Index: head/sys/kern/subr_smp.c =================================================================== --- head/sys/kern/subr_smp.c (revision 355240) +++ head/sys/kern/subr_smp.c (revision 355241) @@ -1,1259 +1,1259 @@ /*- * SPDX-License-Identifier: BSD-2-Clause-FreeBSD * * Copyright (c) 2001, John Baldwin . * * 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. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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. */ /* * This module holds the global variables and machine independent functions * used for the kernel SMP support. */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "opt_sched.h" #ifdef SMP MALLOC_DEFINE(M_TOPO, "toponodes", "SMP topology data"); volatile cpuset_t stopped_cpus; volatile cpuset_t started_cpus; volatile cpuset_t suspended_cpus; cpuset_t hlt_cpus_mask; cpuset_t logical_cpus_mask; void (*cpustop_restartfunc)(void); #endif static int sysctl_kern_smp_active(SYSCTL_HANDLER_ARGS); /* This is used in modules that need to work in both SMP and UP. */ cpuset_t all_cpus; int mp_ncpus; /* export this for libkvm consumers. */ int mp_maxcpus = MAXCPU; volatile int smp_started; u_int mp_maxid; static SYSCTL_NODE(_kern, OID_AUTO, smp, CTLFLAG_RD|CTLFLAG_CAPRD, NULL, "Kernel SMP"); SYSCTL_INT(_kern_smp, OID_AUTO, maxid, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_maxid, 0, "Max CPU ID."); SYSCTL_INT(_kern_smp, OID_AUTO, maxcpus, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_maxcpus, 0, "Max number of CPUs that the system was compiled for."); SYSCTL_PROC(_kern_smp, OID_AUTO, active, CTLFLAG_RD|CTLTYPE_INT|CTLFLAG_MPSAFE, NULL, 0, sysctl_kern_smp_active, "I", "Indicates system is running in SMP mode"); int smp_disabled = 0; /* has smp been disabled? */ SYSCTL_INT(_kern_smp, OID_AUTO, disabled, CTLFLAG_RDTUN|CTLFLAG_CAPRD, &smp_disabled, 0, "SMP has been disabled from the loader"); int smp_cpus = 1; /* how many cpu's running */ SYSCTL_INT(_kern_smp, OID_AUTO, cpus, CTLFLAG_RD|CTLFLAG_CAPRD, &smp_cpus, 0, "Number of CPUs online"); int smp_threads_per_core = 1; /* how many SMT threads are running per core */ SYSCTL_INT(_kern_smp, OID_AUTO, threads_per_core, CTLFLAG_RD|CTLFLAG_CAPRD, &smp_threads_per_core, 0, "Number of SMT threads online per core"); int mp_ncores = -1; /* how many physical cores running */ SYSCTL_INT(_kern_smp, OID_AUTO, cores, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_ncores, 0, "Number of CPUs online"); int smp_topology = 0; /* Which topology we're using. */ SYSCTL_INT(_kern_smp, OID_AUTO, topology, CTLFLAG_RDTUN, &smp_topology, 0, "Topology override setting; 0 is default provided by hardware."); #ifdef SMP /* Enable forwarding of a signal to a process running on a different CPU */ static int forward_signal_enabled = 1; SYSCTL_INT(_kern_smp, OID_AUTO, forward_signal_enabled, CTLFLAG_RW, &forward_signal_enabled, 0, "Forwarding of a signal to a process on a different CPU"); /* Variables needed for SMP rendezvous. */ static volatile int smp_rv_ncpus; static void (*volatile smp_rv_setup_func)(void *arg); static void (*volatile smp_rv_action_func)(void *arg); static void (*volatile smp_rv_teardown_func)(void *arg); static void *volatile smp_rv_func_arg; static volatile int smp_rv_waiters[4]; /* * Shared mutex to restrict busywaits between smp_rendezvous() and * smp(_targeted)_tlb_shootdown(). A deadlock occurs if both of these * functions trigger at once and cause multiple CPUs to busywait with * interrupts disabled. */ struct mtx smp_ipi_mtx; /* * Let the MD SMP code initialize mp_maxid very early if it can. */ static void mp_setmaxid(void *dummy) { cpu_mp_setmaxid(); KASSERT(mp_ncpus >= 1, ("%s: CPU count < 1", __func__)); KASSERT(mp_ncpus > 1 || mp_maxid == 0, ("%s: one CPU but mp_maxid is not zero", __func__)); KASSERT(mp_maxid >= mp_ncpus - 1, ("%s: counters out of sync: max %d, count %d", __func__, mp_maxid, mp_ncpus)); } SYSINIT(cpu_mp_setmaxid, SI_SUB_TUNABLES, SI_ORDER_FIRST, mp_setmaxid, NULL); /* * Call the MD SMP initialization code. */ static void mp_start(void *dummy) { mtx_init(&smp_ipi_mtx, "smp rendezvous", NULL, MTX_SPIN); /* Probe for MP hardware. */ if (smp_disabled != 0 || cpu_mp_probe() == 0) { mp_ncores = 1; mp_ncpus = 1; CPU_SETOF(PCPU_GET(cpuid), &all_cpus); return; } cpu_mp_start(); printf("FreeBSD/SMP: Multiprocessor System Detected: %d CPUs\n", mp_ncpus); /* Provide a default for most architectures that don't have SMT/HTT. */ if (mp_ncores < 0) mp_ncores = mp_ncpus; cpu_mp_announce(); } SYSINIT(cpu_mp, SI_SUB_CPU, SI_ORDER_THIRD, mp_start, NULL); void forward_signal(struct thread *td) { int id; /* * signotify() has already set TDF_ASTPENDING and TDF_NEEDSIGCHECK on * this thread, so all we need to do is poke it if it is currently * executing so that it executes ast(). */ THREAD_LOCK_ASSERT(td, MA_OWNED); KASSERT(TD_IS_RUNNING(td), ("forward_signal: thread is not TDS_RUNNING")); CTR1(KTR_SMP, "forward_signal(%p)", td->td_proc); if (!smp_started || cold || panicstr) return; if (!forward_signal_enabled) return; /* No need to IPI ourself. */ if (td == curthread) return; id = td->td_oncpu; if (id == NOCPU) return; ipi_cpu(id, IPI_AST); } /* * When called the executing CPU will send an IPI to all other CPUs * requesting that they halt execution. * * Usually (but not necessarily) called with 'other_cpus' as its arg. * * - Signals all CPUs in map to stop. * - Waits for each to stop. * * Returns: * -1: error * 0: NA * 1: ok * */ #if defined(__amd64__) || defined(__i386__) #define X86 1 #else #define X86 0 #endif static int generic_stop_cpus(cpuset_t map, u_int type) { #ifdef KTR char cpusetbuf[CPUSETBUFSIZ]; #endif static volatile u_int stopping_cpu = NOCPU; int i; volatile cpuset_t *cpus; KASSERT( type == IPI_STOP || type == IPI_STOP_HARD #if X86 || type == IPI_SUSPEND #endif , ("%s: invalid stop type", __func__)); if (!smp_started) return (0); CTR2(KTR_SMP, "stop_cpus(%s) with %u type", cpusetobj_strprint(cpusetbuf, &map), type); #if X86 /* * When suspending, ensure there are are no IPIs in progress. * IPIs that have been issued, but not yet delivered (e.g. * not pending on a vCPU when running under virtualization) * will be lost, violating FreeBSD's assumption of reliable * IPI delivery. */ if (type == IPI_SUSPEND) mtx_lock_spin(&smp_ipi_mtx); #endif #if X86 if (!nmi_is_broadcast || nmi_kdb_lock == 0) { #endif if (stopping_cpu != PCPU_GET(cpuid)) while (atomic_cmpset_int(&stopping_cpu, NOCPU, PCPU_GET(cpuid)) == 0) while (stopping_cpu != NOCPU) cpu_spinwait(); /* spin */ /* send the stop IPI to all CPUs in map */ ipi_selected(map, type); #if X86 } #endif #if X86 if (type == IPI_SUSPEND) cpus = &suspended_cpus; else #endif cpus = &stopped_cpus; i = 0; while (!CPU_SUBSET(cpus, &map)) { /* spin */ cpu_spinwait(); i++; if (i == 100000000) { printf("timeout stopping cpus\n"); break; } } #if X86 if (type == IPI_SUSPEND) mtx_unlock_spin(&smp_ipi_mtx); #endif stopping_cpu = NOCPU; return (1); } int stop_cpus(cpuset_t map) { return (generic_stop_cpus(map, IPI_STOP)); } int stop_cpus_hard(cpuset_t map) { return (generic_stop_cpus(map, IPI_STOP_HARD)); } #if X86 int suspend_cpus(cpuset_t map) { return (generic_stop_cpus(map, IPI_SUSPEND)); } #endif /* * Called by a CPU to restart stopped CPUs. * * Usually (but not necessarily) called with 'stopped_cpus' as its arg. * * - Signals all CPUs in map to restart. * - Waits for each to restart. * * Returns: * -1: error * 0: NA * 1: ok */ static int generic_restart_cpus(cpuset_t map, u_int type) { #ifdef KTR char cpusetbuf[CPUSETBUFSIZ]; #endif volatile cpuset_t *cpus; #if X86 KASSERT(type == IPI_STOP || type == IPI_STOP_HARD || type == IPI_SUSPEND, ("%s: invalid stop type", __func__)); if (!smp_started) return (0); CTR1(KTR_SMP, "restart_cpus(%s)", cpusetobj_strprint(cpusetbuf, &map)); if (type == IPI_SUSPEND) cpus = &resuming_cpus; else cpus = &stopped_cpus; /* signal other cpus to restart */ if (type == IPI_SUSPEND) CPU_COPY_STORE_REL(&map, &toresume_cpus); else CPU_COPY_STORE_REL(&map, &started_cpus); /* * Wake up any CPUs stopped with MWAIT. From MI code we can't tell if * MONITOR/MWAIT is enabled, but the potentially redundant writes are * relatively inexpensive. */ if (type == IPI_STOP) { struct monitorbuf *mb; u_int id; CPU_FOREACH(id) { if (!CPU_ISSET(id, &map)) continue; mb = &pcpu_find(id)->pc_monitorbuf; atomic_store_int(&mb->stop_state, MONITOR_STOPSTATE_RUNNING); } } if (!nmi_is_broadcast || nmi_kdb_lock == 0) { /* wait for each to clear its bit */ while (CPU_OVERLAP(cpus, &map)) cpu_spinwait(); } #else /* !X86 */ KASSERT(type == IPI_STOP || type == IPI_STOP_HARD, ("%s: invalid stop type", __func__)); if (!smp_started) return (0); CTR1(KTR_SMP, "restart_cpus(%s)", cpusetobj_strprint(cpusetbuf, &map)); cpus = &stopped_cpus; /* signal other cpus to restart */ CPU_COPY_STORE_REL(&map, &started_cpus); /* wait for each to clear its bit */ while (CPU_OVERLAP(cpus, &map)) cpu_spinwait(); #endif return (1); } int restart_cpus(cpuset_t map) { return (generic_restart_cpus(map, IPI_STOP)); } #if X86 int resume_cpus(cpuset_t map) { return (generic_restart_cpus(map, IPI_SUSPEND)); } #endif #undef X86 /* * All-CPU rendezvous. CPUs are signalled, all execute the setup function * (if specified), rendezvous, execute the action function (if specified), * rendezvous again, execute the teardown function (if specified), and then * resume. * * Note that the supplied external functions _must_ be reentrant and aware * that they are running in parallel and in an unknown lock context. */ void smp_rendezvous_action(void) { struct thread *td; void *local_func_arg; void (*local_setup_func)(void*); void (*local_action_func)(void*); void (*local_teardown_func)(void*); #ifdef INVARIANTS int owepreempt; #endif /* Ensure we have up-to-date values. */ atomic_add_acq_int(&smp_rv_waiters[0], 1); while (smp_rv_waiters[0] < smp_rv_ncpus) cpu_spinwait(); /* Fetch rendezvous parameters after acquire barrier. */ local_func_arg = smp_rv_func_arg; local_setup_func = smp_rv_setup_func; local_action_func = smp_rv_action_func; local_teardown_func = smp_rv_teardown_func; /* * Use a nested critical section to prevent any preemptions * from occurring during a rendezvous action routine. * Specifically, if a rendezvous handler is invoked via an IPI * and the interrupted thread was in the critical_exit() * function after setting td_critnest to 0 but before * performing a deferred preemption, this routine can be * invoked with td_critnest set to 0 and td_owepreempt true. * In that case, a critical_exit() during the rendezvous * action would trigger a preemption which is not permitted in * a rendezvous action. To fix this, wrap all of the * rendezvous action handlers in a critical section. We * cannot use a regular critical section however as having * critical_exit() preempt from this routine would also be * problematic (the preemption must not occur before the IPI * has been acknowledged via an EOI). Instead, we * intentionally ignore td_owepreempt when leaving the * critical section. This should be harmless because we do * not permit rendezvous action routines to schedule threads, * and thus td_owepreempt should never transition from 0 to 1 * during this routine. */ td = curthread; td->td_critnest++; #ifdef INVARIANTS owepreempt = td->td_owepreempt; #endif /* * If requested, run a setup function before the main action * function. Ensure all CPUs have completed the setup * function before moving on to the action function. */ if (local_setup_func != smp_no_rendezvous_barrier) { if (smp_rv_setup_func != NULL) smp_rv_setup_func(smp_rv_func_arg); atomic_add_int(&smp_rv_waiters[1], 1); while (smp_rv_waiters[1] < smp_rv_ncpus) cpu_spinwait(); } if (local_action_func != NULL) local_action_func(local_func_arg); if (local_teardown_func != smp_no_rendezvous_barrier) { /* * Signal that the main action has been completed. If a * full exit rendezvous is requested, then all CPUs will * wait here until all CPUs have finished the main action. */ atomic_add_int(&smp_rv_waiters[2], 1); while (smp_rv_waiters[2] < smp_rv_ncpus) cpu_spinwait(); if (local_teardown_func != NULL) local_teardown_func(local_func_arg); } /* * Signal that the rendezvous is fully completed by this CPU. * This means that no member of smp_rv_* pseudo-structure will be * accessed by this target CPU after this point; in particular, * memory pointed by smp_rv_func_arg. * * The release semantic ensures that all accesses performed by * the current CPU are visible when smp_rendezvous_cpus() * returns, by synchronizing with the * atomic_load_acq_int(&smp_rv_waiters[3]). */ atomic_add_rel_int(&smp_rv_waiters[3], 1); td->td_critnest--; KASSERT(owepreempt == td->td_owepreempt, ("rendezvous action changed td_owepreempt")); } void smp_rendezvous_cpus(cpuset_t map, void (* setup_func)(void *), void (* action_func)(void *), void (* teardown_func)(void *), void *arg) { int curcpumap, i, ncpus = 0; /* Look comments in the !SMP case. */ if (!smp_started) { spinlock_enter(); if (setup_func != NULL) setup_func(arg); if (action_func != NULL) action_func(arg); if (teardown_func != NULL) teardown_func(arg); spinlock_exit(); return; } CPU_FOREACH(i) { if (CPU_ISSET(i, &map)) ncpus++; } if (ncpus == 0) panic("ncpus is 0 with non-zero map"); mtx_lock_spin(&smp_ipi_mtx); /* Pass rendezvous parameters via global variables. */ smp_rv_ncpus = ncpus; smp_rv_setup_func = setup_func; smp_rv_action_func = action_func; smp_rv_teardown_func = teardown_func; smp_rv_func_arg = arg; smp_rv_waiters[1] = 0; smp_rv_waiters[2] = 0; smp_rv_waiters[3] = 0; atomic_store_rel_int(&smp_rv_waiters[0], 0); /* * Signal other processors, which will enter the IPI with * interrupts off. */ curcpumap = CPU_ISSET(curcpu, &map); CPU_CLR(curcpu, &map); ipi_selected(map, IPI_RENDEZVOUS); /* Check if the current CPU is in the map */ if (curcpumap != 0) smp_rendezvous_action(); /* * Ensure that the master CPU waits for all the other * CPUs to finish the rendezvous, so that smp_rv_* * pseudo-structure and the arg are guaranteed to not * be in use. * * Load acquire synchronizes with the release add in * smp_rendezvous_action(), which ensures that our caller sees * all memory actions done by the called functions on other * CPUs. */ while (atomic_load_acq_int(&smp_rv_waiters[3]) < ncpus) cpu_spinwait(); mtx_unlock_spin(&smp_ipi_mtx); } void smp_rendezvous(void (* setup_func)(void *), void (* action_func)(void *), void (* teardown_func)(void *), void *arg) { smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, arg); } static struct cpu_group group[MAXCPU * MAX_CACHE_LEVELS + 1]; struct cpu_group * smp_topo(void) { char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; struct cpu_group *top; /* * Check for a fake topology request for debugging purposes. */ switch (smp_topology) { case 1: /* Dual core with no sharing. */ top = smp_topo_1level(CG_SHARE_NONE, 2, 0); break; case 2: /* No topology, all cpus are equal. */ top = smp_topo_none(); break; case 3: /* Dual core with shared L2. */ top = smp_topo_1level(CG_SHARE_L2, 2, 0); break; case 4: /* quad core, shared l3 among each package, private l2. */ top = smp_topo_1level(CG_SHARE_L3, 4, 0); break; case 5: /* quad core, 2 dualcore parts on each package share l2. */ top = smp_topo_2level(CG_SHARE_NONE, 2, CG_SHARE_L2, 2, 0); break; case 6: /* Single-core 2xHTT */ top = smp_topo_1level(CG_SHARE_L1, 2, CG_FLAG_HTT); break; case 7: /* quad core with a shared l3, 8 threads sharing L2. */ top = smp_topo_2level(CG_SHARE_L3, 4, CG_SHARE_L2, 8, CG_FLAG_SMT); break; default: /* Default, ask the system what it wants. */ top = cpu_topo(); break; } /* * Verify the returned topology. */ if (top->cg_count != mp_ncpus) panic("Built bad topology at %p. CPU count %d != %d", top, top->cg_count, mp_ncpus); if (CPU_CMP(&top->cg_mask, &all_cpus)) panic("Built bad topology at %p. CPU mask (%s) != (%s)", top, cpusetobj_strprint(cpusetbuf, &top->cg_mask), cpusetobj_strprint(cpusetbuf2, &all_cpus)); /* * Collapse nonsense levels that may be created out of convenience by * the MD layers. They cause extra work in the search functions. */ while (top->cg_children == 1) { top = &top->cg_child[0]; top->cg_parent = NULL; } return (top); } struct cpu_group * smp_topo_alloc(u_int count) { static u_int index; u_int curr; curr = index; index += count; return (&group[curr]); } struct cpu_group * smp_topo_none(void) { struct cpu_group *top; top = &group[0]; top->cg_parent = NULL; top->cg_child = NULL; top->cg_mask = all_cpus; top->cg_count = mp_ncpus; top->cg_children = 0; top->cg_level = CG_SHARE_NONE; top->cg_flags = 0; return (top); } static int smp_topo_addleaf(struct cpu_group *parent, struct cpu_group *child, int share, int count, int flags, int start) { char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; cpuset_t mask; int i; CPU_ZERO(&mask); for (i = 0; i < count; i++, start++) CPU_SET(start, &mask); child->cg_parent = parent; child->cg_child = NULL; child->cg_children = 0; child->cg_level = share; child->cg_count = count; child->cg_flags = flags; child->cg_mask = mask; parent->cg_children++; for (; parent != NULL; parent = parent->cg_parent) { if (CPU_OVERLAP(&parent->cg_mask, &child->cg_mask)) panic("Duplicate children in %p. mask (%s) child (%s)", parent, cpusetobj_strprint(cpusetbuf, &parent->cg_mask), cpusetobj_strprint(cpusetbuf2, &child->cg_mask)); CPU_OR(&parent->cg_mask, &child->cg_mask); parent->cg_count += child->cg_count; } return (start); } struct cpu_group * smp_topo_1level(int share, int count, int flags) { struct cpu_group *child; struct cpu_group *top; int packages; int cpu; int i; cpu = 0; top = &group[0]; packages = mp_ncpus / count; top->cg_child = child = &group[1]; top->cg_level = CG_SHARE_NONE; for (i = 0; i < packages; i++, child++) cpu = smp_topo_addleaf(top, child, share, count, flags, cpu); return (top); } struct cpu_group * smp_topo_2level(int l2share, int l2count, int l1share, int l1count, int l1flags) { struct cpu_group *top; struct cpu_group *l1g; struct cpu_group *l2g; int cpu; int i; int j; cpu = 0; top = &group[0]; l2g = &group[1]; top->cg_child = l2g; top->cg_level = CG_SHARE_NONE; top->cg_children = mp_ncpus / (l2count * l1count); l1g = l2g + top->cg_children; for (i = 0; i < top->cg_children; i++, l2g++) { l2g->cg_parent = top; l2g->cg_child = l1g; l2g->cg_level = l2share; for (j = 0; j < l2count; j++, l1g++) cpu = smp_topo_addleaf(l2g, l1g, l1share, l1count, l1flags, cpu); } return (top); } struct cpu_group * smp_topo_find(struct cpu_group *top, int cpu) { struct cpu_group *cg; cpuset_t mask; int children; int i; CPU_SETOF(cpu, &mask); cg = top; for (;;) { if (!CPU_OVERLAP(&cg->cg_mask, &mask)) return (NULL); if (cg->cg_children == 0) return (cg); children = cg->cg_children; for (i = 0, cg = cg->cg_child; i < children; cg++, i++) if (CPU_OVERLAP(&cg->cg_mask, &mask)) break; } return (NULL); } #else /* !SMP */ void smp_rendezvous_cpus(cpuset_t map, void (*setup_func)(void *), void (*action_func)(void *), void (*teardown_func)(void *), void *arg) { /* * In the !SMP case we just need to ensure the same initial conditions * as the SMP case. */ spinlock_enter(); if (setup_func != NULL) setup_func(arg); if (action_func != NULL) action_func(arg); if (teardown_func != NULL) teardown_func(arg); spinlock_exit(); } void smp_rendezvous(void (*setup_func)(void *), void (*action_func)(void *), void (*teardown_func)(void *), void *arg) { smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, arg); } /* * Provide dummy SMP support for UP kernels. Modules that need to use SMP * APIs will still work using this dummy support. */ static void mp_setvariables_for_up(void *dummy) { mp_ncpus = 1; mp_ncores = 1; mp_maxid = PCPU_GET(cpuid); CPU_SETOF(mp_maxid, &all_cpus); KASSERT(PCPU_GET(cpuid) == 0, ("UP must have a CPU ID of zero")); } SYSINIT(cpu_mp_setvariables, SI_SUB_TUNABLES, SI_ORDER_FIRST, mp_setvariables_for_up, NULL); #endif /* SMP */ void smp_no_rendezvous_barrier(void *dummy) { #ifdef SMP KASSERT((!smp_started),("smp_no_rendezvous called and smp is started")); #endif } /* * Wait for specified idle threads to switch once. This ensures that even * preempted threads have cycled through the switch function once, * exiting their codepaths. This allows us to change global pointers * with no other synchronization. */ int quiesce_cpus(cpuset_t map, const char *wmesg, int prio) { struct pcpu *pcpu; u_int gen[MAXCPU]; int error; int cpu; error = 0; for (cpu = 0; cpu <= mp_maxid; cpu++) { if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) continue; pcpu = pcpu_find(cpu); gen[cpu] = pcpu->pc_idlethread->td_generation; } for (cpu = 0; cpu <= mp_maxid; cpu++) { if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) continue; pcpu = pcpu_find(cpu); thread_lock(curthread); sched_bind(curthread, cpu); thread_unlock(curthread); while (gen[cpu] == pcpu->pc_idlethread->td_generation) { error = tsleep(quiesce_cpus, prio, wmesg, 1); if (error != EWOULDBLOCK) goto out; error = 0; } } out: thread_lock(curthread); sched_unbind(curthread); thread_unlock(curthread); return (error); } int quiesce_all_cpus(const char *wmesg, int prio) { return quiesce_cpus(all_cpus, wmesg, prio); } /* * Observe all CPUs not executing in critical section. * We are not in one so the check for us is safe. If the found * thread changes to something else we know the section was * exited as well. */ void quiesce_all_critical(void) { struct thread *td, *newtd; struct pcpu *pcpu; int cpu; MPASS(curthread->td_critnest == 0); CPU_FOREACH(cpu) { pcpu = cpuid_to_pcpu[cpu]; td = pcpu->pc_curthread; for (;;) { if (td->td_critnest == 0) break; cpu_spinwait(); newtd = (struct thread *) - atomic_load_acq_ptr((u_long *)pcpu->pc_curthread); + atomic_load_acq_ptr((void *)pcpu->pc_curthread); if (td != newtd) break; } } } static void cpus_fence_seq_cst_issue(void *arg __unused) { atomic_thread_fence_seq_cst(); } /* * Send an IPI forcing a sequentially consistent fence. * * Allows replacement of an explicitly fence with a compiler barrier. * Trades speed up during normal execution for a significant slowdown when * the barrier is needed. */ void cpus_fence_seq_cst(void) { #ifdef SMP smp_rendezvous( smp_no_rendezvous_barrier, cpus_fence_seq_cst_issue, smp_no_rendezvous_barrier, NULL ); #else cpus_fence_seq_cst_issue(NULL); #endif } /* Extra care is taken with this sysctl because the data type is volatile */ static int sysctl_kern_smp_active(SYSCTL_HANDLER_ARGS) { int error, active; active = smp_started; error = SYSCTL_OUT(req, &active, sizeof(active)); return (error); } #ifdef SMP void topo_init_node(struct topo_node *node) { bzero(node, sizeof(*node)); TAILQ_INIT(&node->children); } void topo_init_root(struct topo_node *root) { topo_init_node(root); root->type = TOPO_TYPE_SYSTEM; } /* * Add a child node with the given ID under the given parent. * Do nothing if there is already a child with that ID. */ struct topo_node * topo_add_node_by_hwid(struct topo_node *parent, int hwid, topo_node_type type, uintptr_t subtype) { struct topo_node *node; TAILQ_FOREACH_REVERSE(node, &parent->children, topo_children, siblings) { if (node->hwid == hwid && node->type == type && node->subtype == subtype) { return (node); } } node = malloc(sizeof(*node), M_TOPO, M_WAITOK); topo_init_node(node); node->parent = parent; node->hwid = hwid; node->type = type; node->subtype = subtype; TAILQ_INSERT_TAIL(&parent->children, node, siblings); parent->nchildren++; return (node); } /* * Find a child node with the given ID under the given parent. */ struct topo_node * topo_find_node_by_hwid(struct topo_node *parent, int hwid, topo_node_type type, uintptr_t subtype) { struct topo_node *node; TAILQ_FOREACH(node, &parent->children, siblings) { if (node->hwid == hwid && node->type == type && node->subtype == subtype) { return (node); } } return (NULL); } /* * Given a node change the order of its parent's child nodes such * that the node becomes the firt child while preserving the cyclic * order of the children. In other words, the given node is promoted * by rotation. */ void topo_promote_child(struct topo_node *child) { struct topo_node *next; struct topo_node *node; struct topo_node *parent; parent = child->parent; next = TAILQ_NEXT(child, siblings); TAILQ_REMOVE(&parent->children, child, siblings); TAILQ_INSERT_HEAD(&parent->children, child, siblings); while (next != NULL) { node = next; next = TAILQ_NEXT(node, siblings); TAILQ_REMOVE(&parent->children, node, siblings); TAILQ_INSERT_AFTER(&parent->children, child, node, siblings); child = node; } } /* * Iterate to the next node in the depth-first search (traversal) of * the topology tree. */ struct topo_node * topo_next_node(struct topo_node *top, struct topo_node *node) { struct topo_node *next; if ((next = TAILQ_FIRST(&node->children)) != NULL) return (next); if ((next = TAILQ_NEXT(node, siblings)) != NULL) return (next); while (node != top && (node = node->parent) != top) if ((next = TAILQ_NEXT(node, siblings)) != NULL) return (next); return (NULL); } /* * Iterate to the next node in the depth-first search of the topology tree, * but without descending below the current node. */ struct topo_node * topo_next_nonchild_node(struct topo_node *top, struct topo_node *node) { struct topo_node *next; if ((next = TAILQ_NEXT(node, siblings)) != NULL) return (next); while (node != top && (node = node->parent) != top) if ((next = TAILQ_NEXT(node, siblings)) != NULL) return (next); return (NULL); } /* * Assign the given ID to the given topology node that represents a logical * processor. */ void topo_set_pu_id(struct topo_node *node, cpuid_t id) { KASSERT(node->type == TOPO_TYPE_PU, ("topo_set_pu_id: wrong node type: %u", node->type)); KASSERT(CPU_EMPTY(&node->cpuset) && node->cpu_count == 0, ("topo_set_pu_id: cpuset already not empty")); node->id = id; CPU_SET(id, &node->cpuset); node->cpu_count = 1; node->subtype = 1; while ((node = node->parent) != NULL) { KASSERT(!CPU_ISSET(id, &node->cpuset), ("logical ID %u is already set in node %p", id, node)); CPU_SET(id, &node->cpuset); node->cpu_count++; } } static struct topology_spec { topo_node_type type; bool match_subtype; uintptr_t subtype; } topology_level_table[TOPO_LEVEL_COUNT] = { [TOPO_LEVEL_PKG] = { .type = TOPO_TYPE_PKG, }, [TOPO_LEVEL_GROUP] = { .type = TOPO_TYPE_GROUP, }, [TOPO_LEVEL_CACHEGROUP] = { .type = TOPO_TYPE_CACHE, .match_subtype = true, .subtype = CG_SHARE_L3, }, [TOPO_LEVEL_CORE] = { .type = TOPO_TYPE_CORE, }, [TOPO_LEVEL_THREAD] = { .type = TOPO_TYPE_PU, }, }; static bool topo_analyze_table(struct topo_node *root, int all, enum topo_level level, struct topo_analysis *results) { struct topology_spec *spec; struct topo_node *node; int count; if (level >= TOPO_LEVEL_COUNT) return (true); spec = &topology_level_table[level]; count = 0; node = topo_next_node(root, root); while (node != NULL) { if (node->type != spec->type || (spec->match_subtype && node->subtype != spec->subtype)) { node = topo_next_node(root, node); continue; } if (!all && CPU_EMPTY(&node->cpuset)) { node = topo_next_nonchild_node(root, node); continue; } count++; if (!topo_analyze_table(node, all, level + 1, results)) return (false); node = topo_next_nonchild_node(root, node); } /* No explicit subgroups is essentially one subgroup. */ if (count == 0) { count = 1; if (!topo_analyze_table(root, all, level + 1, results)) return (false); } if (results->entities[level] == -1) results->entities[level] = count; else if (results->entities[level] != count) return (false); return (true); } /* * Check if the topology is uniform, that is, each package has the same number * of cores in it and each core has the same number of threads (logical * processors) in it. If so, calculate the number of packages, the number of * groups per package, the number of cachegroups per group, and the number of * logical processors per cachegroup. 'all' parameter tells whether to include * administratively disabled logical processors into the analysis. */ int topo_analyze(struct topo_node *topo_root, int all, struct topo_analysis *results) { results->entities[TOPO_LEVEL_PKG] = -1; results->entities[TOPO_LEVEL_CORE] = -1; results->entities[TOPO_LEVEL_THREAD] = -1; results->entities[TOPO_LEVEL_GROUP] = -1; results->entities[TOPO_LEVEL_CACHEGROUP] = -1; if (!topo_analyze_table(topo_root, all, TOPO_LEVEL_PKG, results)) return (0); KASSERT(results->entities[TOPO_LEVEL_PKG] > 0, ("bug in topology or analysis")); return (1); } #endif /* SMP */