non-interactive timeshare
* threads. The timeshare priorities are split up into four ranges.
* The first range handles interactive threads. The last three ranges
* (NHALF, x, and NHALF) handle non-interactive threads with the outer
* ranges supporting nice values.
*/
#define PRI_TIMESHARE_RANGE (PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE + 1)
#define PRI_INTERACT_RANGE ((PRI_TIMESHARE_RANGE - SCHED_PRI_NRESV) / 2)
#define PRI_BATCH_RANGE (PRI_TIMESHARE_RANGE - PRI_INTERACT_RANGE)
#define PRI_MIN_INTERACT PRI_MIN_TIMESHARE
#define PRI_MAX_INTERACT (PRI_MIN_TIMESHARE + PRI_INTERACT_RANGE - 1)
#define PRI_MIN_BATCH (PRI_MIN_TIMESHARE + PRI_INTERACT_RANGE)
#define PRI_MAX_BATCH PRI_MAX_TIMESHARE
/*
* Cpu percentage computation macros and defines.
*
* SCHED_TICK_SECS: Number of seconds to average the cpu usage across.
* SCHED_TICK_TARG: Number of hz ticks to average the cpu usage across.
* SCHED_TICK_MAX: Maximum number of ticks before scaling back.
* SCHED_TICK_SHIFT: Shift factor to avoid rounding away results.
* SCHED_TICK_HZ: Compute the number of hz ticks for a given ticks count.
* SCHED_TICK_TOTAL: Gives the amount of time we've been recording ticks.
*/
#define SCHED_TICK_SECS 10
#define SCHED_TICK_TARG (hz * SCHED_TICK_SECS)
#define SCHED_TICK_MAX (SCHED_TICK_TARG + hz)
#define SCHED_TICK_SHIFT 10
#define SCHED_TICK_HZ(ts) ((ts)->ts_ticks >> SCHED_TICK_SHIFT)
#define SCHED_TICK_TOTAL(ts) (max((ts)->ts_ltick - (ts)->ts_ftick, hz))
/*
* These macros determine priorities for non-interactive threads. They are
* assigned a priority based on their recent cpu utilization as expressed
* by the ratio of ticks to the tick total. NHALF priorities at the start
* and end of the MIN to MAX timeshare range are only reachable with negative
* or positive nice respectively.
*
* PRI_RANGE: Priority range for utilization dependent priorities.
* PRI_NRESV: Number of nice values.
* PRI_TICKS: Compute a priority in PRI_RANGE from the ticks count and total.
* PRI_NICE: Determines the part of the priority inherited from nice.
*/
#define SCHED_PRI_NRESV (PRIO_MAX - PRIO_MIN)
#define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2)
#define SCHED_PRI_MIN (PRI_MIN_BATCH + SCHED_PRI_NHALF)
#define SCHED_PRI_MAX (PRI_MAX_BATCH - SCHED_PRI_NHALF)
#define SCHED_PRI_RANGE (SCHED_PRI_MAX - SCHED_PRI_MIN + 1)
#define SCHED_PRI_TICKS(ts) \
(SCHED_TICK_HZ((ts)) / \
(roundup(SCHED_TICK_TOTAL((ts)), SCHED_PRI_RANGE) / SCHED_PRI_RANGE))
#define SCHED_PRI_NICE(nice) (nice)
/*
* These determine the interactivity of a process. Interactivity differs from
* cpu utilization in that it expresses the voluntary time slept vs time ran
* while cpu utilization includes all time not running. This more accurately
* models the intent of the thread.
*
* SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate
* before throttling back.
* SLP_RUN_FORK: Maximum slp+run time to inherit at fork time.
* INTERACT_MAX: Maximum interactivity value. Smaller is better.
* INTERACT_THRESH: Threshold for placement on the current runq.
*/
#define SCHED_SLP_RUN_MAX ((hz * 5) << SCHED_TICK_SHIFT)
#define SCHED_SLP_RUN_FORK ((hz / 2) << SCHED_TICK_SHIFT)
#define SCHED_INTERACT_MAX (100)
#define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2)
#define SCHED_INTERACT_THRESH (30)
/*
* These parameters determine the slice behavior for batch work.
*/
#define SCHED_SLICE_DEFAULT_DIVISOR 10 /* ~94 ms, 12 stathz ticks. */
#define SCHED_SLICE_MIN_DIVISOR 6 /* DEFAULT/MIN = ~16 ms. */
/* Flags kept in td_flags. */
#define TDF_SLICEEND TDF_SCHED2 /* Thread time slice is over. */
/*
* tickincr: Converts a stathz tick into a hz domain scaled by
* the shift factor. Without the shift the error rate
* due to rounding would be unacceptably high.
* realstathz: stathz is sometimes 0 and run off of hz.
* sched_slice: Runtime of each thread before rescheduling.
* preempt_thresh: Priority threshold for preemption and remote IPIs.
*/
static int sched_interact = SCHED_INTERACT_THRESH;
static int tickincr = 8 << SCHED_TICK_SHIFT;
static int realstathz = 127; /* reset during boot. */
static int sched_slice = 10; /* reset during boot. */
static int sched_slice_min = 1; /* reset during boot. */
#ifdef PREEMPTION
#ifdef FULL_PREEMPTION
static int preempt_thresh = PRI_MAX_IDLE;
#else
static int preempt_thresh = PRI_MIN_KERN;
#endif
#else
static int preempt_thresh = 0;
#endif
static int static_boost = PRI_MIN_BATCH;
static int sched_idlespins = 10000;
static int sched_idlespinthresh = -1;
/*
* tdq - per processor runqs and statistics. All fields are protected by the
* tdq_lock. The load and lowpri may be accessed without to avoid excess
* locking in sched_pickcpu();
*/
struct tdq {
/*
* Ordered to improve efficiency of cpu_search() and switch().
* tdq_lock is padded to avoid false sharing with tdq_load and
* tdq_cpu_idle.
*/
struct mtx_padalign tdq_lock; /* run queue lock. */
struct cpu_group *tdq_cg; /* Pointer to cpu topology. */
volatile int tdq_load; /* Aggregate load. */
volatile int tdq_cpu_idle; /* cpu_idle() is active. */
int tdq_sysload; /* For loadavg, !ITHD load. */
volatile int tdq_transferable; /* Transferable thread count. */
volatile short tdq_switchcnt; /* Switches this tick. */
volatile short tdq_oldswitchcnt; /* Switches last tick. */
u_char tdq_lowpri; /* Lowest priority thread. */
u_char tdq_ipipending; /* IPI pending. */
u_char tdq_idx; /* Current insert index. */
u_char tdq_ridx; /* Current removal index. */
struct runq tdq_realtime; /* real-time run queue. */
struct runq tdq_timeshare; /* timeshare run queue. */
struct runq tdq_idle; /* Queue of IDLE threads. */
char tdq_name[TDQ_NAME_LEN];
#ifdef KTR
char tdq_loadname[TDQ_LOADNAME_LEN];
#endif
} __aligned(64);
/* Idle thread states and config. */
#define TDQ_RUNNING 1
#define TDQ_IDLE 2
#ifdef SMP
struct cpu_group *cpu_top; /* CPU topology */
#define SCHED_AFFINITY_DEFAULT (max(1, hz / 1000))
#define SCHED_AFFINITY(ts, t) ((ts)->ts_rltick > ticks - ((t) * affinity))
/*
* Run-time tunables.
*/
static int rebalance = 1;
static int balance_interval = 128; /* Default set in sched_initticks(). */
static int affinity;
static int steal_idle = 1;
static int steal_thresh = 2;
static int always_steal = 0;
static int trysteal_limit = 2;
/*
* One thread queue per processor.
*/
static struct tdq tdq_cpu[MAXCPU];
static struct tdq *balance_tdq;
static int balance_ticks;
DPCPU_DEFINE_STATIC(uint32_t, randomval);
#define TDQ_SELF() (&tdq_cpu[PCPU_GET(cpuid)])
#define TDQ_CPU(x) (&tdq_cpu[(x)])
#define TDQ_ID(x) ((int)((x) - tdq_cpu))
#else /* !SMP */
static struct tdq tdq_cpu;
#define TDQ_ID(x) (0)
#define TDQ_SELF() (&tdq_cpu)
#define TDQ_CPU(x) (&tdq_cpu)
#endif
#define TDQ_LOCK_ASSERT(t, type) mtx_assert(TDQ_LOCKPTR((t)), (type))
#define TDQ_LOCK(t) mtx_lock_spin(TDQ_LOCKPTR((t)))
#define TDQ_LOCK_FLAGS(t, f) mtx_lock_spin_flags(TDQ_LOCKPTR((t)), (f))
#define TDQ_UNLOCK(t) mtx_unlock_spin(TDQ_LOCKPTR((t)))
#define TDQ_LOCKPTR(t) ((struct mtx *)(&(t)->tdq_lock))
static void sched_priority(struct thread *);
static void sched_thread_priority(struct thread *, u_char);
static int sched_interact_score(struct thread *);
static void sched_interact_update(struct thread *);
static void sched_interact_fork(struct thread *);
static void sched_pctcpu_update(struct td_sched *, int);
/* Operations on per processor queues */
static struct thread *tdq_choose(struct tdq *);
static void tdq_setup(struct tdq *);
static void tdq_load_add(struct tdq *, struct thread *);
static void tdq_load_rem(struct tdq *, struct thread *);
static __inline void tdq_runq_add(struct tdq *, struct thread *, int);
static __inline void tdq_runq_rem(struct tdq *, struct thread *);
static inline int sched_shouldpreempt(int, int, int);
void tdq_print(int cpu);
static void runq_print(struct runq *rq);
static void tdq_add(struct tdq *, struct thread *, int);
#ifdef SMP
static struct thread *tdq_move(struct tdq *, struct tdq *);
static int tdq_idled(struct tdq *);
static void tdq_notify(struct tdq *, struct thread *);
static struct thread *tdq_steal(struct tdq *, int);
static struct thread *runq_steal(struct runq *, int);
static int sched_pickcpu(struct thread *, int);
static void sched_balance(void);
static int sched_balance_pair(struct tdq *, struct tdq *);
static inline struct tdq *sched_setcpu(struct thread *, int, int);
static inline void thread_unblock_switch(struct thread *, struct mtx *);
static struct mtx *sched_switch_migrate(struct tdq *, struct thread *, int);
static int sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS);
static int sysctl_kern_sched_topology_spec_internal(struct sbuf *sb,
struct cpu_group *cg, int indent);
#endif
static void sched_setup(void *dummy);
SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL);
static void sched_initticks(void *dummy);
SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks,
NULL);
SDT_PROVIDER_DEFINE(sched);
SDT_PROBE_DEFINE3(sched, , , change__pri, "struct thread *",
"struct proc *", "uint8_t");
SDT_PROBE_DEFINE3(sched, , , dequeue, "struct thread *",
"struct proc *", "void *");
SDT_PROBE_DEFINE4(sched, , , enqueue, "struct thread *",
"struct proc *", "void *", "int");
SDT_PROBE_DEFINE4(sched, , , lend__pri, "struct thread *",
"struct proc *", "uint8_t", "struct thread *");
SDT_PROBE_DEFINE2(sched, , , load__change, "int", "int");
SDT_PROBE_DEFINE2(sched, , , off__cpu, "struct thread *",
"struct proc *");
SDT_PROBE_DEFINE(sched, , , on__cpu);
SDT_PROBE_DEFINE(sched, , , remain__cpu);
SDT_PROBE_DEFINE2(sched, , , surrender, "struct thread *",
"struct proc *");
/*
* Print the threads waiting on a run-queue.
*/
static void
runq_print(struct runq *rq)
{
struct rqhead *rqh;
struct thread *td;
int pri;
int j;
int i;
for (i = 0; i < RQB_LEN; i++) {
printf("\t\trunq bits %d 0x%zx\n",
i, rq->rq_status.rqb_bits[i]);
for (j = 0; j < RQB_BPW; j++)
if (rq->rq_status.rqb_bits[i] & (1ul << j)) {
pri = j + (i << RQB_L2BPW);
rqh = &rq->rq_queues[pri];
TAILQ_FOREACH(td, rqh, td_runq) {
printf("\t\t\ttd %p(%s) priority %d rqindex %d pri %d\n",
td, td->td_name, td->td_priority,
td->td_rqindex, pri);
}
}
}
}
/*
* Print the status of a per-cpu thread queue. Should be a ddb show cmd.
*/
void
tdq_print(int cpu)
{
struct tdq *tdq;
tdq = TDQ_CPU(cpu);
printf("tdq %d:\n", TDQ_ID(tdq));
printf("\tlock %p\n", TDQ_LOCKPTR(tdq));
printf("\tLock name: %s\n", tdq->tdq_name);
printf("\tload: %d\n", tdq->tdq_load);
printf("\tswitch cnt: %d\n", tdq->tdq_switchcnt);
printf("\told switch cnt: %d\n", tdq->tdq_oldswitchcnt);
printf("\ttimeshare idx: %d\n", tdq->tdq_idx);
printf("\ttimeshare ridx: %d\n", tdq->tdq_ridx);
printf("\tload transferable: %d\n", tdq->tdq_transferable);
printf("\tlowest priority: %d\n", tdq->tdq_lowpri);
printf("\trealtime runq:\n");
runq_print(&tdq->tdq_realtime);
printf("\ttimeshare runq:\n");
runq_print(&tdq->tdq_timeshare);
printf("\tidle runq:\n");
runq_print(&tdq->tdq_idle);
}
static inline int
sched_shouldpreempt(int pri, int cpri, int remote)
{
/*
* If the new priority is not better than the current priority there is
* nothing to do.
*/
if (pri >= cpri)
return (0);
/*
* Always preempt idle.
*/
if (cpri >= PRI_MIN_IDLE)
return (1);
/*
* If preemption is disabled don't preempt others.
*/
if (preempt_thresh == 0)
return (0);
/*
* Preempt if we exceed the threshold.
*/
if (pri <= preempt_thresh)
return (1);
/*
* If we're interactive or better and there is non-interactive
* or worse running preempt only remote processors.
*/
if (remote && pri <= PRI_MAX_INTERACT && cpri > PRI_MAX_INTERACT)
return (1);
return (0);
}
/*
* Add a thread to the actual run-queue. Keeps transferable counts up to
* date with what is actually on the run-queue. Selects the correct
* queue position for timeshare threads.
*/
static __inline void
tdq_runq_add(struct tdq *tdq, struct thread *td, int flags)
{
struct td_sched *ts;
u_char pri;
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
THREAD_LOCK_ASSERT(td, MA_OWNED);
pri = td->td_priority;
ts = td_get_sched(td);
TD_SET_RUNQ(td);
if (THREAD_CAN_MIGRATE(td)) {
tdq->tdq_transferable++;
ts->ts_flags |= TSF_XFERABLE;
}
if (pri < PRI_MIN_BATCH) {
ts->ts_runq = &tdq->tdq_realtime;
} else if (pri <= PRI_MAX_BATCH) {
ts->ts_runq = &tdq->tdq_timeshare;
KASSERT(pri <= PRI_MAX_BATCH && pri >= PRI_MIN_BATCH,
("Invalid priority %d on timeshare runq", pri));
/*
* This queue contains only priorities between MIN and MAX
* realtime. Use the whole queue to represent these values.
*/
if ((flags & (SRQ_BORROWING|SRQ_PREEMPTED)) == 0) {
pri = RQ_NQS * (pri - PRI_MIN_BATCH) / PRI_BATCH_RANGE;
pri = (pri + tdq->tdq_idx) % RQ_NQS;
/*
* This effectively shortens the queue by one so we
* can have a one slot difference between idx and
* ridx while we wait for threads to drain.
*/
if (tdq->tdq_ridx != tdq->tdq_idx &&
pri == tdq->tdq_ridx)
pri = (unsigned char)(pri - 1) % RQ_NQS;
} else
pri = tdq->tdq_ridx;
runq_add_pri(ts->ts_runq, td, pri, flags);
return;
} else
ts->ts_runq = &tdq->tdq_idle;
runq_add(ts->ts_runq, td, flags);
}
/*
* Remove a thread from a run-queue. This typically happens when a thread
* is selected to run. Running threads are not on the queue and the
* transferable count does not reflect them.
*/
static __inline void
tdq_runq_rem(struct tdq *tdq, struct thread *td)
{
struct td_sched *ts;
ts = td_get_sched(td);
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
KASSERT(ts->ts_runq != NULL,
("tdq_runq_remove: thread %p null ts_runq", td));
if (ts->ts_flags & TSF_XFERABLE) {
tdq->tdq_transferable--;
ts->ts_flags &= ~TSF_XFERABLE;
}
if (ts->ts_runq == &tdq->tdq_timeshare) {
if (tdq->tdq_idx != tdq->tdq_ridx)
runq_remove_idx(ts->ts_runq, td, &tdq->tdq_ridx);
else
runq_remove_idx(ts->ts_runq, td, NULL);
} else
runq_remove(ts->ts_runq, td);
}
/*
* Load is maintained for all threads RUNNING and ON_RUNQ. Add the load
* for this thread to the referenced thread queue.
*/
static void
tdq_load_add(struct tdq *tdq, struct thread *td)
{
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
THREAD_LOCK_ASSERT(td, MA_OWNED);
tdq->tdq_load++;
if ((td->td_flags & TDF_NOLOAD) == 0)
tdq->tdq_sysload++;
KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load);
SDT_PROBE2(sched, , , load__change, (int)TDQ_ID(tdq), tdq->tdq_load);
}
/*
* Remove the load from a thread that is transitioning to a sleep state or
* exiting.
*/
static void
tdq_load_rem(struct tdq *tdq, struct thread *td)
{
THREAD_LOCK_ASSERT(td, MA_OWNED);
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
KASSERT(tdq->tdq_load != 0,
("tdq_load_rem: Removing with 0 load on queue %d", TDQ_ID(tdq)));
tdq->tdq_load--;
if ((td->td_flags & TDF_NOLOAD) == 0)
tdq->tdq_sysload--;
KTR_COUNTER0(KTR_SCHED, "load", tdq->tdq_loadname, tdq->tdq_load);
SDT_PROBE2(sched, , , load__change, (int)TDQ_ID(tdq), tdq->tdq_load);
}
/*
* Bound timeshare latency by decreasing slice size as load increases. We
* consider the maximum latency as the sum of the threads waiting to run
* aside from curthread and target no more than sched_slice latency but
* no less than sched_slice_min runtime.
*/
static inline int
tdq_slice(struct tdq *tdq)
{
int load;
/*
* It is safe to use sys_load here because this is called from
* contexts where timeshare threads are running and so there
* cannot be higher priority load in the system.
*/
load = tdq->tdq_sysload - 1;
if (load >= SCHED_SLICE_MIN_DIVISOR)
return (sched_slice_min);
if (load <= 1)
return (sched_slice);
return (sched_slice / load);
}
/*
* Set lowpri to its exact value by searching the run-queue and
* evaluating curthread. curthread may be passed as an optimization.
*/
static void
tdq_setlowpri(struct tdq *tdq, struct thread *ctd)
{
struct thread *td;
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
if (ctd == NULL)
ctd = pcpu_find(TDQ_ID(tdq))->pc_curthread;
td = tdq_choose(tdq);
if (td == NULL || td->td_priority > ctd->td_priority)
tdq->tdq_lowpri = ctd->td_priority;
else
tdq->tdq_lowpri = td->td_priority;
}
#ifdef SMP
/*
* We need some randomness. Implement a classic Linear Congruential
* Generator X_{n+1}=(aX_n+c) mod m. These values are optimized for
* m = 2^32, a = 69069 and c = 5. We only return the upper 16 bits
* of the random state (in the low bits of our answer) to keep
* the maximum randomness.
*/
static uint32_t
sched_random(void)
{
uint32_t *rndptr;
rndptr = DPCPU_PTR(randomval);
*rndptr = *rndptr * 69069 + 5;
return (*rndptr >> 16);
}
struct cpu_search {
cpuset_t cs_mask;
u_int cs_prefer;
int cs_pri; /* Min priority for low. */
int cs_limit; /* Max load for low, min load for high. */
int cs_cpu;
int cs_load;
};
#define CPU_SEARCH_LOWEST 0x1
#define CPU_SEARCH_HIGHEST 0x2
#define CPU_SEARCH_BOTH (CPU_SEARCH_LOWEST|CPU_SEARCH_HIGHEST)
#define CPUSET_FOREACH(cpu, mask) \
for ((cpu) = 0; (cpu) <= mp_maxid; (cpu)++) \
if (CPU_ISSET(cpu, &mask))
static __always_inline int cpu_search(const struct cpu_group *cg,
struct cpu_search *low, struct cpu_search *high, const int match);
int __noinline cpu_search_lowest(const struct cpu_group *cg,
struct cpu_search *low);
int __noinline cpu_search_highest(const struct cpu_group *cg,
struct cpu_search *high);
int __noinline cpu_search_both(const struct cpu_group *cg,
struct cpu_search *low, struct cpu_search *high);
/*
* Search the tree of cpu_groups for the lowest or highest loaded cpu
* according to the match argument. This routine actually compares the
* load on all paths through the tree and finds the least loaded cpu on
* the least loaded path, which may differ from the least loaded cpu in
* the system. This balances work among caches and buses.
*
* This inline is instantiated in three forms below using constants for the
* match argument. It is reduced to the minimum set for each case. It is
* also recursive to the depth of the tree.
*/
static __always_inline int
cpu_search(const struct cpu_group *cg, struct cpu_search *low,
struct cpu_search *high, const int match)
{
struct cpu_search lgroup;
struct cpu_search hgroup;
cpuset_t cpumask;
struct cpu_group *child;
struct tdq *tdq;
int cpu, i, hload, lload, load, total, rnd;
total = 0;
cpumask = cg->cg_mask;
if (match & CPU_SEARCH_LOWEST) {
lload = INT_MAX;
lgroup = *low;
}
if (match & CPU_SEARCH_HIGHEST) {
hload = INT_MIN;
hgroup = *high;
}
/* Iterate through the child CPU groups and then remaining CPUs. */
for (i = cg->cg_children, cpu = mp_maxid; ; ) {
if (i == 0) {
#ifdef HAVE_INLINE_FFSL
cpu = CPU_FFS(&cpumask) - 1;
#else
while (cpu >= 0 && !CPU_ISSET(cpu, &cpumask))
cpu--;
#endif
if (cpu < 0)
break;
child = NULL;
} else
child = &cg->cg_child[i - 1];
if (match & CPU_SEARCH_LOWEST)
lgroup.cs_cpu = -1;
if (match & CPU_SEARCH_HIGHEST)
hgroup.cs_cpu = -1;
if (child) { /* Handle child CPU group. */
CPU_NAND(&cpumask, &child->cg_mask);
switch (match) {
case CPU_SEARCH_LOWEST:
load = cpu_search_lowest(child, &lgroup);
break;
case CPU_SEARCH_HIGHEST:
load = cpu_search_highest(child, &hgroup);
break;
case CPU_SEARCH_BOTH:
load = cpu_search_both(child, &lgroup, &hgroup);
break;
}
} else { /* Handle child CPU. */
CPU_CLR(cpu, &cpumask);
tdq = TDQ_CPU(cpu);
load = tdq->tdq_load * 256;
rnd = sched_random() % 32;
if (match & CPU_SEARCH_LOWEST) {
if (cpu == low->cs_prefer)
load -= 64;
/* If that CPU is allowed and get data. */
if (tdq->tdq_lowpri > lgroup.cs_pri &&
tdq->tdq_load <= lgroup.cs_limit &&
CPU_ISSET(cpu, &lgroup.cs_mask)) {
lgroup.cs_cpu = cpu;
lgroup.cs_load = load - rnd;
}
}
if (match & CPU_SEARCH_HIGHEST)
if (tdq->tdq_load >= hgroup.cs_limit &&
tdq->tdq_transferable &&
CPU_ISSET(cpu, &hgroup.cs_mask)) {
hgroup.cs_cpu = cpu;
hgroup.cs_load = load - rnd;
}
}
total += load;
/* We have info about child item. Compare it. */
if (match & CPU_SEARCH_LOWEST) {
if (lgroup.cs_cpu >= 0 &&
(load < lload ||
(load == lload && lgroup.cs_load < low->cs_load))) {
lload = load;
low->cs_cpu = lgroup.cs_cpu;
low->cs_load = lgroup.cs_load;
}
}
if (match & CPU_SEARCH_HIGHEST)
if (hgroup.cs_cpu >= 0 &&
(load > hload ||
(load == hload && hgroup.cs_load > high->cs_load))) {
hload = load;
high->cs_cpu = hgroup.cs_cpu;
high->cs_load = hgroup.cs_load;
}
if (child) {
i--;
if (i == 0 && CPU_EMPTY(&cpumask))
break;
}
#ifndef HAVE_INLINE_FFSL
else
cpu--;
#endif
}
return (total);
}
/*
* cpu_search instantiations must pass constants to maintain the inline
* optimization.
*/
int
cpu_search_lowest(const struct cpu_group *cg, struct cpu_search *low)
{
return cpu_search(cg, low, NULL, CPU_SEARCH_LOWEST);
}
int
cpu_search_highest(const struct cpu_group *cg, struct cpu_search *high)
{
return cpu_search(cg, NULL, high, CPU_SEARCH_HIGHEST);
}
int
cpu_search_both(const struct cpu_group *cg, struct cpu_search *low,
struct cpu_search *high)
{
return cpu_search(cg, low, high, CPU_SEARCH_BOTH);
}
/*
* Find the cpu with the least load via the least loaded path that has a
* lowpri greater than pri pri. A pri of -1 indicates any priority is
* acceptable.
*/
static inline int
sched_lowest(const struct cpu_group *cg, cpuset_t mask, int pri, int maxload,
int prefer)
{
struct cpu_search low;
low.cs_cpu = -1;
low.cs_prefer = prefer;
low.cs_mask = mask;
low.cs_pri = pri;
low.cs_limit = maxload;
cpu_search_lowest(cg, &low);
return low.cs_cpu;
}
/*
* Find the cpu with the highest load via the highest loaded path.
*/
static inline int
sched_highest(const struct cpu_group *cg, cpuset_t mask, int minload)
{
struct cpu_search high;
high.cs_cpu = -1;
high.cs_mask = mask;
high.cs_limit = minload;
cpu_search_highest(cg, &high);
return high.cs_cpu;
}
static void
sched_balance_group(struct cpu_group *cg)
{
cpuset_t hmask, lmask;
int high, low, anylow;
CPU_FILL(&hmask);
for (;;) {
high = sched_highest(cg, hmask, 2);
/* Stop if there is no more CPU with transferrable threads. */
if (high == -1)
break;
CPU_CLR(high, &hmask);
CPU_COPY(&hmask, &lmask);
/* Stop if there is no more CPU left for low. */
if (CPU_EMPTY(&lmask))
break;
anylow = 1;
nextlow:
low = sched_lowest(cg, lmask, -1,
TDQ_CPU(high)->tdq_load - 1, high);
/* Stop if we looked well and found no less loaded CPU. */
if (anylow && low == -1)
break;
/* Go to next high if we found no less loaded CPU. */
if (low == -1)
continue;
/* Transfer thread from high to low. */
if (sched_balance_pair(TDQ_CPU(high), TDQ_CPU(low))) {
/* CPU that got thread can no longer be a donor. */
CPU_CLR(low, &hmask);
} else {
/*
* If failed, then there is no threads on high
* that can run on this low. Drop low from low
* mask and look for different one.
*/
CPU_CLR(low, &lmask);
anylow = 0;
goto nextlow;
}
}
}
static void
sched_balance(void)
{
struct tdq *tdq;
balance_ticks = max(balance_interval / 2, 1) +
(sched_random() % balance_interval);
tdq = TDQ_SELF();
TDQ_UNLOCK(tdq);
sched_balance_group(cpu_top);
TDQ_LOCK(tdq);
}
/*
* Lock two thread queues using their address to maintain lock order.
*/
static void
tdq_lock_pair(struct tdq *one, struct tdq *two)
{
if (one < two) {
TDQ_LOCK(one);
TDQ_LOCK_FLAGS(two, MTX_DUPOK);
} else {
TDQ_LOCK(two);
TDQ_LOCK_FLAGS(one, MTX_DUPOK);
}
}
/*
* Unlock two thread queues. Order is not important here.
*/
static void
tdq_unlock_pair(struct tdq *one, struct tdq *two)
{
TDQ_UNLOCK(one);
TDQ_UNLOCK(two);
}
/*
* Transfer load between two imbalanced thread queues.
*/
static int
sched_balance_pair(struct tdq *high, struct tdq *low)
{
struct thread *td;
int cpu;
tdq_lock_pair(high, low);
td = NULL;
/*
* Transfer a thread from high to low.
*/
if (high->tdq_transferable != 0 && high->tdq_load > low->tdq_load &&
(td = tdq_move(high, low)) != NULL) {
/*
* In case the target isn't the current cpu notify it of the
* new load, possibly sending an IPI to force it to reschedule.
*/
cpu = TDQ_ID(low);
if (cpu != PCPU_GET(cpuid))
tdq_notify(low, td);
}
tdq_unlock_pair(high, low);
return (td != NULL);
}
/*
* Move a thread from one thread queue to another.
*/
static struct thread *
tdq_move(struct tdq *from, struct tdq *to)
{
struct td_sched *ts;
struct thread *td;
struct tdq *tdq;
int cpu;
TDQ_LOCK_ASSERT(from, MA_OWNED);
TDQ_LOCK_ASSERT(to, MA_OWNED);
tdq = from;
cpu = TDQ_ID(to);
td = tdq_steal(tdq, cpu);
if (td == NULL)
return (NULL);
ts = td_get_sched(td);
/*
* Although the run queue is locked the thread may be blocked. Lock
* it to clear this and acquire the run-queue lock.
*/
thread_lock(td);
/* Drop recursive lock on from acquired via thread_lock(). */
TDQ_UNLOCK(from);
sched_rem(td);
ts->ts_cpu = cpu;
td->td_lock = TDQ_LOCKPTR(to);
tdq_add(to, td, SRQ_YIELDING);
return (td);
}
/*
* This tdq has idled. Try to steal a thread from another cpu and switch
* to it.
*/
static int
tdq_idled(struct tdq *tdq)
{
struct cpu_group *cg;
struct tdq *steal;
cpuset_t mask;
int cpu, switchcnt;
if (smp_started == 0 || steal_idle == 0 || tdq->tdq_cg == NULL)
return (1);
CPU_FILL(&mask);
CPU_CLR(PCPU_GET(cpuid), &mask);
restart:
switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
for (cg = tdq->tdq_cg; ; ) {
cpu = sched_highest(cg, mask, steal_thresh);
/*
* We were assigned a thread but not preempted. Returning
* 0 here will cause our caller to switch to it.
*/
if (tdq->tdq_load)
return (0);
if (cpu == -1) {
cg = cg->cg_parent;
if (cg == NULL)
return (1);
continue;
}
steal = TDQ_CPU(cpu);
/*
* The data returned by sched_highest() is stale and
* the chosen CPU no longer has an eligible thread.
*
* Testing this ahead of tdq_lock_pair() only catches
* this situation about 20% of the time on an 8 core
* 16 thread Ryzen 7, but it still helps performance.
*/
if (steal->tdq_load < steal_thresh ||
steal->tdq_transferable == 0)
goto restart;
tdq_lock_pair(tdq, steal);
/*
* We were assigned a thread while waiting for the locks.
* Switch to it now instead of stealing a thread.
*/
if (tdq->tdq_load)
break;
/*
* The data returned by sched_highest() is stale and
* the chosen CPU no longer has an eligible thread, or
* we were preempted and the CPU loading info may be out
* of date. The latter is rare. In either case restart
* the search.
*/
if (steal->tdq_load < steal_thresh ||
steal->tdq_transferable == 0 ||
switchcnt != tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt) {
tdq_unlock_pair(tdq, steal);
goto restart;
}
/*
* Steal the thread and switch to it.
*/
if (tdq_move(steal, tdq) != NULL)
break;
/*
* We failed to acquire a thread even though it looked
* like one was available. This could be due to affinity
* restrictions or for other reasons. Loop again after
* removing this CPU from the set. The restart logic
* above does not restore this CPU to the set due to the
* likelyhood of failing here again.
*/
CPU_CLR(cpu, &mask);
tdq_unlock_pair(tdq, steal);
}
TDQ_UNLOCK(steal);
mi_switch(SW_VOL | SWT_IDLE, NULL);
thread_unlock(curthread);
return (0);
}
/*
* Notify a remote cpu of new work. Sends an IPI if criteria are met.
*/
static void
tdq_notify(struct tdq *tdq, struct thread *td)
{
struct thread *ctd;
int pri;
int cpu;
if (tdq->tdq_ipipending)
return;
cpu = td_get_sched(td)->ts_cpu;
pri = td->td_priority;
ctd = pcpu_find(cpu)->pc_curthread;
if (!sched_shouldpreempt(pri, ctd->td_priority, 1))
return;
/*
* Make sure that our caller's earlier update to tdq_load is
* globally visible before we read tdq_cpu_idle. Idle thread
* accesses both of them without locks, and the order is important.
*/
atomic_thread_fence_seq_cst();
if (TD_IS_IDLETHREAD(ctd)) {
/*
* If the MD code has an idle wakeup routine try that before
* falling back to IPI.
*/
if (!tdq->tdq_cpu_idle || cpu_idle_wakeup(cpu))
return;
}
tdq->tdq_ipipending = 1;
ipi_cpu(cpu, IPI_PREEMPT);
}
/*
* Steals load from a timeshare queue. Honors the rotating queue head
* index.
*/
static struct thread *
runq_steal_from(struct runq *rq, int cpu, u_char start)
{
struct rqbits *rqb;
struct rqhead *rqh;
struct thread *td, *first;
int bit;
int i;
rqb = &rq->rq_status;
bit = start & (RQB_BPW -1);
first = NULL;
again:
for (i = RQB_WORD(start); i < RQB_LEN; bit = 0, i++) {
if (rqb->rqb_bits[i] == 0)
continue;
if (bit == 0)
bit = RQB_FFS(rqb->rqb_bits[i]);
for (; bit < RQB_BPW; bit++) {
if ((rqb->rqb_bits[i] & (1ul << bit)) == 0)
continue;
rqh = &rq->rq_queues[bit + (i << RQB_L2BPW)];
TAILQ_FOREACH(td, rqh, td_runq) {
if (first && THREAD_CAN_MIGRATE(td) &&
THREAD_CAN_SCHED(td, cpu))
return (td);
first = td;
}
}
}
if (start != 0) {
start = 0;
goto again;
}
if (first && THREAD_CAN_MIGRATE(first) &&
THREAD_CAN_SCHED(first, cpu))
return (first);
return (NULL);
}
/*
* Steals load from a standard linear queue.
*/
static struct thread *
runq_steal(struct runq *rq, int cpu)
{
struct rqhead *rqh;
struct rqbits *rqb;
struct thread *td;
int word;
int bit;
rqb = &rq->rq_status;
for (word = 0; word < RQB_LEN; word++) {
if (rqb->rqb_bits[word] == 0)
continue;
for (bit = 0; bit < RQB_BPW; bit++) {
if ((rqb->rqb_bits[word] & (1ul << bit)) == 0)
continue;
rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)];
TAILQ_FOREACH(td, rqh, td_runq)
if (THREAD_CAN_MIGRATE(td) &&
THREAD_CAN_SCHED(td, cpu))
return (td);
}
}
return (NULL);
}
/*
* Attempt to steal a thread in priority order from a thread queue.
*/
static struct thread *
tdq_steal(struct tdq *tdq, int cpu)
{
struct thread *td;
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
if ((td = runq_steal(&tdq->tdq_realtime, cpu)) != NULL)
return (td);
if ((td = runq_steal_from(&tdq->tdq_timeshare,
cpu, tdq->tdq_ridx)) != NULL)
return (td);
return (runq_steal(&tdq->tdq_idle, cpu));
}
/*
* Sets the thread lock and ts_cpu to match the requested cpu. Unlocks the
* current lock and returns with the assigned queue locked.
*/
static inline struct tdq *
sched_setcpu(struct thread *td, int cpu, int flags)
{
struct tdq *tdq;
THREAD_LOCK_ASSERT(td, MA_OWNED);
tdq = TDQ_CPU(cpu);
td_get_sched(td)->ts_cpu = cpu;
/*
* If the lock matches just return the queue.
*/
if (td->td_lock == TDQ_LOCKPTR(tdq))
return (tdq);
#ifdef notyet
/*
* If the thread isn't running its lockptr is a
* turnstile or a sleepqueue. We can just lock_set without
* blocking.
*/
if (TD_CAN_RUN(td)) {
TDQ_LOCK(tdq);
thread_lock_set(td, TDQ_LOCKPTR(tdq));
return (tdq);
}
#endif
/*
* The hard case, migration, we need to block the thread first to
* prevent order reversals with other cpus locks.
*/
spinlock_enter();
thread_lock_block(td);
TDQ_LOCK(tdq);
thread_lock_unblock(td, TDQ_LOCKPTR(tdq));
spinlock_exit();
return (tdq);
}
SCHED_STAT_DEFINE(pickcpu_intrbind, "Soft interrupt binding");
SCHED_STAT_DEFINE(pickcpu_idle_affinity, "Picked idle cpu based on affinity");
SCHED_STAT_DEFINE(pickcpu_affinity, "Picked cpu based on affinity");
SCHED_STAT_DEFINE(pickcpu_lowest, "Selected lowest load");
SCHED_STAT_DEFINE(pickcpu_local, "Migrated to current cpu");
SCHED_STAT_DEFINE(pickcpu_migration, "Selection may have caused migration");
static int
sched_pickcpu(struct thread *td, int flags)
{
struct cpu_group *cg, *ccg;
struct td_sched *ts;
struct tdq *tdq;
cpuset_t mask;
int cpu, pri, self;
self = PCPU_GET(cpuid);
ts = td_get_sched(td);
KASSERT(!CPU_ABSENT(ts->ts_cpu), ("sched_pickcpu: Start scheduler on "
"absent CPU %d for thread %s.", ts->ts_cpu, td->td_name));
if (smp_started == 0)
return (self);
/*
* Don't migrate a running thread from sched_switch().
*/
if ((flags & SRQ_OURSELF) || !THREAD_CAN_MIGRATE(td))
return (ts->ts_cpu);
/*
* Prefer to run interrupt threads on the processors that generate
* the interrupt.
*/
pri = td->td_priority;
if (td->td_priority <= PRI_MAX_ITHD && THREAD_CAN_SCHED(td, self) &&
curthread->td_intr_nesting_level && ts->ts_cpu != self) {
SCHED_STAT_INC(pickcpu_intrbind);
ts->ts_cpu = self;
if (TDQ_CPU(self)->tdq_lowpri > pri) {
SCHED_STAT_INC(pickcpu_affinity);
return (ts->ts_cpu);
}
}
/*
* If the thread can run on the last cpu and the affinity has not
* expired and it is idle, run it there.
*/
tdq = TDQ_CPU(ts->ts_cpu);
cg = tdq->tdq_cg;
if (THREAD_CAN_SCHED(td, ts->ts_cpu) &&
tdq->tdq_lowpri >= PRI_MIN_IDLE &&
SCHED_AFFINITY(ts, CG_SHARE_L2)) {
if (cg->cg_flags & CG_FLAG_THREAD) {
CPUSET_FOREACH(cpu, cg->cg_mask) {
if (TDQ_CPU(cpu)->tdq_lowpri < PRI_MIN_IDLE)
break;
}
} else
cpu = INT_MAX;
if (cpu > mp_maxid) {
SCHED_STAT_INC(pickcpu_idle_affinity);
return (ts->ts_cpu);
}
}
/*
* Search for the last level cache CPU group in the tree.
* Skip caches with expired affinity time and SMT groups.
* Affinity to higher level caches will be handled less aggressively.
*/
for (ccg = NULL; cg != NULL; cg = cg->cg_parent) {
if (cg->cg_flags & CG_FLAG_THREAD)
continue;
if (!SCHED_AFFINITY(ts, cg->cg_level))
continue;
ccg = cg;
}
if (ccg != NULL)
cg = ccg;
cpu = -1;
/* Search the group for the less loaded idle CPU we can run now. */
mask = td->td_cpuset->cs_mask;
if (cg != NULL && cg != cpu_top &&
CPU_CMP(&cg->cg_mask, &cpu_top->cg_mask) != 0)
cpu = sched_lowest(cg, mask, max(pri, PRI_MAX_TIMESHARE),
INT_MAX, ts->ts_cpu);
/* Search globally for the less loaded CPU we can run now. */
if (cpu == -1)
cpu = sched_lowest(cpu_top, mask, pri, INT_MAX, ts->ts_cpu);
/* Search globally for the less loaded CPU. */
if (cpu == -1)
cpu = sched_lowest(cpu_top, mask, -1, INT_MAX, ts->ts_cpu);
KASSERT(cpu != -1, ("sched_pickcpu: Failed to find a cpu."));
KASSERT(!CPU_ABSENT(cpu), ("sched_pickcpu: Picked absent CPU %d.", cpu));
/*
* Compare the lowest loaded cpu to current cpu.
*/
if (THREAD_CAN_SCHED(td, self) && TDQ_CPU(self)->tdq_lowpri > pri &&
TDQ_CPU(cpu)->tdq_lowpri < PRI_MIN_IDLE &&
TDQ_CPU(self)->tdq_load <= TDQ_CPU(cpu)->tdq_load + 1) {
SCHED_STAT_INC(pickcpu_local);
cpu = self;
} else
SCHED_STAT_INC(pickcpu_lowest);
if (cpu != ts->ts_cpu)
SCHED_STAT_INC(pickcpu_migration);
return (cpu);
}
#endif
/*
* Pick the highest priority task we have and return it.
*/
static struct thread *
tdq_choose(struct tdq *tdq)
{
struct thread *td;
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
td = runq_choose(&tdq->tdq_realtime);
if (td != NULL)
return (td);
td = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx);
if (td != NULL) {
KASSERT(td->td_priority >= PRI_MIN_BATCH,
("tdq_choose: Invalid priority on timeshare queue %d",
td->td_priority));
return (td);
}
td = runq_choose(&tdq->tdq_idle);
if (td != NULL) {
KASSERT(td->td_priority >= PRI_MIN_IDLE,
("tdq_choose: Invalid priority on idle queue %d",
td->td_priority));
return (td);
}
return (NULL);
}
/*
* Initialize a thread queue.
*/
static void
tdq_setup(struct tdq *tdq)
{
if (bootverbose)
printf("ULE: setup cpu %d\n", TDQ_ID(tdq));
runq_init(&tdq->tdq_realtime);
runq_init(&tdq->tdq_timeshare);
runq_init(&tdq->tdq_idle);
snprintf(tdq->tdq_name, sizeof(tdq->tdq_name),
"sched lock %d", (int)TDQ_ID(tdq));
mtx_init(&tdq->tdq_lock, tdq->tdq_name, "sched lock",
MTX_SPIN | MTX_RECURSE);
#ifdef KTR
snprintf(tdq->tdq_loadname, sizeof(tdq->tdq_loadname),
"CPU %d load", (int)TDQ_ID(tdq));
#endif
}
#ifdef SMP
static void
sched_setup_smp(void)
{
struct tdq *tdq;
int i;
cpu_top = smp_topo();
CPU_FOREACH(i) {
tdq = TDQ_CPU(i);
tdq_setup(tdq);
tdq->tdq_cg = smp_topo_find(cpu_top, i);
if (tdq->tdq_cg == NULL)
panic("Can't find cpu group for %d\n", i);
}
balance_tdq = TDQ_SELF();
}
#endif
/*
* Setup the thread queues and initialize the topology based on MD
* information.
*/
static void
sched_setup(void *dummy)
{
struct tdq *tdq;
tdq = TDQ_SELF();
#ifdef SMP
sched_setup_smp();
#else
tdq_setup(tdq);
#endif
/* Add thread0's load since it's running. */
TDQ_LOCK(tdq);
thread0.td_lock = TDQ_LOCKPTR(TDQ_SELF());
tdq_load_add(tdq, &thread0);
tdq->tdq_lowpri = thread0.td_priority;
TDQ_UNLOCK(tdq);
}
/*
* This routine determines time constants after stathz and hz are setup.
*/
/* ARGSUSED */
static void
sched_initticks(void *dummy)
{
int incr;
realstathz = stathz ? stathz : hz;
sched_slice = realstathz / SCHED_SLICE_DEFAULT_DIVISOR;
sched_slice_min = sched_slice / SCHED_SLICE_MIN_DIVISOR;
hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) /
realstathz);
/*
* tickincr is shifted out by 10 to avoid rounding errors due to
* hz not being evenly divisible by stathz on all platforms.
*/
incr = (hz << SCHED_TICK_SHIFT) / realstathz;
/*
* This does not work for values of stathz that are more than
* 1 << SCHED_TICK_SHIFT * hz. In practice this does not happen.
*/
if (incr == 0)
incr = 1;
tickincr = incr;
#ifdef SMP
/*
* Set the default balance interval now that we know
* what realstathz is.
*/
balance_interval = realstathz;
balance_ticks = balance_interval;
affinity = SCHED_AFFINITY_DEFAULT;
#endif
if (sched_idlespinthresh < 0)
sched_idlespinthresh = 2 * max(10000, 6 * hz) / realstathz;
}
/*
* This is the core of the interactivity algorithm. Determines a score based
* on past behavior. It is the ratio of sleep time to run time scaled to
* a [0, 100] integer. This is the voluntary sleep time of a process, which
* differs from the cpu usage because it does not account for time spent
* waiting on a run-queue. Would be prettier if we had floating point.
*
* When a thread's sleep time is greater than its run time the
* calculation is:
*
* scaling factor
* interactivity score = ---------------------
* sleep time / run time
*
*
* When a thread's run time is greater than its sleep time the
* calculation is:
*
* scaling factor
* interactivity score = --------------------- + scaling factor
* run time / sleep time
*/
static int
sched_interact_score(struct thread *td)
{
struct td_sched *ts;
int div;
ts = td_get_sched(td);
/*
* The score is only needed if this is likely to be an interactive
* task. Don't go through the expense of computing it if there's
* no chance.
*/
if (sched_interact <= SCHED_INTERACT_HALF &&
ts->ts_runtime >= ts->ts_slptime)
return (SCHED_INTERACT_HALF);
if (ts->ts_runtime > ts->ts_slptime) {
div = max(1, ts->ts_runtime / SCHED_INTERACT_HALF);
return (SCHED_INTERACT_HALF +
(SCHED_INTERACT_HALF - (ts->ts_slptime / div)));
}
if (ts->ts_slptime > ts->ts_runtime) {
div = max(1, ts->ts_slptime / SCHED_INTERACT_HALF);
return (ts->ts_runtime / div);
}
/* runtime == slptime */
if (ts->ts_runtime)
return (SCHED_INTERACT_HALF);
/*
* This can happen if slptime and runtime are 0.
*/
return (0);
}
/*
* Scale the scheduling priority according to the "interactivity" of this
* process.
*/
static void
sched_priority(struct thread *td)
{
int score;
int pri;
if (PRI_BASE(td->td_pri_class) != PRI_TIMESHARE)
return;
/*
* If the score is interactive we place the thread in the realtime
* queue with a priority that is less than kernel and interrupt
* priorities. These threads are not subject to nice restrictions.
*
* Scores greater than this are placed on the normal timeshare queue
* where the priority is partially decided by the most recent cpu
* utilization and the rest is decided by nice value.
*
* The nice value of the process has a linear effect on the calculated
* score. Negative nice values make it easier for a thread to be
* considered interactive.
*/
score = imax(0, sched_interact_score(td) + td->td_proc->p_nice);
if (score < sched_interact) {
pri = PRI_MIN_INTERACT;
pri += ((PRI_MAX_INTERACT - PRI_MIN_INTERACT + 1) /
sched_interact) * score;
KASSERT(pri >= PRI_MIN_INTERACT && pri <= PRI_MAX_INTERACT,
("sched_priority: invalid interactive priority %d score %d",
pri, score));
} else {
pri = SCHED_PRI_MIN;
if (td_get_sched(td)->ts_ticks)
pri += min(SCHED_PRI_TICKS(td_get_sched(td)),
SCHED_PRI_RANGE - 1);
pri += SCHED_PRI_NICE(td->td_proc->p_nice);
KASSERT(pri >= PRI_MIN_BATCH && pri <= PRI_MAX_BATCH,
("sched_priority: invalid priority %d: nice %d, "
"ticks %d ftick %d ltick %d tick pri %d",
pri, td->td_proc->p_nice, td_get_sched(td)->ts_ticks,
td_get_sched(td)->ts_ftick, td_get_sched(td)->ts_ltick,
SCHED_PRI_TICKS(td_get_sched(td))));
}
sched_user_prio(td, pri);
return;
}
/*
* This routine enforces a maximum limit on the amount of scheduling history
* kept. It is called after either the slptime or runtime is adjusted. This
* function is ugly due to integer math.
*/
static void
sched_interact_update(struct thread *td)
{
struct td_sched *ts;
u_int sum;
ts = td_get_sched(td);
sum = ts->ts_runtime + ts->ts_slptime;
if (sum < SCHED_SLP_RUN_MAX)
return;
/*
* This only happens from two places:
* 1) We have added an unusual amount of run time from fork_exit.
* 2) We have added an unusual amount of sleep time from sched_sleep().
*/
if (sum > SCHED_SLP_RUN_MAX * 2) {
if (ts->ts_runtime > ts->ts_slptime) {
ts->ts_runtime = SCHED_SLP_RUN_MAX;
ts->ts_slptime = 1;
} else {
ts->ts_slptime = SCHED_SLP_RUN_MAX;
ts->ts_runtime = 1;
}
return;
}
/*
* If we have exceeded by more than 1/5th then the algorithm below
* will not bring us back into range. Dividing by two here forces
* us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX]
*/
if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) {
ts->ts_runtime /= 2;
ts->ts_slptime /= 2;
return;
}
ts->ts_runtime = (ts->ts_runtime / 5) * 4;
ts->ts_slptime = (ts->ts_slptime / 5) * 4;
}
/*
* Scale back the interactivity history when a child thread is created. The
* history is inherited from the parent but the thread may behave totally
* differently. For example, a shell spawning a compiler process. We want
* to learn that the compiler is behaving badly very quickly.
*/
static void
sched_interact_fork(struct thread *td)
{
struct td_sched *ts;
int ratio;
int sum;
ts = td_get_sched(td);
sum = ts->ts_runtime + ts->ts_slptime;
if (sum > SCHED_SLP_RUN_FORK) {
ratio = sum / SCHED_SLP_RUN_FORK;
ts->ts_runtime /= ratio;
ts->ts_slptime /= ratio;
}
}
/*
* Called from proc0_init() to setup the scheduler fields.
*/
void
schedinit(void)
{
struct td_sched *ts0;
/*
* Set up the scheduler specific parts of thread0.
*/
ts0 = td_get_sched(&thread0);
ts0->ts_ltick = ticks;
ts0->ts_ftick = ticks;
ts0->ts_slice = 0;
ts0->ts_cpu = curcpu; /* set valid CPU number */
}
/*
* This is only somewhat accurate since given many processes of the same
* priority they will switch when their slices run out, which will be
* at most sched_slice stathz ticks.
*/
int
sched_rr_interval(void)
{
/* Convert sched_slice from stathz to hz. */
return (imax(1, (sched_slice * hz + realstathz / 2) / realstathz));
}
/*
* Update the percent cpu tracking information when it is requested or
* the total history exceeds the maximum. We keep a sliding history of
* tick counts that slowly decays. This is less precise than the 4BSD
* mechanism since it happens with less regular and frequent events.
*/
static void
sched_pctcpu_update(struct td_sched *ts, int run)
{
int t = ticks;
/*
* The signed difference may be negative if the thread hasn't run for
* over half of the ticks rollover period.
*/
if ((u_int)(t - ts->ts_ltick) >= SCHED_TICK_TARG) {
ts->ts_ticks = 0;
ts->ts_ftick = t - SCHED_TICK_TARG;
} else if (t - ts->ts_ftick >= SCHED_TICK_MAX) {
ts->ts_ticks = (ts->ts_ticks / (ts->ts_ltick - ts->ts_ftick)) *
(ts->ts_ltick - (t - SCHED_TICK_TARG));
ts->ts_ftick = t - SCHED_TICK_TARG;
}
if (run)
ts->ts_ticks += (t - ts->ts_ltick) << SCHED_TICK_SHIFT;
ts->ts_ltick = t;
}
/*
* Adjust the priority of a thread. Move it to the appropriate run-queue
* if necessary. This is the back-end for several priority related
* functions.
*/
static void
sched_thread_priority(struct thread *td, u_char prio)
{
struct td_sched *ts;
struct tdq *tdq;
int oldpri;
KTR_POINT3(KTR_SCHED, "thread", sched_tdname(td), "prio",
"prio:%d", td->td_priority, "new prio:%d", prio,
KTR_ATTR_LINKED, sched_tdname(curthread));
SDT_PROBE3(sched, , , change__pri, td, td->td_proc, prio);
if (td != curthread && prio < td->td_priority) {
KTR_POINT3(KTR_SCHED, "thread", sched_tdname(curthread),
"lend prio", "prio:%d", td->td_priority, "new prio:%d",
prio, KTR_ATTR_LINKED, sched_tdname(td));
SDT_PROBE4(sched, , , lend__pri, td, td->td_proc, prio,
curthread);
}
ts = td_get_sched(td);
THREAD_LOCK_ASSERT(td, MA_OWNED);
if (td->td_priority == prio)
return;
/*
* If the priority has been elevated due to priority
* propagation, we may have to move ourselves to a new
* queue. This could be optimized to not re-add in some
* cases.
*/
if (TD_ON_RUNQ(td) && prio < td->td_priority) {
sched_rem(td);
td->td_priority = prio;
sched_add(td, SRQ_BORROWING);
return;
}
/*
* If the thread is currently running we may have to adjust the lowpri
* information so other cpus are aware of our current priority.
*/
if (TD_IS_RUNNING(td)) {
tdq = TDQ_CPU(ts->ts_cpu);
oldpri = td->td_priority;
td->td_priority = prio;
if (prio < tdq->tdq_lowpri)
tdq->tdq_lowpri = prio;
else if (tdq->tdq_lowpri == oldpri)
tdq_setlowpri(tdq, td);
return;
}
td->td_priority = prio;
}
/*
* Update a thread's priority when it is lent another thread's
* priority.
*/
void
sched_lend_prio(struct thread *td, u_char prio)
{
td->td_flags |= TDF_BORROWING;
sched_thread_priority(td, prio);
}
/*
* Restore a thread's priority when priority propagation is
* over. The prio argument is the minimum priority the thread
* needs to have to satisfy other possible priority lending
* requests. If the thread's regular priority is less
* important than prio, the thread will keep a priority boost
* of prio.
*/
void
sched_unlend_prio(struct thread *td, u_char prio)
{
u_char base_pri;
if (td->td_base_pri >= PRI_MIN_TIMESHARE &&
td->td_base_pri <= PRI_MAX_TIMESHARE)
base_pri = td->td_user_pri;
else
base_pri = td->td_base_pri;
if (prio >= base_pri) {
td->td_flags &= ~TDF_BORROWING;
sched_thread_priority(td, base_pri);
} else
sched_lend_prio(td, prio);
}
/*
* Standard entry for setting the priority to an absolute value.
*/
void
sched_prio(struct thread *td, u_char prio)
{
u_char oldprio;
/* First, update the base priority. */
td->td_base_pri = prio;
/*
* If the thread is borrowing another thread's priority, don't
* ever lower the priority.
*/
if (td->td_flags & TDF_BORROWING && td->td_priority < prio)
return;
/* Change the real priority. */
oldprio = td->td_priority;
sched_thread_priority(td, prio);
/*
* If the thread is on a turnstile, then let the turnstile update
* its state.
*/
if (TD_ON_LOCK(td) && oldprio != prio)
turnstile_adjust(td, oldprio);
}
/*
* Set the base user priority, does not effect current running priority.
*/
void
sched_user_prio(struct thread *td, u_char prio)
{
td->td_base_user_pri = prio;
if (td->td_lend_user_pri <= prio)
return;
td->td_user_pri = prio;
}
void
sched_lend_user_prio(struct thread *td, u_char prio)
{
THREAD_LOCK_ASSERT(td, MA_OWNED);
td->td_lend_user_pri = prio;
td->td_user_pri = min(prio, td->td_base_user_pri);
if (td->td_priority > td->td_user_pri)
sched_prio(td, td->td_user_pri);
else if (td->td_priority != td->td_user_pri)
td->td_flags |= TDF_NEEDRESCHED;
}
+/*
+ * Like the above but first check if there is anything to do.
+ */
+void
+sched_lend_user_prio_cond(struct thread *td, u_char prio)
+{
+
+ if (td->td_lend_user_pri != prio)
+ goto lend;
+ if (td->td_user_pri != min(prio, td->td_base_user_pri))
+ goto lend;
+ if (td->td_priority >= td->td_user_pri)
+ goto lend;
+ return;
+
+lend:
+ thread_lock(td);
+ sched_lend_user_prio(td, prio);
+ thread_unlock(td);
+}
+
#ifdef SMP
/*
* This tdq is about to idle. Try to steal a thread from another CPU before
* choosing the idle thread.
*/
static void
tdq_trysteal(struct tdq *tdq)
{
struct cpu_group *cg;
struct tdq *steal;
cpuset_t mask;
int cpu, i;
if (smp_started == 0 || trysteal_limit == 0 || tdq->tdq_cg == NULL)
return;
CPU_FILL(&mask);
CPU_CLR(PCPU_GET(cpuid), &mask);
/* We don't want to be preempted while we're iterating. */
spinlock_enter();
TDQ_UNLOCK(tdq);
for (i = 1, cg = tdq->tdq_cg; ; ) {
cpu = sched_highest(cg, mask, steal_thresh);
/*
* If a thread was added while interrupts were disabled don't
* steal one here.
*/
if (tdq->tdq_load > 0) {
TDQ_LOCK(tdq);
break;
}
if (cpu == -1) {
i++;
cg = cg->cg_parent;
if (cg == NULL || i > trysteal_limit) {
TDQ_LOCK(tdq);
break;
}
continue;
}
steal = TDQ_CPU(cpu);
/*
* The data returned by sched_highest() is stale and
* the chosen CPU no longer has an eligible thread.
*/
if (steal->tdq_load < steal_thresh ||
steal->tdq_transferable == 0)
continue;
tdq_lock_pair(tdq, steal);
/*
* If we get to this point, unconditonally exit the loop
* to bound the time spent in the critcal section.
*
* If a thread was added while interrupts were disabled don't
* steal one here.
*/
if (tdq->tdq_load > 0) {
TDQ_UNLOCK(steal);
break;
}
/*
* The data returned by sched_highest() is stale and
* the chosen CPU no longer has an eligible thread.
*/
if (steal->tdq_load < steal_thresh ||
steal->tdq_transferable == 0) {
TDQ_UNLOCK(steal);
break;
}
/*
* If we fail to acquire one due to affinity restrictions,
* bail out and let the idle thread to a more complete search
* outside of a critical section.
*/
if (tdq_move(steal, tdq) == NULL) {
TDQ_UNLOCK(steal);
break;
}
TDQ_UNLOCK(steal);
break;
}
spinlock_exit();
}
#endif
/*
* Handle migration from sched_switch(). This happens only for
* cpu binding.
*/
static struct mtx *
sched_switch_migrate(struct tdq *tdq, struct thread *td, int flags)
{
struct tdq *tdn;
KASSERT(!CPU_ABSENT(td_get_sched(td)->ts_cpu), ("sched_switch_migrate: "
"thread %s queued on absent CPU %d.", td->td_name,
td_get_sched(td)->ts_cpu));
tdn = TDQ_CPU(td_get_sched(td)->ts_cpu);
#ifdef SMP
tdq_load_rem(tdq, td);
/*
* Do the lock dance required to avoid LOR. We grab an extra
* spinlock nesting to prevent preemption while we're
* not holding either run-queue lock.
*/
spinlock_enter();
thread_lock_block(td); /* This releases the lock on tdq. */
/*
* Acquire both run-queue locks before placing the thread on the new
* run-queue to avoid deadlocks created by placing a thread with a
* blocked lock on the run-queue of a remote processor. The deadlock
* occurs when a third processor attempts to lock the two queues in
* question while the target processor is spinning with its own
* run-queue lock held while waiting for the blocked lock to clear.
*/
tdq_lock_pair(tdn, tdq);
tdq_add(tdn, td, flags);
tdq_notify(tdn, td);
TDQ_UNLOCK(tdn);
spinlock_exit();
#endif
return (TDQ_LOCKPTR(tdn));
}
/*
* Variadic version of thread_lock_unblock() that does not assume td_lock
* is blocked.
*/
static inline void
thread_unblock_switch(struct thread *td, struct mtx *mtx)
{
atomic_store_rel_ptr((volatile uintptr_t *)&td->td_lock,
(uintptr_t)mtx);
}
/*
* Switch threads. This function has to handle threads coming in while
* blocked for some reason, running, or idle. It also must deal with
* migrating a thread from one queue to another as running threads may
* be assigned elsewhere via binding.
*/
void
sched_switch(struct thread *td, struct thread *newtd, int flags)
{
struct tdq *tdq;
struct td_sched *ts;
struct mtx *mtx;
int srqflag;
int cpuid, preempted;
THREAD_LOCK_ASSERT(td, MA_OWNED);
KASSERT(newtd == NULL, ("sched_switch: Unsupported newtd argument"));
cpuid = PCPU_GET(cpuid);
tdq = TDQ_CPU(cpuid);
ts = td_get_sched(td);
mtx = td->td_lock;
sched_pctcpu_update(ts, 1);
ts->ts_rltick = ticks;
td->td_lastcpu = td->td_oncpu;
td->td_oncpu = NOCPU;
preempted = (td->td_flags & TDF_SLICEEND) == 0 &&
(flags & SW_PREEMPT) != 0;
td->td_flags &= ~(TDF_NEEDRESCHED | TDF_SLICEEND);
td->td_owepreempt = 0;
if (!TD_IS_IDLETHREAD(td))
tdq->tdq_switchcnt++;
/*
* The lock pointer in an idle thread should never change. Reset it
* to CAN_RUN as well.
*/
if (TD_IS_IDLETHREAD(td)) {
MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
TD_SET_CAN_RUN(td);
} else if (TD_IS_RUNNING(td)) {
MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
srqflag = preempted ?
SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED :
SRQ_OURSELF|SRQ_YIELDING;
#ifdef SMP
if (THREAD_CAN_MIGRATE(td) && !THREAD_CAN_SCHED(td, ts->ts_cpu))
ts->ts_cpu = sched_pickcpu(td, 0);
#endif
if (ts->ts_cpu == cpuid)
tdq_runq_add(tdq, td, srqflag);
else {
KASSERT(THREAD_CAN_MIGRATE(td) ||
(ts->ts_flags & TSF_BOUND) != 0,
("Thread %p shouldn't migrate", td));
mtx = sched_switch_migrate(tdq, td, srqflag);
}
} else {
/* This thread must be going to sleep. */
TDQ_LOCK(tdq);
mtx = thread_lock_block(td);
tdq_load_rem(tdq, td);
#ifdef SMP
if (tdq->tdq_load == 0)
tdq_trysteal(tdq);
#endif
}
#if (KTR_COMPILE & KTR_SCHED) != 0
if (TD_IS_IDLETHREAD(td))
KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "idle",
"prio:%d", td->td_priority);
else
KTR_STATE3(KTR_SCHED, "thread", sched_tdname(td), KTDSTATE(td),
"prio:%d", td->td_priority, "wmesg:\"%s\"", td->td_wmesg,
"lockname:\"%s\"", td->td_lockname);
#endif
/*
* We enter here with the thread blocked and assigned to the
* appropriate cpu run-queue or sleep-queue and with the current
* thread-queue locked.
*/
TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED);
newtd = choosethread();
/*
* Call the MD code to switch contexts if necessary.
*/
if (td != newtd) {
#ifdef HWPMC_HOOKS
if (PMC_PROC_IS_USING_PMCS(td->td_proc))
PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
#endif
SDT_PROBE2(sched, , , off__cpu, newtd, newtd->td_proc);
lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object);
TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd;
sched_pctcpu_update(td_get_sched(newtd), 0);
#ifdef KDTRACE_HOOKS
/*
* If DTrace has set the active vtime enum to anything
* other than INACTIVE (0), then it should have set the
* function to call.
*/
if (dtrace_vtime_active)
(*dtrace_vtime_switch_func)(newtd);
#endif
cpu_switch(td, newtd, mtx);
/*
* We may return from cpu_switch on a different cpu. However,
* we always return with td_lock pointing to the current cpu's
* run queue lock.
*/
cpuid = PCPU_GET(cpuid);
tdq = TDQ_CPU(cpuid);
lock_profile_obtain_lock_success(
&TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__);
SDT_PROBE0(sched, , , on__cpu);
#ifdef HWPMC_HOOKS
if (PMC_PROC_IS_USING_PMCS(td->td_proc))
PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN);
#endif
} else {
thread_unblock_switch(td, mtx);
SDT_PROBE0(sched, , , remain__cpu);
}
KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "running",
"prio:%d", td->td_priority);
/*
* Assert that all went well and return.
*/
TDQ_LOCK_ASSERT(tdq, MA_OWNED|MA_NOTRECURSED);
MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
td->td_oncpu = cpuid;
}
/*
* Adjust thread priorities as a result of a nice request.
*/
void
sched_nice(struct proc *p, int nice)
{
struct thread *td;
PROC_LOCK_ASSERT(p, MA_OWNED);
p->p_nice = nice;
FOREACH_THREAD_IN_PROC(p, td) {
thread_lock(td);
sched_priority(td);
sched_prio(td, td->td_base_user_pri);
thread_unlock(td);
}
}
/*
* Record the sleep time for the interactivity scorer.
*/
void
sched_sleep(struct thread *td, int prio)
{
THREAD_LOCK_ASSERT(td, MA_OWNED);
td->td_slptick = ticks;
if (TD_IS_SUSPENDED(td) || prio >= PSOCK)
td->td_flags |= TDF_CANSWAP;
if (PRI_BASE(td->td_pri_class) != PRI_TIMESHARE)
return;
if (static_boost == 1 && prio)
sched_prio(td, prio);
else if (static_boost && td->td_priority > static_boost)
sched_prio(td, static_boost);
}
/*
* Schedule a thread to resume execution and record how long it voluntarily
* slept. We also update the pctcpu, interactivity, and priority.
*/
void
sched_wakeup(struct thread *td)
{
struct td_sched *ts;
int slptick;
THREAD_LOCK_ASSERT(td, MA_OWNED);
ts = td_get_sched(td);
td->td_flags &= ~TDF_CANSWAP;
/*
* If we slept for more than a tick update our interactivity and
* priority.
*/
slptick = td->td_slptick;
td->td_slptick = 0;
if (slptick && slptick != ticks) {
ts->ts_slptime += (ticks - slptick) << SCHED_TICK_SHIFT;
sched_interact_update(td);
sched_pctcpu_update(ts, 0);
}
/*
* Reset the slice value since we slept and advanced the round-robin.
*/
ts->ts_slice = 0;
sched_add(td, SRQ_BORING);
}
/*
* Penalize the parent for creating a new child and initialize the child's
* priority.
*/
void
sched_fork(struct thread *td, struct thread *child)
{
THREAD_LOCK_ASSERT(td, MA_OWNED);
sched_pctcpu_update(td_get_sched(td), 1);
sched_fork_thread(td, child);
/*
* Penalize the parent and child for forking.
*/
sched_interact_fork(child);
sched_priority(child);
td_get_sched(td)->ts_runtime += tickincr;
sched_interact_update(td);
sched_priority(td);
}
/*
* Fork a new thread, may be within the same process.
*/
void
sched_fork_thread(struct thread *td, struct thread *child)
{
struct td_sched *ts;
struct td_sched *ts2;
struct tdq *tdq;
tdq = TDQ_SELF();
THREAD_LOCK_ASSERT(td, MA_OWNED);
/*
* Initialize child.
*/
ts = td_get_sched(td);
ts2 = td_get_sched(child);
child->td_oncpu = NOCPU;
child->td_lastcpu = NOCPU;
child->td_lock = TDQ_LOCKPTR(tdq);
child->td_cpuset = cpuset_ref(td->td_cpuset);
child->td_domain.dr_policy = td->td_cpuset->cs_domain;
ts2->ts_cpu = ts->ts_cpu;
ts2->ts_flags = 0;
/*
* Grab our parents cpu estimation information.
*/
ts2->ts_ticks = ts->ts_ticks;
ts2->ts_ltick = ts->ts_ltick;
ts2->ts_ftick = ts->ts_ftick;
/*
* Do not inherit any borrowed priority from the parent.
*/
child->td_priority = child->td_base_pri;
/*
* And update interactivity score.
*/
ts2->ts_slptime = ts->ts_slptime;
ts2->ts_runtime = ts->ts_runtime;
/* Attempt to quickly learn interactivity. */
ts2->ts_slice = tdq_slice(tdq) - sched_slice_min;
#ifdef KTR
bzero(ts2->ts_name, sizeof(ts2->ts_name));
#endif
}
/*
* Adjust the priority class of a thread.
*/
void
sched_class(struct thread *td, int class)
{
THREAD_LOCK_ASSERT(td, MA_OWNED);
if (td->td_pri_class == class)
return;
td->td_pri_class = class;
}
/*
* Return some of the child's priority and interactivity to the parent.
*/
void
sched_exit(struct proc *p, struct thread *child)
{
struct thread *td;
KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "proc exit",
"prio:%d", child->td_priority);
PROC_LOCK_ASSERT(p, MA_OWNED);
td = FIRST_THREAD_IN_PROC(p);
sched_exit_thread(td, child);
}
/*
* Penalize another thread for the time spent on this one. This helps to
* worsen the priority and interactivity of processes which schedule batch
* jobs such as make. This has little effect on the make process itself but
* causes new processes spawned by it to receive worse scores immediately.
*/
void
sched_exit_thread(struct thread *td, struct thread *child)
{
KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "thread exit",
"prio:%d", child->td_priority);
/*
* Give the child's runtime to the parent without returning the
* sleep time as a penalty to the parent. This causes shells that
* launch expensive things to mark their children as expensive.
*/
thread_lock(td);
td_get_sched(td)->ts_runtime += td_get_sched(child)->ts_runtime;
sched_interact_update(td);
sched_priority(td);
thread_unlock(td);
}
void
sched_preempt(struct thread *td)
{
struct tdq *tdq;
SDT_PROBE2(sched, , , surrender, td, td->td_proc);
thread_lock(td);
tdq = TDQ_SELF();
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
tdq->tdq_ipipending = 0;
if (td->td_priority > tdq->tdq_lowpri) {
int flags;
flags = SW_INVOL | SW_PREEMPT;
if (td->td_critnest > 1)
td->td_owepreempt = 1;
else if (TD_IS_IDLETHREAD(td))
mi_switch(flags | SWT_REMOTEWAKEIDLE, NULL);
else
mi_switch(flags | SWT_REMOTEPREEMPT, NULL);
}
thread_unlock(td);
}
/*
* Fix priorities on return to user-space. Priorities may be elevated due
* to static priorities in msleep() or similar.
*/
void
sched_userret_slowpath(struct thread *td)
{
thread_lock(td);
td->td_priority = td->td_user_pri;
td->td_base_pri = td->td_user_pri;
tdq_setlowpri(TDQ_SELF(), td);
thread_unlock(td);
}
/*
* Handle a stathz tick. This is really only relevant for timeshare
* threads.
*/
void
sched_clock(struct thread *td)
{
struct tdq *tdq;
struct td_sched *ts;
THREAD_LOCK_ASSERT(td, MA_OWNED);
tdq = TDQ_SELF();
#ifdef SMP
/*
* We run the long term load balancer infrequently on the first cpu.
*/
if (balance_tdq == tdq && smp_started != 0 && rebalance != 0) {
if (balance_ticks && --balance_ticks == 0)
sched_balance();
}
#endif
/*
* Save the old switch count so we have a record of the last ticks
* activity. Initialize the new switch count based on our load.
* If there is some activity seed it to reflect that.
*/
tdq->tdq_oldswitchcnt = tdq->tdq_switchcnt;
tdq->tdq_switchcnt = tdq->tdq_load;
/*
* Advance the insert index once for each tick to ensure that all
* threads get a chance to run.
*/
if (tdq->tdq_idx == tdq->tdq_ridx) {
tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS;
if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx]))
tdq->tdq_ridx = tdq->tdq_idx;
}
ts = td_get_sched(td);
sched_pctcpu_update(ts, 1);
if (td->td_pri_class & PRI_FIFO_BIT)
return;
if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) {
/*
* We used a tick; charge it to the thread so
* that we can compute our interactivity.
*/
td_get_sched(td)->ts_runtime += tickincr;
sched_interact_update(td);
sched_priority(td);
}
/*
* Force a context switch if the current thread has used up a full
* time slice (default is 100ms).
*/
if (!TD_IS_IDLETHREAD(td) && ++ts->ts_slice >= tdq_slice(tdq)) {
ts->ts_slice = 0;
td->td_flags |= TDF_NEEDRESCHED | TDF_SLICEEND;
}
}
u_int
sched_estcpu(struct thread *td __unused)
{
return (0);
}
/*
* Return whether the current CPU has runnable tasks. Used for in-kernel
* cooperative idle threads.
*/
int
sched_runnable(void)
{
struct tdq *tdq;
int load;
load = 1;
tdq = TDQ_SELF();
if ((curthread->td_flags & TDF_IDLETD) != 0) {
if (tdq->tdq_load > 0)
goto out;
} else
if (tdq->tdq_load - 1 > 0)
goto out;
load = 0;
out:
return (load);
}
/*
* Choose the highest priority thread to run. The thread is removed from
* the run-queue while running however the load remains. For SMP we set
* the tdq in the global idle bitmask if it idles here.
*/
struct thread *
sched_choose(void)
{
struct thread *td;
struct tdq *tdq;
tdq = TDQ_SELF();
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
td = tdq_choose(tdq);
if (td) {
tdq_runq_rem(tdq, td);
tdq->tdq_lowpri = td->td_priority;
return (td);
}
tdq->tdq_lowpri = PRI_MAX_IDLE;
return (PCPU_GET(idlethread));
}
/*
* Set owepreempt if necessary. Preemption never happens directly in ULE,
* we always request it once we exit a critical section.
*/
static inline void
sched_setpreempt(struct thread *td)
{
struct thread *ctd;
int cpri;
int pri;
THREAD_LOCK_ASSERT(curthread, MA_OWNED);
ctd = curthread;
pri = td->td_priority;
cpri = ctd->td_priority;
if (pri < cpri)
ctd->td_flags |= TDF_NEEDRESCHED;
if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd))
return;
if (!sched_shouldpreempt(pri, cpri, 0))
return;
ctd->td_owepreempt = 1;
}
/*
* Add a thread to a thread queue. Select the appropriate runq and add the
* thread to it. This is the internal function called when the tdq is
* predetermined.
*/
void
tdq_add(struct tdq *tdq, struct thread *td, int flags)
{
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
KASSERT((td->td_inhibitors == 0),
("sched_add: trying to run inhibited thread"));
KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)),
("sched_add: bad thread state"));
KASSERT(td->td_flags & TDF_INMEM,
("sched_add: thread swapped out"));
if (td->td_priority < tdq->tdq_lowpri)
tdq->tdq_lowpri = td->td_priority;
tdq_runq_add(tdq, td, flags);
tdq_load_add(tdq, td);
}
/*
* Select the target thread queue and add a thread to it. Request
* preemption or IPI a remote processor if required.
*/
void
sched_add(struct thread *td, int flags)
{
struct tdq *tdq;
#ifdef SMP
int cpu;
#endif
KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add",
"prio:%d", td->td_priority, KTR_ATTR_LINKED,
sched_tdname(curthread));
KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup",
KTR_ATTR_LINKED, sched_tdname(td));
SDT_PROBE4(sched, , , enqueue, td, td->td_proc, NULL,
flags & SRQ_PREEMPTED);
THREAD_LOCK_ASSERT(td, MA_OWNED);
/*
* Recalculate the priority before we select the target cpu or
* run-queue.
*/
if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE)
sched_priority(td);
#ifdef SMP
/*
* Pick the destination cpu and if it isn't ours transfer to the
* target cpu.
*/
cpu = sched_pickcpu(td, flags);
tdq = sched_setcpu(td, cpu, flags);
tdq_add(tdq, td, flags);
if (cpu != PCPU_GET(cpuid)) {
tdq_notify(tdq, td);
return;
}
#else
tdq = TDQ_SELF();
TDQ_LOCK(tdq);
/*
* Now that the thread is moving to the run-queue, set the lock
* to the scheduler's lock.
*/
thread_lock_set(td, TDQ_LOCKPTR(tdq));
tdq_add(tdq, td, flags);
#endif
if (!(flags & SRQ_YIELDING))
sched_setpreempt(td);
}
/*
* Remove a thread from a run-queue without running it. This is used
* when we're stealing a thread from a remote queue. Otherwise all threads
* exit by calling sched_exit_thread() and sched_throw() themselves.
*/
void
sched_rem(struct thread *td)
{
struct tdq *tdq;
KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "runq rem",
"prio:%d", td->td_priority);
SDT_PROBE3(sched, , , dequeue, td, td->td_proc, NULL);
tdq = TDQ_CPU(td_get_sched(td)->ts_cpu);
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
KASSERT(TD_ON_RUNQ(td),
("sched_rem: thread not on run queue"));
tdq_runq_rem(tdq, td);
tdq_load_rem(tdq, td);
TD_SET_CAN_RUN(td);
if (td->td_priority == tdq->tdq_lowpri)
tdq_setlowpri(tdq, NULL);
}
/*
* Fetch cpu utilization information. Updates on demand.
*/
fixpt_t
sched_pctcpu(struct thread *td)
{
fixpt_t pctcpu;
struct td_sched *ts;
pctcpu = 0;
ts = td_get_sched(td);
THREAD_LOCK_ASSERT(td, MA_OWNED);
sched_pctcpu_update(ts, TD_IS_RUNNING(td));
if (ts->ts_ticks) {
int rtick;
/* How many rtick per second ? */
rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz);
pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT;
}
return (pctcpu);
}
/*
* Enforce affinity settings for a thread. Called after adjustments to
* cpumask.
*/
void
sched_affinity(struct thread *td)
{
#ifdef SMP
struct td_sched *ts;
THREAD_LOCK_ASSERT(td, MA_OWNED);
ts = td_get_sched(td);
if (THREAD_CAN_SCHED(td, ts->ts_cpu))
return;
if (TD_ON_RUNQ(td)) {
sched_rem(td);
sched_add(td, SRQ_BORING);
return;
}
if (!TD_IS_RUNNING(td))
return;
/*
* Force a switch before returning to userspace. If the
* target thread is not running locally send an ipi to force
* the issue.
*/
td->td_flags |= TDF_NEEDRESCHED;
if (td != curthread)
ipi_cpu(ts->ts_cpu, IPI_PREEMPT);
#endif
}
/*
* Bind a thread to a target cpu.
*/
void
sched_bind(struct thread *td, int cpu)
{
struct td_sched *ts;
THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED);
KASSERT(td == curthread, ("sched_bind: can only bind curthread"));
ts = td_get_sched(td);
if (ts->ts_flags & TSF_BOUND)
sched_unbind(td);
KASSERT(THREAD_CAN_MIGRATE(td), ("%p must be migratable", td));
ts->ts_flags |= TSF_BOUND;
sched_pin();
if (PCPU_GET(cpuid) == cpu)
return;
ts->ts_cpu = cpu;
/* When we return from mi_switch we'll be on the correct cpu. */
mi_switch(SW_VOL, NULL);
}
/*
* Release a bound thread.
*/
void
sched_unbind(struct thread *td)
{
struct td_sched *ts;
THREAD_LOCK_ASSERT(td, MA_OWNED);
KASSERT(td == curthread, ("sched_unbind: can only bind curthread"));
ts = td_get_sched(td);
if ((ts->ts_flags & TSF_BOUND) == 0)
return;
ts->ts_flags &= ~TSF_BOUND;
sched_unpin();
}
int
sched_is_bound(struct thread *td)
{
THREAD_LOCK_ASSERT(td, MA_OWNED);
return (td_get_sched(td)->ts_flags & TSF_BOUND);
}
/*
* Basic yield call.
*/
void
sched_relinquish(struct thread *td)
{
thread_lock(td);
mi_switch(SW_VOL | SWT_RELINQUISH, NULL);
thread_unlock(td);
}
/*
* Return the total system load.
*/
int
sched_load(void)
{
#ifdef SMP
int total;
int i;
total = 0;
CPU_FOREACH(i)
total += TDQ_CPU(i)->tdq_sysload;
return (total);
#else
return (TDQ_SELF()->tdq_sysload);
#endif
}
int
sched_sizeof_proc(void)
{
return (sizeof(struct proc));
}
int
sched_sizeof_thread(void)
{
return (sizeof(struct thread) + sizeof(struct td_sched));
}
#ifdef SMP
#define TDQ_IDLESPIN(tdq) \
((tdq)->tdq_cg != NULL && ((tdq)->tdq_cg->cg_flags & CG_FLAG_THREAD) == 0)
#else
#define TDQ_IDLESPIN(tdq) 1
#endif
/*
* The actual idle process.
*/
void
sched_idletd(void *dummy)
{
struct thread *td;
struct tdq *tdq;
int oldswitchcnt, switchcnt;
int i;
mtx_assert(&Giant, MA_NOTOWNED);
td = curthread;
tdq = TDQ_SELF();
THREAD_NO_SLEEPING();
oldswitchcnt = -1;
for (;;) {
if (tdq->tdq_load) {
thread_lock(td);
mi_switch(SW_VOL | SWT_IDLE, NULL);
thread_unlock(td);
}
switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
#ifdef SMP
if (always_steal || switchcnt != oldswitchcnt) {
oldswitchcnt = switchcnt;
if (tdq_idled(tdq) == 0)
continue;
}
switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
#else
oldswitchcnt = switchcnt;
#endif
/*
* If we're switching very frequently, spin while checking
* for load rather than entering a low power state that
* may require an IPI. However, don't do any busy
* loops while on SMT machines as this simply steals
* cycles from cores doing useful work.
*/
if (TDQ_IDLESPIN(tdq) && switchcnt > sched_idlespinthresh) {
for (i = 0; i < sched_idlespins; i++) {
if (tdq->tdq_load)
break;
cpu_spinwait();
}
}
/* If there was context switch during spin, restart it. */
switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
if (tdq->tdq_load != 0 || switchcnt != oldswitchcnt)
continue;
/* Run main MD idle handler. */
tdq->tdq_cpu_idle = 1;
/*
* Make sure that tdq_cpu_idle update is globally visible
* before cpu_idle() read tdq_load. The order is important
* to avoid race with tdq_notify.
*/
atomic_thread_fence_seq_cst();
/*
* Checking for again after the fence picks up assigned
* threads often enough to make it worthwhile to do so in
* order to avoid calling cpu_idle().
*/
if (tdq->tdq_load != 0) {
tdq->tdq_cpu_idle = 0;
continue;
}
cpu_idle(switchcnt * 4 > sched_idlespinthresh);
tdq->tdq_cpu_idle = 0;
/*
* Account thread-less hardware interrupts and
* other wakeup reasons equal to context switches.
*/
switchcnt = tdq->tdq_switchcnt + tdq->tdq_oldswitchcnt;
if (switchcnt != oldswitchcnt)
continue;
tdq->tdq_switchcnt++;
oldswitchcnt++;
}
}
/*
* A CPU is entering for the first time or a thread is exiting.
*/
void
sched_throw(struct thread *td)
{
struct thread *newtd;
struct tdq *tdq;
tdq = TDQ_SELF();
if (td == NULL) {
/* Correct spinlock nesting and acquire the correct lock. */
TDQ_LOCK(tdq);
spinlock_exit();
PCPU_SET(switchtime, cpu_ticks());
PCPU_SET(switchticks, ticks);
} else {
MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
tdq_load_rem(tdq, td);
lock_profile_release_lock(&TDQ_LOCKPTR(tdq)->lock_object);
td->td_lastcpu = td->td_oncpu;
td->td_oncpu = NOCPU;
}
KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count"));
newtd = choosethread();
TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd;
cpu_throw(td, newtd); /* doesn't return */
}
/*
* This is called from fork_exit(). Just acquire the correct locks and
* let fork do the rest of the work.
*/
void
sched_fork_exit(struct thread *td)
{
struct tdq *tdq;
int cpuid;
/*
* Finish setting up thread glue so that it begins execution in a
* non-nested critical section with the scheduler lock held.
*/
cpuid = PCPU_GET(cpuid);
tdq = TDQ_CPU(cpuid);
if (TD_IS_IDLETHREAD(td))
td->td_lock = TDQ_LOCKPTR(tdq);
MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
td->td_oncpu = cpuid;
TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED);
lock_profile_obtain_lock_success(
&TDQ_LOCKPTR(tdq)->lock_object, 0, 0, __FILE__, __LINE__);
KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "running",
"prio:%d", td->td_priority);
SDT_PROBE0(sched, , , on__cpu);
}
/*
* Create on first use to catch odd startup conditons.
*/
char *
sched_tdname(struct thread *td)
{
#ifdef KTR
struct td_sched *ts;
ts = td_get_sched(td);
if (ts->ts_name[0] == '\0')
snprintf(ts->ts_name, sizeof(ts->ts_name),
"%s tid %d", td->td_name, td->td_tid);
return (ts->ts_name);
#else
return (td->td_name);
#endif
}
#ifdef KTR
void
sched_clear_tdname(struct thread *td)
{
struct td_sched *ts;
ts = td_get_sched(td);
ts->ts_name[0] = '\0';
}
#endif
#ifdef SMP
/*
* Build the CPU topology dump string. Is recursively called to collect
* the topology tree.
*/
static int
sysctl_kern_sched_topology_spec_internal(struct sbuf *sb, struct cpu_group *cg,
int indent)
{
char cpusetbuf[CPUSETBUFSIZ];
int i, first;
sbuf_printf(sb, "%*s<group level=\"%d\" cache-level=\"%d\">\n", indent,
"", 1 + indent / 2, cg->cg_level);
sbuf_printf(sb, "%*s <cpu count=\"%d\" mask=\"%s\">", indent, "",
cg->cg_count, cpusetobj_strprint(cpusetbuf, &cg->cg_mask));
first = TRUE;
for (i = 0; i < MAXCPU; i++) {
if (CPU_ISSET(i, &cg->cg_mask)) {
if (!first)
sbuf_printf(sb, ", ");
else
first = FALSE;
sbuf_printf(sb, "%d", i);
}
}
sbuf_printf(sb, "</cpu>\n");
if (cg->cg_flags != 0) {
sbuf_printf(sb, "%*s <flags>", indent, "");
if ((cg->cg_flags & CG_FLAG_HTT) != 0)
sbuf_printf(sb, "<flag name=\"HTT\">HTT group</flag>");
if ((cg->cg_flags & CG_FLAG_THREAD) != 0)
sbuf_printf(sb, "<flag name=\"THREAD\">THREAD group</flag>");
if ((cg->cg_flags & CG_FLAG_SMT) != 0)
sbuf_printf(sb, "<flag name=\"SMT\">SMT group</flag>");
sbuf_printf(sb, "</flags>\n");
}
if (cg->cg_children > 0) {
sbuf_printf(sb, "%*s <children>\n", indent, "");
for (i = 0; i < cg->cg_children; i++)
sysctl_kern_sched_topology_spec_internal(sb,
&cg->cg_child[i], indent+2);
sbuf_printf(sb, "%*s </children>\n", indent, "");
}
sbuf_printf(sb, "%*s</group>\n", indent, "");
return (0);
}
/*
* Sysctl handler for retrieving topology dump. It's a wrapper for
* the recursive sysctl_kern_smp_topology_spec_internal().
*/
static int
sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS)
{
struct sbuf *topo;
int err;
KASSERT(cpu_top != NULL, ("cpu_top isn't initialized"));
topo = sbuf_new_for_sysctl(NULL, NULL, 512, req);
if (topo == NULL)
return (ENOMEM);
sbuf_printf(topo, "<groups>\n");
err = sysctl_kern_sched_topology_spec_internal(topo, cpu_top, 1);
sbuf_printf(topo, "</groups>\n");
if (err == 0) {
err = sbuf_finish(topo);
}
sbuf_delete(topo);
return (err);
}
#endif
static int
sysctl_kern_quantum(SYSCTL_HANDLER_ARGS)
{
int error, new_val, period;
period = 1000000 / realstathz;
new_val = period * sched_slice;
error = sysctl_handle_int(oidp, &new_val, 0, req);
if (error != 0 || req->newptr == NULL)
return (error);
if (new_val <= 0)
return (EINVAL);
sched_slice = imax(1, (new_val + period / 2) / period);
sched_slice_min = sched_slice / SCHED_SLICE_MIN_DIVISOR;
hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) /
realstathz);
return (0);
}
SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler");
SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ULE", 0,
"Scheduler name");
SYSCTL_PROC(_kern_sched, OID_AUTO, quantum, CTLTYPE_INT | CTLFLAG_RW,
NULL, 0, sysctl_kern_quantum, "I",
"Quantum for timeshare threads in microseconds");
SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0,
"Quantum for timeshare threads in stathz ticks");
SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0,
"Interactivity score threshold");
SYSCTL_INT(_kern_sched, OID_AUTO, preempt_thresh, CTLFLAG_RW,
&preempt_thresh, 0,
"Maximal (lowest) priority for preemption");
SYSCTL_INT(_kern_sched, OID_AUTO, static_boost, CTLFLAG_RW, &static_boost, 0,
"Assign static kernel priorities to sleeping threads");
SYSCTL_INT(_kern_sched, OID_AUTO, idlespins, CTLFLAG_RW, &sched_idlespins, 0,
"Number of times idle thread will spin waiting for new work");
SYSCTL_INT(_kern_sched, OID_AUTO, idlespinthresh, CTLFLAG_RW,
&sched_idlespinthresh, 0,
"Threshold before we will permit idle thread spinning");
#ifdef SMP
SYSCTL_INT(_kern_sched, OID_AUTO, affinity, CTLFLAG_RW, &affinity, 0,
"Number of hz ticks to keep thread affinity for");
SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0,
"Enables the long-term load balancer");
SYSCTL_INT(_kern_sched, OID_AUTO, balance_interval, CTLFLAG_RW,
&balance_interval, 0,
"Average period in stathz ticks to run the long-term balancer");
SYSCTL_INT(_kern_sched, OID_AUTO, steal_idle, CTLFLAG_RW, &steal_idle, 0,
"Attempts to steal work from other cores before idling");
SYSCTL_INT(_kern_sched, OID_AUTO, steal_thresh, CTLFLAG_RW, &steal_thresh, 0,
"Minimum load on remote CPU before we'll steal");
SYSCTL_INT(_kern_sched, OID_AUTO, trysteal_limit, CTLFLAG_RW, &trysteal_limit,
0, "Topological distance limit for stealing threads in sched_switch()");
SYSCTL_INT(_kern_sched, OID_AUTO, always_steal, CTLFLAG_RW, &always_steal, 0,
"Always run the stealer from the idle thread");
SYSCTL_PROC(_kern_sched, OID_AUTO, topology_spec, CTLTYPE_STRING |
CTLFLAG_MPSAFE | CTLFLAG_RD, NULL, 0, sysctl_kern_sched_topology_spec, "A",
"XML dump of detected CPU topology");
#endif
/* ps compat. All cpu percentages from ULE are weighted. */
static int ccpu = 0;
SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
Index: head/sys/sys/sched.h
===================================================================
--- head/sys/sys/sched.h (revision 347354)
+++ head/sys/sys/sched.h (revision 347355)
@@ -1,266 +1,267 @@
/*-
* SPDX-License-Identifier: BSD-4-Clause
*
* Copyright (c) 1996, 1997
* HD Associates, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by HD Associates, Inc
* and Jukka Antero Ukkonen.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY HD ASSOCIATES AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL HD ASSOCIATES OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*-
* Copyright (c) 2002-2008, Jeffrey Roberson <jeff@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _SCHED_H_
#define _SCHED_H_
#ifdef _KERNEL
/*
* General scheduling info.
*
* sched_load:
* Total runnable non-ithread threads in the system.
*
* sched_runnable:
* Runnable threads for this processor.
*/
int sched_load(void);
int sched_rr_interval(void);
int sched_runnable(void);
/*
* Proc related scheduling hooks.
*/
void sched_exit(struct proc *p, struct thread *childtd);
void sched_fork(struct thread *td, struct thread *childtd);
void sched_fork_exit(struct thread *td);
void sched_class(struct thread *td, int class);
void sched_nice(struct proc *p, int nice);
/*
* Threads are switched in and out, block on resources, have temporary
* priorities inherited from their procs, and use up cpu time.
*/
void sched_exit_thread(struct thread *td, struct thread *child);
u_int sched_estcpu(struct thread *td);
void sched_fork_thread(struct thread *td, struct thread *child);
void sched_lend_prio(struct thread *td, u_char prio);
void sched_lend_user_prio(struct thread *td, u_char pri);
+void sched_lend_user_prio_cond(struct thread *td, u_char pri);
fixpt_t sched_pctcpu(struct thread *td);
void sched_prio(struct thread *td, u_char prio);
void sched_sleep(struct thread *td, int prio);
void sched_switch(struct thread *td, struct thread *newtd, int flags);
void sched_throw(struct thread *td);
void sched_unlend_prio(struct thread *td, u_char prio);
void sched_user_prio(struct thread *td, u_char prio);
void sched_userret_slowpath(struct thread *td);
void sched_wakeup(struct thread *td);
#ifdef RACCT
#ifdef SCHED_4BSD
fixpt_t sched_pctcpu_delta(struct thread *td);
#endif
#endif
static inline void
sched_userret(struct thread *td)
{
/*
* XXX we cheat slightly on the locking here to avoid locking in
* the usual case. Setting td_priority here is essentially an
* incomplete workaround for not setting it properly elsewhere.
* Now that some interrupt handlers are threads, not setting it
* properly elsewhere can clobber it in the window between setting
* it here and returning to user mode, so don't waste time setting
* it perfectly here.
*/
KASSERT((td->td_flags & TDF_BORROWING) == 0,
("thread with borrowed priority returning to userland"));
if (__predict_false(td->td_priority != td->td_user_pri))
sched_userret_slowpath(td);
}
/*
* Threads are moved on and off of run queues
*/
void sched_add(struct thread *td, int flags);
void sched_clock(struct thread *td);
void sched_preempt(struct thread *td);
void sched_rem(struct thread *td);
void sched_relinquish(struct thread *td);
struct thread *sched_choose(void);
void sched_idletd(void *);
/*
* Binding makes cpu affinity permanent while pinning is used to temporarily
* hold a thread on a particular CPU.
*/
void sched_bind(struct thread *td, int cpu);
static __inline void sched_pin(void);
void sched_unbind(struct thread *td);
static __inline void sched_unpin(void);
int sched_is_bound(struct thread *td);
void sched_affinity(struct thread *td);
/*
* These procedures tell the process data structure allocation code how
* many bytes to actually allocate.
*/
int sched_sizeof_proc(void);
int sched_sizeof_thread(void);
/*
* This routine provides a consistent thread name for use with KTR graphing
* functions.
*/
char *sched_tdname(struct thread *td);
#ifdef KTR
void sched_clear_tdname(struct thread *td);
#endif
static __inline void
sched_pin(void)
{
curthread->td_pinned++;
__compiler_membar();
}
static __inline void
sched_unpin(void)
{
__compiler_membar();
curthread->td_pinned--;
}
/* sched_add arguments (formerly setrunqueue) */
#define SRQ_BORING 0x0000 /* No special circumstances. */
#define SRQ_YIELDING 0x0001 /* We are yielding (from mi_switch). */
#define SRQ_OURSELF 0x0002 /* It is ourself (from mi_switch). */
#define SRQ_INTR 0x0004 /* It is probably urgent. */
#define SRQ_PREEMPTED 0x0008 /* has been preempted.. be kind */
#define SRQ_BORROWING 0x0010 /* Priority updated due to prio_lend */
/* Scheduler stats. */
#ifdef SCHED_STATS
DPCPU_DECLARE(long, sched_switch_stats[SWT_COUNT]);
#define SCHED_STAT_DEFINE_VAR(name, ptr, descr) \
static void name ## _add_proc(void *dummy __unused) \
{ \
\
SYSCTL_ADD_PROC(NULL, \
SYSCTL_STATIC_CHILDREN(_kern_sched_stats), OID_AUTO, \
#name, CTLTYPE_LONG|CTLFLAG_RD|CTLFLAG_MPSAFE, \
ptr, 0, sysctl_dpcpu_long, "LU", descr); \
} \
SYSINIT(name, SI_SUB_LAST, SI_ORDER_MIDDLE, name ## _add_proc, NULL);
#define SCHED_STAT_DEFINE(name, descr) \
DPCPU_DEFINE(unsigned long, name); \
SCHED_STAT_DEFINE_VAR(name, &DPCPU_NAME(name), descr)
/*
* Sched stats are always incremented in critical sections so no atomic
* is necesssary to increment them.
*/
#define SCHED_STAT_INC(var) DPCPU_GET(var)++;
#else
#define SCHED_STAT_DEFINE_VAR(name, descr, ptr)
#define SCHED_STAT_DEFINE(name, descr)
#define SCHED_STAT_INC(var) (void)0
#endif
/*
* Fixup scheduler state for proc0 and thread0
*/
void schedinit(void);
#endif /* _KERNEL */
/* POSIX 1003.1b Process Scheduling */
/*
* POSIX scheduling policies
*/
#define SCHED_FIFO 1
#define SCHED_OTHER 2
#define SCHED_RR 3
struct sched_param {
int sched_priority;
};
/*
* POSIX scheduling declarations for userland.
*/
#ifndef _KERNEL
#include <sys/cdefs.h>
#include <sys/_timespec.h>
#include <sys/_types.h>
#ifndef _PID_T_DECLARED
typedef __pid_t pid_t;
#define _PID_T_DECLARED
#endif
__BEGIN_DECLS
int sched_get_priority_max(int);
int sched_get_priority_min(int);
int sched_getparam(pid_t, struct sched_param *);
int sched_getscheduler(pid_t);
int sched_rr_get_interval(pid_t, struct timespec *);
int sched_setparam(pid_t, const struct sched_param *);
int sched_setscheduler(pid_t, int, const struct sched_param *);
int sched_yield(void);
__END_DECLS
#endif
#endif /* !_SCHED_H_ */