diff --git a/sys/kern/kern_mutex.c b/sys/kern/kern_mutex.c index 7f348530ed31..6071ac7fd6f1 100644 --- a/sys/kern/kern_mutex.c +++ b/sys/kern/kern_mutex.c @@ -1,1353 +1,1356 @@ /*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1998 Berkeley Software Design, 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. Berkeley Software Design Inc's name may not be used to endorse or * promote products derived from this software without specific prior * written permission. * * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``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 BERKELEY SOFTWARE DESIGN INC 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. * * from BSDI $Id: mutex_witness.c,v 1.1.2.20 2000/04/27 03:10:27 cp Exp $ * and BSDI $Id: synch_machdep.c,v 2.3.2.39 2000/04/27 03:10:25 cp Exp $ */ /* * Machine independent bits of mutex implementation. */ #include #include "opt_adaptive_mutexes.h" #include "opt_ddb.h" #include "opt_hwpmc_hooks.h" #include "opt_sched.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES) #define ADAPTIVE_MUTEXES #endif #ifdef HWPMC_HOOKS #include PMC_SOFT_DEFINE( , , lock, failed); #endif /* * Return the mutex address when the lock cookie address is provided. * This functionality assumes that struct mtx* have a member named mtx_lock. */ #define mtxlock2mtx(c) (__containerof(c, struct mtx, mtx_lock)) /* * Internal utility macros. */ #define mtx_unowned(m) ((m)->mtx_lock == MTX_UNOWNED) #define mtx_destroyed(m) ((m)->mtx_lock == MTX_DESTROYED) static void assert_mtx(const struct lock_object *lock, int what); #ifdef DDB static void db_show_mtx(const struct lock_object *lock); #endif static void lock_mtx(struct lock_object *lock, uintptr_t how); static void lock_spin(struct lock_object *lock, uintptr_t how); #ifdef KDTRACE_HOOKS static int owner_mtx(const struct lock_object *lock, struct thread **owner); #endif static uintptr_t unlock_mtx(struct lock_object *lock); static uintptr_t unlock_spin(struct lock_object *lock); /* * Lock classes for sleep and spin mutexes. */ struct lock_class lock_class_mtx_sleep = { .lc_name = "sleep mutex", .lc_flags = LC_SLEEPLOCK | LC_RECURSABLE, .lc_assert = assert_mtx, #ifdef DDB .lc_ddb_show = db_show_mtx, #endif .lc_lock = lock_mtx, .lc_unlock = unlock_mtx, #ifdef KDTRACE_HOOKS .lc_owner = owner_mtx, #endif }; struct lock_class lock_class_mtx_spin = { .lc_name = "spin mutex", .lc_flags = LC_SPINLOCK | LC_RECURSABLE, .lc_assert = assert_mtx, #ifdef DDB .lc_ddb_show = db_show_mtx, #endif .lc_lock = lock_spin, .lc_unlock = unlock_spin, #ifdef KDTRACE_HOOKS .lc_owner = owner_mtx, #endif }; #ifdef ADAPTIVE_MUTEXES #ifdef MUTEX_CUSTOM_BACKOFF static SYSCTL_NODE(_debug, OID_AUTO, mtx, CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, "mtx debugging"); static struct lock_delay_config __read_frequently mtx_delay; SYSCTL_U16(_debug_mtx, OID_AUTO, delay_base, CTLFLAG_RW, &mtx_delay.base, 0, ""); SYSCTL_U16(_debug_mtx, OID_AUTO, delay_max, CTLFLAG_RW, &mtx_delay.max, 0, ""); LOCK_DELAY_SYSINIT_DEFAULT(mtx_delay); #else #define mtx_delay locks_delay #endif #endif #ifdef MUTEX_SPIN_CUSTOM_BACKOFF static SYSCTL_NODE(_debug, OID_AUTO, mtx_spin, CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, "mtx spin debugging"); static struct lock_delay_config __read_frequently mtx_spin_delay; SYSCTL_INT(_debug_mtx_spin, OID_AUTO, delay_base, CTLFLAG_RW, &mtx_spin_delay.base, 0, ""); SYSCTL_INT(_debug_mtx_spin, OID_AUTO, delay_max, CTLFLAG_RW, &mtx_spin_delay.max, 0, ""); LOCK_DELAY_SYSINIT_DEFAULT(mtx_spin_delay); #else #define mtx_spin_delay locks_delay #endif /* * System-wide mutexes */ struct mtx blocked_lock; struct mtx __exclusive_cache_line Giant; static void _mtx_lock_indefinite_check(struct mtx *, struct lock_delay_arg *); void assert_mtx(const struct lock_object *lock, int what) { /* * Treat LA_LOCKED as if LA_XLOCKED was asserted. * * Some callers of lc_assert uses LA_LOCKED to indicate that either * a shared lock or write lock was held, while other callers uses * the more strict LA_XLOCKED (used as MA_OWNED). * * Mutex is the only lock class that can not be shared, as a result, * we can reasonably consider the caller really intends to assert * LA_XLOCKED when they are asserting LA_LOCKED on a mutex object. */ if (what & LA_LOCKED) { what &= ~LA_LOCKED; what |= LA_XLOCKED; } mtx_assert((const struct mtx *)lock, what); } void lock_mtx(struct lock_object *lock, uintptr_t how) { mtx_lock((struct mtx *)lock); } void lock_spin(struct lock_object *lock, uintptr_t how) { mtx_lock_spin((struct mtx *)lock); } uintptr_t unlock_mtx(struct lock_object *lock) { struct mtx *m; m = (struct mtx *)lock; mtx_assert(m, MA_OWNED | MA_NOTRECURSED); mtx_unlock(m); return (0); } uintptr_t unlock_spin(struct lock_object *lock) { struct mtx *m; m = (struct mtx *)lock; mtx_assert(m, MA_OWNED | MA_NOTRECURSED); mtx_unlock_spin(m); return (0); } #ifdef KDTRACE_HOOKS int owner_mtx(const struct lock_object *lock, struct thread **owner) { const struct mtx *m; uintptr_t x; m = (const struct mtx *)lock; x = m->mtx_lock; *owner = (struct thread *)(x & ~MTX_FLAGMASK); return (*owner != NULL); } #endif /* * Function versions of the inlined __mtx_* macros. These are used by * modules and can also be called from assembly language if needed. */ void __mtx_lock_flags(volatile uintptr_t *c, int opts, const char *file, int line) { struct mtx *m; uintptr_t tid, v; m = mtxlock2mtx(c); KASSERT(kdb_active != 0 || SCHEDULER_STOPPED() || !TD_IS_IDLETHREAD(curthread), ("mtx_lock() by idle thread %p on sleep mutex %s @ %s:%d", curthread, m->lock_object.lo_name, file, line)); KASSERT(m->mtx_lock != MTX_DESTROYED, ("mtx_lock() of destroyed mutex @ %s:%d", file, line)); KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep, ("mtx_lock() of spin mutex %s @ %s:%d", m->lock_object.lo_name, file, line)); WITNESS_CHECKORDER(&m->lock_object, (opts & ~MTX_RECURSE) | LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); tid = (uintptr_t)curthread; v = MTX_UNOWNED; if (!_mtx_obtain_lock_fetch(m, &v, tid)) _mtx_lock_sleep(m, v, opts, file, line); else LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(adaptive__acquire, m, 0, 0, file, line); LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file, line); WITNESS_LOCK(&m->lock_object, (opts & ~MTX_RECURSE) | LOP_EXCLUSIVE, file, line); TD_LOCKS_INC(curthread); } void __mtx_unlock_flags(volatile uintptr_t *c, int opts, const char *file, int line) { struct mtx *m; m = mtxlock2mtx(c); KASSERT(m->mtx_lock != MTX_DESTROYED, ("mtx_unlock() of destroyed mutex @ %s:%d", file, line)); KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep, ("mtx_unlock() of spin mutex %s @ %s:%d", m->lock_object.lo_name, file, line)); WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file, line); mtx_assert(m, MA_OWNED); #ifdef LOCK_PROFILING __mtx_unlock_sleep(c, (uintptr_t)curthread, opts, file, line); #else __mtx_unlock(m, curthread, opts, file, line); #endif TD_LOCKS_DEC(curthread); } void __mtx_lock_spin_flags(volatile uintptr_t *c, int opts, const char *file, int line) { struct mtx *m; #ifdef SMP uintptr_t tid, v; #endif m = mtxlock2mtx(c); KASSERT(m->mtx_lock != MTX_DESTROYED, ("mtx_lock_spin() of destroyed mutex @ %s:%d", file, line)); KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, ("mtx_lock_spin() of sleep mutex %s @ %s:%d", m->lock_object.lo_name, file, line)); if (mtx_owned(m)) KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0 || (opts & MTX_RECURSE) != 0, ("mtx_lock_spin: recursed on non-recursive mutex %s @ %s:%d\n", m->lock_object.lo_name, file, line)); opts &= ~MTX_RECURSE; WITNESS_CHECKORDER(&m->lock_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); #ifdef SMP spinlock_enter(); tid = (uintptr_t)curthread; v = MTX_UNOWNED; if (!_mtx_obtain_lock_fetch(m, &v, tid)) _mtx_lock_spin(m, v, opts, file, line); else LOCKSTAT_PROFILE_OBTAIN_SPIN_LOCK_SUCCESS(spin__acquire, m, 0, 0, file, line); #else __mtx_lock_spin(m, curthread, opts, file, line); #endif LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file, line); WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); } int __mtx_trylock_spin_flags(volatile uintptr_t *c, int opts, const char *file, int line) { struct mtx *m; if (SCHEDULER_STOPPED()) return (1); m = mtxlock2mtx(c); KASSERT(m->mtx_lock != MTX_DESTROYED, ("mtx_trylock_spin() of destroyed mutex @ %s:%d", file, line)); KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, ("mtx_trylock_spin() of sleep mutex %s @ %s:%d", m->lock_object.lo_name, file, line)); KASSERT((opts & MTX_RECURSE) == 0, ("mtx_trylock_spin: unsupp. opt MTX_RECURSE on mutex %s @ %s:%d\n", m->lock_object.lo_name, file, line)); if (__mtx_trylock_spin(m, curthread, opts, file, line)) { LOCK_LOG_TRY("LOCK", &m->lock_object, opts, 1, file, line); WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); return (1); } LOCK_LOG_TRY("LOCK", &m->lock_object, opts, 0, file, line); return (0); } void __mtx_unlock_spin_flags(volatile uintptr_t *c, int opts, const char *file, int line) { struct mtx *m; m = mtxlock2mtx(c); KASSERT(m->mtx_lock != MTX_DESTROYED, ("mtx_unlock_spin() of destroyed mutex @ %s:%d", file, line)); KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, ("mtx_unlock_spin() of sleep mutex %s @ %s:%d", m->lock_object.lo_name, file, line)); WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file, line); mtx_assert(m, MA_OWNED); __mtx_unlock_spin(m); } /* * The important part of mtx_trylock{,_flags}() * Tries to acquire lock `m.' If this function is called on a mutex that * is already owned, it will recursively acquire the lock. */ int _mtx_trylock_flags_int(struct mtx *m, int opts LOCK_FILE_LINE_ARG_DEF) { struct thread *td; uintptr_t tid, v; #ifdef LOCK_PROFILING uint64_t waittime = 0; int contested = 0; #endif int rval; bool recursed; td = curthread; tid = (uintptr_t)td; if (SCHEDULER_STOPPED_TD(td)) return (1); KASSERT(kdb_active != 0 || !TD_IS_IDLETHREAD(td), ("mtx_trylock() by idle thread %p on sleep mutex %s @ %s:%d", curthread, m->lock_object.lo_name, file, line)); KASSERT(m->mtx_lock != MTX_DESTROYED, ("mtx_trylock() of destroyed mutex @ %s:%d", file, line)); KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep, ("mtx_trylock() of spin mutex %s @ %s:%d", m->lock_object.lo_name, file, line)); rval = 1; recursed = false; v = MTX_UNOWNED; for (;;) { if (_mtx_obtain_lock_fetch(m, &v, tid)) break; if (v == MTX_UNOWNED) continue; if (v == tid && ((m->lock_object.lo_flags & LO_RECURSABLE) != 0 || (opts & MTX_RECURSE) != 0)) { m->mtx_recurse++; atomic_set_ptr(&m->mtx_lock, MTX_RECURSED); recursed = true; break; } rval = 0; break; } opts &= ~MTX_RECURSE; LOCK_LOG_TRY("LOCK", &m->lock_object, opts, rval, file, line); if (rval) { WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE | LOP_TRYLOCK, file, line); TD_LOCKS_INC(curthread); if (!recursed) LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(adaptive__acquire, m, contested, waittime, file, line); } return (rval); } int _mtx_trylock_flags_(volatile uintptr_t *c, int opts, const char *file, int line) { struct mtx *m; m = mtxlock2mtx(c); return (_mtx_trylock_flags_int(m, opts LOCK_FILE_LINE_ARG)); } /* * __mtx_lock_sleep: the tougher part of acquiring an MTX_DEF lock. * * We call this if the lock is either contested (i.e. we need to go to * sleep waiting for it), or if we need to recurse on it. */ #if LOCK_DEBUG > 0 void __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t v, int opts, const char *file, int line) #else void __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t v) #endif { struct thread *td; struct mtx *m; struct turnstile *ts; uintptr_t tid; struct thread *owner; #ifdef LOCK_PROFILING int contested = 0; uint64_t waittime = 0; #endif #if defined(ADAPTIVE_MUTEXES) || defined(KDTRACE_HOOKS) struct lock_delay_arg lda; #endif #ifdef KDTRACE_HOOKS u_int sleep_cnt = 0; int64_t sleep_time = 0; int64_t all_time = 0; #endif #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) int doing_lockprof = 0; #endif td = curthread; tid = (uintptr_t)td; m = mtxlock2mtx(c); #ifdef KDTRACE_HOOKS if (LOCKSTAT_PROFILE_ENABLED(adaptive__acquire)) { while (v == MTX_UNOWNED) { if (_mtx_obtain_lock_fetch(m, &v, tid)) goto out_lockstat; } doing_lockprof = 1; all_time -= lockstat_nsecs(&m->lock_object); } #endif #ifdef LOCK_PROFILING doing_lockprof = 1; #endif if (SCHEDULER_STOPPED_TD(td)) return; if (__predict_false(v == MTX_UNOWNED)) v = MTX_READ_VALUE(m); if (__predict_false(lv_mtx_owner(v) == td)) { KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0 || (opts & MTX_RECURSE) != 0, ("_mtx_lock_sleep: recursed on non-recursive mutex %s @ %s:%d\n", m->lock_object.lo_name, file, line)); #if LOCK_DEBUG > 0 opts &= ~MTX_RECURSE; #endif m->mtx_recurse++; atomic_set_ptr(&m->mtx_lock, MTX_RECURSED); if (LOCK_LOG_TEST(&m->lock_object, opts)) CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m); return; } #if LOCK_DEBUG > 0 opts &= ~MTX_RECURSE; #endif #if defined(ADAPTIVE_MUTEXES) lock_delay_arg_init(&lda, &mtx_delay); #elif defined(KDTRACE_HOOKS) lock_delay_arg_init_noadapt(&lda); #endif #ifdef HWPMC_HOOKS PMC_SOFT_CALL( , , lock, failed); #endif lock_profile_obtain_lock_failed(&m->lock_object, false, &contested, &waittime); if (LOCK_LOG_TEST(&m->lock_object, opts)) CTR4(KTR_LOCK, "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d", m->lock_object.lo_name, (void *)m->mtx_lock, file, line); + THREAD_CONTENDS_ON_LOCK(&m->lock_object); + for (;;) { if (v == MTX_UNOWNED) { if (_mtx_obtain_lock_fetch(m, &v, tid)) break; continue; } #ifdef KDTRACE_HOOKS lda.spin_cnt++; #endif #ifdef ADAPTIVE_MUTEXES /* * If the owner is running on another CPU, spin until the * owner stops running or the state of the lock changes. */ owner = lv_mtx_owner(v); if (TD_IS_RUNNING(owner)) { if (LOCK_LOG_TEST(&m->lock_object, 0)) CTR3(KTR_LOCK, "%s: spinning on %p held by %p", __func__, m, owner); KTR_STATE1(KTR_SCHED, "thread", sched_tdname((struct thread *)tid), "spinning", "lockname:\"%s\"", m->lock_object.lo_name); do { lock_delay(&lda); v = MTX_READ_VALUE(m); owner = lv_mtx_owner(v); } while (v != MTX_UNOWNED && TD_IS_RUNNING(owner)); KTR_STATE0(KTR_SCHED, "thread", sched_tdname((struct thread *)tid), "running"); continue; } #endif ts = turnstile_trywait(&m->lock_object); v = MTX_READ_VALUE(m); retry_turnstile: /* * Check if the lock has been released while spinning for * the turnstile chain lock. */ if (v == MTX_UNOWNED) { turnstile_cancel(ts); continue; } #ifdef ADAPTIVE_MUTEXES /* * The current lock owner might have started executing * on another CPU (or the lock could have changed * owners) while we were waiting on the turnstile * chain lock. If so, drop the turnstile lock and try * again. */ owner = lv_mtx_owner(v); if (TD_IS_RUNNING(owner)) { turnstile_cancel(ts); continue; } #endif /* * If the mutex isn't already contested and a failure occurs * setting the contested bit, the mutex was either released * or the state of the MTX_RECURSED bit changed. */ if ((v & MTX_CONTESTED) == 0 && !atomic_fcmpset_ptr(&m->mtx_lock, &v, v | MTX_CONTESTED)) { goto retry_turnstile; } /* * We definitely must sleep for this lock. */ mtx_assert(m, MA_NOTOWNED); /* * Block on the turnstile. */ #ifdef KDTRACE_HOOKS sleep_time -= lockstat_nsecs(&m->lock_object); #endif #ifndef ADAPTIVE_MUTEXES owner = mtx_owner(m); #endif MPASS(owner == mtx_owner(m)); turnstile_wait(ts, owner, TS_EXCLUSIVE_QUEUE); #ifdef KDTRACE_HOOKS sleep_time += lockstat_nsecs(&m->lock_object); sleep_cnt++; #endif v = MTX_READ_VALUE(m); } + THREAD_CONTENTION_DONE(&m->lock_object); #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) if (__predict_true(!doing_lockprof)) return; #endif #ifdef KDTRACE_HOOKS all_time += lockstat_nsecs(&m->lock_object); if (sleep_time) LOCKSTAT_RECORD1(adaptive__block, m, sleep_time); /* * Only record the loops spinning and not sleeping. */ if (lda.spin_cnt > sleep_cnt) LOCKSTAT_RECORD1(adaptive__spin, m, all_time - sleep_time); out_lockstat: #endif LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(adaptive__acquire, m, contested, waittime, file, line); } #ifdef SMP /* * _mtx_lock_spin_cookie: the tougher part of acquiring an MTX_SPIN lock. * * This is only called if we need to actually spin for the lock. Recursion * is handled inline. */ #if LOCK_DEBUG > 0 void _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t v, int opts, const char *file, int line) #else void _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t v) #endif { struct mtx *m; struct lock_delay_arg lda; uintptr_t tid; #ifdef LOCK_PROFILING int contested = 0; uint64_t waittime = 0; #endif #ifdef KDTRACE_HOOKS int64_t spin_time = 0; #endif #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) int doing_lockprof = 0; #endif tid = (uintptr_t)curthread; m = mtxlock2mtx(c); #ifdef KDTRACE_HOOKS if (LOCKSTAT_PROFILE_ENABLED(adaptive__acquire)) { while (v == MTX_UNOWNED) { if (_mtx_obtain_lock_fetch(m, &v, tid)) goto out_lockstat; } doing_lockprof = 1; spin_time -= lockstat_nsecs(&m->lock_object); } #endif #ifdef LOCK_PROFILING doing_lockprof = 1; #endif if (__predict_false(v == MTX_UNOWNED)) v = MTX_READ_VALUE(m); if (__predict_false(v == tid)) { m->mtx_recurse++; return; } if (SCHEDULER_STOPPED()) return; if (LOCK_LOG_TEST(&m->lock_object, opts)) CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m); KTR_STATE1(KTR_SCHED, "thread", sched_tdname((struct thread *)tid), "spinning", "lockname:\"%s\"", m->lock_object.lo_name); lock_delay_arg_init(&lda, &mtx_spin_delay); #ifdef HWPMC_HOOKS PMC_SOFT_CALL( , , lock, failed); #endif lock_profile_obtain_lock_failed(&m->lock_object, true, &contested, &waittime); for (;;) { if (v == MTX_UNOWNED) { if (_mtx_obtain_lock_fetch(m, &v, tid)) break; continue; } /* Give interrupts a chance while we spin. */ spinlock_exit(); do { if (__predict_true(lda.spin_cnt < 10000000)) { lock_delay(&lda); } else { _mtx_lock_indefinite_check(m, &lda); } v = MTX_READ_VALUE(m); } while (v != MTX_UNOWNED); spinlock_enter(); } if (LOCK_LOG_TEST(&m->lock_object, opts)) CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m); KTR_STATE0(KTR_SCHED, "thread", sched_tdname((struct thread *)tid), "running"); #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) if (__predict_true(!doing_lockprof)) return; #endif #ifdef KDTRACE_HOOKS spin_time += lockstat_nsecs(&m->lock_object); if (lda.spin_cnt != 0) LOCKSTAT_RECORD1(spin__spin, m, spin_time); out_lockstat: #endif LOCKSTAT_PROFILE_OBTAIN_SPIN_LOCK_SUCCESS(spin__acquire, m, contested, waittime, file, line); } #endif /* SMP */ #ifdef INVARIANTS static void thread_lock_validate(struct mtx *m, int opts, const char *file, int line) { KASSERT(m->mtx_lock != MTX_DESTROYED, ("thread_lock() of destroyed mutex @ %s:%d", file, line)); KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, ("thread_lock() of sleep mutex %s @ %s:%d", m->lock_object.lo_name, file, line)); KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) == 0, ("thread_lock: got a recursive mutex %s @ %s:%d\n", m->lock_object.lo_name, file, line)); WITNESS_CHECKORDER(&m->lock_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); } #else #define thread_lock_validate(m, opts, file, line) do { } while (0) #endif #ifndef LOCK_PROFILING #if LOCK_DEBUG > 0 void _thread_lock(struct thread *td, int opts, const char *file, int line) #else void _thread_lock(struct thread *td) #endif { struct mtx *m; uintptr_t tid; tid = (uintptr_t)curthread; if (__predict_false(LOCKSTAT_PROFILE_ENABLED(spin__acquire))) goto slowpath_noirq; spinlock_enter(); m = td->td_lock; thread_lock_validate(m, 0, file, line); if (__predict_false(m == &blocked_lock)) goto slowpath_unlocked; if (__predict_false(!_mtx_obtain_lock(m, tid))) goto slowpath_unlocked; if (__predict_true(m == td->td_lock)) { WITNESS_LOCK(&m->lock_object, LOP_EXCLUSIVE, file, line); return; } _mtx_release_lock_quick(m); slowpath_unlocked: spinlock_exit(); slowpath_noirq: #if LOCK_DEBUG > 0 thread_lock_flags_(td, opts, file, line); #else thread_lock_flags_(td, 0, 0, 0); #endif } #endif void thread_lock_flags_(struct thread *td, int opts, const char *file, int line) { struct mtx *m; uintptr_t tid, v; struct lock_delay_arg lda; #ifdef LOCK_PROFILING int contested = 0; uint64_t waittime = 0; #endif #ifdef KDTRACE_HOOKS int64_t spin_time = 0; #endif #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) int doing_lockprof = 1; #endif tid = (uintptr_t)curthread; if (SCHEDULER_STOPPED()) { /* * Ensure that spinlock sections are balanced even when the * scheduler is stopped, since we may otherwise inadvertently * re-enable interrupts while dumping core. */ spinlock_enter(); return; } lock_delay_arg_init(&lda, &mtx_spin_delay); #ifdef HWPMC_HOOKS PMC_SOFT_CALL( , , lock, failed); #endif #ifdef LOCK_PROFILING doing_lockprof = 1; #elif defined(KDTRACE_HOOKS) doing_lockprof = lockstat_enabled; #endif #ifdef KDTRACE_HOOKS if (__predict_false(doing_lockprof)) spin_time -= lockstat_nsecs(&td->td_lock->lock_object); #endif spinlock_enter(); for (;;) { retry: m = td->td_lock; thread_lock_validate(m, opts, file, line); v = MTX_READ_VALUE(m); for (;;) { if (v == MTX_UNOWNED) { if (_mtx_obtain_lock_fetch(m, &v, tid)) break; continue; } MPASS(v != tid); lock_profile_obtain_lock_failed(&m->lock_object, true, &contested, &waittime); /* Give interrupts a chance while we spin. */ spinlock_exit(); do { if (__predict_true(lda.spin_cnt < 10000000)) { lock_delay(&lda); } else { _mtx_lock_indefinite_check(m, &lda); } if (m != td->td_lock) { spinlock_enter(); goto retry; } v = MTX_READ_VALUE(m); } while (v != MTX_UNOWNED); spinlock_enter(); } if (m == td->td_lock) break; _mtx_release_lock_quick(m); } LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file, line); WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) if (__predict_true(!doing_lockprof)) return; #endif #ifdef KDTRACE_HOOKS spin_time += lockstat_nsecs(&m->lock_object); #endif LOCKSTAT_PROFILE_OBTAIN_SPIN_LOCK_SUCCESS(spin__acquire, m, contested, waittime, file, line); #ifdef KDTRACE_HOOKS if (lda.spin_cnt != 0) LOCKSTAT_RECORD1(thread__spin, m, spin_time); #endif } struct mtx * thread_lock_block(struct thread *td) { struct mtx *lock; lock = td->td_lock; mtx_assert(lock, MA_OWNED); td->td_lock = &blocked_lock; return (lock); } void thread_lock_unblock(struct thread *td, struct mtx *new) { mtx_assert(new, MA_OWNED); KASSERT(td->td_lock == &blocked_lock, ("thread %p lock %p not blocked_lock %p", td, td->td_lock, &blocked_lock)); atomic_store_rel_ptr((volatile void *)&td->td_lock, (uintptr_t)new); } void thread_lock_block_wait(struct thread *td) { while (td->td_lock == &blocked_lock) cpu_spinwait(); /* Acquire fence to be certain that all thread state is visible. */ atomic_thread_fence_acq(); } void thread_lock_set(struct thread *td, struct mtx *new) { struct mtx *lock; mtx_assert(new, MA_OWNED); lock = td->td_lock; mtx_assert(lock, MA_OWNED); td->td_lock = new; mtx_unlock_spin(lock); } /* * __mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock. * * We are only called here if the lock is recursed, contested (i.e. we * need to wake up a blocked thread) or lockstat probe is active. */ #if LOCK_DEBUG > 0 void __mtx_unlock_sleep(volatile uintptr_t *c, uintptr_t v, int opts, const char *file, int line) #else void __mtx_unlock_sleep(volatile uintptr_t *c, uintptr_t v) #endif { struct mtx *m; struct turnstile *ts; uintptr_t tid; if (SCHEDULER_STOPPED()) return; tid = (uintptr_t)curthread; m = mtxlock2mtx(c); if (__predict_false(v == tid)) v = MTX_READ_VALUE(m); if (__predict_false(v & MTX_RECURSED)) { if (--(m->mtx_recurse) == 0) atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED); if (LOCK_LOG_TEST(&m->lock_object, opts)) CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m); return; } LOCKSTAT_PROFILE_RELEASE_LOCK(adaptive__release, m); if (v == tid && _mtx_release_lock(m, tid)) return; /* * We have to lock the chain before the turnstile so this turnstile * can be removed from the hash list if it is empty. */ turnstile_chain_lock(&m->lock_object); _mtx_release_lock_quick(m); ts = turnstile_lookup(&m->lock_object); MPASS(ts != NULL); if (LOCK_LOG_TEST(&m->lock_object, opts)) CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m); turnstile_broadcast(ts, TS_EXCLUSIVE_QUEUE); /* * This turnstile is now no longer associated with the mutex. We can * unlock the chain lock so a new turnstile may take it's place. */ turnstile_unpend(ts); turnstile_chain_unlock(&m->lock_object); } /* * All the unlocking of MTX_SPIN locks is done inline. * See the __mtx_unlock_spin() macro for the details. */ /* * The backing function for the INVARIANTS-enabled mtx_assert() */ #ifdef INVARIANT_SUPPORT void __mtx_assert(const volatile uintptr_t *c, int what, const char *file, int line) { const struct mtx *m; if (KERNEL_PANICKED() || dumping || SCHEDULER_STOPPED()) return; m = mtxlock2mtx(c); switch (what) { case MA_OWNED: case MA_OWNED | MA_RECURSED: case MA_OWNED | MA_NOTRECURSED: if (!mtx_owned(m)) panic("mutex %s not owned at %s:%d", m->lock_object.lo_name, file, line); if (mtx_recursed(m)) { if ((what & MA_NOTRECURSED) != 0) panic("mutex %s recursed at %s:%d", m->lock_object.lo_name, file, line); } else if ((what & MA_RECURSED) != 0) { panic("mutex %s unrecursed at %s:%d", m->lock_object.lo_name, file, line); } break; case MA_NOTOWNED: if (mtx_owned(m)) panic("mutex %s owned at %s:%d", m->lock_object.lo_name, file, line); break; default: panic("unknown mtx_assert at %s:%d", file, line); } } #endif /* * General init routine used by the MTX_SYSINIT() macro. */ void mtx_sysinit(void *arg) { struct mtx_args *margs = arg; mtx_init((struct mtx *)margs->ma_mtx, margs->ma_desc, NULL, margs->ma_opts); } /* * Mutex initialization routine; initialize lock `m' of type contained in * `opts' with options contained in `opts' and name `name.' The optional * lock type `type' is used as a general lock category name for use with * witness. */ void _mtx_init(volatile uintptr_t *c, const char *name, const char *type, int opts) { struct mtx *m; struct lock_class *class; int flags; m = mtxlock2mtx(c); MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE | MTX_NOWITNESS | MTX_DUPOK | MTX_NOPROFILE | MTX_NEW)) == 0); ASSERT_ATOMIC_LOAD_PTR(m->mtx_lock, ("%s: mtx_lock not aligned for %s: %p", __func__, name, &m->mtx_lock)); /* Determine lock class and lock flags. */ if (opts & MTX_SPIN) class = &lock_class_mtx_spin; else class = &lock_class_mtx_sleep; flags = 0; if (opts & MTX_QUIET) flags |= LO_QUIET; if (opts & MTX_RECURSE) flags |= LO_RECURSABLE; if ((opts & MTX_NOWITNESS) == 0) flags |= LO_WITNESS; if (opts & MTX_DUPOK) flags |= LO_DUPOK; if (opts & MTX_NOPROFILE) flags |= LO_NOPROFILE; if (opts & MTX_NEW) flags |= LO_NEW; /* Initialize mutex. */ lock_init(&m->lock_object, class, name, type, flags); m->mtx_lock = MTX_UNOWNED; m->mtx_recurse = 0; } /* * Remove lock `m' from all_mtx queue. We don't allow MTX_QUIET to be * passed in as a flag here because if the corresponding mtx_init() was * called with MTX_QUIET set, then it will already be set in the mutex's * flags. */ void _mtx_destroy(volatile uintptr_t *c) { struct mtx *m; m = mtxlock2mtx(c); if (!mtx_owned(m)) MPASS(mtx_unowned(m)); else { MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0); /* Perform the non-mtx related part of mtx_unlock_spin(). */ if (LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin) { lock_profile_release_lock(&m->lock_object, true); spinlock_exit(); } else { TD_LOCKS_DEC(curthread); lock_profile_release_lock(&m->lock_object, false); } /* Tell witness this isn't locked to make it happy. */ WITNESS_UNLOCK(&m->lock_object, LOP_EXCLUSIVE, __FILE__, __LINE__); } m->mtx_lock = MTX_DESTROYED; lock_destroy(&m->lock_object); } /* * Intialize the mutex code and system mutexes. This is called from the MD * startup code prior to mi_startup(). The per-CPU data space needs to be * setup before this is called. */ void mutex_init(void) { /* Setup turnstiles so that sleep mutexes work. */ init_turnstiles(); /* * Initialize mutexes. */ mtx_init(&Giant, "Giant", NULL, MTX_DEF | MTX_RECURSE); mtx_init(&blocked_lock, "blocked lock", NULL, MTX_SPIN); blocked_lock.mtx_lock = 0xdeadc0de; /* Always blocked. */ mtx_init(&proc0.p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK); mtx_init(&proc0.p_slock, "process slock", NULL, MTX_SPIN); mtx_init(&proc0.p_statmtx, "pstatl", NULL, MTX_SPIN); mtx_init(&proc0.p_itimmtx, "pitiml", NULL, MTX_SPIN); mtx_init(&proc0.p_profmtx, "pprofl", NULL, MTX_SPIN); mtx_init(&devmtx, "cdev", NULL, MTX_DEF); mtx_lock(&Giant); } static void __noinline _mtx_lock_indefinite_check(struct mtx *m, struct lock_delay_arg *ldap) { struct thread *td; ldap->spin_cnt++; if (ldap->spin_cnt < 60000000 || kdb_active || KERNEL_PANICKED()) cpu_lock_delay(); else { td = mtx_owner(m); /* If the mutex is unlocked, try again. */ if (td == NULL) return; printf( "spin lock %p (%s) held by %p (tid %d) too long\n", m, m->lock_object.lo_name, td, td->td_tid); #ifdef WITNESS witness_display_spinlock(&m->lock_object, td, printf); #endif panic("spin lock held too long"); } cpu_spinwait(); } void mtx_spin_wait_unlocked(struct mtx *m) { struct lock_delay_arg lda; KASSERT(m->mtx_lock != MTX_DESTROYED, ("%s() of destroyed mutex %p", __func__, m)); KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, ("%s() of sleep mutex %p (%s)", __func__, m, m->lock_object.lo_name)); KASSERT(!mtx_owned(m), ("%s() waiting on myself on lock %p (%s)", __func__, m, m->lock_object.lo_name)); lda.spin_cnt = 0; while (atomic_load_acq_ptr(&m->mtx_lock) != MTX_UNOWNED) { if (__predict_true(lda.spin_cnt < 10000000)) { cpu_spinwait(); lda.spin_cnt++; } else { _mtx_lock_indefinite_check(m, &lda); } } } void mtx_wait_unlocked(struct mtx *m) { struct thread *owner; uintptr_t v; KASSERT(m->mtx_lock != MTX_DESTROYED, ("%s() of destroyed mutex %p", __func__, m)); KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep, ("%s() not a sleep mutex %p (%s)", __func__, m, m->lock_object.lo_name)); KASSERT(!mtx_owned(m), ("%s() waiting on myself on lock %p (%s)", __func__, m, m->lock_object.lo_name)); for (;;) { v = atomic_load_acq_ptr(&m->mtx_lock); if (v == MTX_UNOWNED) { break; } owner = lv_mtx_owner(v); if (!TD_IS_RUNNING(owner)) { mtx_lock(m); mtx_unlock(m); break; } cpu_spinwait(); } } #ifdef DDB void db_show_mtx(const struct lock_object *lock) { struct thread *td; const struct mtx *m; m = (const struct mtx *)lock; db_printf(" flags: {"); if (LOCK_CLASS(lock) == &lock_class_mtx_spin) db_printf("SPIN"); else db_printf("DEF"); if (m->lock_object.lo_flags & LO_RECURSABLE) db_printf(", RECURSE"); if (m->lock_object.lo_flags & LO_DUPOK) db_printf(", DUPOK"); db_printf("}\n"); db_printf(" state: {"); if (mtx_unowned(m)) db_printf("UNOWNED"); else if (mtx_destroyed(m)) db_printf("DESTROYED"); else { db_printf("OWNED"); if (m->mtx_lock & MTX_CONTESTED) db_printf(", CONTESTED"); if (m->mtx_lock & MTX_RECURSED) db_printf(", RECURSED"); } db_printf("}\n"); if (!mtx_unowned(m) && !mtx_destroyed(m)) { td = mtx_owner(m); db_printf(" owner: %p (tid %d, pid %d, \"%s\")\n", td, td->td_tid, td->td_proc->p_pid, td->td_name); if (mtx_recursed(m)) db_printf(" recursed: %d\n", m->mtx_recurse); } } #endif diff --git a/sys/kern/kern_rwlock.c b/sys/kern/kern_rwlock.c index 5705de0f311f..83d5862a6667 100644 --- a/sys/kern/kern_rwlock.c +++ b/sys/kern/kern_rwlock.c @@ -1,1562 +1,1568 @@ /*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2006 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. */ /* * Machine independent bits of reader/writer lock implementation. */ #include #include "opt_ddb.h" #include "opt_hwpmc_hooks.h" #include "opt_no_adaptive_rwlocks.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if defined(SMP) && !defined(NO_ADAPTIVE_RWLOCKS) #define ADAPTIVE_RWLOCKS #endif #ifdef HWPMC_HOOKS #include PMC_SOFT_DECLARE( , , lock, failed); #endif /* * Return the rwlock address when the lock cookie address is provided. * This functionality assumes that struct rwlock* have a member named rw_lock. */ #define rwlock2rw(c) (__containerof(c, struct rwlock, rw_lock)) #ifdef DDB #include static void db_show_rwlock(const struct lock_object *lock); #endif static void assert_rw(const struct lock_object *lock, int what); static void lock_rw(struct lock_object *lock, uintptr_t how); #ifdef KDTRACE_HOOKS static int owner_rw(const struct lock_object *lock, struct thread **owner); #endif static uintptr_t unlock_rw(struct lock_object *lock); struct lock_class lock_class_rw = { .lc_name = "rw", .lc_flags = LC_SLEEPLOCK | LC_RECURSABLE | LC_UPGRADABLE, .lc_assert = assert_rw, #ifdef DDB .lc_ddb_show = db_show_rwlock, #endif .lc_lock = lock_rw, .lc_unlock = unlock_rw, #ifdef KDTRACE_HOOKS .lc_owner = owner_rw, #endif }; #ifdef ADAPTIVE_RWLOCKS #ifdef RWLOCK_CUSTOM_BACKOFF static u_short __read_frequently rowner_retries; static u_short __read_frequently rowner_loops; static SYSCTL_NODE(_debug, OID_AUTO, rwlock, CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, "rwlock debugging"); SYSCTL_U16(_debug_rwlock, OID_AUTO, retry, CTLFLAG_RW, &rowner_retries, 0, ""); SYSCTL_U16(_debug_rwlock, OID_AUTO, loops, CTLFLAG_RW, &rowner_loops, 0, ""); static struct lock_delay_config __read_frequently rw_delay; SYSCTL_U16(_debug_rwlock, OID_AUTO, delay_base, CTLFLAG_RW, &rw_delay.base, 0, ""); SYSCTL_U16(_debug_rwlock, OID_AUTO, delay_max, CTLFLAG_RW, &rw_delay.max, 0, ""); static void rw_lock_delay_init(void *arg __unused) { lock_delay_default_init(&rw_delay); rowner_retries = 10; rowner_loops = max(10000, rw_delay.max); } LOCK_DELAY_SYSINIT(rw_lock_delay_init); #else #define rw_delay locks_delay #define rowner_retries locks_delay_retries #define rowner_loops locks_delay_loops #endif #endif /* * Return a pointer to the owning thread if the lock is write-locked or * NULL if the lock is unlocked or read-locked. */ #define lv_rw_wowner(v) \ ((v) & RW_LOCK_READ ? NULL : \ (struct thread *)RW_OWNER((v))) #define rw_wowner(rw) lv_rw_wowner(RW_READ_VALUE(rw)) /* * Returns if a write owner is recursed. Write ownership is not assured * here and should be previously checked. */ #define rw_recursed(rw) ((rw)->rw_recurse != 0) /* * Return true if curthread helds the lock. */ #define rw_wlocked(rw) (rw_wowner((rw)) == curthread) /* * Return a pointer to the owning thread for this lock who should receive * any priority lent by threads that block on this lock. Currently this * is identical to rw_wowner(). */ #define rw_owner(rw) rw_wowner(rw) #ifndef INVARIANTS #define __rw_assert(c, what, file, line) #endif void assert_rw(const struct lock_object *lock, int what) { rw_assert((const struct rwlock *)lock, what); } void lock_rw(struct lock_object *lock, uintptr_t how) { struct rwlock *rw; rw = (struct rwlock *)lock; if (how) rw_rlock(rw); else rw_wlock(rw); } uintptr_t unlock_rw(struct lock_object *lock) { struct rwlock *rw; rw = (struct rwlock *)lock; rw_assert(rw, RA_LOCKED | LA_NOTRECURSED); if (rw->rw_lock & RW_LOCK_READ) { rw_runlock(rw); return (1); } else { rw_wunlock(rw); return (0); } } #ifdef KDTRACE_HOOKS int owner_rw(const struct lock_object *lock, struct thread **owner) { const struct rwlock *rw = (const struct rwlock *)lock; uintptr_t x = rw->rw_lock; *owner = rw_wowner(rw); return ((x & RW_LOCK_READ) != 0 ? (RW_READERS(x) != 0) : (*owner != NULL)); } #endif void _rw_init_flags(volatile uintptr_t *c, const char *name, int opts) { struct rwlock *rw; int flags; rw = rwlock2rw(c); MPASS((opts & ~(RW_DUPOK | RW_NOPROFILE | RW_NOWITNESS | RW_QUIET | RW_RECURSE | RW_NEW)) == 0); ASSERT_ATOMIC_LOAD_PTR(rw->rw_lock, ("%s: rw_lock not aligned for %s: %p", __func__, name, &rw->rw_lock)); flags = LO_UPGRADABLE; if (opts & RW_DUPOK) flags |= LO_DUPOK; if (opts & RW_NOPROFILE) flags |= LO_NOPROFILE; if (!(opts & RW_NOWITNESS)) flags |= LO_WITNESS; if (opts & RW_RECURSE) flags |= LO_RECURSABLE; if (opts & RW_QUIET) flags |= LO_QUIET; if (opts & RW_NEW) flags |= LO_NEW; lock_init(&rw->lock_object, &lock_class_rw, name, NULL, flags); rw->rw_lock = RW_UNLOCKED; rw->rw_recurse = 0; } void _rw_destroy(volatile uintptr_t *c) { struct rwlock *rw; rw = rwlock2rw(c); KASSERT(rw->rw_lock == RW_UNLOCKED, ("rw lock %p not unlocked", rw)); KASSERT(rw->rw_recurse == 0, ("rw lock %p still recursed", rw)); rw->rw_lock = RW_DESTROYED; lock_destroy(&rw->lock_object); } void rw_sysinit(void *arg) { struct rw_args *args; args = arg; rw_init_flags((struct rwlock *)args->ra_rw, args->ra_desc, args->ra_flags); } int _rw_wowned(const volatile uintptr_t *c) { return (rw_wowner(rwlock2rw(c)) == curthread); } void _rw_wlock_cookie(volatile uintptr_t *c, const char *file, int line) { struct rwlock *rw; uintptr_t tid, v; rw = rwlock2rw(c); KASSERT(kdb_active != 0 || SCHEDULER_STOPPED() || !TD_IS_IDLETHREAD(curthread), ("rw_wlock() by idle thread %p on rwlock %s @ %s:%d", curthread, rw->lock_object.lo_name, file, line)); KASSERT(rw->rw_lock != RW_DESTROYED, ("rw_wlock() of destroyed rwlock @ %s:%d", file, line)); WITNESS_CHECKORDER(&rw->lock_object, LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); tid = (uintptr_t)curthread; v = RW_UNLOCKED; if (!_rw_write_lock_fetch(rw, &v, tid)) _rw_wlock_hard(rw, v, file, line); else LOCKSTAT_PROFILE_OBTAIN_RWLOCK_SUCCESS(rw__acquire, rw, 0, 0, file, line, LOCKSTAT_WRITER); LOCK_LOG_LOCK("WLOCK", &rw->lock_object, 0, rw->rw_recurse, file, line); WITNESS_LOCK(&rw->lock_object, LOP_EXCLUSIVE, file, line); TD_LOCKS_INC(curthread); } int __rw_try_wlock_int(struct rwlock *rw LOCK_FILE_LINE_ARG_DEF) { struct thread *td; uintptr_t tid, v; int rval; bool recursed; td = curthread; tid = (uintptr_t)td; if (SCHEDULER_STOPPED_TD(td)) return (1); KASSERT(kdb_active != 0 || !TD_IS_IDLETHREAD(td), ("rw_try_wlock() by idle thread %p on rwlock %s @ %s:%d", curthread, rw->lock_object.lo_name, file, line)); KASSERT(rw->rw_lock != RW_DESTROYED, ("rw_try_wlock() of destroyed rwlock @ %s:%d", file, line)); rval = 1; recursed = false; v = RW_UNLOCKED; for (;;) { if (atomic_fcmpset_acq_ptr(&rw->rw_lock, &v, tid)) break; if (v == RW_UNLOCKED) continue; if (v == tid && (rw->lock_object.lo_flags & LO_RECURSABLE)) { rw->rw_recurse++; atomic_set_ptr(&rw->rw_lock, RW_LOCK_WRITER_RECURSED); break; } rval = 0; break; } LOCK_LOG_TRY("WLOCK", &rw->lock_object, 0, rval, file, line); if (rval) { WITNESS_LOCK(&rw->lock_object, LOP_EXCLUSIVE | LOP_TRYLOCK, file, line); if (!recursed) LOCKSTAT_PROFILE_OBTAIN_RWLOCK_SUCCESS(rw__acquire, rw, 0, 0, file, line, LOCKSTAT_WRITER); TD_LOCKS_INC(curthread); } return (rval); } int __rw_try_wlock(volatile uintptr_t *c, const char *file, int line) { struct rwlock *rw; rw = rwlock2rw(c); return (__rw_try_wlock_int(rw LOCK_FILE_LINE_ARG)); } void _rw_wunlock_cookie(volatile uintptr_t *c, const char *file, int line) { struct rwlock *rw; rw = rwlock2rw(c); KASSERT(rw->rw_lock != RW_DESTROYED, ("rw_wunlock() of destroyed rwlock @ %s:%d", file, line)); __rw_assert(c, RA_WLOCKED, file, line); WITNESS_UNLOCK(&rw->lock_object, LOP_EXCLUSIVE, file, line); LOCK_LOG_LOCK("WUNLOCK", &rw->lock_object, 0, rw->rw_recurse, file, line); #ifdef LOCK_PROFILING _rw_wunlock_hard(rw, (uintptr_t)curthread, file, line); #else __rw_wunlock(rw, curthread, file, line); #endif TD_LOCKS_DEC(curthread); } /* * Determines whether a new reader can acquire a lock. Succeeds if the * reader already owns a read lock and the lock is locked for read to * prevent deadlock from reader recursion. Also succeeds if the lock * is unlocked and has no writer waiters or spinners. Failing otherwise * prioritizes writers before readers. */ static bool __always_inline __rw_can_read(struct thread *td, uintptr_t v, bool fp) { if ((v & (RW_LOCK_READ | RW_LOCK_WRITE_WAITERS | RW_LOCK_WRITE_SPINNER)) == RW_LOCK_READ) return (true); if (!fp && td->td_rw_rlocks && (v & RW_LOCK_READ)) return (true); return (false); } static bool __always_inline __rw_rlock_try(struct rwlock *rw, struct thread *td, uintptr_t *vp, bool fp LOCK_FILE_LINE_ARG_DEF) { /* * Handle the easy case. If no other thread has a write * lock, then try to bump up the count of read locks. Note * that we have to preserve the current state of the * RW_LOCK_WRITE_WAITERS flag. If we fail to acquire a * read lock, then rw_lock must have changed, so restart * the loop. Note that this handles the case of a * completely unlocked rwlock since such a lock is encoded * as a read lock with no waiters. */ while (__rw_can_read(td, *vp, fp)) { if (atomic_fcmpset_acq_ptr(&rw->rw_lock, vp, *vp + RW_ONE_READER)) { if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR4(KTR_LOCK, "%s: %p succeed %p -> %p", __func__, rw, (void *)*vp, (void *)(*vp + RW_ONE_READER)); td->td_rw_rlocks++; return (true); } } return (false); } static void __noinline __rw_rlock_hard(struct rwlock *rw, struct thread *td, uintptr_t v LOCK_FILE_LINE_ARG_DEF) { struct turnstile *ts; struct thread *owner; #ifdef ADAPTIVE_RWLOCKS int spintries = 0; int i, n; #endif #ifdef LOCK_PROFILING uint64_t waittime = 0; int contested = 0; #endif #if defined(ADAPTIVE_RWLOCKS) || defined(KDTRACE_HOOKS) struct lock_delay_arg lda; #endif #ifdef KDTRACE_HOOKS u_int sleep_cnt = 0; int64_t sleep_time = 0; int64_t all_time = 0; #endif #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) uintptr_t state = 0; int doing_lockprof = 0; #endif #ifdef KDTRACE_HOOKS if (LOCKSTAT_PROFILE_ENABLED(rw__acquire)) { if (__rw_rlock_try(rw, td, &v, false LOCK_FILE_LINE_ARG)) goto out_lockstat; doing_lockprof = 1; all_time -= lockstat_nsecs(&rw->lock_object); state = v; } #endif #ifdef LOCK_PROFILING doing_lockprof = 1; state = v; #endif if (SCHEDULER_STOPPED()) return; #if defined(ADAPTIVE_RWLOCKS) lock_delay_arg_init(&lda, &rw_delay); #elif defined(KDTRACE_HOOKS) lock_delay_arg_init_noadapt(&lda); #endif #ifdef HWPMC_HOOKS PMC_SOFT_CALL( , , lock, failed); #endif lock_profile_obtain_lock_failed(&rw->lock_object, false, &contested, &waittime); + THREAD_CONTENDS_ON_LOCK(&rw->lock_object); + for (;;) { if (__rw_rlock_try(rw, td, &v, false LOCK_FILE_LINE_ARG)) break; #ifdef KDTRACE_HOOKS lda.spin_cnt++; #endif #ifdef ADAPTIVE_RWLOCKS /* * If the owner is running on another CPU, spin until * the owner stops running or the state of the lock * changes. */ if ((v & RW_LOCK_READ) == 0) { owner = (struct thread *)RW_OWNER(v); if (TD_IS_RUNNING(owner)) { if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR3(KTR_LOCK, "%s: spinning on %p held by %p", __func__, rw, owner); KTR_STATE1(KTR_SCHED, "thread", sched_tdname(curthread), "spinning", "lockname:\"%s\"", rw->lock_object.lo_name); do { lock_delay(&lda); v = RW_READ_VALUE(rw); owner = lv_rw_wowner(v); } while (owner != NULL && TD_IS_RUNNING(owner)); KTR_STATE0(KTR_SCHED, "thread", sched_tdname(curthread), "running"); continue; } } else { if ((v & RW_LOCK_WRITE_SPINNER) && RW_READERS(v) == 0) { MPASS(!__rw_can_read(td, v, false)); lock_delay_spin(2); v = RW_READ_VALUE(rw); continue; } if (spintries < rowner_retries) { spintries++; KTR_STATE1(KTR_SCHED, "thread", sched_tdname(curthread), "spinning", "lockname:\"%s\"", rw->lock_object.lo_name); n = RW_READERS(v); for (i = 0; i < rowner_loops; i += n) { lock_delay_spin(n); v = RW_READ_VALUE(rw); if (!(v & RW_LOCK_READ)) break; n = RW_READERS(v); if (n == 0) break; if (__rw_can_read(td, v, false)) break; } #ifdef KDTRACE_HOOKS lda.spin_cnt += rowner_loops - i; #endif KTR_STATE0(KTR_SCHED, "thread", sched_tdname(curthread), "running"); if (i < rowner_loops) continue; } } #endif /* * Okay, now it's the hard case. Some other thread already * has a write lock or there are write waiters present, * acquire the turnstile lock so we can begin the process * of blocking. */ ts = turnstile_trywait(&rw->lock_object); /* * The lock might have been released while we spun, so * recheck its state and restart the loop if needed. */ v = RW_READ_VALUE(rw); retry_ts: if (((v & RW_LOCK_WRITE_SPINNER) && RW_READERS(v) == 0) || __rw_can_read(td, v, false)) { turnstile_cancel(ts); continue; } owner = lv_rw_wowner(v); #ifdef ADAPTIVE_RWLOCKS /* * The current lock owner might have started executing * on another CPU (or the lock could have changed * owners) while we were waiting on the turnstile * chain lock. If so, drop the turnstile lock and try * again. */ if (owner != NULL) { if (TD_IS_RUNNING(owner)) { turnstile_cancel(ts); continue; } } #endif /* * The lock is held in write mode or it already has waiters. */ MPASS(!__rw_can_read(td, v, false)); /* * If the RW_LOCK_READ_WAITERS flag is already set, then * we can go ahead and block. If it is not set then try * to set it. If we fail to set it drop the turnstile * lock and restart the loop. */ if (!(v & RW_LOCK_READ_WAITERS)) { if (!atomic_fcmpset_ptr(&rw->rw_lock, &v, v | RW_LOCK_READ_WAITERS)) goto retry_ts; if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p set read waiters flag", __func__, rw); } /* * We were unable to acquire the lock and the read waiters * flag is set, so we must block on the turnstile. */ if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p blocking on turnstile", __func__, rw); #ifdef KDTRACE_HOOKS sleep_time -= lockstat_nsecs(&rw->lock_object); #endif MPASS(owner == rw_owner(rw)); turnstile_wait(ts, owner, TS_SHARED_QUEUE); #ifdef KDTRACE_HOOKS sleep_time += lockstat_nsecs(&rw->lock_object); sleep_cnt++; #endif if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p resuming from turnstile", __func__, rw); v = RW_READ_VALUE(rw); } + THREAD_CONTENTION_DONE(&rw->lock_object); #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) if (__predict_true(!doing_lockprof)) return; #endif #ifdef KDTRACE_HOOKS all_time += lockstat_nsecs(&rw->lock_object); if (sleep_time) LOCKSTAT_RECORD4(rw__block, rw, sleep_time, LOCKSTAT_READER, (state & RW_LOCK_READ) == 0, (state & RW_LOCK_READ) == 0 ? 0 : RW_READERS(state)); /* Record only the loops spinning and not sleeping. */ if (lda.spin_cnt > sleep_cnt) LOCKSTAT_RECORD4(rw__spin, rw, all_time - sleep_time, LOCKSTAT_READER, (state & RW_LOCK_READ) == 0, (state & RW_LOCK_READ) == 0 ? 0 : RW_READERS(state)); out_lockstat: #endif /* * TODO: acquire "owner of record" here. Here be turnstile dragons * however. turnstiles don't like owners changing between calls to * turnstile_wait() currently. */ LOCKSTAT_PROFILE_OBTAIN_RWLOCK_SUCCESS(rw__acquire, rw, contested, waittime, file, line, LOCKSTAT_READER); } void __rw_rlock_int(struct rwlock *rw LOCK_FILE_LINE_ARG_DEF) { struct thread *td; uintptr_t v; td = curthread; KASSERT(kdb_active != 0 || SCHEDULER_STOPPED_TD(td) || !TD_IS_IDLETHREAD(td), ("rw_rlock() by idle thread %p on rwlock %s @ %s:%d", td, rw->lock_object.lo_name, file, line)); KASSERT(rw->rw_lock != RW_DESTROYED, ("rw_rlock() of destroyed rwlock @ %s:%d", file, line)); KASSERT(rw_wowner(rw) != td, ("rw_rlock: wlock already held for %s @ %s:%d", rw->lock_object.lo_name, file, line)); WITNESS_CHECKORDER(&rw->lock_object, LOP_NEWORDER, file, line, NULL); v = RW_READ_VALUE(rw); if (__predict_false(LOCKSTAT_PROFILE_ENABLED(rw__acquire) || !__rw_rlock_try(rw, td, &v, true LOCK_FILE_LINE_ARG))) __rw_rlock_hard(rw, td, v LOCK_FILE_LINE_ARG); else lock_profile_obtain_lock_success(&rw->lock_object, false, 0, 0, file, line); LOCK_LOG_LOCK("RLOCK", &rw->lock_object, 0, 0, file, line); WITNESS_LOCK(&rw->lock_object, 0, file, line); TD_LOCKS_INC(curthread); } void __rw_rlock(volatile uintptr_t *c, const char *file, int line) { struct rwlock *rw; rw = rwlock2rw(c); __rw_rlock_int(rw LOCK_FILE_LINE_ARG); } int __rw_try_rlock_int(struct rwlock *rw LOCK_FILE_LINE_ARG_DEF) { uintptr_t x; if (SCHEDULER_STOPPED()) return (1); KASSERT(kdb_active != 0 || !TD_IS_IDLETHREAD(curthread), ("rw_try_rlock() by idle thread %p on rwlock %s @ %s:%d", curthread, rw->lock_object.lo_name, file, line)); x = rw->rw_lock; for (;;) { KASSERT(rw->rw_lock != RW_DESTROYED, ("rw_try_rlock() of destroyed rwlock @ %s:%d", file, line)); if (!(x & RW_LOCK_READ)) break; if (atomic_fcmpset_acq_ptr(&rw->rw_lock, &x, x + RW_ONE_READER)) { LOCK_LOG_TRY("RLOCK", &rw->lock_object, 0, 1, file, line); WITNESS_LOCK(&rw->lock_object, LOP_TRYLOCK, file, line); LOCKSTAT_PROFILE_OBTAIN_RWLOCK_SUCCESS(rw__acquire, rw, 0, 0, file, line, LOCKSTAT_READER); TD_LOCKS_INC(curthread); curthread->td_rw_rlocks++; return (1); } } LOCK_LOG_TRY("RLOCK", &rw->lock_object, 0, 0, file, line); return (0); } int __rw_try_rlock(volatile uintptr_t *c, const char *file, int line) { struct rwlock *rw; rw = rwlock2rw(c); return (__rw_try_rlock_int(rw LOCK_FILE_LINE_ARG)); } static bool __always_inline __rw_runlock_try(struct rwlock *rw, struct thread *td, uintptr_t *vp) { for (;;) { if (RW_READERS(*vp) > 1 || !(*vp & RW_LOCK_WAITERS)) { if (atomic_fcmpset_rel_ptr(&rw->rw_lock, vp, *vp - RW_ONE_READER)) { if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR4(KTR_LOCK, "%s: %p succeeded %p -> %p", __func__, rw, (void *)*vp, (void *)(*vp - RW_ONE_READER)); td->td_rw_rlocks--; return (true); } continue; } break; } return (false); } static void __noinline __rw_runlock_hard(struct rwlock *rw, struct thread *td, uintptr_t v LOCK_FILE_LINE_ARG_DEF) { struct turnstile *ts; uintptr_t setv, queue; if (SCHEDULER_STOPPED()) return; if (__rw_runlock_try(rw, td, &v)) goto out_lockstat; /* * Ok, we know we have waiters and we think we are the * last reader, so grab the turnstile lock. */ turnstile_chain_lock(&rw->lock_object); v = RW_READ_VALUE(rw); for (;;) { if (__rw_runlock_try(rw, td, &v)) break; MPASS(v & RW_LOCK_WAITERS); /* * Try to drop our lock leaving the lock in a unlocked * state. * * If you wanted to do explicit lock handoff you'd have to * do it here. You'd also want to use turnstile_signal() * and you'd have to handle the race where a higher * priority thread blocks on the write lock before the * thread you wakeup actually runs and have the new thread * "steal" the lock. For now it's a lot simpler to just * wakeup all of the waiters. * * As above, if we fail, then another thread might have * acquired a read lock, so drop the turnstile lock and * restart. */ setv = RW_UNLOCKED; queue = TS_SHARED_QUEUE; if (v & RW_LOCK_WRITE_WAITERS) { queue = TS_EXCLUSIVE_QUEUE; setv |= (v & RW_LOCK_READ_WAITERS); } setv |= (v & RW_LOCK_WRITE_SPINNER); if (!atomic_fcmpset_rel_ptr(&rw->rw_lock, &v, setv)) continue; if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p last succeeded with waiters", __func__, rw); /* * Ok. The lock is released and all that's left is to * wake up the waiters. Note that the lock might not be * free anymore, but in that case the writers will just * block again if they run before the new lock holder(s) * release the lock. */ ts = turnstile_lookup(&rw->lock_object); MPASS(ts != NULL); turnstile_broadcast(ts, queue); turnstile_unpend(ts); td->td_rw_rlocks--; break; } turnstile_chain_unlock(&rw->lock_object); out_lockstat: LOCKSTAT_PROFILE_RELEASE_RWLOCK(rw__release, rw, LOCKSTAT_READER); } void _rw_runlock_cookie_int(struct rwlock *rw LOCK_FILE_LINE_ARG_DEF) { struct thread *td; uintptr_t v; KASSERT(rw->rw_lock != RW_DESTROYED, ("rw_runlock() of destroyed rwlock @ %s:%d", file, line)); __rw_assert(&rw->rw_lock, RA_RLOCKED, file, line); WITNESS_UNLOCK(&rw->lock_object, 0, file, line); LOCK_LOG_LOCK("RUNLOCK", &rw->lock_object, 0, 0, file, line); td = curthread; v = RW_READ_VALUE(rw); if (__predict_false(LOCKSTAT_PROFILE_ENABLED(rw__release) || !__rw_runlock_try(rw, td, &v))) __rw_runlock_hard(rw, td, v LOCK_FILE_LINE_ARG); else lock_profile_release_lock(&rw->lock_object, false); TD_LOCKS_DEC(curthread); } void _rw_runlock_cookie(volatile uintptr_t *c, const char *file, int line) { struct rwlock *rw; rw = rwlock2rw(c); _rw_runlock_cookie_int(rw LOCK_FILE_LINE_ARG); } #ifdef ADAPTIVE_RWLOCKS static inline void rw_drop_critical(uintptr_t v, bool *in_critical, int *extra_work) { if (v & RW_LOCK_WRITE_SPINNER) return; if (*in_critical) { critical_exit(); *in_critical = false; (*extra_work)--; } } #else #define rw_drop_critical(v, in_critical, extra_work) do { } while (0) #endif /* * This function is called when we are unable to obtain a write lock on the * first try. This means that at least one other thread holds either a * read or write lock. */ void __rw_wlock_hard(volatile uintptr_t *c, uintptr_t v LOCK_FILE_LINE_ARG_DEF) { uintptr_t tid; struct rwlock *rw; struct turnstile *ts; struct thread *owner; #ifdef ADAPTIVE_RWLOCKS int spintries = 0; int i, n; enum { READERS, WRITER } sleep_reason = READERS; bool in_critical = false; #endif uintptr_t setv; #ifdef LOCK_PROFILING uint64_t waittime = 0; int contested = 0; #endif #if defined(ADAPTIVE_RWLOCKS) || defined(KDTRACE_HOOKS) struct lock_delay_arg lda; #endif #ifdef KDTRACE_HOOKS u_int sleep_cnt = 0; int64_t sleep_time = 0; int64_t all_time = 0; #endif #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) uintptr_t state = 0; int doing_lockprof = 0; #endif int extra_work = 0; tid = (uintptr_t)curthread; rw = rwlock2rw(c); #ifdef KDTRACE_HOOKS if (LOCKSTAT_PROFILE_ENABLED(rw__acquire)) { while (v == RW_UNLOCKED) { if (_rw_write_lock_fetch(rw, &v, tid)) goto out_lockstat; } extra_work = 1; doing_lockprof = 1; all_time -= lockstat_nsecs(&rw->lock_object); state = v; } #endif #ifdef LOCK_PROFILING extra_work = 1; doing_lockprof = 1; state = v; #endif if (SCHEDULER_STOPPED()) return; if (__predict_false(v == RW_UNLOCKED)) v = RW_READ_VALUE(rw); if (__predict_false(lv_rw_wowner(v) == (struct thread *)tid)) { KASSERT(rw->lock_object.lo_flags & LO_RECURSABLE, ("%s: recursing but non-recursive rw %s @ %s:%d\n", __func__, rw->lock_object.lo_name, file, line)); rw->rw_recurse++; atomic_set_ptr(&rw->rw_lock, RW_LOCK_WRITER_RECURSED); if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p recursing", __func__, rw); return; } if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR5(KTR_LOCK, "%s: %s contested (lock=%p) at %s:%d", __func__, rw->lock_object.lo_name, (void *)rw->rw_lock, file, line); #if defined(ADAPTIVE_RWLOCKS) lock_delay_arg_init(&lda, &rw_delay); #elif defined(KDTRACE_HOOKS) lock_delay_arg_init_noadapt(&lda); #endif #ifdef HWPMC_HOOKS PMC_SOFT_CALL( , , lock, failed); #endif lock_profile_obtain_lock_failed(&rw->lock_object, false, &contested, &waittime); + THREAD_CONTENDS_ON_LOCK(&rw->lock_object); + for (;;) { if (v == RW_UNLOCKED) { if (_rw_write_lock_fetch(rw, &v, tid)) break; continue; } #ifdef KDTRACE_HOOKS lda.spin_cnt++; #endif #ifdef ADAPTIVE_RWLOCKS if (v == (RW_LOCK_READ | RW_LOCK_WRITE_SPINNER)) { if (atomic_fcmpset_acq_ptr(&rw->rw_lock, &v, tid)) break; continue; } /* * If the lock is write locked and the owner is * running on another CPU, spin until the owner stops * running or the state of the lock changes. */ if (!(v & RW_LOCK_READ)) { rw_drop_critical(v, &in_critical, &extra_work); sleep_reason = WRITER; owner = lv_rw_wowner(v); if (!TD_IS_RUNNING(owner)) goto ts; if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR3(KTR_LOCK, "%s: spinning on %p held by %p", __func__, rw, owner); KTR_STATE1(KTR_SCHED, "thread", sched_tdname(curthread), "spinning", "lockname:\"%s\"", rw->lock_object.lo_name); do { lock_delay(&lda); v = RW_READ_VALUE(rw); owner = lv_rw_wowner(v); } while (owner != NULL && TD_IS_RUNNING(owner)); KTR_STATE0(KTR_SCHED, "thread", sched_tdname(curthread), "running"); continue; } else if (RW_READERS(v) > 0) { sleep_reason = READERS; if (spintries == rowner_retries) goto ts; if (!(v & RW_LOCK_WRITE_SPINNER)) { if (!in_critical) { critical_enter(); in_critical = true; extra_work++; } if (!atomic_fcmpset_ptr(&rw->rw_lock, &v, v | RW_LOCK_WRITE_SPINNER)) { critical_exit(); in_critical = false; extra_work--; continue; } } spintries++; KTR_STATE1(KTR_SCHED, "thread", sched_tdname(curthread), "spinning", "lockname:\"%s\"", rw->lock_object.lo_name); n = RW_READERS(v); for (i = 0; i < rowner_loops; i += n) { lock_delay_spin(n); v = RW_READ_VALUE(rw); if (!(v & RW_LOCK_WRITE_SPINNER)) break; if (!(v & RW_LOCK_READ)) break; n = RW_READERS(v); if (n == 0) break; } #ifdef KDTRACE_HOOKS lda.spin_cnt += i; #endif KTR_STATE0(KTR_SCHED, "thread", sched_tdname(curthread), "running"); if (i < rowner_loops) continue; } ts: #endif ts = turnstile_trywait(&rw->lock_object); v = RW_READ_VALUE(rw); retry_ts: owner = lv_rw_wowner(v); #ifdef ADAPTIVE_RWLOCKS /* * The current lock owner might have started executing * on another CPU (or the lock could have changed * owners) while we were waiting on the turnstile * chain lock. If so, drop the turnstile lock and try * again. */ if (owner != NULL) { if (TD_IS_RUNNING(owner)) { turnstile_cancel(ts); rw_drop_critical(v, &in_critical, &extra_work); continue; } } else if (RW_READERS(v) > 0 && sleep_reason == WRITER) { turnstile_cancel(ts); rw_drop_critical(v, &in_critical, &extra_work); continue; } #endif /* * Check for the waiters flags about this rwlock. * If the lock was released, without maintain any pending * waiters queue, simply try to acquire it. * If a pending waiters queue is present, claim the lock * ownership and maintain the pending queue. */ setv = v & (RW_LOCK_WAITERS | RW_LOCK_WRITE_SPINNER); if ((v & ~setv) == RW_UNLOCKED) { setv &= ~RW_LOCK_WRITE_SPINNER; if (atomic_fcmpset_acq_ptr(&rw->rw_lock, &v, tid | setv)) { if (setv) turnstile_claim(ts); else turnstile_cancel(ts); break; } goto retry_ts; } #ifdef ADAPTIVE_RWLOCKS if (in_critical) { if ((v & RW_LOCK_WRITE_SPINNER) || !((v & RW_LOCK_WRITE_WAITERS))) { setv = v & ~RW_LOCK_WRITE_SPINNER; setv |= RW_LOCK_WRITE_WAITERS; if (!atomic_fcmpset_ptr(&rw->rw_lock, &v, setv)) goto retry_ts; } critical_exit(); in_critical = false; extra_work--; } else { #endif /* * If the RW_LOCK_WRITE_WAITERS flag isn't set, then try to * set it. If we fail to set it, then loop back and try * again. */ if (!(v & RW_LOCK_WRITE_WAITERS)) { if (!atomic_fcmpset_ptr(&rw->rw_lock, &v, v | RW_LOCK_WRITE_WAITERS)) goto retry_ts; if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p set write waiters flag", __func__, rw); } #ifdef ADAPTIVE_RWLOCKS } #endif /* * We were unable to acquire the lock and the write waiters * flag is set, so we must block on the turnstile. */ if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p blocking on turnstile", __func__, rw); #ifdef KDTRACE_HOOKS sleep_time -= lockstat_nsecs(&rw->lock_object); #endif MPASS(owner == rw_owner(rw)); turnstile_wait(ts, owner, TS_EXCLUSIVE_QUEUE); #ifdef KDTRACE_HOOKS sleep_time += lockstat_nsecs(&rw->lock_object); sleep_cnt++; #endif if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p resuming from turnstile", __func__, rw); #ifdef ADAPTIVE_RWLOCKS spintries = 0; #endif v = RW_READ_VALUE(rw); } + THREAD_CONTENTION_DONE(&rw->lock_object); if (__predict_true(!extra_work)) return; #ifdef ADAPTIVE_RWLOCKS if (in_critical) critical_exit(); #endif #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) if (__predict_true(!doing_lockprof)) return; #endif #ifdef KDTRACE_HOOKS all_time += lockstat_nsecs(&rw->lock_object); if (sleep_time) LOCKSTAT_RECORD4(rw__block, rw, sleep_time, LOCKSTAT_WRITER, (state & RW_LOCK_READ) == 0, (state & RW_LOCK_READ) == 0 ? 0 : RW_READERS(state)); /* Record only the loops spinning and not sleeping. */ if (lda.spin_cnt > sleep_cnt) LOCKSTAT_RECORD4(rw__spin, rw, all_time - sleep_time, LOCKSTAT_WRITER, (state & RW_LOCK_READ) == 0, (state & RW_LOCK_READ) == 0 ? 0 : RW_READERS(state)); out_lockstat: #endif LOCKSTAT_PROFILE_OBTAIN_RWLOCK_SUCCESS(rw__acquire, rw, contested, waittime, file, line, LOCKSTAT_WRITER); } /* * This function is called if lockstat is active or the first try at releasing * a write lock failed. The latter means that the lock is recursed or one of * the 2 waiter bits must be set indicating that at least one thread is waiting * on this lock. */ void __rw_wunlock_hard(volatile uintptr_t *c, uintptr_t v LOCK_FILE_LINE_ARG_DEF) { struct rwlock *rw; struct turnstile *ts; uintptr_t tid, setv; int queue; tid = (uintptr_t)curthread; if (SCHEDULER_STOPPED()) return; rw = rwlock2rw(c); if (__predict_false(v == tid)) v = RW_READ_VALUE(rw); if (v & RW_LOCK_WRITER_RECURSED) { if (--(rw->rw_recurse) == 0) atomic_clear_ptr(&rw->rw_lock, RW_LOCK_WRITER_RECURSED); if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p unrecursing", __func__, rw); return; } LOCKSTAT_PROFILE_RELEASE_RWLOCK(rw__release, rw, LOCKSTAT_WRITER); if (v == tid && _rw_write_unlock(rw, tid)) return; KASSERT(rw->rw_lock & (RW_LOCK_READ_WAITERS | RW_LOCK_WRITE_WAITERS), ("%s: neither of the waiter flags are set", __func__)); if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p contested", __func__, rw); turnstile_chain_lock(&rw->lock_object); /* * Use the same algo as sx locks for now. Prefer waking up shared * waiters if we have any over writers. This is probably not ideal. * * 'v' is the value we are going to write back to rw_lock. If we * have waiters on both queues, we need to preserve the state of * the waiter flag for the queue we don't wake up. For now this is * hardcoded for the algorithm mentioned above. * * In the case of both readers and writers waiting we wakeup the * readers but leave the RW_LOCK_WRITE_WAITERS flag set. If a * new writer comes in before a reader it will claim the lock up * above. There is probably a potential priority inversion in * there that could be worked around either by waking both queues * of waiters or doing some complicated lock handoff gymnastics. */ setv = RW_UNLOCKED; v = RW_READ_VALUE(rw); queue = TS_SHARED_QUEUE; if (v & RW_LOCK_WRITE_WAITERS) { queue = TS_EXCLUSIVE_QUEUE; setv |= (v & RW_LOCK_READ_WAITERS); } atomic_store_rel_ptr(&rw->rw_lock, setv); /* Wake up all waiters for the specific queue. */ if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR3(KTR_LOCK, "%s: %p waking up %s waiters", __func__, rw, queue == TS_SHARED_QUEUE ? "read" : "write"); ts = turnstile_lookup(&rw->lock_object); MPASS(ts != NULL); turnstile_broadcast(ts, queue); turnstile_unpend(ts); turnstile_chain_unlock(&rw->lock_object); } /* * Attempt to do a non-blocking upgrade from a read lock to a write * lock. This will only succeed if this thread holds a single read * lock. Returns true if the upgrade succeeded and false otherwise. */ int __rw_try_upgrade_int(struct rwlock *rw LOCK_FILE_LINE_ARG_DEF) { uintptr_t v, setv, tid; struct turnstile *ts; int success; if (SCHEDULER_STOPPED()) return (1); KASSERT(rw->rw_lock != RW_DESTROYED, ("rw_try_upgrade() of destroyed rwlock @ %s:%d", file, line)); __rw_assert(&rw->rw_lock, RA_RLOCKED, file, line); /* * Attempt to switch from one reader to a writer. If there * are any write waiters, then we will have to lock the * turnstile first to prevent races with another writer * calling turnstile_wait() before we have claimed this * turnstile. So, do the simple case of no waiters first. */ tid = (uintptr_t)curthread; success = 0; v = RW_READ_VALUE(rw); for (;;) { if (RW_READERS(v) > 1) break; if (!(v & RW_LOCK_WAITERS)) { success = atomic_fcmpset_acq_ptr(&rw->rw_lock, &v, tid); if (!success) continue; break; } /* * Ok, we think we have waiters, so lock the turnstile. */ ts = turnstile_trywait(&rw->lock_object); v = RW_READ_VALUE(rw); retry_ts: if (RW_READERS(v) > 1) { turnstile_cancel(ts); break; } /* * Try to switch from one reader to a writer again. This time * we honor the current state of the waiters flags. * If we obtain the lock with the flags set, then claim * ownership of the turnstile. */ setv = tid | (v & RW_LOCK_WAITERS); success = atomic_fcmpset_ptr(&rw->rw_lock, &v, setv); if (success) { if (v & RW_LOCK_WAITERS) turnstile_claim(ts); else turnstile_cancel(ts); break; } goto retry_ts; } LOCK_LOG_TRY("WUPGRADE", &rw->lock_object, 0, success, file, line); if (success) { curthread->td_rw_rlocks--; WITNESS_UPGRADE(&rw->lock_object, LOP_EXCLUSIVE | LOP_TRYLOCK, file, line); LOCKSTAT_RECORD0(rw__upgrade, rw); } return (success); } int __rw_try_upgrade(volatile uintptr_t *c, const char *file, int line) { struct rwlock *rw; rw = rwlock2rw(c); return (__rw_try_upgrade_int(rw LOCK_FILE_LINE_ARG)); } /* * Downgrade a write lock into a single read lock. */ void __rw_downgrade_int(struct rwlock *rw LOCK_FILE_LINE_ARG_DEF) { struct turnstile *ts; uintptr_t tid, v; int rwait, wwait; if (SCHEDULER_STOPPED()) return; KASSERT(rw->rw_lock != RW_DESTROYED, ("rw_downgrade() of destroyed rwlock @ %s:%d", file, line)); __rw_assert(&rw->rw_lock, RA_WLOCKED | RA_NOTRECURSED, file, line); #ifndef INVARIANTS if (rw_recursed(rw)) panic("downgrade of a recursed lock"); #endif WITNESS_DOWNGRADE(&rw->lock_object, 0, file, line); /* * Convert from a writer to a single reader. First we handle * the easy case with no waiters. If there are any waiters, we * lock the turnstile and "disown" the lock. */ tid = (uintptr_t)curthread; if (atomic_cmpset_rel_ptr(&rw->rw_lock, tid, RW_READERS_LOCK(1))) goto out; /* * Ok, we think we have waiters, so lock the turnstile so we can * read the waiter flags without any races. */ turnstile_chain_lock(&rw->lock_object); v = rw->rw_lock & RW_LOCK_WAITERS; rwait = v & RW_LOCK_READ_WAITERS; wwait = v & RW_LOCK_WRITE_WAITERS; MPASS(rwait | wwait); /* * Downgrade from a write lock while preserving waiters flag * and give up ownership of the turnstile. */ ts = turnstile_lookup(&rw->lock_object); MPASS(ts != NULL); if (!wwait) v &= ~RW_LOCK_READ_WAITERS; atomic_store_rel_ptr(&rw->rw_lock, RW_READERS_LOCK(1) | v); /* * Wake other readers if there are no writers pending. Otherwise they * won't be able to acquire the lock anyway. */ if (rwait && !wwait) { turnstile_broadcast(ts, TS_SHARED_QUEUE); turnstile_unpend(ts); } else turnstile_disown(ts); turnstile_chain_unlock(&rw->lock_object); out: curthread->td_rw_rlocks++; LOCK_LOG_LOCK("WDOWNGRADE", &rw->lock_object, 0, 0, file, line); LOCKSTAT_RECORD0(rw__downgrade, rw); } void __rw_downgrade(volatile uintptr_t *c, const char *file, int line) { struct rwlock *rw; rw = rwlock2rw(c); __rw_downgrade_int(rw LOCK_FILE_LINE_ARG); } #ifdef INVARIANT_SUPPORT #ifndef INVARIANTS #undef __rw_assert #endif /* * In the non-WITNESS case, rw_assert() can only detect that at least * *some* thread owns an rlock, but it cannot guarantee that *this* * thread owns an rlock. */ void __rw_assert(const volatile uintptr_t *c, int what, const char *file, int line) { const struct rwlock *rw; if (SCHEDULER_STOPPED()) return; rw = rwlock2rw(c); switch (what) { case RA_LOCKED: case RA_LOCKED | RA_RECURSED: case RA_LOCKED | RA_NOTRECURSED: case RA_RLOCKED: case RA_RLOCKED | RA_RECURSED: case RA_RLOCKED | RA_NOTRECURSED: #ifdef WITNESS witness_assert(&rw->lock_object, what, file, line); #else /* * If some other thread has a write lock or we have one * and are asserting a read lock, fail. Also, if no one * has a lock at all, fail. */ if (rw->rw_lock == RW_UNLOCKED || (!(rw->rw_lock & RW_LOCK_READ) && (what & RA_RLOCKED || rw_wowner(rw) != curthread))) panic("Lock %s not %slocked @ %s:%d\n", rw->lock_object.lo_name, (what & RA_RLOCKED) ? "read " : "", file, line); if (!(rw->rw_lock & RW_LOCK_READ) && !(what & RA_RLOCKED)) { if (rw_recursed(rw)) { if (what & RA_NOTRECURSED) panic("Lock %s recursed @ %s:%d\n", rw->lock_object.lo_name, file, line); } else if (what & RA_RECURSED) panic("Lock %s not recursed @ %s:%d\n", rw->lock_object.lo_name, file, line); } #endif break; case RA_WLOCKED: case RA_WLOCKED | RA_RECURSED: case RA_WLOCKED | RA_NOTRECURSED: if (rw_wowner(rw) != curthread) panic("Lock %s not exclusively locked @ %s:%d\n", rw->lock_object.lo_name, file, line); if (rw_recursed(rw)) { if (what & RA_NOTRECURSED) panic("Lock %s recursed @ %s:%d\n", rw->lock_object.lo_name, file, line); } else if (what & RA_RECURSED) panic("Lock %s not recursed @ %s:%d\n", rw->lock_object.lo_name, file, line); break; case RA_UNLOCKED: #ifdef WITNESS witness_assert(&rw->lock_object, what, file, line); #else /* * If we hold a write lock fail. We can't reliably check * to see if we hold a read lock or not. */ if (rw_wowner(rw) == curthread) panic("Lock %s exclusively locked @ %s:%d\n", rw->lock_object.lo_name, file, line); #endif break; default: panic("Unknown rw lock assertion: %d @ %s:%d", what, file, line); } } #endif /* INVARIANT_SUPPORT */ #ifdef DDB void db_show_rwlock(const struct lock_object *lock) { const struct rwlock *rw; struct thread *td; rw = (const struct rwlock *)lock; db_printf(" state: "); if (rw->rw_lock == RW_UNLOCKED) db_printf("UNLOCKED\n"); else if (rw->rw_lock == RW_DESTROYED) { db_printf("DESTROYED\n"); return; } else if (rw->rw_lock & RW_LOCK_READ) db_printf("RLOCK: %ju locks\n", (uintmax_t)(RW_READERS(rw->rw_lock))); else { td = rw_wowner(rw); db_printf("WLOCK: %p (tid %d, pid %d, \"%s\")\n", td, td->td_tid, td->td_proc->p_pid, td->td_name); if (rw_recursed(rw)) db_printf(" recursed: %u\n", rw->rw_recurse); } db_printf(" waiters: "); switch (rw->rw_lock & (RW_LOCK_READ_WAITERS | RW_LOCK_WRITE_WAITERS)) { case RW_LOCK_READ_WAITERS: db_printf("readers\n"); break; case RW_LOCK_WRITE_WAITERS: db_printf("writers\n"); break; case RW_LOCK_READ_WAITERS | RW_LOCK_WRITE_WAITERS: db_printf("readers and writers\n"); break; default: db_printf("none\n"); break; } } #endif diff --git a/sys/kern/kern_sx.c b/sys/kern/kern_sx.c index 81e46fceed5e..bc8a1214689f 100644 --- a/sys/kern/kern_sx.c +++ b/sys/kern/kern_sx.c @@ -1,1556 +1,1562 @@ /*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2007 Attilio Rao * Copyright (c) 2001 Jason Evans * 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(s), this list of conditions and the following disclaimer as * the first lines of this file unmodified other than the possible * addition of one or more copyright notices. * 2. Redistributions in binary form must reproduce the above copyright * notice(s), 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 COPYRIGHT HOLDER(S) ``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 COPYRIGHT HOLDER(S) 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. */ /* * Shared/exclusive locks. This implementation attempts to ensure * deterministic lock granting behavior, so that slocks and xlocks are * interleaved. * * Priority propagation will not generally raise the priority of lock holders, * so should not be relied upon in combination with sx locks. */ #include "opt_ddb.h" #include "opt_hwpmc_hooks.h" #include "opt_no_adaptive_sx.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if defined(SMP) && !defined(NO_ADAPTIVE_SX) #include #endif #ifdef DDB #include #endif #if defined(SMP) && !defined(NO_ADAPTIVE_SX) #define ADAPTIVE_SX #endif #ifdef HWPMC_HOOKS #include PMC_SOFT_DECLARE( , , lock, failed); #endif /* Handy macros for sleep queues. */ #define SQ_EXCLUSIVE_QUEUE 0 #define SQ_SHARED_QUEUE 1 /* * Variations on DROP_GIANT()/PICKUP_GIANT() for use in this file. We * drop Giant anytime we have to sleep or if we adaptively spin. */ #define GIANT_DECLARE \ int _giantcnt = 0; \ WITNESS_SAVE_DECL(Giant) \ #define GIANT_SAVE(work) do { \ if (__predict_false(mtx_owned(&Giant))) { \ work++; \ WITNESS_SAVE(&Giant.lock_object, Giant); \ while (mtx_owned(&Giant)) { \ _giantcnt++; \ mtx_unlock(&Giant); \ } \ } \ } while (0) #define GIANT_RESTORE() do { \ if (_giantcnt > 0) { \ mtx_assert(&Giant, MA_NOTOWNED); \ while (_giantcnt--) \ mtx_lock(&Giant); \ WITNESS_RESTORE(&Giant.lock_object, Giant); \ } \ } while (0) /* * Returns true if an exclusive lock is recursed. It assumes * curthread currently has an exclusive lock. */ #define sx_recursed(sx) ((sx)->sx_recurse != 0) static void assert_sx(const struct lock_object *lock, int what); #ifdef DDB static void db_show_sx(const struct lock_object *lock); #endif static void lock_sx(struct lock_object *lock, uintptr_t how); #ifdef KDTRACE_HOOKS static int owner_sx(const struct lock_object *lock, struct thread **owner); #endif static uintptr_t unlock_sx(struct lock_object *lock); struct lock_class lock_class_sx = { .lc_name = "sx", .lc_flags = LC_SLEEPLOCK | LC_SLEEPABLE | LC_RECURSABLE | LC_UPGRADABLE, .lc_assert = assert_sx, #ifdef DDB .lc_ddb_show = db_show_sx, #endif .lc_lock = lock_sx, .lc_unlock = unlock_sx, #ifdef KDTRACE_HOOKS .lc_owner = owner_sx, #endif }; #ifndef INVARIANTS #define _sx_assert(sx, what, file, line) #endif #ifdef ADAPTIVE_SX #ifdef SX_CUSTOM_BACKOFF static u_short __read_frequently asx_retries; static u_short __read_frequently asx_loops; static SYSCTL_NODE(_debug, OID_AUTO, sx, CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, "sxlock debugging"); SYSCTL_U16(_debug_sx, OID_AUTO, retries, CTLFLAG_RW, &asx_retries, 0, ""); SYSCTL_U16(_debug_sx, OID_AUTO, loops, CTLFLAG_RW, &asx_loops, 0, ""); static struct lock_delay_config __read_frequently sx_delay; SYSCTL_U16(_debug_sx, OID_AUTO, delay_base, CTLFLAG_RW, &sx_delay.base, 0, ""); SYSCTL_U16(_debug_sx, OID_AUTO, delay_max, CTLFLAG_RW, &sx_delay.max, 0, ""); static void sx_lock_delay_init(void *arg __unused) { lock_delay_default_init(&sx_delay); asx_retries = 10; asx_loops = max(10000, sx_delay.max); } LOCK_DELAY_SYSINIT(sx_lock_delay_init); #else #define sx_delay locks_delay #define asx_retries locks_delay_retries #define asx_loops locks_delay_loops #endif #endif void assert_sx(const struct lock_object *lock, int what) { sx_assert((const struct sx *)lock, what); } void lock_sx(struct lock_object *lock, uintptr_t how) { struct sx *sx; sx = (struct sx *)lock; if (how) sx_slock(sx); else sx_xlock(sx); } uintptr_t unlock_sx(struct lock_object *lock) { struct sx *sx; sx = (struct sx *)lock; sx_assert(sx, SA_LOCKED | SA_NOTRECURSED); if (sx_xlocked(sx)) { sx_xunlock(sx); return (0); } else { sx_sunlock(sx); return (1); } } #ifdef KDTRACE_HOOKS int owner_sx(const struct lock_object *lock, struct thread **owner) { const struct sx *sx; uintptr_t x; sx = (const struct sx *)lock; x = sx->sx_lock; *owner = NULL; return ((x & SX_LOCK_SHARED) != 0 ? (SX_SHARERS(x) != 0) : ((*owner = (struct thread *)SX_OWNER(x)) != NULL)); } #endif void sx_sysinit(void *arg) { struct sx_args *sargs = arg; sx_init_flags(sargs->sa_sx, sargs->sa_desc, sargs->sa_flags); } void sx_init_flags(struct sx *sx, const char *description, int opts) { int flags; MPASS((opts & ~(SX_QUIET | SX_RECURSE | SX_NOWITNESS | SX_DUPOK | SX_NOPROFILE | SX_NEW)) == 0); ASSERT_ATOMIC_LOAD_PTR(sx->sx_lock, ("%s: sx_lock not aligned for %s: %p", __func__, description, &sx->sx_lock)); flags = LO_SLEEPABLE | LO_UPGRADABLE; if (opts & SX_DUPOK) flags |= LO_DUPOK; if (opts & SX_NOPROFILE) flags |= LO_NOPROFILE; if (!(opts & SX_NOWITNESS)) flags |= LO_WITNESS; if (opts & SX_RECURSE) flags |= LO_RECURSABLE; if (opts & SX_QUIET) flags |= LO_QUIET; if (opts & SX_NEW) flags |= LO_NEW; lock_init(&sx->lock_object, &lock_class_sx, description, NULL, flags); sx->sx_lock = SX_LOCK_UNLOCKED; sx->sx_recurse = 0; } void sx_destroy(struct sx *sx) { KASSERT(sx->sx_lock == SX_LOCK_UNLOCKED, ("sx lock still held")); KASSERT(sx->sx_recurse == 0, ("sx lock still recursed")); sx->sx_lock = SX_LOCK_DESTROYED; lock_destroy(&sx->lock_object); } int sx_try_slock_int(struct sx *sx LOCK_FILE_LINE_ARG_DEF) { uintptr_t x; if (SCHEDULER_STOPPED()) return (1); KASSERT(kdb_active != 0 || !TD_IS_IDLETHREAD(curthread), ("sx_try_slock() by idle thread %p on sx %s @ %s:%d", curthread, sx->lock_object.lo_name, file, line)); x = sx->sx_lock; for (;;) { KASSERT(x != SX_LOCK_DESTROYED, ("sx_try_slock() of destroyed sx @ %s:%d", file, line)); if (!(x & SX_LOCK_SHARED)) break; if (atomic_fcmpset_acq_ptr(&sx->sx_lock, &x, x + SX_ONE_SHARER)) { LOCK_LOG_TRY("SLOCK", &sx->lock_object, 0, 1, file, line); WITNESS_LOCK(&sx->lock_object, LOP_TRYLOCK, file, line); LOCKSTAT_PROFILE_OBTAIN_RWLOCK_SUCCESS(sx__acquire, sx, 0, 0, file, line, LOCKSTAT_READER); TD_LOCKS_INC(curthread); curthread->td_sx_slocks++; return (1); } } LOCK_LOG_TRY("SLOCK", &sx->lock_object, 0, 0, file, line); return (0); } int sx_try_slock_(struct sx *sx, const char *file, int line) { return (sx_try_slock_int(sx LOCK_FILE_LINE_ARG)); } int _sx_xlock(struct sx *sx, int opts, const char *file, int line) { uintptr_t tid, x; int error = 0; KASSERT(kdb_active != 0 || SCHEDULER_STOPPED() || !TD_IS_IDLETHREAD(curthread), ("sx_xlock() by idle thread %p on sx %s @ %s:%d", curthread, sx->lock_object.lo_name, file, line)); KASSERT(sx->sx_lock != SX_LOCK_DESTROYED, ("sx_xlock() of destroyed sx @ %s:%d", file, line)); WITNESS_CHECKORDER(&sx->lock_object, LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); tid = (uintptr_t)curthread; x = SX_LOCK_UNLOCKED; if (!atomic_fcmpset_acq_ptr(&sx->sx_lock, &x, tid)) error = _sx_xlock_hard(sx, x, opts LOCK_FILE_LINE_ARG); else LOCKSTAT_PROFILE_OBTAIN_RWLOCK_SUCCESS(sx__acquire, sx, 0, 0, file, line, LOCKSTAT_WRITER); if (!error) { LOCK_LOG_LOCK("XLOCK", &sx->lock_object, 0, sx->sx_recurse, file, line); WITNESS_LOCK(&sx->lock_object, LOP_EXCLUSIVE, file, line); TD_LOCKS_INC(curthread); } return (error); } int sx_try_xlock_int(struct sx *sx LOCK_FILE_LINE_ARG_DEF) { struct thread *td; uintptr_t tid, x; int rval; bool recursed; td = curthread; tid = (uintptr_t)td; if (SCHEDULER_STOPPED_TD(td)) return (1); KASSERT(kdb_active != 0 || !TD_IS_IDLETHREAD(td), ("sx_try_xlock() by idle thread %p on sx %s @ %s:%d", curthread, sx->lock_object.lo_name, file, line)); KASSERT(sx->sx_lock != SX_LOCK_DESTROYED, ("sx_try_xlock() of destroyed sx @ %s:%d", file, line)); rval = 1; recursed = false; x = SX_LOCK_UNLOCKED; for (;;) { if (atomic_fcmpset_acq_ptr(&sx->sx_lock, &x, tid)) break; if (x == SX_LOCK_UNLOCKED) continue; if (x == tid && (sx->lock_object.lo_flags & LO_RECURSABLE)) { sx->sx_recurse++; atomic_set_ptr(&sx->sx_lock, SX_LOCK_RECURSED); break; } rval = 0; break; } LOCK_LOG_TRY("XLOCK", &sx->lock_object, 0, rval, file, line); if (rval) { WITNESS_LOCK(&sx->lock_object, LOP_EXCLUSIVE | LOP_TRYLOCK, file, line); if (!recursed) LOCKSTAT_PROFILE_OBTAIN_RWLOCK_SUCCESS(sx__acquire, sx, 0, 0, file, line, LOCKSTAT_WRITER); TD_LOCKS_INC(curthread); } return (rval); } int sx_try_xlock_(struct sx *sx, const char *file, int line) { return (sx_try_xlock_int(sx LOCK_FILE_LINE_ARG)); } void _sx_xunlock(struct sx *sx, const char *file, int line) { KASSERT(sx->sx_lock != SX_LOCK_DESTROYED, ("sx_xunlock() of destroyed sx @ %s:%d", file, line)); _sx_assert(sx, SA_XLOCKED, file, line); WITNESS_UNLOCK(&sx->lock_object, LOP_EXCLUSIVE, file, line); LOCK_LOG_LOCK("XUNLOCK", &sx->lock_object, 0, sx->sx_recurse, file, line); #if LOCK_DEBUG > 0 _sx_xunlock_hard(sx, (uintptr_t)curthread, file, line); #else __sx_xunlock(sx, curthread, file, line); #endif TD_LOCKS_DEC(curthread); } /* * Try to do a non-blocking upgrade from a shared lock to an exclusive lock. * This will only succeed if this thread holds a single shared lock. * Return 1 if if the upgrade succeed, 0 otherwise. */ int sx_try_upgrade_int(struct sx *sx LOCK_FILE_LINE_ARG_DEF) { uintptr_t x; uintptr_t waiters; int success; if (SCHEDULER_STOPPED()) return (1); KASSERT(sx->sx_lock != SX_LOCK_DESTROYED, ("sx_try_upgrade() of destroyed sx @ %s:%d", file, line)); _sx_assert(sx, SA_SLOCKED, file, line); /* * Try to switch from one shared lock to an exclusive lock. We need * to maintain the SX_LOCK_EXCLUSIVE_WAITERS flag if set so that * we will wake up the exclusive waiters when we drop the lock. */ success = 0; x = SX_READ_VALUE(sx); for (;;) { if (SX_SHARERS(x) > 1) break; waiters = (x & SX_LOCK_WAITERS); if (atomic_fcmpset_acq_ptr(&sx->sx_lock, &x, (uintptr_t)curthread | waiters)) { success = 1; break; } } LOCK_LOG_TRY("XUPGRADE", &sx->lock_object, 0, success, file, line); if (success) { curthread->td_sx_slocks--; WITNESS_UPGRADE(&sx->lock_object, LOP_EXCLUSIVE | LOP_TRYLOCK, file, line); LOCKSTAT_RECORD0(sx__upgrade, sx); } return (success); } int sx_try_upgrade_(struct sx *sx, const char *file, int line) { return (sx_try_upgrade_int(sx LOCK_FILE_LINE_ARG)); } /* * Downgrade an unrecursed exclusive lock into a single shared lock. */ void sx_downgrade_int(struct sx *sx LOCK_FILE_LINE_ARG_DEF) { uintptr_t x; int wakeup_swapper; if (SCHEDULER_STOPPED()) return; KASSERT(sx->sx_lock != SX_LOCK_DESTROYED, ("sx_downgrade() of destroyed sx @ %s:%d", file, line)); _sx_assert(sx, SA_XLOCKED | SA_NOTRECURSED, file, line); #ifndef INVARIANTS if (sx_recursed(sx)) panic("downgrade of a recursed lock"); #endif WITNESS_DOWNGRADE(&sx->lock_object, 0, file, line); /* * Try to switch from an exclusive lock with no shared waiters * to one sharer with no shared waiters. If there are * exclusive waiters, we don't need to lock the sleep queue so * long as we preserve the flag. We do one quick try and if * that fails we grab the sleepq lock to keep the flags from * changing and do it the slow way. * * We have to lock the sleep queue if there are shared waiters * so we can wake them up. */ x = sx->sx_lock; if (!(x & SX_LOCK_SHARED_WAITERS) && atomic_cmpset_rel_ptr(&sx->sx_lock, x, SX_SHARERS_LOCK(1) | (x & SX_LOCK_EXCLUSIVE_WAITERS))) goto out; /* * Lock the sleep queue so we can read the waiters bits * without any races and wakeup any shared waiters. */ sleepq_lock(&sx->lock_object); /* * Preserve SX_LOCK_EXCLUSIVE_WAITERS while downgraded to a single * shared lock. If there are any shared waiters, wake them up. */ wakeup_swapper = 0; x = sx->sx_lock; atomic_store_rel_ptr(&sx->sx_lock, SX_SHARERS_LOCK(1) | (x & SX_LOCK_EXCLUSIVE_WAITERS)); if (x & SX_LOCK_SHARED_WAITERS) wakeup_swapper = sleepq_broadcast(&sx->lock_object, SLEEPQ_SX, 0, SQ_SHARED_QUEUE); sleepq_release(&sx->lock_object); if (wakeup_swapper) kick_proc0(); out: curthread->td_sx_slocks++; LOCK_LOG_LOCK("XDOWNGRADE", &sx->lock_object, 0, 0, file, line); LOCKSTAT_RECORD0(sx__downgrade, sx); } void sx_downgrade_(struct sx *sx, const char *file, int line) { sx_downgrade_int(sx LOCK_FILE_LINE_ARG); } #ifdef ADAPTIVE_SX static inline void sx_drop_critical(uintptr_t x, bool *in_critical, int *extra_work) { if (x & SX_LOCK_WRITE_SPINNER) return; if (*in_critical) { critical_exit(); *in_critical = false; (*extra_work)--; } } #else #define sx_drop_critical(x, in_critical, extra_work) do { } while (0) #endif /* * This function represents the so-called 'hard case' for sx_xlock * operation. All 'easy case' failures are redirected to this. Note * that ideally this would be a static function, but it needs to be * accessible from at least sx.h. */ int _sx_xlock_hard(struct sx *sx, uintptr_t x, int opts LOCK_FILE_LINE_ARG_DEF) { GIANT_DECLARE; uintptr_t tid, setx; #ifdef ADAPTIVE_SX struct thread *owner; u_int i, n, spintries = 0; enum { READERS, WRITER } sleep_reason = READERS; bool in_critical = false; #endif #ifdef LOCK_PROFILING uint64_t waittime = 0; int contested = 0; #endif int error = 0; #if defined(ADAPTIVE_SX) || defined(KDTRACE_HOOKS) struct lock_delay_arg lda; #endif #ifdef KDTRACE_HOOKS u_int sleep_cnt = 0; int64_t sleep_time = 0; int64_t all_time = 0; #endif #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) uintptr_t state = 0; int doing_lockprof = 0; #endif int extra_work = 0; tid = (uintptr_t)curthread; #ifdef KDTRACE_HOOKS if (LOCKSTAT_PROFILE_ENABLED(sx__acquire)) { while (x == SX_LOCK_UNLOCKED) { if (atomic_fcmpset_acq_ptr(&sx->sx_lock, &x, tid)) goto out_lockstat; } extra_work = 1; doing_lockprof = 1; all_time -= lockstat_nsecs(&sx->lock_object); state = x; } #endif #ifdef LOCK_PROFILING extra_work = 1; doing_lockprof = 1; state = x; #endif if (SCHEDULER_STOPPED()) return (0); if (__predict_false(x == SX_LOCK_UNLOCKED)) x = SX_READ_VALUE(sx); /* If we already hold an exclusive lock, then recurse. */ if (__predict_false(lv_sx_owner(x) == (struct thread *)tid)) { KASSERT((sx->lock_object.lo_flags & LO_RECURSABLE) != 0, ("_sx_xlock_hard: recursed on non-recursive sx %s @ %s:%d\n", sx->lock_object.lo_name, file, line)); sx->sx_recurse++; atomic_set_ptr(&sx->sx_lock, SX_LOCK_RECURSED); if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p recursing", __func__, sx); return (0); } if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR5(KTR_LOCK, "%s: %s contested (lock=%p) at %s:%d", __func__, sx->lock_object.lo_name, (void *)sx->sx_lock, file, line); #if defined(ADAPTIVE_SX) lock_delay_arg_init(&lda, &sx_delay); #elif defined(KDTRACE_HOOKS) lock_delay_arg_init_noadapt(&lda); #endif #ifdef HWPMC_HOOKS PMC_SOFT_CALL( , , lock, failed); #endif lock_profile_obtain_lock_failed(&sx->lock_object, false, &contested, &waittime); #ifndef INVARIANTS GIANT_SAVE(extra_work); #endif + THREAD_CONTENDS_ON_LOCK(&sx->lock_object); + for (;;) { if (x == SX_LOCK_UNLOCKED) { if (atomic_fcmpset_acq_ptr(&sx->sx_lock, &x, tid)) break; continue; } #ifdef INVARIANTS GIANT_SAVE(extra_work); #endif #ifdef KDTRACE_HOOKS lda.spin_cnt++; #endif #ifdef ADAPTIVE_SX if (x == (SX_LOCK_SHARED | SX_LOCK_WRITE_SPINNER)) { if (atomic_fcmpset_acq_ptr(&sx->sx_lock, &x, tid)) break; continue; } /* * If the lock is write locked and the owner is * running on another CPU, spin until the owner stops * running or the state of the lock changes. */ if ((x & SX_LOCK_SHARED) == 0) { sx_drop_critical(x, &in_critical, &extra_work); sleep_reason = WRITER; owner = lv_sx_owner(x); if (!TD_IS_RUNNING(owner)) goto sleepq; if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR3(KTR_LOCK, "%s: spinning on %p held by %p", __func__, sx, owner); KTR_STATE1(KTR_SCHED, "thread", sched_tdname(curthread), "spinning", "lockname:\"%s\"", sx->lock_object.lo_name); do { lock_delay(&lda); x = SX_READ_VALUE(sx); owner = lv_sx_owner(x); } while (owner != NULL && TD_IS_RUNNING(owner)); KTR_STATE0(KTR_SCHED, "thread", sched_tdname(curthread), "running"); continue; } else if (SX_SHARERS(x) > 0) { sleep_reason = READERS; if (spintries == asx_retries) goto sleepq; if (!(x & SX_LOCK_WRITE_SPINNER)) { if (!in_critical) { critical_enter(); in_critical = true; extra_work++; } if (!atomic_fcmpset_ptr(&sx->sx_lock, &x, x | SX_LOCK_WRITE_SPINNER)) { critical_exit(); in_critical = false; extra_work--; continue; } } spintries++; KTR_STATE1(KTR_SCHED, "thread", sched_tdname(curthread), "spinning", "lockname:\"%s\"", sx->lock_object.lo_name); n = SX_SHARERS(x); for (i = 0; i < asx_loops; i += n) { lock_delay_spin(n); x = SX_READ_VALUE(sx); if (!(x & SX_LOCK_WRITE_SPINNER)) break; if (!(x & SX_LOCK_SHARED)) break; n = SX_SHARERS(x); if (n == 0) break; } #ifdef KDTRACE_HOOKS lda.spin_cnt += i; #endif KTR_STATE0(KTR_SCHED, "thread", sched_tdname(curthread), "running"); if (i < asx_loops) continue; } sleepq: #endif sleepq_lock(&sx->lock_object); x = SX_READ_VALUE(sx); retry_sleepq: /* * If the lock was released while spinning on the * sleep queue chain lock, try again. */ if (x == SX_LOCK_UNLOCKED) { sleepq_release(&sx->lock_object); sx_drop_critical(x, &in_critical, &extra_work); continue; } #ifdef ADAPTIVE_SX /* * The current lock owner might have started executing * on another CPU (or the lock could have changed * owners) while we were waiting on the sleep queue * chain lock. If so, drop the sleep queue lock and try * again. */ if (!(x & SX_LOCK_SHARED)) { owner = (struct thread *)SX_OWNER(x); if (TD_IS_RUNNING(owner)) { sleepq_release(&sx->lock_object); sx_drop_critical(x, &in_critical, &extra_work); continue; } } else if (SX_SHARERS(x) > 0 && sleep_reason == WRITER) { sleepq_release(&sx->lock_object); sx_drop_critical(x, &in_critical, &extra_work); continue; } #endif /* * If an exclusive lock was released with both shared * and exclusive waiters and a shared waiter hasn't * woken up and acquired the lock yet, sx_lock will be * set to SX_LOCK_UNLOCKED | SX_LOCK_EXCLUSIVE_WAITERS. * If we see that value, try to acquire it once. Note * that we have to preserve SX_LOCK_EXCLUSIVE_WAITERS * as there are other exclusive waiters still. If we * fail, restart the loop. */ setx = x & (SX_LOCK_WAITERS | SX_LOCK_WRITE_SPINNER); if ((x & ~setx) == SX_LOCK_SHARED) { setx &= ~SX_LOCK_WRITE_SPINNER; if (!atomic_fcmpset_acq_ptr(&sx->sx_lock, &x, tid | setx)) goto retry_sleepq; sleepq_release(&sx->lock_object); CTR2(KTR_LOCK, "%s: %p claimed by new writer", __func__, sx); break; } #ifdef ADAPTIVE_SX /* * It is possible we set the SX_LOCK_WRITE_SPINNER bit. * It is an invariant that when the bit is set, there is * a writer ready to grab the lock. Thus clear the bit since * we are going to sleep. */ if (in_critical) { if ((x & SX_LOCK_WRITE_SPINNER) || !((x & SX_LOCK_EXCLUSIVE_WAITERS))) { setx = x & ~SX_LOCK_WRITE_SPINNER; setx |= SX_LOCK_EXCLUSIVE_WAITERS; if (!atomic_fcmpset_ptr(&sx->sx_lock, &x, setx)) { goto retry_sleepq; } } critical_exit(); in_critical = false; } else { #endif /* * Try to set the SX_LOCK_EXCLUSIVE_WAITERS. If we fail, * than loop back and retry. */ if (!(x & SX_LOCK_EXCLUSIVE_WAITERS)) { if (!atomic_fcmpset_ptr(&sx->sx_lock, &x, x | SX_LOCK_EXCLUSIVE_WAITERS)) { goto retry_sleepq; } if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p set excl waiters flag", __func__, sx); } #ifdef ADAPTIVE_SX } #endif /* * Since we have been unable to acquire the exclusive * lock and the exclusive waiters flag is set, we have * to sleep. */ if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p blocking on sleep queue", __func__, sx); #ifdef KDTRACE_HOOKS sleep_time -= lockstat_nsecs(&sx->lock_object); #endif sleepq_add(&sx->lock_object, NULL, sx->lock_object.lo_name, SLEEPQ_SX | ((opts & SX_INTERRUPTIBLE) ? SLEEPQ_INTERRUPTIBLE : 0), SQ_EXCLUSIVE_QUEUE); if (!(opts & SX_INTERRUPTIBLE)) sleepq_wait(&sx->lock_object, 0); else error = sleepq_wait_sig(&sx->lock_object, 0); #ifdef KDTRACE_HOOKS sleep_time += lockstat_nsecs(&sx->lock_object); sleep_cnt++; #endif if (error) { if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: interruptible sleep by %p suspended by signal", __func__, sx); break; } if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p resuming from sleep queue", __func__, sx); x = SX_READ_VALUE(sx); } + THREAD_CONTENTION_DONE(&sx->lock_object); if (__predict_true(!extra_work)) return (error); #ifdef ADAPTIVE_SX if (in_critical) critical_exit(); #endif GIANT_RESTORE(); #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) if (__predict_true(!doing_lockprof)) return (error); #endif #ifdef KDTRACE_HOOKS all_time += lockstat_nsecs(&sx->lock_object); if (sleep_time) LOCKSTAT_RECORD4(sx__block, sx, sleep_time, LOCKSTAT_WRITER, (state & SX_LOCK_SHARED) == 0, (state & SX_LOCK_SHARED) == 0 ? 0 : SX_SHARERS(state)); if (lda.spin_cnt > sleep_cnt) LOCKSTAT_RECORD4(sx__spin, sx, all_time - sleep_time, LOCKSTAT_WRITER, (state & SX_LOCK_SHARED) == 0, (state & SX_LOCK_SHARED) == 0 ? 0 : SX_SHARERS(state)); out_lockstat: #endif if (!error) LOCKSTAT_PROFILE_OBTAIN_RWLOCK_SUCCESS(sx__acquire, sx, contested, waittime, file, line, LOCKSTAT_WRITER); return (error); } /* * This function represents the so-called 'hard case' for sx_xunlock * operation. All 'easy case' failures are redirected to this. Note * that ideally this would be a static function, but it needs to be * accessible from at least sx.h. */ void _sx_xunlock_hard(struct sx *sx, uintptr_t x LOCK_FILE_LINE_ARG_DEF) { uintptr_t tid, setx; int queue, wakeup_swapper; if (SCHEDULER_STOPPED()) return; tid = (uintptr_t)curthread; if (__predict_false(x == tid)) x = SX_READ_VALUE(sx); MPASS(!(x & SX_LOCK_SHARED)); if (__predict_false(x & SX_LOCK_RECURSED)) { /* The lock is recursed, unrecurse one level. */ if ((--sx->sx_recurse) == 0) atomic_clear_ptr(&sx->sx_lock, SX_LOCK_RECURSED); if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p unrecursing", __func__, sx); return; } LOCKSTAT_PROFILE_RELEASE_RWLOCK(sx__release, sx, LOCKSTAT_WRITER); if (x == tid && atomic_cmpset_rel_ptr(&sx->sx_lock, tid, SX_LOCK_UNLOCKED)) return; if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p contested", __func__, sx); sleepq_lock(&sx->lock_object); x = SX_READ_VALUE(sx); MPASS(x & (SX_LOCK_SHARED_WAITERS | SX_LOCK_EXCLUSIVE_WAITERS)); /* * The wake up algorithm here is quite simple and probably not * ideal. It gives precedence to shared waiters if they are * present. For this condition, we have to preserve the * state of the exclusive waiters flag. * If interruptible sleeps left the shared queue empty avoid a * starvation for the threads sleeping on the exclusive queue by giving * them precedence and cleaning up the shared waiters bit anyway. */ setx = SX_LOCK_UNLOCKED; queue = SQ_SHARED_QUEUE; if ((x & SX_LOCK_EXCLUSIVE_WAITERS) != 0 && sleepq_sleepcnt(&sx->lock_object, SQ_EXCLUSIVE_QUEUE) != 0) { queue = SQ_EXCLUSIVE_QUEUE; setx |= (x & SX_LOCK_SHARED_WAITERS); } atomic_store_rel_ptr(&sx->sx_lock, setx); /* Wake up all the waiters for the specific queue. */ if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR3(KTR_LOCK, "%s: %p waking up all threads on %s queue", __func__, sx, queue == SQ_SHARED_QUEUE ? "shared" : "exclusive"); wakeup_swapper = sleepq_broadcast(&sx->lock_object, SLEEPQ_SX, 0, queue); sleepq_release(&sx->lock_object); if (wakeup_swapper) kick_proc0(); } static bool __always_inline __sx_can_read(struct thread *td, uintptr_t x, bool fp) { if ((x & (SX_LOCK_SHARED | SX_LOCK_EXCLUSIVE_WAITERS | SX_LOCK_WRITE_SPINNER)) == SX_LOCK_SHARED) return (true); if (!fp && td->td_sx_slocks && (x & SX_LOCK_SHARED)) return (true); return (false); } static bool __always_inline __sx_slock_try(struct sx *sx, struct thread *td, uintptr_t *xp, bool fp LOCK_FILE_LINE_ARG_DEF) { /* * If no other thread has an exclusive lock then try to bump up * the count of sharers. Since we have to preserve the state * of SX_LOCK_EXCLUSIVE_WAITERS, if we fail to acquire the * shared lock loop back and retry. */ while (__sx_can_read(td, *xp, fp)) { if (atomic_fcmpset_acq_ptr(&sx->sx_lock, xp, *xp + SX_ONE_SHARER)) { if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR4(KTR_LOCK, "%s: %p succeed %p -> %p", __func__, sx, (void *)*xp, (void *)(*xp + SX_ONE_SHARER)); td->td_sx_slocks++; return (true); } } return (false); } static int __noinline _sx_slock_hard(struct sx *sx, int opts, uintptr_t x LOCK_FILE_LINE_ARG_DEF) { GIANT_DECLARE; struct thread *td; #ifdef ADAPTIVE_SX struct thread *owner; u_int i, n, spintries = 0; #endif #ifdef LOCK_PROFILING uint64_t waittime = 0; int contested = 0; #endif int error = 0; #if defined(ADAPTIVE_SX) || defined(KDTRACE_HOOKS) struct lock_delay_arg lda; #endif #ifdef KDTRACE_HOOKS u_int sleep_cnt = 0; int64_t sleep_time = 0; int64_t all_time = 0; #endif #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) uintptr_t state = 0; #endif int extra_work __sdt_used = 0; td = curthread; #ifdef KDTRACE_HOOKS if (LOCKSTAT_PROFILE_ENABLED(sx__acquire)) { if (__sx_slock_try(sx, td, &x, false LOCK_FILE_LINE_ARG)) goto out_lockstat; extra_work = 1; all_time -= lockstat_nsecs(&sx->lock_object); state = x; } #endif #ifdef LOCK_PROFILING extra_work = 1; state = x; #endif if (SCHEDULER_STOPPED()) return (0); #if defined(ADAPTIVE_SX) lock_delay_arg_init(&lda, &sx_delay); #elif defined(KDTRACE_HOOKS) lock_delay_arg_init_noadapt(&lda); #endif #ifdef HWPMC_HOOKS PMC_SOFT_CALL( , , lock, failed); #endif lock_profile_obtain_lock_failed(&sx->lock_object, false, &contested, &waittime); #ifndef INVARIANTS GIANT_SAVE(extra_work); #endif + THREAD_CONTENDS_ON_LOCK(&sx->lock_object); + /* * As with rwlocks, we don't make any attempt to try to block * shared locks once there is an exclusive waiter. */ for (;;) { if (__sx_slock_try(sx, td, &x, false LOCK_FILE_LINE_ARG)) break; #ifdef INVARIANTS GIANT_SAVE(extra_work); #endif #ifdef KDTRACE_HOOKS lda.spin_cnt++; #endif #ifdef ADAPTIVE_SX /* * If the owner is running on another CPU, spin until * the owner stops running or the state of the lock * changes. */ if ((x & SX_LOCK_SHARED) == 0) { owner = lv_sx_owner(x); if (TD_IS_RUNNING(owner)) { if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR3(KTR_LOCK, "%s: spinning on %p held by %p", __func__, sx, owner); KTR_STATE1(KTR_SCHED, "thread", sched_tdname(curthread), "spinning", "lockname:\"%s\"", sx->lock_object.lo_name); do { lock_delay(&lda); x = SX_READ_VALUE(sx); owner = lv_sx_owner(x); } while (owner != NULL && TD_IS_RUNNING(owner)); KTR_STATE0(KTR_SCHED, "thread", sched_tdname(curthread), "running"); continue; } } else { if ((x & SX_LOCK_WRITE_SPINNER) && SX_SHARERS(x) == 0) { MPASS(!__sx_can_read(td, x, false)); lock_delay_spin(2); x = SX_READ_VALUE(sx); continue; } if (spintries < asx_retries) { KTR_STATE1(KTR_SCHED, "thread", sched_tdname(curthread), "spinning", "lockname:\"%s\"", sx->lock_object.lo_name); n = SX_SHARERS(x); for (i = 0; i < asx_loops; i += n) { lock_delay_spin(n); x = SX_READ_VALUE(sx); if (!(x & SX_LOCK_SHARED)) break; n = SX_SHARERS(x); if (n == 0) break; if (__sx_can_read(td, x, false)) break; } #ifdef KDTRACE_HOOKS lda.spin_cnt += i; #endif KTR_STATE0(KTR_SCHED, "thread", sched_tdname(curthread), "running"); if (i < asx_loops) continue; } } #endif /* * Some other thread already has an exclusive lock, so * start the process of blocking. */ sleepq_lock(&sx->lock_object); x = SX_READ_VALUE(sx); retry_sleepq: if (((x & SX_LOCK_WRITE_SPINNER) && SX_SHARERS(x) == 0) || __sx_can_read(td, x, false)) { sleepq_release(&sx->lock_object); continue; } #ifdef ADAPTIVE_SX /* * If the owner is running on another CPU, spin until * the owner stops running or the state of the lock * changes. */ if (!(x & SX_LOCK_SHARED)) { owner = (struct thread *)SX_OWNER(x); if (TD_IS_RUNNING(owner)) { sleepq_release(&sx->lock_object); x = SX_READ_VALUE(sx); continue; } } #endif /* * Try to set the SX_LOCK_SHARED_WAITERS flag. If we * fail to set it drop the sleep queue lock and loop * back. */ if (!(x & SX_LOCK_SHARED_WAITERS)) { if (!atomic_fcmpset_ptr(&sx->sx_lock, &x, x | SX_LOCK_SHARED_WAITERS)) goto retry_sleepq; if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p set shared waiters flag", __func__, sx); } /* * Since we have been unable to acquire the shared lock, * we have to sleep. */ if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p blocking on sleep queue", __func__, sx); #ifdef KDTRACE_HOOKS sleep_time -= lockstat_nsecs(&sx->lock_object); #endif sleepq_add(&sx->lock_object, NULL, sx->lock_object.lo_name, SLEEPQ_SX | ((opts & SX_INTERRUPTIBLE) ? SLEEPQ_INTERRUPTIBLE : 0), SQ_SHARED_QUEUE); if (!(opts & SX_INTERRUPTIBLE)) sleepq_wait(&sx->lock_object, 0); else error = sleepq_wait_sig(&sx->lock_object, 0); #ifdef KDTRACE_HOOKS sleep_time += lockstat_nsecs(&sx->lock_object); sleep_cnt++; #endif if (error) { if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: interruptible sleep by %p suspended by signal", __func__, sx); break; } if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p resuming from sleep queue", __func__, sx); x = SX_READ_VALUE(sx); } + THREAD_CONTENTION_DONE(&sx->lock_object); #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) if (__predict_true(!extra_work)) return (error); #endif #ifdef KDTRACE_HOOKS all_time += lockstat_nsecs(&sx->lock_object); if (sleep_time) LOCKSTAT_RECORD4(sx__block, sx, sleep_time, LOCKSTAT_READER, (state & SX_LOCK_SHARED) == 0, (state & SX_LOCK_SHARED) == 0 ? 0 : SX_SHARERS(state)); if (lda.spin_cnt > sleep_cnt) LOCKSTAT_RECORD4(sx__spin, sx, all_time - sleep_time, LOCKSTAT_READER, (state & SX_LOCK_SHARED) == 0, (state & SX_LOCK_SHARED) == 0 ? 0 : SX_SHARERS(state)); out_lockstat: #endif if (error == 0) { LOCKSTAT_PROFILE_OBTAIN_RWLOCK_SUCCESS(sx__acquire, sx, contested, waittime, file, line, LOCKSTAT_READER); } GIANT_RESTORE(); return (error); } int _sx_slock_int(struct sx *sx, int opts LOCK_FILE_LINE_ARG_DEF) { struct thread *td; uintptr_t x; int error; KASSERT(kdb_active != 0 || SCHEDULER_STOPPED() || !TD_IS_IDLETHREAD(curthread), ("sx_slock() by idle thread %p on sx %s @ %s:%d", curthread, sx->lock_object.lo_name, file, line)); KASSERT(sx->sx_lock != SX_LOCK_DESTROYED, ("sx_slock() of destroyed sx @ %s:%d", file, line)); WITNESS_CHECKORDER(&sx->lock_object, LOP_NEWORDER, file, line, NULL); error = 0; td = curthread; x = SX_READ_VALUE(sx); if (__predict_false(LOCKSTAT_PROFILE_ENABLED(sx__acquire) || !__sx_slock_try(sx, td, &x, true LOCK_FILE_LINE_ARG))) error = _sx_slock_hard(sx, opts, x LOCK_FILE_LINE_ARG); else lock_profile_obtain_lock_success(&sx->lock_object, false, 0, 0, file, line); if (error == 0) { LOCK_LOG_LOCK("SLOCK", &sx->lock_object, 0, 0, file, line); WITNESS_LOCK(&sx->lock_object, 0, file, line); TD_LOCKS_INC(curthread); } return (error); } int _sx_slock(struct sx *sx, int opts, const char *file, int line) { return (_sx_slock_int(sx, opts LOCK_FILE_LINE_ARG)); } static bool __always_inline _sx_sunlock_try(struct sx *sx, struct thread *td, uintptr_t *xp) { for (;;) { if (SX_SHARERS(*xp) > 1 || !(*xp & SX_LOCK_WAITERS)) { if (atomic_fcmpset_rel_ptr(&sx->sx_lock, xp, *xp - SX_ONE_SHARER)) { if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR4(KTR_LOCK, "%s: %p succeeded %p -> %p", __func__, sx, (void *)*xp, (void *)(*xp - SX_ONE_SHARER)); td->td_sx_slocks--; return (true); } continue; } break; } return (false); } static void __noinline _sx_sunlock_hard(struct sx *sx, struct thread *td, uintptr_t x LOCK_FILE_LINE_ARG_DEF) { int wakeup_swapper = 0; uintptr_t setx, queue; if (SCHEDULER_STOPPED()) return; if (_sx_sunlock_try(sx, td, &x)) goto out_lockstat; sleepq_lock(&sx->lock_object); x = SX_READ_VALUE(sx); for (;;) { if (_sx_sunlock_try(sx, td, &x)) break; /* * Wake up semantic here is quite simple: * Just wake up all the exclusive waiters. * Note that the state of the lock could have changed, * so if it fails loop back and retry. */ setx = SX_LOCK_UNLOCKED; queue = SQ_SHARED_QUEUE; if (x & SX_LOCK_EXCLUSIVE_WAITERS) { setx |= (x & SX_LOCK_SHARED_WAITERS); queue = SQ_EXCLUSIVE_QUEUE; } setx |= (x & SX_LOCK_WRITE_SPINNER); if (!atomic_fcmpset_rel_ptr(&sx->sx_lock, &x, setx)) continue; if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p waking up all thread on" "exclusive queue", __func__, sx); wakeup_swapper = sleepq_broadcast(&sx->lock_object, SLEEPQ_SX, 0, queue); td->td_sx_slocks--; break; } sleepq_release(&sx->lock_object); if (wakeup_swapper) kick_proc0(); out_lockstat: LOCKSTAT_PROFILE_RELEASE_RWLOCK(sx__release, sx, LOCKSTAT_READER); } void _sx_sunlock_int(struct sx *sx LOCK_FILE_LINE_ARG_DEF) { struct thread *td; uintptr_t x; KASSERT(sx->sx_lock != SX_LOCK_DESTROYED, ("sx_sunlock() of destroyed sx @ %s:%d", file, line)); _sx_assert(sx, SA_SLOCKED, file, line); WITNESS_UNLOCK(&sx->lock_object, 0, file, line); LOCK_LOG_LOCK("SUNLOCK", &sx->lock_object, 0, 0, file, line); td = curthread; x = SX_READ_VALUE(sx); if (__predict_false(LOCKSTAT_PROFILE_ENABLED(sx__release) || !_sx_sunlock_try(sx, td, &x))) _sx_sunlock_hard(sx, td, x LOCK_FILE_LINE_ARG); else lock_profile_release_lock(&sx->lock_object, false); TD_LOCKS_DEC(curthread); } void _sx_sunlock(struct sx *sx, const char *file, int line) { _sx_sunlock_int(sx LOCK_FILE_LINE_ARG); } #ifdef INVARIANT_SUPPORT #ifndef INVARIANTS #undef _sx_assert #endif /* * In the non-WITNESS case, sx_assert() can only detect that at least * *some* thread owns an slock, but it cannot guarantee that *this* * thread owns an slock. */ void _sx_assert(const struct sx *sx, int what, const char *file, int line) { #ifndef WITNESS int slocked = 0; #endif if (SCHEDULER_STOPPED()) return; switch (what) { case SA_SLOCKED: case SA_SLOCKED | SA_NOTRECURSED: case SA_SLOCKED | SA_RECURSED: #ifndef WITNESS slocked = 1; /* FALLTHROUGH */ #endif case SA_LOCKED: case SA_LOCKED | SA_NOTRECURSED: case SA_LOCKED | SA_RECURSED: #ifdef WITNESS witness_assert(&sx->lock_object, what, file, line); #else /* * If some other thread has an exclusive lock or we * have one and are asserting a shared lock, fail. * Also, if no one has a lock at all, fail. */ if (sx->sx_lock == SX_LOCK_UNLOCKED || (!(sx->sx_lock & SX_LOCK_SHARED) && (slocked || sx_xholder(sx) != curthread))) panic("Lock %s not %slocked @ %s:%d\n", sx->lock_object.lo_name, slocked ? "share " : "", file, line); if (!(sx->sx_lock & SX_LOCK_SHARED)) { if (sx_recursed(sx)) { if (what & SA_NOTRECURSED) panic("Lock %s recursed @ %s:%d\n", sx->lock_object.lo_name, file, line); } else if (what & SA_RECURSED) panic("Lock %s not recursed @ %s:%d\n", sx->lock_object.lo_name, file, line); } #endif break; case SA_XLOCKED: case SA_XLOCKED | SA_NOTRECURSED: case SA_XLOCKED | SA_RECURSED: if (sx_xholder(sx) != curthread) panic("Lock %s not exclusively locked @ %s:%d\n", sx->lock_object.lo_name, file, line); if (sx_recursed(sx)) { if (what & SA_NOTRECURSED) panic("Lock %s recursed @ %s:%d\n", sx->lock_object.lo_name, file, line); } else if (what & SA_RECURSED) panic("Lock %s not recursed @ %s:%d\n", sx->lock_object.lo_name, file, line); break; case SA_UNLOCKED: #ifdef WITNESS witness_assert(&sx->lock_object, what, file, line); #else /* * If we hold an exclusve lock fail. We can't * reliably check to see if we hold a shared lock or * not. */ if (sx_xholder(sx) == curthread) panic("Lock %s exclusively locked @ %s:%d\n", sx->lock_object.lo_name, file, line); #endif break; default: panic("Unknown sx lock assertion: %d @ %s:%d", what, file, line); } } #endif /* INVARIANT_SUPPORT */ #ifdef DDB static void db_show_sx(const struct lock_object *lock) { struct thread *td; const struct sx *sx; sx = (const struct sx *)lock; db_printf(" state: "); if (sx->sx_lock == SX_LOCK_UNLOCKED) db_printf("UNLOCKED\n"); else if (sx->sx_lock == SX_LOCK_DESTROYED) { db_printf("DESTROYED\n"); return; } else if (sx->sx_lock & SX_LOCK_SHARED) db_printf("SLOCK: %ju\n", (uintmax_t)SX_SHARERS(sx->sx_lock)); else { td = sx_xholder(sx); db_printf("XLOCK: %p (tid %d, pid %d, \"%s\")\n", td, td->td_tid, td->td_proc->p_pid, td->td_name); if (sx_recursed(sx)) db_printf(" recursed: %d\n", sx->sx_recurse); } db_printf(" waiters: "); switch(sx->sx_lock & (SX_LOCK_SHARED_WAITERS | SX_LOCK_EXCLUSIVE_WAITERS)) { case SX_LOCK_SHARED_WAITERS: db_printf("shared\n"); break; case SX_LOCK_EXCLUSIVE_WAITERS: db_printf("exclusive\n"); break; case SX_LOCK_SHARED_WAITERS | SX_LOCK_EXCLUSIVE_WAITERS: db_printf("exclusive and shared\n"); break; default: db_printf("none\n"); } } /* * Check to see if a thread that is blocked on a sleep queue is actually * blocked on an sx lock. If so, output some details and return true. * If the lock has an exclusive owner, return that in *ownerp. */ int sx_chain(struct thread *td, struct thread **ownerp) { const struct sx *sx; /* * Check to see if this thread is blocked on an sx lock. * First, we check the lock class. If that is ok, then we * compare the lock name against the wait message. */ sx = td->td_wchan; if (LOCK_CLASS(&sx->lock_object) != &lock_class_sx || sx->lock_object.lo_name != td->td_wmesg) return (0); /* We think we have an sx lock, so output some details. */ db_printf("blocked on sx \"%s\" ", td->td_wmesg); *ownerp = sx_xholder(sx); if (sx->sx_lock & SX_LOCK_SHARED) db_printf("SLOCK (count %ju)\n", (uintmax_t)SX_SHARERS(sx->sx_lock)); else db_printf("XLOCK\n"); return (1); } #endif diff --git a/sys/kern/kern_thread.c b/sys/kern/kern_thread.c index dcebb08956e6..3bc8546db594 100644 --- a/sys/kern/kern_thread.c +++ b/sys/kern/kern_thread.c @@ -1,1812 +1,1812 @@ /*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (C) 2001 Julian Elischer . * 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(s), this list of conditions and the following disclaimer as * the first lines of this file unmodified other than the possible * addition of one or more copyright notices. * 2. Redistributions in binary form must reproduce the above copyright * notice(s), 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 COPYRIGHT HOLDER(S) ``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 COPYRIGHT HOLDER(S) 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 "opt_witness.h" #include "opt_hwpmc_hooks.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef HWPMC_HOOKS #include #endif #include #include #include #include #include #include #include #include /* * Asserts below verify the stability of struct thread and struct proc * layout, as exposed by KBI to modules. On head, the KBI is allowed * to drift, change to the structures must be accompanied by the * assert update. * * On the stable branches after KBI freeze, conditions must not be * violated. Typically new fields are moved to the end of the * structures. */ #ifdef __amd64__ _Static_assert(offsetof(struct thread, td_flags) == 0x108, "struct thread KBI td_flags"); _Static_assert(offsetof(struct thread, td_pflags) == 0x114, "struct thread KBI td_pflags"); -_Static_assert(offsetof(struct thread, td_frame) == 0x4b0, +_Static_assert(offsetof(struct thread, td_frame) == 0x4b8, "struct thread KBI td_frame"); _Static_assert(offsetof(struct thread, td_emuldata) == 0x6c0, "struct thread KBI td_emuldata"); _Static_assert(offsetof(struct proc, p_flag) == 0xb8, "struct proc KBI p_flag"); _Static_assert(offsetof(struct proc, p_pid) == 0xc4, "struct proc KBI p_pid"); _Static_assert(offsetof(struct proc, p_filemon) == 0x3c8, "struct proc KBI p_filemon"); _Static_assert(offsetof(struct proc, p_comm) == 0x3e0, "struct proc KBI p_comm"); _Static_assert(offsetof(struct proc, p_emuldata) == 0x4d0, "struct proc KBI p_emuldata"); #endif #ifdef __i386__ _Static_assert(offsetof(struct thread, td_flags) == 0x9c, "struct thread KBI td_flags"); _Static_assert(offsetof(struct thread, td_pflags) == 0xa8, "struct thread KBI td_pflags"); -_Static_assert(offsetof(struct thread, td_frame) == 0x314, +_Static_assert(offsetof(struct thread, td_frame) == 0x318, "struct thread KBI td_frame"); -_Static_assert(offsetof(struct thread, td_emuldata) == 0x358, +_Static_assert(offsetof(struct thread, td_emuldata) == 0x35c, "struct thread KBI td_emuldata"); _Static_assert(offsetof(struct proc, p_flag) == 0x6c, "struct proc KBI p_flag"); _Static_assert(offsetof(struct proc, p_pid) == 0x78, "struct proc KBI p_pid"); _Static_assert(offsetof(struct proc, p_filemon) == 0x270, "struct proc KBI p_filemon"); _Static_assert(offsetof(struct proc, p_comm) == 0x284, "struct proc KBI p_comm"); _Static_assert(offsetof(struct proc, p_emuldata) == 0x318, "struct proc KBI p_emuldata"); #endif SDT_PROVIDER_DECLARE(proc); SDT_PROBE_DEFINE(proc, , , lwp__exit); /* * thread related storage. */ static uma_zone_t thread_zone; struct thread_domain_data { struct thread *tdd_zombies; int tdd_reapticks; } __aligned(CACHE_LINE_SIZE); static struct thread_domain_data thread_domain_data[MAXMEMDOM]; static struct task thread_reap_task; static struct callout thread_reap_callout; static void thread_zombie(struct thread *); static void thread_reap(void); static void thread_reap_all(void); static void thread_reap_task_cb(void *, int); static void thread_reap_callout_cb(void *); static int thread_unsuspend_one(struct thread *td, struct proc *p, bool boundary); static void thread_free_batched(struct thread *td); static __exclusive_cache_line struct mtx tid_lock; static bitstr_t *tid_bitmap; static MALLOC_DEFINE(M_TIDHASH, "tidhash", "thread hash"); static int maxthread; SYSCTL_INT(_kern, OID_AUTO, maxthread, CTLFLAG_RDTUN, &maxthread, 0, "Maximum number of threads"); static __exclusive_cache_line int nthreads; static LIST_HEAD(tidhashhead, thread) *tidhashtbl; static u_long tidhash; static u_long tidhashlock; static struct rwlock *tidhashtbl_lock; #define TIDHASH(tid) (&tidhashtbl[(tid) & tidhash]) #define TIDHASHLOCK(tid) (&tidhashtbl_lock[(tid) & tidhashlock]) EVENTHANDLER_LIST_DEFINE(thread_ctor); EVENTHANDLER_LIST_DEFINE(thread_dtor); EVENTHANDLER_LIST_DEFINE(thread_init); EVENTHANDLER_LIST_DEFINE(thread_fini); static bool thread_count_inc_try(void) { int nthreads_new; nthreads_new = atomic_fetchadd_int(&nthreads, 1) + 1; if (nthreads_new >= maxthread - 100) { if (priv_check_cred(curthread->td_ucred, PRIV_MAXPROC) != 0 || nthreads_new >= maxthread) { atomic_subtract_int(&nthreads, 1); return (false); } } return (true); } static bool thread_count_inc(void) { static struct timeval lastfail; static int curfail; thread_reap(); if (thread_count_inc_try()) { return (true); } thread_reap_all(); if (thread_count_inc_try()) { return (true); } if (ppsratecheck(&lastfail, &curfail, 1)) { printf("maxthread limit exceeded by uid %u " "(pid %d); consider increasing kern.maxthread\n", curthread->td_ucred->cr_ruid, curproc->p_pid); } return (false); } static void thread_count_sub(int n) { atomic_subtract_int(&nthreads, n); } static void thread_count_dec(void) { thread_count_sub(1); } static lwpid_t tid_alloc(void) { static lwpid_t trytid; lwpid_t tid; mtx_lock(&tid_lock); /* * It is an invariant that the bitmap is big enough to hold maxthread * IDs. If we got to this point there has to be at least one free. */ if (trytid >= maxthread) trytid = 0; bit_ffc_at(tid_bitmap, trytid, maxthread, &tid); if (tid == -1) { KASSERT(trytid != 0, ("unexpectedly ran out of IDs")); trytid = 0; bit_ffc_at(tid_bitmap, trytid, maxthread, &tid); KASSERT(tid != -1, ("unexpectedly ran out of IDs")); } bit_set(tid_bitmap, tid); trytid = tid + 1; mtx_unlock(&tid_lock); return (tid + NO_PID); } static void tid_free_locked(lwpid_t rtid) { lwpid_t tid; mtx_assert(&tid_lock, MA_OWNED); KASSERT(rtid >= NO_PID, ("%s: invalid tid %d\n", __func__, rtid)); tid = rtid - NO_PID; KASSERT(bit_test(tid_bitmap, tid) != 0, ("thread ID %d not allocated\n", rtid)); bit_clear(tid_bitmap, tid); } static void tid_free(lwpid_t rtid) { mtx_lock(&tid_lock); tid_free_locked(rtid); mtx_unlock(&tid_lock); } static void tid_free_batch(lwpid_t *batch, int n) { int i; mtx_lock(&tid_lock); for (i = 0; i < n; i++) { tid_free_locked(batch[i]); } mtx_unlock(&tid_lock); } /* * Batching for thread reapping. */ struct tidbatch { lwpid_t tab[16]; int n; }; static void tidbatch_prep(struct tidbatch *tb) { tb->n = 0; } static void tidbatch_add(struct tidbatch *tb, struct thread *td) { KASSERT(tb->n < nitems(tb->tab), ("%s: count too high %d", __func__, tb->n)); tb->tab[tb->n] = td->td_tid; tb->n++; } static void tidbatch_process(struct tidbatch *tb) { KASSERT(tb->n <= nitems(tb->tab), ("%s: count too high %d", __func__, tb->n)); if (tb->n == nitems(tb->tab)) { tid_free_batch(tb->tab, tb->n); tb->n = 0; } } static void tidbatch_final(struct tidbatch *tb) { KASSERT(tb->n <= nitems(tb->tab), ("%s: count too high %d", __func__, tb->n)); if (tb->n != 0) { tid_free_batch(tb->tab, tb->n); } } /* * Batching thread count free, for consistency */ struct tdcountbatch { int n; }; static void tdcountbatch_prep(struct tdcountbatch *tb) { tb->n = 0; } static void tdcountbatch_add(struct tdcountbatch *tb, struct thread *td __unused) { tb->n++; } static void tdcountbatch_process(struct tdcountbatch *tb) { if (tb->n == 32) { thread_count_sub(tb->n); tb->n = 0; } } static void tdcountbatch_final(struct tdcountbatch *tb) { if (tb->n != 0) { thread_count_sub(tb->n); } } /* * Prepare a thread for use. */ static int thread_ctor(void *mem, int size, void *arg, int flags) { struct thread *td; td = (struct thread *)mem; TD_SET_STATE(td, TDS_INACTIVE); td->td_lastcpu = td->td_oncpu = NOCPU; /* * Note that td_critnest begins life as 1 because the thread is not * running and is thereby implicitly waiting to be on the receiving * end of a context switch. */ td->td_critnest = 1; td->td_lend_user_pri = PRI_MAX; #ifdef AUDIT audit_thread_alloc(td); #endif #ifdef KDTRACE_HOOKS kdtrace_thread_ctor(td); #endif umtx_thread_alloc(td); MPASS(td->td_sel == NULL); return (0); } /* * Reclaim a thread after use. */ static void thread_dtor(void *mem, int size, void *arg) { struct thread *td; td = (struct thread *)mem; #ifdef INVARIANTS /* Verify that this thread is in a safe state to free. */ switch (TD_GET_STATE(td)) { case TDS_INHIBITED: case TDS_RUNNING: case TDS_CAN_RUN: case TDS_RUNQ: /* * We must never unlink a thread that is in one of * these states, because it is currently active. */ panic("bad state for thread unlinking"); /* NOTREACHED */ case TDS_INACTIVE: break; default: panic("bad thread state"); /* NOTREACHED */ } #endif #ifdef AUDIT audit_thread_free(td); #endif #ifdef KDTRACE_HOOKS kdtrace_thread_dtor(td); #endif /* Free all OSD associated to this thread. */ osd_thread_exit(td); ast_kclear(td); seltdfini(td); } /* * Initialize type-stable parts of a thread (when newly created). */ static int thread_init(void *mem, int size, int flags) { struct thread *td; td = (struct thread *)mem; td->td_allocdomain = vm_phys_domain(vtophys(td)); td->td_sleepqueue = sleepq_alloc(); td->td_turnstile = turnstile_alloc(); td->td_rlqe = NULL; EVENTHANDLER_DIRECT_INVOKE(thread_init, td); umtx_thread_init(td); td->td_kstack = 0; td->td_sel = NULL; return (0); } /* * Tear down type-stable parts of a thread (just before being discarded). */ static void thread_fini(void *mem, int size) { struct thread *td; td = (struct thread *)mem; EVENTHANDLER_DIRECT_INVOKE(thread_fini, td); rlqentry_free(td->td_rlqe); turnstile_free(td->td_turnstile); sleepq_free(td->td_sleepqueue); umtx_thread_fini(td); MPASS(td->td_sel == NULL); } /* * For a newly created process, * link up all the structures and its initial threads etc. * called from: * {arch}/{arch}/machdep.c {arch}_init(), init386() etc. * proc_dtor() (should go away) * proc_init() */ void proc_linkup0(struct proc *p, struct thread *td) { TAILQ_INIT(&p->p_threads); /* all threads in proc */ proc_linkup(p, td); } void proc_linkup(struct proc *p, struct thread *td) { sigqueue_init(&p->p_sigqueue, p); p->p_ksi = ksiginfo_alloc(M_WAITOK); if (p->p_ksi != NULL) { /* XXX p_ksi may be null if ksiginfo zone is not ready */ p->p_ksi->ksi_flags = KSI_EXT | KSI_INS; } LIST_INIT(&p->p_mqnotifier); p->p_numthreads = 0; thread_link(td, p); } static void ast_suspend(struct thread *td, int tda __unused) { struct proc *p; p = td->td_proc; /* * We need to check to see if we have to exit or wait due to a * single threading requirement or some other STOP condition. */ PROC_LOCK(p); thread_suspend_check(0); PROC_UNLOCK(p); } extern int max_threads_per_proc; /* * Initialize global thread allocation resources. */ void threadinit(void) { u_long i; lwpid_t tid0; /* * Place an upper limit on threads which can be allocated. * * Note that other factors may make the de facto limit much lower. * * Platform limits are somewhat arbitrary but deemed "more than good * enough" for the foreseable future. */ if (maxthread == 0) { #ifdef _LP64 maxthread = MIN(maxproc * max_threads_per_proc, 1000000); #else maxthread = MIN(maxproc * max_threads_per_proc, 100000); #endif } mtx_init(&tid_lock, "TID lock", NULL, MTX_DEF); tid_bitmap = bit_alloc(maxthread, M_TIDHASH, M_WAITOK); /* * Handle thread0. */ thread_count_inc(); tid0 = tid_alloc(); if (tid0 != THREAD0_TID) panic("tid0 %d != %d\n", tid0, THREAD0_TID); thread_zone = uma_zcreate("THREAD", sched_sizeof_thread(), thread_ctor, thread_dtor, thread_init, thread_fini, 32 - 1, UMA_ZONE_NOFREE); tidhashtbl = hashinit(maxproc / 2, M_TIDHASH, &tidhash); tidhashlock = (tidhash + 1) / 64; if (tidhashlock > 0) tidhashlock--; tidhashtbl_lock = malloc(sizeof(*tidhashtbl_lock) * (tidhashlock + 1), M_TIDHASH, M_WAITOK | M_ZERO); for (i = 0; i < tidhashlock + 1; i++) rw_init(&tidhashtbl_lock[i], "tidhash"); TASK_INIT(&thread_reap_task, 0, thread_reap_task_cb, NULL); callout_init(&thread_reap_callout, 1); callout_reset(&thread_reap_callout, 5 * hz, thread_reap_callout_cb, NULL); ast_register(TDA_SUSPEND, ASTR_ASTF_REQUIRED, 0, ast_suspend); } /* * Place an unused thread on the zombie list. */ void thread_zombie(struct thread *td) { struct thread_domain_data *tdd; struct thread *ztd; tdd = &thread_domain_data[td->td_allocdomain]; ztd = atomic_load_ptr(&tdd->tdd_zombies); for (;;) { td->td_zombie = ztd; if (atomic_fcmpset_rel_ptr((uintptr_t *)&tdd->tdd_zombies, (uintptr_t *)&ztd, (uintptr_t)td)) break; continue; } } /* * Release a thread that has exited after cpu_throw(). */ void thread_stash(struct thread *td) { atomic_subtract_rel_int(&td->td_proc->p_exitthreads, 1); thread_zombie(td); } /* * Reap zombies from passed domain. */ static void thread_reap_domain(struct thread_domain_data *tdd) { struct thread *itd, *ntd; struct tidbatch tidbatch; struct credbatch credbatch; struct limbatch limbatch; struct tdcountbatch tdcountbatch; /* * Reading upfront is pessimal if followed by concurrent atomic_swap, * but most of the time the list is empty. */ if (tdd->tdd_zombies == NULL) return; itd = (struct thread *)atomic_swap_ptr((uintptr_t *)&tdd->tdd_zombies, (uintptr_t)NULL); if (itd == NULL) return; /* * Multiple CPUs can get here, the race is fine as ticks is only * advisory. */ tdd->tdd_reapticks = ticks; tidbatch_prep(&tidbatch); credbatch_prep(&credbatch); limbatch_prep(&limbatch); tdcountbatch_prep(&tdcountbatch); while (itd != NULL) { ntd = itd->td_zombie; EVENTHANDLER_DIRECT_INVOKE(thread_dtor, itd); tidbatch_add(&tidbatch, itd); credbatch_add(&credbatch, itd); limbatch_add(&limbatch, itd); tdcountbatch_add(&tdcountbatch, itd); thread_free_batched(itd); tidbatch_process(&tidbatch); credbatch_process(&credbatch); limbatch_process(&limbatch); tdcountbatch_process(&tdcountbatch); itd = ntd; } tidbatch_final(&tidbatch); credbatch_final(&credbatch); limbatch_final(&limbatch); tdcountbatch_final(&tdcountbatch); } /* * Reap zombies from all domains. */ static void thread_reap_all(void) { struct thread_domain_data *tdd; int i, domain; domain = PCPU_GET(domain); for (i = 0; i < vm_ndomains; i++) { tdd = &thread_domain_data[(i + domain) % vm_ndomains]; thread_reap_domain(tdd); } } /* * Reap zombies from local domain. */ static void thread_reap(void) { struct thread_domain_data *tdd; int domain; domain = PCPU_GET(domain); tdd = &thread_domain_data[domain]; thread_reap_domain(tdd); } static void thread_reap_task_cb(void *arg __unused, int pending __unused) { thread_reap_all(); } static void thread_reap_callout_cb(void *arg __unused) { struct thread_domain_data *tdd; int i, cticks, lticks; bool wantreap; wantreap = false; cticks = atomic_load_int(&ticks); for (i = 0; i < vm_ndomains; i++) { tdd = &thread_domain_data[i]; lticks = tdd->tdd_reapticks; if (tdd->tdd_zombies != NULL && (u_int)(cticks - lticks) > 5 * hz) { wantreap = true; break; } } if (wantreap) taskqueue_enqueue(taskqueue_thread, &thread_reap_task); callout_reset(&thread_reap_callout, 5 * hz, thread_reap_callout_cb, NULL); } /* * Calling this function guarantees that any thread that exited before * the call is reaped when the function returns. By 'exited' we mean * a thread removed from the process linkage with thread_unlink(). * Practically this means that caller must lock/unlock corresponding * process lock before the call, to synchronize with thread_exit(). */ void thread_reap_barrier(void) { struct task *t; /* * First do context switches to each CPU to ensure that all * PCPU pc_deadthreads are moved to zombie list. */ quiesce_all_cpus("", PDROP); /* * Second, fire the task in the same thread as normal * thread_reap() is done, to serialize reaping. */ t = malloc(sizeof(*t), M_TEMP, M_WAITOK); TASK_INIT(t, 0, thread_reap_task_cb, t); taskqueue_enqueue(taskqueue_thread, t); taskqueue_drain(taskqueue_thread, t); free(t, M_TEMP); } /* * Allocate a thread. */ struct thread * thread_alloc(int pages) { struct thread *td; lwpid_t tid; if (!thread_count_inc()) { return (NULL); } tid = tid_alloc(); td = uma_zalloc(thread_zone, M_WAITOK); KASSERT(td->td_kstack == 0, ("thread_alloc got thread with kstack")); if (!vm_thread_new(td, pages)) { uma_zfree(thread_zone, td); tid_free(tid); thread_count_dec(); return (NULL); } td->td_tid = tid; bzero(&td->td_sa.args, sizeof(td->td_sa.args)); kmsan_thread_alloc(td); cpu_thread_alloc(td); EVENTHANDLER_DIRECT_INVOKE(thread_ctor, td); return (td); } int thread_alloc_stack(struct thread *td, int pages) { KASSERT(td->td_kstack == 0, ("thread_alloc_stack called on a thread with kstack")); if (!vm_thread_new(td, pages)) return (0); cpu_thread_alloc(td); return (1); } /* * Deallocate a thread. */ static void thread_free_batched(struct thread *td) { lock_profile_thread_exit(td); if (td->td_cpuset) cpuset_rel(td->td_cpuset); td->td_cpuset = NULL; cpu_thread_free(td); if (td->td_kstack != 0) vm_thread_dispose(td); callout_drain(&td->td_slpcallout); /* * Freeing handled by the caller. */ td->td_tid = -1; kmsan_thread_free(td); uma_zfree(thread_zone, td); } void thread_free(struct thread *td) { lwpid_t tid; EVENTHANDLER_DIRECT_INVOKE(thread_dtor, td); tid = td->td_tid; thread_free_batched(td); tid_free(tid); thread_count_dec(); } void thread_cow_get_proc(struct thread *newtd, struct proc *p) { PROC_LOCK_ASSERT(p, MA_OWNED); newtd->td_realucred = crcowget(p->p_ucred); newtd->td_ucred = newtd->td_realucred; newtd->td_limit = lim_hold(p->p_limit); newtd->td_cowgen = p->p_cowgen; } void thread_cow_get(struct thread *newtd, struct thread *td) { MPASS(td->td_realucred == td->td_ucred); newtd->td_realucred = crcowget(td->td_realucred); newtd->td_ucred = newtd->td_realucred; newtd->td_limit = lim_hold(td->td_limit); newtd->td_cowgen = td->td_cowgen; } void thread_cow_free(struct thread *td) { if (td->td_realucred != NULL) crcowfree(td); if (td->td_limit != NULL) lim_free(td->td_limit); } void thread_cow_update(struct thread *td) { struct proc *p; struct ucred *oldcred; struct plimit *oldlimit; p = td->td_proc; PROC_LOCK(p); oldcred = crcowsync(); oldlimit = lim_cowsync(); td->td_cowgen = p->p_cowgen; PROC_UNLOCK(p); if (oldcred != NULL) crfree(oldcred); if (oldlimit != NULL) lim_free(oldlimit); } void thread_cow_synced(struct thread *td) { struct proc *p; p = td->td_proc; PROC_LOCK_ASSERT(p, MA_OWNED); MPASS(td->td_cowgen != p->p_cowgen); MPASS(td->td_ucred == p->p_ucred); MPASS(td->td_limit == p->p_limit); td->td_cowgen = p->p_cowgen; } /* * Discard the current thread and exit from its context. * Always called with scheduler locked. * * Because we can't free a thread while we're operating under its context, * push the current thread into our CPU's deadthread holder. This means * we needn't worry about someone else grabbing our context before we * do a cpu_throw(). */ void thread_exit(void) { uint64_t runtime, new_switchtime; struct thread *td; struct thread *td2; struct proc *p; int wakeup_swapper; td = curthread; p = td->td_proc; PROC_SLOCK_ASSERT(p, MA_OWNED); mtx_assert(&Giant, MA_NOTOWNED); PROC_LOCK_ASSERT(p, MA_OWNED); KASSERT(p != NULL, ("thread exiting without a process")); CTR3(KTR_PROC, "thread_exit: thread %p (pid %ld, %s)", td, (long)p->p_pid, td->td_name); SDT_PROBE0(proc, , , lwp__exit); KASSERT(TAILQ_EMPTY(&td->td_sigqueue.sq_list), ("signal pending")); MPASS(td->td_realucred == td->td_ucred); /* * drop FPU & debug register state storage, or any other * architecture specific resources that * would not be on a new untouched process. */ cpu_thread_exit(td); /* * The last thread is left attached to the process * So that the whole bundle gets recycled. Skip * all this stuff if we never had threads. * EXIT clears all sign of other threads when * it goes to single threading, so the last thread always * takes the short path. */ if (p->p_flag & P_HADTHREADS) { if (p->p_numthreads > 1) { atomic_add_int(&td->td_proc->p_exitthreads, 1); thread_unlink(td); td2 = FIRST_THREAD_IN_PROC(p); sched_exit_thread(td2, td); /* * The test below is NOT true if we are the * sole exiting thread. P_STOPPED_SINGLE is unset * in exit1() after it is the only survivor. */ if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) { if (p->p_numthreads == p->p_suspcount) { thread_lock(p->p_singlethread); wakeup_swapper = thread_unsuspend_one( p->p_singlethread, p, false); if (wakeup_swapper) kick_proc0(); } } PCPU_SET(deadthread, td); } else { /* * The last thread is exiting.. but not through exit() */ panic ("thread_exit: Last thread exiting on its own"); } } #ifdef HWPMC_HOOKS /* * If this thread is part of a process that is being tracked by hwpmc(4), * inform the module of the thread's impending exit. */ if (PMC_PROC_IS_USING_PMCS(td->td_proc)) { PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT); PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_EXIT, NULL); } else if (PMC_SYSTEM_SAMPLING_ACTIVE()) PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_EXIT_LOG, NULL); #endif PROC_UNLOCK(p); PROC_STATLOCK(p); thread_lock(td); PROC_SUNLOCK(p); /* Do the same timestamp bookkeeping that mi_switch() would do. */ new_switchtime = cpu_ticks(); runtime = new_switchtime - PCPU_GET(switchtime); td->td_runtime += runtime; td->td_incruntime += runtime; PCPU_SET(switchtime, new_switchtime); PCPU_SET(switchticks, ticks); VM_CNT_INC(v_swtch); /* Save our resource usage in our process. */ td->td_ru.ru_nvcsw++; ruxagg_locked(p, td); rucollect(&p->p_ru, &td->td_ru); PROC_STATUNLOCK(p); TD_SET_STATE(td, TDS_INACTIVE); #ifdef WITNESS witness_thread_exit(td); #endif CTR1(KTR_PROC, "thread_exit: cpu_throw() thread %p", td); sched_throw(td); panic("I'm a teapot!"); /* NOTREACHED */ } /* * Do any thread specific cleanups that may be needed in wait() * called with Giant, proc and schedlock not held. */ void thread_wait(struct proc *p) { struct thread *td; mtx_assert(&Giant, MA_NOTOWNED); KASSERT(p->p_numthreads == 1, ("multiple threads in thread_wait()")); KASSERT(p->p_exitthreads == 0, ("p_exitthreads leaking")); td = FIRST_THREAD_IN_PROC(p); /* Lock the last thread so we spin until it exits cpu_throw(). */ thread_lock(td); thread_unlock(td); lock_profile_thread_exit(td); cpuset_rel(td->td_cpuset); td->td_cpuset = NULL; cpu_thread_clean(td); thread_cow_free(td); callout_drain(&td->td_slpcallout); thread_reap(); /* check for zombie threads etc. */ } /* * Link a thread to a process. * set up anything that needs to be initialized for it to * be used by the process. */ void thread_link(struct thread *td, struct proc *p) { /* * XXX This can't be enabled because it's called for proc0 before * its lock has been created. * PROC_LOCK_ASSERT(p, MA_OWNED); */ TD_SET_STATE(td, TDS_INACTIVE); td->td_proc = p; td->td_flags = TDF_INMEM; LIST_INIT(&td->td_contested); LIST_INIT(&td->td_lprof[0]); LIST_INIT(&td->td_lprof[1]); #ifdef EPOCH_TRACE SLIST_INIT(&td->td_epochs); #endif sigqueue_init(&td->td_sigqueue, p); callout_init(&td->td_slpcallout, 1); TAILQ_INSERT_TAIL(&p->p_threads, td, td_plist); p->p_numthreads++; } /* * Called from: * thread_exit() */ void thread_unlink(struct thread *td) { struct proc *p = td->td_proc; PROC_LOCK_ASSERT(p, MA_OWNED); #ifdef EPOCH_TRACE MPASS(SLIST_EMPTY(&td->td_epochs)); #endif TAILQ_REMOVE(&p->p_threads, td, td_plist); p->p_numthreads--; /* could clear a few other things here */ /* Must NOT clear links to proc! */ } static int calc_remaining(struct proc *p, int mode) { int remaining; PROC_LOCK_ASSERT(p, MA_OWNED); PROC_SLOCK_ASSERT(p, MA_OWNED); if (mode == SINGLE_EXIT) remaining = p->p_numthreads; else if (mode == SINGLE_BOUNDARY) remaining = p->p_numthreads - p->p_boundary_count; else if (mode == SINGLE_NO_EXIT || mode == SINGLE_ALLPROC) remaining = p->p_numthreads - p->p_suspcount; else panic("calc_remaining: wrong mode %d", mode); return (remaining); } static int remain_for_mode(int mode) { return (mode == SINGLE_ALLPROC ? 0 : 1); } static int weed_inhib(int mode, struct thread *td2, struct proc *p) { int wakeup_swapper; PROC_LOCK_ASSERT(p, MA_OWNED); PROC_SLOCK_ASSERT(p, MA_OWNED); THREAD_LOCK_ASSERT(td2, MA_OWNED); wakeup_swapper = 0; /* * Since the thread lock is dropped by the scheduler we have * to retry to check for races. */ restart: switch (mode) { case SINGLE_EXIT: if (TD_IS_SUSPENDED(td2)) { wakeup_swapper |= thread_unsuspend_one(td2, p, true); thread_lock(td2); goto restart; } if (TD_CAN_ABORT(td2)) { wakeup_swapper |= sleepq_abort(td2, EINTR); return (wakeup_swapper); } break; case SINGLE_BOUNDARY: case SINGLE_NO_EXIT: if (TD_IS_SUSPENDED(td2) && (td2->td_flags & TDF_BOUNDARY) == 0) { wakeup_swapper |= thread_unsuspend_one(td2, p, false); thread_lock(td2); goto restart; } if (TD_CAN_ABORT(td2)) { wakeup_swapper |= sleepq_abort(td2, ERESTART); return (wakeup_swapper); } break; case SINGLE_ALLPROC: /* * ALLPROC suspend tries to avoid spurious EINTR for * threads sleeping interruptable, by suspending the * thread directly, similarly to sig_suspend_threads(). * Since such sleep is not neccessary performed at the user * boundary, TDF_ALLPROCSUSP is used to avoid immediate * un-suspend. */ if (TD_IS_SUSPENDED(td2) && (td2->td_flags & TDF_ALLPROCSUSP) == 0) { wakeup_swapper |= thread_unsuspend_one(td2, p, false); thread_lock(td2); goto restart; } if (TD_CAN_ABORT(td2)) { td2->td_flags |= TDF_ALLPROCSUSP; wakeup_swapper |= sleepq_abort(td2, ERESTART); return (wakeup_swapper); } break; default: break; } thread_unlock(td2); return (wakeup_swapper); } /* * Enforce single-threading. * * Returns 1 if the caller must abort (another thread is waiting to * exit the process or similar). Process is locked! * Returns 0 when you are successfully the only thread running. * A process has successfully single threaded in the suspend mode when * There are no threads in user mode. Threads in the kernel must be * allowed to continue until they get to the user boundary. They may even * copy out their return values and data before suspending. They may however be * accelerated in reaching the user boundary as we will wake up * any sleeping threads that are interruptable. (PCATCH). */ int thread_single(struct proc *p, int mode) { struct thread *td; struct thread *td2; int remaining, wakeup_swapper; td = curthread; KASSERT(mode == SINGLE_EXIT || mode == SINGLE_BOUNDARY || mode == SINGLE_ALLPROC || mode == SINGLE_NO_EXIT, ("invalid mode %d", mode)); /* * If allowing non-ALLPROC singlethreading for non-curproc * callers, calc_remaining() and remain_for_mode() should be * adjusted to also account for td->td_proc != p. For now * this is not implemented because it is not used. */ KASSERT((mode == SINGLE_ALLPROC && td->td_proc != p) || (mode != SINGLE_ALLPROC && td->td_proc == p), ("mode %d proc %p curproc %p", mode, p, td->td_proc)); mtx_assert(&Giant, MA_NOTOWNED); PROC_LOCK_ASSERT(p, MA_OWNED); /* * Is someone already single threading? * Or may be singlethreading is not needed at all. */ if (mode == SINGLE_ALLPROC) { while ((p->p_flag & P_STOPPED_SINGLE) != 0) { if ((p->p_flag2 & P2_WEXIT) != 0) return (1); msleep(&p->p_flag, &p->p_mtx, PCATCH, "thrsgl", 0); } } else if ((p->p_flag & P_HADTHREADS) == 0) return (0); if (p->p_singlethread != NULL && p->p_singlethread != td) return (1); if (mode == SINGLE_EXIT) { p->p_flag |= P_SINGLE_EXIT; p->p_flag &= ~P_SINGLE_BOUNDARY; } else { p->p_flag &= ~P_SINGLE_EXIT; if (mode == SINGLE_BOUNDARY) p->p_flag |= P_SINGLE_BOUNDARY; else p->p_flag &= ~P_SINGLE_BOUNDARY; } if (mode == SINGLE_ALLPROC) p->p_flag |= P_TOTAL_STOP; p->p_flag |= P_STOPPED_SINGLE; PROC_SLOCK(p); p->p_singlethread = td; remaining = calc_remaining(p, mode); while (remaining != remain_for_mode(mode)) { if (P_SHOULDSTOP(p) != P_STOPPED_SINGLE) goto stopme; wakeup_swapper = 0; FOREACH_THREAD_IN_PROC(p, td2) { if (td2 == td) continue; thread_lock(td2); ast_sched_locked(td2, TDA_SUSPEND); if (TD_IS_INHIBITED(td2)) { wakeup_swapper |= weed_inhib(mode, td2, p); #ifdef SMP } else if (TD_IS_RUNNING(td2)) { forward_signal(td2); thread_unlock(td2); #endif } else thread_unlock(td2); } if (wakeup_swapper) kick_proc0(); remaining = calc_remaining(p, mode); /* * Maybe we suspended some threads.. was it enough? */ if (remaining == remain_for_mode(mode)) break; stopme: /* * Wake us up when everyone else has suspended. * In the mean time we suspend as well. */ thread_suspend_switch(td, p); remaining = calc_remaining(p, mode); } if (mode == SINGLE_EXIT) { /* * Convert the process to an unthreaded process. The * SINGLE_EXIT is called by exit1() or execve(), in * both cases other threads must be retired. */ KASSERT(p->p_numthreads == 1, ("Unthreading with >1 threads")); p->p_singlethread = NULL; p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT | P_HADTHREADS); /* * Wait for any remaining threads to exit cpu_throw(). */ while (p->p_exitthreads != 0) { PROC_SUNLOCK(p); PROC_UNLOCK(p); sched_relinquish(td); PROC_LOCK(p); PROC_SLOCK(p); } } else if (mode == SINGLE_BOUNDARY) { /* * Wait until all suspended threads are removed from * the processors. The thread_suspend_check() * increments p_boundary_count while it is still * running, which makes it possible for the execve() * to destroy vmspace while our other threads are * still using the address space. * * We lock the thread, which is only allowed to * succeed after context switch code finished using * the address space. */ FOREACH_THREAD_IN_PROC(p, td2) { if (td2 == td) continue; thread_lock(td2); KASSERT((td2->td_flags & TDF_BOUNDARY) != 0, ("td %p not on boundary", td2)); KASSERT(TD_IS_SUSPENDED(td2), ("td %p is not suspended", td2)); thread_unlock(td2); } } PROC_SUNLOCK(p); return (0); } bool thread_suspend_check_needed(void) { struct proc *p; struct thread *td; td = curthread; p = td->td_proc; PROC_LOCK_ASSERT(p, MA_OWNED); return (P_SHOULDSTOP(p) || ((p->p_flag & P_TRACED) != 0 && (td->td_dbgflags & TDB_SUSPEND) != 0)); } /* * Called in from locations that can safely check to see * whether we have to suspend or at least throttle for a * single-thread event (e.g. fork). * * Such locations include userret(). * If the "return_instead" argument is non zero, the thread must be able to * accept 0 (caller may continue), or 1 (caller must abort) as a result. * * The 'return_instead' argument tells the function if it may do a * thread_exit() or suspend, or whether the caller must abort and back * out instead. * * If the thread that set the single_threading request has set the * P_SINGLE_EXIT bit in the process flags then this call will never return * if 'return_instead' is false, but will exit. * * P_SINGLE_EXIT | return_instead == 0| return_instead != 0 *---------------+--------------------+--------------------- * 0 | returns 0 | returns 0 or 1 * | when ST ends | immediately *---------------+--------------------+--------------------- * 1 | thread exits | returns 1 * | | immediately * 0 = thread_exit() or suspension ok, * other = return error instead of stopping the thread. * * While a full suspension is under effect, even a single threading * thread would be suspended if it made this call (but it shouldn't). * This call should only be made from places where * thread_exit() would be safe as that may be the outcome unless * return_instead is set. */ int thread_suspend_check(int return_instead) { struct thread *td; struct proc *p; int wakeup_swapper; td = curthread; p = td->td_proc; mtx_assert(&Giant, MA_NOTOWNED); PROC_LOCK_ASSERT(p, MA_OWNED); while (thread_suspend_check_needed()) { if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) { KASSERT(p->p_singlethread != NULL, ("singlethread not set")); /* * The only suspension in action is a * single-threading. Single threader need not stop. * It is safe to access p->p_singlethread unlocked * because it can only be set to our address by us. */ if (p->p_singlethread == td) return (0); /* Exempt from stopping. */ } if ((p->p_flag & P_SINGLE_EXIT) && return_instead) return (EINTR); /* Should we goto user boundary if we didn't come from there? */ if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE && (p->p_flag & P_SINGLE_BOUNDARY) && return_instead) return (ERESTART); /* * Ignore suspend requests if they are deferred. */ if ((td->td_flags & TDF_SBDRY) != 0) { KASSERT(return_instead, ("TDF_SBDRY set for unsafe thread_suspend_check")); KASSERT((td->td_flags & (TDF_SEINTR | TDF_SERESTART)) != (TDF_SEINTR | TDF_SERESTART), ("both TDF_SEINTR and TDF_SERESTART")); return (TD_SBDRY_INTR(td) ? TD_SBDRY_ERRNO(td) : 0); } /* * If the process is waiting for us to exit, * this thread should just suicide. * Assumes that P_SINGLE_EXIT implies P_STOPPED_SINGLE. */ if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td)) { PROC_UNLOCK(p); /* * Allow Linux emulation layer to do some work * before thread suicide. */ if (__predict_false(p->p_sysent->sv_thread_detach != NULL)) (p->p_sysent->sv_thread_detach)(td); umtx_thread_exit(td); kern_thr_exit(td); panic("stopped thread did not exit"); } PROC_SLOCK(p); thread_stopped(p); if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) { if (p->p_numthreads == p->p_suspcount + 1) { thread_lock(p->p_singlethread); wakeup_swapper = thread_unsuspend_one( p->p_singlethread, p, false); if (wakeup_swapper) kick_proc0(); } } PROC_UNLOCK(p); thread_lock(td); /* * When a thread suspends, it just * gets taken off all queues. */ thread_suspend_one(td); if (return_instead == 0) { p->p_boundary_count++; td->td_flags |= TDF_BOUNDARY; } PROC_SUNLOCK(p); mi_switch(SW_INVOL | SWT_SUSPEND); PROC_LOCK(p); } return (0); } /* * Check for possible stops and suspensions while executing a * casueword or similar transiently failing operation. * * The sleep argument controls whether the function can handle a stop * request itself or it should return ERESTART and the request is * proceed at the kernel/user boundary in ast. * * Typically, when retrying due to casueword(9) failure (rv == 1), we * should handle the stop requests there, with exception of cases when * the thread owns a kernel resource, for instance busied the umtx * key, or when functions return immediately if thread_check_susp() * returned non-zero. On the other hand, retrying the whole lock * operation, we better not stop there but delegate the handling to * ast. * * If the request is for thread termination P_SINGLE_EXIT, we cannot * handle it at all, and simply return EINTR. */ int thread_check_susp(struct thread *td, bool sleep) { struct proc *p; int error; /* * The check for TDA_SUSPEND is racy, but it is enough to * eventually break the lockstep loop. */ if (!td_ast_pending(td, TDA_SUSPEND)) return (0); error = 0; p = td->td_proc; PROC_LOCK(p); if (p->p_flag & P_SINGLE_EXIT) error = EINTR; else if (P_SHOULDSTOP(p) || ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_SUSPEND))) error = sleep ? thread_suspend_check(0) : ERESTART; PROC_UNLOCK(p); return (error); } void thread_suspend_switch(struct thread *td, struct proc *p) { KASSERT(!TD_IS_SUSPENDED(td), ("already suspended")); PROC_LOCK_ASSERT(p, MA_OWNED); PROC_SLOCK_ASSERT(p, MA_OWNED); /* * We implement thread_suspend_one in stages here to avoid * dropping the proc lock while the thread lock is owned. */ if (p == td->td_proc) { thread_stopped(p); p->p_suspcount++; } PROC_UNLOCK(p); thread_lock(td); ast_unsched_locked(td, TDA_SUSPEND); TD_SET_SUSPENDED(td); sched_sleep(td, 0); PROC_SUNLOCK(p); DROP_GIANT(); mi_switch(SW_VOL | SWT_SUSPEND); PICKUP_GIANT(); PROC_LOCK(p); PROC_SLOCK(p); } void thread_suspend_one(struct thread *td) { struct proc *p; p = td->td_proc; PROC_SLOCK_ASSERT(p, MA_OWNED); THREAD_LOCK_ASSERT(td, MA_OWNED); KASSERT(!TD_IS_SUSPENDED(td), ("already suspended")); p->p_suspcount++; ast_unsched_locked(td, TDA_SUSPEND); TD_SET_SUSPENDED(td); sched_sleep(td, 0); } static int thread_unsuspend_one(struct thread *td, struct proc *p, bool boundary) { THREAD_LOCK_ASSERT(td, MA_OWNED); KASSERT(TD_IS_SUSPENDED(td), ("Thread not suspended")); TD_CLR_SUSPENDED(td); td->td_flags &= ~TDF_ALLPROCSUSP; if (td->td_proc == p) { PROC_SLOCK_ASSERT(p, MA_OWNED); p->p_suspcount--; if (boundary && (td->td_flags & TDF_BOUNDARY) != 0) { td->td_flags &= ~TDF_BOUNDARY; p->p_boundary_count--; } } return (setrunnable(td, 0)); } void thread_run_flash(struct thread *td) { struct proc *p; p = td->td_proc; PROC_LOCK_ASSERT(p, MA_OWNED); if (TD_ON_SLEEPQ(td)) sleepq_remove_nested(td); else thread_lock(td); THREAD_LOCK_ASSERT(td, MA_OWNED); KASSERT(TD_IS_SUSPENDED(td), ("Thread not suspended")); TD_CLR_SUSPENDED(td); PROC_SLOCK(p); MPASS(p->p_suspcount > 0); p->p_suspcount--; PROC_SUNLOCK(p); if (setrunnable(td, 0)) kick_proc0(); } /* * Allow all threads blocked by single threading to continue running. */ void thread_unsuspend(struct proc *p) { struct thread *td; int wakeup_swapper; PROC_LOCK_ASSERT(p, MA_OWNED); PROC_SLOCK_ASSERT(p, MA_OWNED); wakeup_swapper = 0; if (!P_SHOULDSTOP(p)) { FOREACH_THREAD_IN_PROC(p, td) { thread_lock(td); if (TD_IS_SUSPENDED(td)) wakeup_swapper |= thread_unsuspend_one(td, p, true); else thread_unlock(td); } } else if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE && p->p_numthreads == p->p_suspcount) { /* * Stopping everything also did the job for the single * threading request. Now we've downgraded to single-threaded, * let it continue. */ if (p->p_singlethread->td_proc == p) { thread_lock(p->p_singlethread); wakeup_swapper = thread_unsuspend_one( p->p_singlethread, p, false); } } if (wakeup_swapper) kick_proc0(); } /* * End the single threading mode.. */ void thread_single_end(struct proc *p, int mode) { struct thread *td; int wakeup_swapper; KASSERT(mode == SINGLE_EXIT || mode == SINGLE_BOUNDARY || mode == SINGLE_ALLPROC || mode == SINGLE_NO_EXIT, ("invalid mode %d", mode)); PROC_LOCK_ASSERT(p, MA_OWNED); KASSERT((mode == SINGLE_ALLPROC && (p->p_flag & P_TOTAL_STOP) != 0) || (mode != SINGLE_ALLPROC && (p->p_flag & P_TOTAL_STOP) == 0), ("mode %d does not match P_TOTAL_STOP", mode)); KASSERT(mode == SINGLE_ALLPROC || p->p_singlethread == curthread, ("thread_single_end from other thread %p %p", curthread, p->p_singlethread)); KASSERT(mode != SINGLE_BOUNDARY || (p->p_flag & P_SINGLE_BOUNDARY) != 0, ("mis-matched SINGLE_BOUNDARY flags %x", p->p_flag)); p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT | P_SINGLE_BOUNDARY | P_TOTAL_STOP); PROC_SLOCK(p); p->p_singlethread = NULL; wakeup_swapper = 0; /* * If there are other threads they may now run, * unless of course there is a blanket 'stop order' * on the process. The single threader must be allowed * to continue however as this is a bad place to stop. */ if (p->p_numthreads != remain_for_mode(mode) && !P_SHOULDSTOP(p)) { FOREACH_THREAD_IN_PROC(p, td) { thread_lock(td); if (TD_IS_SUSPENDED(td)) { wakeup_swapper |= thread_unsuspend_one(td, p, true); } else thread_unlock(td); } } KASSERT(mode != SINGLE_BOUNDARY || p->p_boundary_count == 0, ("inconsistent boundary count %d", p->p_boundary_count)); PROC_SUNLOCK(p); if (wakeup_swapper) kick_proc0(); wakeup(&p->p_flag); } /* * Locate a thread by number and return with proc lock held. * * thread exit establishes proc -> tidhash lock ordering, but lookup * takes tidhash first and needs to return locked proc. * * The problem is worked around by relying on type-safety of both * structures and doing the work in 2 steps: * - tidhash-locked lookup which saves both thread and proc pointers * - proc-locked verification that the found thread still matches */ static bool tdfind_hash(lwpid_t tid, pid_t pid, struct proc **pp, struct thread **tdp) { #define RUN_THRESH 16 struct proc *p; struct thread *td; int run; bool locked; run = 0; rw_rlock(TIDHASHLOCK(tid)); locked = true; LIST_FOREACH(td, TIDHASH(tid), td_hash) { if (td->td_tid != tid) { run++; continue; } p = td->td_proc; if (pid != -1 && p->p_pid != pid) { td = NULL; break; } if (run > RUN_THRESH) { if (rw_try_upgrade(TIDHASHLOCK(tid))) { LIST_REMOVE(td, td_hash); LIST_INSERT_HEAD(TIDHASH(td->td_tid), td, td_hash); rw_wunlock(TIDHASHLOCK(tid)); locked = false; break; } } break; } if (locked) rw_runlock(TIDHASHLOCK(tid)); if (td == NULL) return (false); *pp = p; *tdp = td; return (true); } struct thread * tdfind(lwpid_t tid, pid_t pid) { struct proc *p; struct thread *td; td = curthread; if (td->td_tid == tid) { if (pid != -1 && td->td_proc->p_pid != pid) return (NULL); PROC_LOCK(td->td_proc); return (td); } for (;;) { if (!tdfind_hash(tid, pid, &p, &td)) return (NULL); PROC_LOCK(p); if (td->td_tid != tid) { PROC_UNLOCK(p); continue; } if (td->td_proc != p) { PROC_UNLOCK(p); continue; } if (p->p_state == PRS_NEW) { PROC_UNLOCK(p); return (NULL); } return (td); } } void tidhash_add(struct thread *td) { rw_wlock(TIDHASHLOCK(td->td_tid)); LIST_INSERT_HEAD(TIDHASH(td->td_tid), td, td_hash); rw_wunlock(TIDHASHLOCK(td->td_tid)); } void tidhash_remove(struct thread *td) { rw_wlock(TIDHASHLOCK(td->td_tid)); LIST_REMOVE(td, td_hash); rw_wunlock(TIDHASHLOCK(td->td_tid)); } diff --git a/sys/sys/proc.h b/sys/sys/proc.h index 8c916173b4ef..dc94d12d16c4 100644 --- a/sys/sys/proc.h +++ b/sys/sys/proc.h @@ -1,1363 +1,1374 @@ /*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1986, 1989, 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. * * @(#)proc.h 8.15 (Berkeley) 5/19/95 */ #ifndef _SYS_PROC_H_ #define _SYS_PROC_H_ #include /* For struct callout. */ #include /* For struct klist. */ #ifdef _KERNEL #include #endif #include #ifndef _KERNEL #include #endif #include #include #include #include #include #include #include /* XXX. */ #include #include #include #include #include #ifndef _KERNEL #include /* For structs itimerval, timeval. */ #else #include #include #endif #include #include #include #include #include /* Machine-dependent proc substruct. */ #ifdef _KERNEL #include #endif /* * One structure allocated per session. * * List of locks * (m) locked by s_mtx mtx * (e) locked by proctree_lock sx * (c) const until freeing */ struct session { u_int s_count; /* Ref cnt; pgrps in session - atomic. */ struct proc *s_leader; /* (m + e) Session leader. */ struct vnode *s_ttyvp; /* (m) Vnode of controlling tty. */ struct cdev_priv *s_ttydp; /* (m) Device of controlling tty. */ struct tty *s_ttyp; /* (e) Controlling tty. */ pid_t s_sid; /* (c) Session ID. */ /* (m) Setlogin() name: */ char s_login[roundup(MAXLOGNAME, sizeof(long))]; struct mtx s_mtx; /* Mutex to protect members. */ }; /* * One structure allocated per process group. * * List of locks * (m) locked by pg_mtx mtx * (e) locked by proctree_lock sx * (c) const until freeing */ struct pgrp { LIST_ENTRY(pgrp) pg_hash; /* (e) Hash chain. */ LIST_HEAD(, proc) pg_members; /* (m + e) Pointer to pgrp members. */ struct session *pg_session; /* (c) Pointer to session. */ struct sigiolst pg_sigiolst; /* (m) List of sigio sources. */ pid_t pg_id; /* (c) Process group id. */ struct mtx pg_mtx; /* Mutex to protect members */ int pg_flags; /* (m) PGRP_ flags */ struct sx pg_killsx; /* Mutual exclusion between group member * fork() and killpg() */ }; #define PGRP_ORPHANED 0x00000001 /* Group is orphaned */ /* * pargs, used to hold a copy of the command line, if it had a sane length. */ struct pargs { u_int ar_ref; /* Reference count. */ u_int ar_length; /* Length. */ u_char ar_args[1]; /* Arguments. */ }; /*- * Description of a process. * * This structure contains the information needed to manage a thread of * control, known in UN*X as a process; it has references to substructures * containing descriptions of things that the process uses, but may share * with related processes. The process structure and the substructures * are always addressable except for those marked "(CPU)" below, * which might be addressable only on a processor on which the process * is running. * * Below is a key of locks used to protect each member of struct proc. The * lock is indicated by a reference to a specific character in parens in the * associated comment. * * - not yet protected * a - only touched by curproc or parent during fork/wait * b - created at fork, never changes * (exception aiods switch vmspaces, but they are also * marked 'P_SYSTEM' so hopefully it will be left alone) * c - locked by proc mtx * d - locked by allproc_lock lock * e - locked by proctree_lock lock * f - session mtx * g - process group mtx * h - callout_lock mtx * i - by curproc or the master session mtx * j - locked by proc slock * k - only accessed by curthread * k*- only accessed by curthread and from an interrupt * kx- only accessed by curthread and by debugger * l - the attaching proc or attaching proc parent * n - not locked, lazy * o - ktrace lock * q - td_contested lock * r - p_peers lock * s - see sleepq_switch(), sleeping_on_old_rtc(), and sleep(9) * t - thread lock * u - process stat lock * w - process timer lock * x - created at fork, only changes during single threading in exec * y - created at first aio, doesn't change until exit or exec at which * point we are single-threaded and only curthread changes it * * If the locking key specifies two identifiers (for example, p_pptr) then * either lock is sufficient for read access, but both locks must be held * for write access. */ struct cpuset; struct filecaps; struct filemon; struct kaioinfo; struct kaudit_record; struct kcov_info; struct kdtrace_proc; struct kdtrace_thread; struct kmsan_td; struct kq_timer_cb_data; struct mqueue_notifier; struct p_sched; struct proc; struct procdesc; struct racct; struct sbuf; struct sleepqueue; struct socket; struct td_sched; struct thread; struct trapframe; struct turnstile; struct vm_map; struct vm_map_entry; struct epoch_tracker; struct syscall_args { u_int code; u_int original_code; struct sysent *callp; register_t args[8]; }; /* * XXX: Does this belong in resource.h or resourcevar.h instead? * Resource usage extension. The times in rusage structs in the kernel are * never up to date. The actual times are kept as runtimes and tick counts * (with control info in the "previous" times), and are converted when * userland asks for rusage info. Backwards compatibility prevents putting * this directly in the user-visible rusage struct. * * Locking for p_rux: (cu) means (u) for p_rux and (c) for p_crux. * Locking for td_rux: (t) for all fields. */ struct rusage_ext { uint64_t rux_runtime; /* (cu) Real time. */ uint64_t rux_uticks; /* (cu) Statclock hits in user mode. */ uint64_t rux_sticks; /* (cu) Statclock hits in sys mode. */ uint64_t rux_iticks; /* (cu) Statclock hits in intr mode. */ uint64_t rux_uu; /* (c) Previous user time in usec. */ uint64_t rux_su; /* (c) Previous sys time in usec. */ uint64_t rux_tu; /* (c) Previous total time in usec. */ }; /* * Kernel runnable context (thread). * This is what is put to sleep and reactivated. * Thread context. Processes may have multiple threads. */ struct thread { struct mtx *volatile td_lock; /* replaces sched lock */ struct proc *td_proc; /* (*) Associated process. */ TAILQ_ENTRY(thread) td_plist; /* (*) All threads in this proc. */ TAILQ_ENTRY(thread) td_runq; /* (t) Run queue. */ union { TAILQ_ENTRY(thread) td_slpq; /* (t) Sleep queue. */ struct thread *td_zombie; /* Zombie list linkage */ }; TAILQ_ENTRY(thread) td_lockq; /* (t) Lock queue. */ LIST_ENTRY(thread) td_hash; /* (d) Hash chain. */ struct cpuset *td_cpuset; /* (t) CPU affinity mask. */ struct domainset_ref td_domain; /* (a) NUMA policy */ struct seltd *td_sel; /* Select queue/channel. */ struct sleepqueue *td_sleepqueue; /* (k) Associated sleep queue. */ struct turnstile *td_turnstile; /* (k) Associated turnstile. */ struct rl_q_entry *td_rlqe; /* (k) Associated range lock entry. */ struct umtx_q *td_umtxq; /* (c?) Link for when we're blocked. */ lwpid_t td_tid; /* (b) Thread ID. */ sigqueue_t td_sigqueue; /* (c) Sigs arrived, not delivered. */ #define td_siglist td_sigqueue.sq_signals u_char td_lend_user_pri; /* (t) Lend user pri. */ u_char td_allocdomain; /* (b) NUMA domain backing this struct thread. */ u_char td_base_ithread_pri; /* (t) Base ithread pri */ struct kmsan_td *td_kmsan; /* (k) KMSAN state */ /* Cleared during fork1(), thread_create(), or kthread_add(). */ #define td_startzero td_flags int td_flags; /* (t) TDF_* flags. */ int td_ast; /* (t) TDA_* indicators */ int td_inhibitors; /* (t) Why can not run. */ int td_pflags; /* (k) Private thread (TDP_*) flags. */ int td_pflags2; /* (k) Private thread (TDP2_*) flags. */ int td_dupfd; /* (k) Ret value from fdopen. XXX */ int td_sqqueue; /* (t) Sleepqueue queue blocked on. */ const void *td_wchan; /* (t) Sleep address. */ const char *td_wmesg; /* (t) Reason for sleep. */ volatile u_char td_owepreempt; /* (k*) Preempt on last critical_exit */ u_char td_tsqueue; /* (t) Turnstile queue blocked on. */ u_char td_stopsched; /* (k) Scheduler stopped. */ int td_locks; /* (k) Debug: count of non-spin locks */ int td_rw_rlocks; /* (k) Count of rwlock read locks. */ int td_sx_slocks; /* (k) Count of sx shared locks. */ int td_lk_slocks; /* (k) Count of lockmgr shared locks. */ + struct lock_object *td_wantedlock; /* (k) Lock we are contending on */ struct turnstile *td_blocked; /* (t) Lock thread is blocked on. */ const char *td_lockname; /* (t) Name of lock blocked on. */ LIST_HEAD(, turnstile) td_contested; /* (q) Contested locks. */ struct lock_list_entry *td_sleeplocks; /* (k) Held sleep locks. */ int td_intr_nesting_level; /* (k) Interrupt recursion. */ int td_pinned; /* (k) Temporary cpu pin count. */ struct ucred *td_realucred; /* (k) Reference to credentials. */ struct ucred *td_ucred; /* (k) Used credentials, temporarily switchable. */ struct plimit *td_limit; /* (k) Resource limits. */ int td_slptick; /* (t) Time at sleep. */ int td_blktick; /* (t) Time spent blocked. */ int td_swvoltick; /* (t) Time at last SW_VOL switch. */ int td_swinvoltick; /* (t) Time at last SW_INVOL switch. */ u_int td_cow; /* (*) Number of copy-on-write faults */ struct rusage td_ru; /* (t) rusage information. */ struct rusage_ext td_rux; /* (t) Internal rusage information. */ uint64_t td_incruntime; /* (t) Cpu ticks to transfer to proc. */ uint64_t td_runtime; /* (t) How many cpu ticks we've run. */ u_int td_pticks; /* (t) Statclock hits for profiling */ u_int td_sticks; /* (t) Statclock hits in system mode. */ u_int td_iticks; /* (t) Statclock hits in intr mode. */ u_int td_uticks; /* (t) Statclock hits in user mode. */ int td_intrval; /* (t) Return value for sleepq. */ sigset_t td_oldsigmask; /* (k) Saved mask from pre sigpause. */ volatile u_int td_generation; /* (k) For detection of preemption */ stack_t td_sigstk; /* (k) Stack ptr and on-stack flag. */ int td_xsig; /* (c) Signal for ptrace */ u_long td_profil_addr; /* (k) Temporary addr until AST. */ u_int td_profil_ticks; /* (k) Temporary ticks until AST. */ char td_name[MAXCOMLEN + 1]; /* (*) Thread name. */ struct file *td_fpop; /* (k) file referencing cdev under op */ int td_dbgflags; /* (c) Userland debugger flags */ siginfo_t td_si; /* (c) For debugger or core file */ int td_ng_outbound; /* (k) Thread entered ng from above. */ struct osd td_osd; /* (k) Object specific data. */ struct vm_map_entry *td_map_def_user; /* (k) Deferred entries. */ pid_t td_dbg_forked; /* (c) Child pid for debugger. */ u_int td_no_sleeping; /* (k) Sleeping disabled count. */ struct vnode *td_vp_reserved;/* (k) Preallocated vnode. */ void *td_su; /* (k) FFS SU private */ sbintime_t td_sleeptimo; /* (t) Sleep timeout. */ int td_rtcgen; /* (s) rtc_generation of abs. sleep */ int td_errno; /* (k) Error from last syscall. */ size_t td_vslock_sz; /* (k) amount of vslock-ed space */ struct kcov_info *td_kcov_info; /* (*) Kernel code coverage data */ long td_ucredref; /* (k) references on td_realucred */ #define td_endzero td_sigmask /* Copied during fork1(), thread_create(), or kthread_add(). */ #define td_startcopy td_endzero sigset_t td_sigmask; /* (c) Current signal mask. */ u_char td_rqindex; /* (t) Run queue index. */ u_char td_base_pri; /* (t) Thread base kernel priority. */ u_char td_priority; /* (t) Thread active priority. */ u_char td_pri_class; /* (t) Scheduling class. */ u_char td_user_pri; /* (t) User pri from estcpu and nice. */ u_char td_base_user_pri; /* (t) Base user pri */ uintptr_t td_rb_list; /* (k) Robust list head. */ uintptr_t td_rbp_list; /* (k) Robust priv list head. */ uintptr_t td_rb_inact; /* (k) Current in-action mutex loc. */ struct syscall_args td_sa; /* (kx) Syscall parameters. Copied on fork for child tracing. */ void *td_sigblock_ptr; /* (k) uptr for fast sigblock. */ uint32_t td_sigblock_val; /* (k) fast sigblock value read at td_sigblock_ptr on kern entry */ #define td_endcopy td_pcb /* * Fields that must be manually set in fork1(), thread_create(), kthread_add(), * or already have been set in the allocator, constructor, etc. */ struct pcb *td_pcb; /* (k) Kernel VA of pcb and kstack. */ enum td_states { TDS_INACTIVE = 0x0, TDS_INHIBITED, TDS_CAN_RUN, TDS_RUNQ, TDS_RUNNING } td_state; /* (t) thread state */ /* Note: td_state must be accessed using TD_{GET,SET}_STATE(). */ union { syscallarg_t tdu_retval[2]; off_t tdu_off; } td_uretoff; /* (k) Syscall aux returns. */ #define td_retval td_uretoff.tdu_retval u_int td_cowgen; /* (k) Generation of COW pointers. */ /* LP64 hole */ struct callout td_slpcallout; /* (h) Callout for sleep. */ struct trapframe *td_frame; /* (k) */ vm_offset_t td_kstack; /* (a) Kernel VA of kstack. */ int td_kstack_pages; /* (a) Size of the kstack. */ volatile u_int td_critnest; /* (k*) Critical section nest level. */ struct mdthread td_md; /* (k) Any machine-dependent fields. */ struct kaudit_record *td_ar; /* (k) Active audit record, if any. */ struct lpohead td_lprof[2]; /* (a) lock profiling objects. */ struct kdtrace_thread *td_dtrace; /* (*) DTrace-specific data. */ struct vnet *td_vnet; /* (k) Effective vnet. */ const char *td_vnet_lpush; /* (k) Debugging vnet push / pop. */ struct trapframe *td_intr_frame;/* (k) Frame of the current irq */ struct proc *td_rfppwait_p; /* (k) The vforked child */ struct vm_page **td_ma; /* (k) uio pages held */ int td_ma_cnt; /* (k) size of *td_ma */ /* LP64 hole */ void *td_emuldata; /* Emulator state data */ int td_lastcpu; /* (t) Last cpu we were on. */ int td_oncpu; /* (t) Which cpu we are on. */ void *td_lkpi_task; /* LinuxKPI task struct pointer */ int td_pmcpend; void *td_remotereq; /* (c) dbg remote request. */ off_t td_ktr_io_lim; /* (k) limit for ktrace file size */ #ifdef EPOCH_TRACE SLIST_HEAD(, epoch_tracker) td_epochs; #endif }; struct thread0_storage { struct thread t0st_thread; uint64_t t0st_sched[10]; }; struct mtx *thread_lock_block(struct thread *); void thread_lock_block_wait(struct thread *); void thread_lock_set(struct thread *, struct mtx *); void thread_lock_unblock(struct thread *, struct mtx *); #define THREAD_LOCK_ASSERT(td, type) \ mtx_assert((td)->td_lock, (type)) #define THREAD_LOCK_BLOCKED_ASSERT(td, type) \ do { \ struct mtx *__m = (td)->td_lock; \ if (__m != &blocked_lock) \ mtx_assert(__m, (type)); \ } while (0) #ifdef INVARIANTS #define THREAD_LOCKPTR_ASSERT(td, lock) \ do { \ struct mtx *__m; \ __m = (td)->td_lock; \ KASSERT(__m == (lock), \ ("Thread %p lock %p does not match %p", td, __m, (lock))); \ } while (0) #define THREAD_LOCKPTR_BLOCKED_ASSERT(td, lock) \ do { \ struct mtx *__m; \ __m = (td)->td_lock; \ KASSERT(__m == (lock) || __m == &blocked_lock, \ ("Thread %p lock %p does not match %p", td, __m, (lock))); \ } while (0) #define TD_LOCKS_INC(td) ((td)->td_locks++) #define TD_LOCKS_DEC(td) do { \ KASSERT(SCHEDULER_STOPPED_TD(td) || (td)->td_locks > 0, \ ("Thread %p owns no locks", (td))); \ (td)->td_locks--; \ } while (0) #else #define THREAD_LOCKPTR_ASSERT(td, lock) #define THREAD_LOCKPTR_BLOCKED_ASSERT(td, lock) #define TD_LOCKS_INC(td) #define TD_LOCKS_DEC(td) #endif /* * Flags kept in td_flags: * To change these you MUST have the scheduler lock. */ #define TDF_BORROWING 0x00000001 /* Thread is borrowing pri from another. */ #define TDF_INPANIC 0x00000002 /* Caused a panic, let it drive crashdump. */ #define TDF_INMEM 0x00000004 /* Thread's stack is in memory. */ #define TDF_SINTR 0x00000008 /* Sleep is interruptible. */ #define TDF_TIMEOUT 0x00000010 /* Timing out during sleep. */ #define TDF_IDLETD 0x00000020 /* This is a per-CPU idle thread. */ #define TDF_CANSWAP 0x00000040 /* Thread can be swapped. */ #define TDF_SIGWAIT 0x00000080 /* Ignore ignored signals */ #define TDF_KTH_SUSP 0x00000100 /* kthread is suspended */ #define TDF_ALLPROCSUSP 0x00000200 /* suspended by SINGLE_ALLPROC */ #define TDF_BOUNDARY 0x00000400 /* Thread suspended at user boundary */ #define TDF_UNUSED1 0x00000800 /* Available */ #define TDF_UNUSED2 0x00001000 /* Available */ #define TDF_SBDRY 0x00002000 /* Stop only on usermode boundary. */ #define TDF_UPIBLOCKED 0x00004000 /* Thread blocked on user PI mutex. */ #define TDF_UNUSED3 0x00008000 /* Available */ #define TDF_UNUSED4 0x00010000 /* Available */ #define TDF_UNUSED5 0x00020000 /* Available */ #define TDF_NOLOAD 0x00040000 /* Ignore during load avg calculations. */ #define TDF_SERESTART 0x00080000 /* ERESTART on stop attempts. */ #define TDF_THRWAKEUP 0x00100000 /* Libthr thread must not suspend itself. */ #define TDF_SEINTR 0x00200000 /* EINTR on stop attempts. */ #define TDF_SWAPINREQ 0x00400000 /* Swapin request due to wakeup. */ #define TDF_UNUSED6 0x00800000 /* Available */ #define TDF_SCHED0 0x01000000 /* Reserved for scheduler private use */ #define TDF_SCHED1 0x02000000 /* Reserved for scheduler private use */ #define TDF_SCHED2 0x04000000 /* Reserved for scheduler private use */ #define TDF_SCHED3 0x08000000 /* Reserved for scheduler private use */ #define TDF_UNUSED7 0x10000000 /* Available */ #define TDF_UNUSED8 0x20000000 /* Available */ #define TDF_UNUSED9 0x40000000 /* Available */ #define TDF_UNUSED10 0x80000000 /* Available */ enum { TDA_AST = 0, /* Special: call all non-flagged AST handlers */ TDA_OWEUPC, TDA_HWPMC, TDA_VFORK, TDA_ALRM, TDA_PROF, TDA_MAC, TDA_SCHED, TDA_UFS, TDA_GEOM, TDA_KQUEUE, TDA_RACCT, TDA_MOD1, /* For third party use, before signals are */ TAD_MOD2, /* processed .. */ TDA_SIG, TDA_KTRACE, TDA_SUSPEND, TDA_SIGSUSPEND, TDA_MOD3, /* .. and after */ TAD_MOD4, TDA_MAX, }; #define TDAI(tda) (1U << (tda)) #define td_ast_pending(td, tda) ((td->td_ast & TDAI(tda)) != 0) /* Userland debug flags */ #define TDB_SUSPEND 0x00000001 /* Thread is suspended by debugger */ #define TDB_XSIG 0x00000002 /* Thread is exchanging signal under trace */ #define TDB_USERWR 0x00000004 /* Debugger modified memory or registers */ #define TDB_SCE 0x00000008 /* Thread performs syscall enter */ #define TDB_SCX 0x00000010 /* Thread performs syscall exit */ #define TDB_EXEC 0x00000020 /* TDB_SCX from exec(2) family */ #define TDB_FORK 0x00000040 /* TDB_SCX from fork(2) that created new process */ #define TDB_STOPATFORK 0x00000080 /* Stop at the return from fork (child only) */ #define TDB_CHILD 0x00000100 /* New child indicator for ptrace() */ #define TDB_BORN 0x00000200 /* New LWP indicator for ptrace() */ #define TDB_EXIT 0x00000400 /* Exiting LWP indicator for ptrace() */ #define TDB_VFORK 0x00000800 /* vfork indicator for ptrace() */ #define TDB_FSTP 0x00001000 /* The thread is PT_ATTACH leader */ #define TDB_STEP 0x00002000 /* (x86) PSL_T set for PT_STEP */ #define TDB_SSWITCH 0x00004000 /* Suspended in ptracestop */ #define TDB_BOUNDARY 0x00008000 /* ptracestop() at boundary */ #define TDB_COREDUMPREQ 0x00010000 /* Coredump request */ #define TDB_SCREMOTEREQ 0x00020000 /* Remote syscall request */ /* * "Private" flags kept in td_pflags: * These are only written by curthread and thus need no locking. */ #define TDP_OLDMASK 0x00000001 /* Need to restore mask after suspend. */ #define TDP_INKTR 0x00000002 /* Thread is currently in KTR code. */ #define TDP_INKTRACE 0x00000004 /* Thread is currently in KTRACE code. */ #define TDP_BUFNEED 0x00000008 /* Do not recurse into the buf flush */ #define TDP_COWINPROGRESS 0x00000010 /* Snapshot copy-on-write in progress. */ #define TDP_ALTSTACK 0x00000020 /* Have alternate signal stack. */ #define TDP_DEADLKTREAT 0x00000040 /* Lock acquisition - deadlock treatment. */ #define TDP_NOFAULTING 0x00000080 /* Do not handle page faults. */ #define TDP_SIGFASTBLOCK 0x00000100 /* Fast sigblock active */ #define TDP_OWEUPC 0x00000200 /* Call addupc() at next AST. */ #define TDP_ITHREAD 0x00000400 /* Thread is an interrupt thread. */ #define TDP_SYNCIO 0x00000800 /* Local override, disable async i/o. */ #define TDP_SCHED1 0x00001000 /* Reserved for scheduler private use */ #define TDP_SCHED2 0x00002000 /* Reserved for scheduler private use */ #define TDP_SCHED3 0x00004000 /* Reserved for scheduler private use */ #define TDP_SCHED4 0x00008000 /* Reserved for scheduler private use */ #define TDP_GEOM 0x00010000 /* Settle GEOM before finishing syscall */ #define TDP_SOFTDEP 0x00020000 /* Stuck processing softdep worklist */ #define TDP_NORUNNINGBUF 0x00040000 /* Ignore runningbufspace check */ #define TDP_WAKEUP 0x00080000 /* Don't sleep in umtx cond_wait */ #define TDP_INBDFLUSH 0x00100000 /* Already in BO_BDFLUSH, do not recurse */ #define TDP_KTHREAD 0x00200000 /* This is an official kernel thread */ #define TDP_CALLCHAIN 0x00400000 /* Capture thread's callchain */ #define TDP_IGNSUSP 0x00800000 /* Permission to ignore the MNTK_SUSPEND* */ #define TDP_AUDITREC 0x01000000 /* Audit record pending on thread */ #define TDP_RFPPWAIT 0x02000000 /* Handle RFPPWAIT on syscall exit */ #define TDP_RESETSPUR 0x04000000 /* Reset spurious page fault history. */ #define TDP_NERRNO 0x08000000 /* Last errno is already in td_errno */ #define TDP_UIOHELD 0x10000000 /* Current uio has pages held in td_ma */ #define TDP_INTCPCALLOUT 0x20000000 /* used by netinet/tcp_timer.c */ #define TDP_EXECVMSPC 0x40000000 /* Execve destroyed old vmspace */ #define TDP_SIGFASTPENDING 0x80000000 /* Pending signal due to sigfastblock */ #define TDP2_SBPAGES 0x00000001 /* Owns sbusy on some pages */ #define TDP2_COMPAT32RB 0x00000002 /* compat32 ABI for robust lists */ #define TDP2_ACCT 0x00000004 /* Doing accounting */ /* * Reasons that the current thread can not be run yet. * More than one may apply. */ #define TDI_SUSPENDED 0x0001 /* On suspension queue. */ #define TDI_SLEEPING 0x0002 /* Actually asleep! (tricky). */ #define TDI_SWAPPED 0x0004 /* Stack not in mem. Bad juju if run. */ #define TDI_LOCK 0x0008 /* Stopped on a lock. */ #define TDI_IWAIT 0x0010 /* Awaiting interrupt. */ #define TD_IS_SLEEPING(td) ((td)->td_inhibitors & TDI_SLEEPING) #define TD_ON_SLEEPQ(td) ((td)->td_wchan != NULL) #define TD_IS_SUSPENDED(td) ((td)->td_inhibitors & TDI_SUSPENDED) #define TD_IS_SWAPPED(td) ((td)->td_inhibitors & TDI_SWAPPED) #define TD_ON_LOCK(td) ((td)->td_inhibitors & TDI_LOCK) #define TD_AWAITING_INTR(td) ((td)->td_inhibitors & TDI_IWAIT) #ifdef _KERNEL #define TD_GET_STATE(td) atomic_load_int(&(td)->td_state) #else #define TD_GET_STATE(td) ((td)->td_state) #endif #define TD_IS_RUNNING(td) (TD_GET_STATE(td) == TDS_RUNNING) #define TD_ON_RUNQ(td) (TD_GET_STATE(td) == TDS_RUNQ) #define TD_CAN_RUN(td) (TD_GET_STATE(td) == TDS_CAN_RUN) #define TD_IS_INHIBITED(td) (TD_GET_STATE(td) == TDS_INHIBITED) #define TD_ON_UPILOCK(td) ((td)->td_flags & TDF_UPIBLOCKED) #define TD_IS_IDLETHREAD(td) ((td)->td_flags & TDF_IDLETD) #define TD_CAN_ABORT(td) (TD_ON_SLEEPQ((td)) && \ ((td)->td_flags & TDF_SINTR) != 0) #define KTDSTATE(td) \ (((td)->td_inhibitors & TDI_SLEEPING) != 0 ? "sleep" : \ ((td)->td_inhibitors & TDI_SUSPENDED) != 0 ? "suspended" : \ ((td)->td_inhibitors & TDI_SWAPPED) != 0 ? "swapped" : \ ((td)->td_inhibitors & TDI_LOCK) != 0 ? "blocked" : \ ((td)->td_inhibitors & TDI_IWAIT) != 0 ? "iwait" : "yielding") #define TD_SET_INHIB(td, inhib) do { \ TD_SET_STATE(td, TDS_INHIBITED); \ (td)->td_inhibitors |= (inhib); \ } while (0) #define TD_CLR_INHIB(td, inhib) do { \ if (((td)->td_inhibitors & (inhib)) && \ (((td)->td_inhibitors &= ~(inhib)) == 0)) \ TD_SET_STATE(td, TDS_CAN_RUN); \ } while (0) #define TD_SET_SLEEPING(td) TD_SET_INHIB((td), TDI_SLEEPING) #define TD_SET_SWAPPED(td) TD_SET_INHIB((td), TDI_SWAPPED) #define TD_SET_LOCK(td) TD_SET_INHIB((td), TDI_LOCK) #define TD_SET_SUSPENDED(td) TD_SET_INHIB((td), TDI_SUSPENDED) #define TD_SET_IWAIT(td) TD_SET_INHIB((td), TDI_IWAIT) #define TD_SET_EXITING(td) TD_SET_INHIB((td), TDI_EXITING) #define TD_CLR_SLEEPING(td) TD_CLR_INHIB((td), TDI_SLEEPING) #define TD_CLR_SWAPPED(td) TD_CLR_INHIB((td), TDI_SWAPPED) #define TD_CLR_LOCK(td) TD_CLR_INHIB((td), TDI_LOCK) #define TD_CLR_SUSPENDED(td) TD_CLR_INHIB((td), TDI_SUSPENDED) #define TD_CLR_IWAIT(td) TD_CLR_INHIB((td), TDI_IWAIT) #ifdef _KERNEL #define TD_SET_STATE(td, state) atomic_store_int(&(td)->td_state, state) #else #define TD_SET_STATE(td, state) (td)->td_state = state #endif #define TD_SET_RUNNING(td) TD_SET_STATE(td, TDS_RUNNING) #define TD_SET_RUNQ(td) TD_SET_STATE(td, TDS_RUNQ) #define TD_SET_CAN_RUN(td) TD_SET_STATE(td, TDS_CAN_RUN) #define TD_SBDRY_INTR(td) \ (((td)->td_flags & (TDF_SEINTR | TDF_SERESTART)) != 0) #define TD_SBDRY_ERRNO(td) \ (((td)->td_flags & TDF_SEINTR) != 0 ? EINTR : ERESTART) /* * Process structure. */ struct proc { LIST_ENTRY(proc) p_list; /* (d) List of all processes. */ TAILQ_HEAD(, thread) p_threads; /* (c) all threads. */ struct mtx p_slock; /* process spin lock */ struct ucred *p_ucred; /* (c) Process owner's identity. */ struct filedesc *p_fd; /* (b) Open files. */ struct filedesc_to_leader *p_fdtol; /* (b) Tracking node */ struct pwddesc *p_pd; /* (b) Cwd, chroot, jail, umask */ struct pstats *p_stats; /* (b) Accounting/statistics (CPU). */ struct plimit *p_limit; /* (c) Resource limits. */ struct callout p_limco; /* (c) Limit callout handle */ struct sigacts *p_sigacts; /* (x) Signal actions, state (CPU). */ int p_flag; /* (c) P_* flags. */ int p_flag2; /* (c) P2_* flags. */ enum p_states { PRS_NEW = 0, /* In creation */ PRS_NORMAL, /* threads can be run. */ PRS_ZOMBIE } p_state; /* (j/c) Process status. */ pid_t p_pid; /* (b) Process identifier. */ LIST_ENTRY(proc) p_hash; /* (d) Hash chain. */ LIST_ENTRY(proc) p_pglist; /* (g + e) List of processes in pgrp. */ struct proc *p_pptr; /* (c + e) Pointer to parent process. */ LIST_ENTRY(proc) p_sibling; /* (e) List of sibling processes. */ LIST_HEAD(, proc) p_children; /* (e) Pointer to list of children. */ struct proc *p_reaper; /* (e) My reaper. */ LIST_HEAD(, proc) p_reaplist; /* (e) List of my descendants (if I am reaper). */ LIST_ENTRY(proc) p_reapsibling; /* (e) List of siblings - descendants of the same reaper. */ struct mtx p_mtx; /* (n) Lock for this struct. */ struct mtx p_statmtx; /* Lock for the stats */ struct mtx p_itimmtx; /* Lock for the virt/prof timers */ struct mtx p_profmtx; /* Lock for the profiling */ struct ksiginfo *p_ksi; /* Locked by parent proc lock */ sigqueue_t p_sigqueue; /* (c) Sigs not delivered to a td. */ #define p_siglist p_sigqueue.sq_signals pid_t p_oppid; /* (c + e) Real parent pid. */ /* The following fields are all zeroed upon creation in fork. */ #define p_startzero p_vmspace struct vmspace *p_vmspace; /* (b) Address space. */ u_int p_swtick; /* (c) Tick when swapped in or out. */ u_int p_cowgen; /* (c) Generation of COW pointers. */ struct itimerval p_realtimer; /* (c) Alarm timer. */ struct rusage p_ru; /* (a) Exit information. */ struct rusage_ext p_rux; /* (cu) Internal resource usage. */ struct rusage_ext p_crux; /* (c) Internal child resource usage. */ int p_profthreads; /* (c) Num threads in addupc_task. */ volatile int p_exitthreads; /* (j) Number of threads exiting */ int p_traceflag; /* (o) Kernel trace points. */ struct ktr_io_params *p_ktrioparms; /* (c + o) Params for ktrace. */ struct vnode *p_textvp; /* (b) Vnode of executable. */ struct vnode *p_textdvp; /* (b) Dir containing textvp. */ char *p_binname; /* (b) Binary hardlink name. */ u_int p_lock; /* (c) Proclock (prevent swap) count. */ struct sigiolst p_sigiolst; /* (c) List of sigio sources. */ int p_sigparent; /* (c) Signal to parent on exit. */ int p_sig; /* (n) For core dump/debugger XXX. */ u_int p_ptevents; /* (c + e) ptrace() event mask. */ struct kaioinfo *p_aioinfo; /* (y) ASYNC I/O info. */ struct thread *p_singlethread;/* (c + j) If single threading this is it */ int p_suspcount; /* (j) Num threads in suspended mode. */ struct thread *p_xthread; /* (c) Trap thread */ int p_boundary_count;/* (j) Num threads at user boundary */ int p_pendingcnt; /* how many signals are pending */ struct itimers *p_itimers; /* (c) POSIX interval timers. */ struct procdesc *p_procdesc; /* (e) Process descriptor, if any. */ u_int p_treeflag; /* (e) P_TREE flags */ int p_pendingexits; /* (c) Count of pending thread exits. */ struct filemon *p_filemon; /* (c) filemon-specific data. */ int p_pdeathsig; /* (c) Signal from parent on exit. */ /* End area that is zeroed on creation. */ #define p_endzero p_magic /* The following fields are all copied upon creation in fork. */ #define p_startcopy p_endzero u_int p_magic; /* (b) Magic number. */ int p_osrel; /* (x) osreldate for the binary (from ELF note, if any) */ uint32_t p_fctl0; /* (x) ABI feature control, ELF note */ char p_comm[MAXCOMLEN + 1]; /* (x) Process name. */ struct sysentvec *p_sysent; /* (b) Syscall dispatch info. */ struct pargs *p_args; /* (c) Process arguments. */ rlim_t p_cpulimit; /* (c) Current CPU limit in seconds. */ signed char p_nice; /* (c) Process "nice" value. */ int p_fibnum; /* in this routing domain XXX MRT */ pid_t p_reapsubtree; /* (e) Pid of the direct child of the reaper which spawned our subtree. */ uint64_t p_elf_flags; /* (x) ELF flags */ void *p_elf_brandinfo; /* (x) Elf_Brandinfo, NULL for non ELF binaries. */ sbintime_t p_umtx_min_timeout; /* End area that is copied on creation. */ #define p_endcopy p_xexit u_int p_xexit; /* (c) Exit code. */ u_int p_xsig; /* (c) Stop/kill sig. */ struct pgrp *p_pgrp; /* (c + e) Pointer to process group. */ struct knlist *p_klist; /* (c) Knotes attached to this proc. */ int p_numthreads; /* (c) Number of threads. */ struct mdproc p_md; /* Any machine-dependent fields. */ struct callout p_itcallout; /* (h + c) Interval timer callout. */ u_short p_acflag; /* (c) Accounting flags. */ struct proc *p_peers; /* (r) */ struct proc *p_leader; /* (b) */ void *p_emuldata; /* (c) Emulator state data. */ struct label *p_label; /* (*) Proc (not subject) MAC label. */ STAILQ_HEAD(, ktr_request) p_ktr; /* (o) KTR event queue. */ LIST_HEAD(, mqueue_notifier) p_mqnotifier; /* (c) mqueue notifiers.*/ struct kdtrace_proc *p_dtrace; /* (*) DTrace-specific data. */ struct cv p_pwait; /* (*) wait cv for exit/exec. */ uint64_t p_prev_runtime; /* (c) Resource usage accounting. */ struct racct *p_racct; /* (b) Resource accounting. */ int p_throttled; /* (c) Flag for racct pcpu throttling */ /* * An orphan is the child that has been re-parented to the * debugger as a result of attaching to it. Need to keep * track of them for parent to be able to collect the exit * status of what used to be children. */ LIST_ENTRY(proc) p_orphan; /* (e) List of orphan processes. */ LIST_HEAD(, proc) p_orphans; /* (e) Pointer to list of orphans. */ TAILQ_HEAD(, kq_timer_cb_data) p_kqtim_stop; /* (c) */ LIST_ENTRY(proc) p_jaillist; /* (d) Jail process linkage. */ }; #define p_session p_pgrp->pg_session #define p_pgid p_pgrp->pg_id #define NOCPU (-1) /* For when we aren't on a CPU. */ #define NOCPU_OLD (255) #define MAXCPU_OLD (254) #define PROC_SLOCK(p) mtx_lock_spin(&(p)->p_slock) #define PROC_SUNLOCK(p) mtx_unlock_spin(&(p)->p_slock) #define PROC_SLOCK_ASSERT(p, type) mtx_assert(&(p)->p_slock, (type)) #define PROC_STATLOCK(p) mtx_lock_spin(&(p)->p_statmtx) #define PROC_STATUNLOCK(p) mtx_unlock_spin(&(p)->p_statmtx) #define PROC_STATLOCK_ASSERT(p, type) mtx_assert(&(p)->p_statmtx, (type)) #define PROC_ITIMLOCK(p) mtx_lock_spin(&(p)->p_itimmtx) #define PROC_ITIMUNLOCK(p) mtx_unlock_spin(&(p)->p_itimmtx) #define PROC_ITIMLOCK_ASSERT(p, type) mtx_assert(&(p)->p_itimmtx, (type)) #define PROC_PROFLOCK(p) mtx_lock_spin(&(p)->p_profmtx) #define PROC_PROFUNLOCK(p) mtx_unlock_spin(&(p)->p_profmtx) #define PROC_PROFLOCK_ASSERT(p, type) mtx_assert(&(p)->p_profmtx, (type)) /* These flags are kept in p_flag. */ #define P_ADVLOCK 0x00000001 /* Process may hold a POSIX advisory lock. */ #define P_CONTROLT 0x00000002 /* Has a controlling terminal. */ #define P_KPROC 0x00000004 /* Kernel process. */ #define P_UNUSED3 0x00000008 /* --available-- */ #define P_PPWAIT 0x00000010 /* Parent is waiting for child to exec/exit. */ #define P_PROFIL 0x00000020 /* Has started profiling. */ #define P_STOPPROF 0x00000040 /* Has thread requesting to stop profiling. */ #define P_HADTHREADS 0x00000080 /* Has had threads (no cleanup shortcuts) */ #define P_SUGID 0x00000100 /* Had set id privileges since last exec. */ #define P_SYSTEM 0x00000200 /* System proc: no sigs, stats or swapping. */ #define P_SINGLE_EXIT 0x00000400 /* Threads suspending should exit, not wait. */ #define P_TRACED 0x00000800 /* Debugged process being traced. */ #define P_WAITED 0x00001000 /* Someone is waiting for us. */ #define P_WEXIT 0x00002000 /* Working on exiting. */ #define P_EXEC 0x00004000 /* Process called exec. */ #define P_WKILLED 0x00008000 /* Killed, go to kernel/user boundary ASAP. */ #define P_CONTINUED 0x00010000 /* Proc has continued from a stopped state. */ #define P_STOPPED_SIG 0x00020000 /* Stopped due to SIGSTOP/SIGTSTP. */ #define P_STOPPED_TRACE 0x00040000 /* Stopped because of tracing. */ #define P_STOPPED_SINGLE 0x00080000 /* Only 1 thread can continue (not to user). */ #define P_PROTECTED 0x00100000 /* Do not kill on memory overcommit. */ #define P_SIGEVENT 0x00200000 /* Process pending signals changed. */ #define P_SINGLE_BOUNDARY 0x00400000 /* Threads should suspend at user boundary. */ #define P_HWPMC 0x00800000 /* Process is using HWPMCs */ #define P_JAILED 0x01000000 /* Process is in jail. */ #define P_TOTAL_STOP 0x02000000 /* Stopped in stop_all_proc. */ #define P_INEXEC 0x04000000 /* Process is in execve(). */ #define P_STATCHILD 0x08000000 /* Child process stopped or exited. */ #define P_INMEM 0x10000000 /* Loaded into memory. */ #define P_SWAPPINGOUT 0x20000000 /* Process is being swapped out. */ #define P_SWAPPINGIN 0x40000000 /* Process is being swapped in. */ #define P_PPTRACE 0x80000000 /* PT_TRACEME by vforked child. */ #define P_STOPPED (P_STOPPED_SIG|P_STOPPED_SINGLE|P_STOPPED_TRACE) #define P_SHOULDSTOP(p) ((p)->p_flag & P_STOPPED) #define P_KILLED(p) ((p)->p_flag & P_WKILLED) /* These flags are kept in p_flag2. */ #define P2_INHERIT_PROTECTED 0x00000001 /* New children get P_PROTECTED. */ #define P2_NOTRACE 0x00000002 /* No ptrace(2) attach or coredumps. */ #define P2_NOTRACE_EXEC 0x00000004 /* Keep P2_NOPTRACE on exec(2). */ #define P2_AST_SU 0x00000008 /* Handles SU ast for kthreads. */ #define P2_PTRACE_FSTP 0x00000010 /* SIGSTOP from PT_ATTACH not yet handled. */ #define P2_TRAPCAP 0x00000020 /* SIGTRAP on ENOTCAPABLE */ #define P2_ASLR_ENABLE 0x00000040 /* Force enable ASLR. */ #define P2_ASLR_DISABLE 0x00000080 /* Force disable ASLR. */ #define P2_ASLR_IGNSTART 0x00000100 /* Enable ASLR to consume sbrk area. */ #define P2_PROTMAX_ENABLE 0x00000200 /* Force enable implied PROT_MAX. */ #define P2_PROTMAX_DISABLE 0x00000400 /* Force disable implied PROT_MAX. */ #define P2_STKGAP_DISABLE 0x00000800 /* Disable stack gap for MAP_STACK */ #define P2_STKGAP_DISABLE_EXEC 0x00001000 /* Stack gap disabled after exec */ #define P2_ITSTOPPED 0x00002000 #define P2_PTRACEREQ 0x00004000 /* Active ptrace req */ #define P2_NO_NEW_PRIVS 0x00008000 /* Ignore setuid */ #define P2_WXORX_DISABLE 0x00010000 /* WX mappings enabled */ #define P2_WXORX_ENABLE_EXEC 0x00020000 /* WXORX enabled after exec */ #define P2_WEXIT 0x00040000 /* exit just started, no external thread_single() is permitted */ #define P2_REAPKILLED 0x00080000 #define P2_MEMBAR_PRIVE 0x00100000 /* membar private expedited registered */ #define P2_MEMBAR_PRIVE_SYNCORE 0x00200000 /* membar private expedited sync core registered */ #define P2_MEMBAR_GLOBE 0x00400000 /* membar global expedited registered */ /* Flags protected by proctree_lock, kept in p_treeflags. */ #define P_TREE_ORPHANED 0x00000001 /* Reparented, on orphan list */ #define P_TREE_FIRST_ORPHAN 0x00000002 /* First element of orphan list */ #define P_TREE_REAPER 0x00000004 /* Reaper of subtree */ #define P_TREE_GRPEXITED 0x00000008 /* exit1() done with job ctl */ /* * These were process status values (p_stat), now they are only used in * legacy conversion code. */ #define SIDL 1 /* Process being created by fork. */ #define SRUN 2 /* Currently runnable. */ #define SSLEEP 3 /* Sleeping on an address. */ #define SSTOP 4 /* Process debugging or suspension. */ #define SZOMB 5 /* Awaiting collection by parent. */ #define SWAIT 6 /* Waiting for interrupt. */ #define SLOCK 7 /* Blocked on a lock. */ #define P_MAGIC 0xbeefface #ifdef _KERNEL /* Types and flags for mi_switch(9). */ #define SW_TYPE_MASK 0xff /* First 8 bits are switch type */ #define SWT_OWEPREEMPT 1 /* Switching due to owepreempt. */ #define SWT_TURNSTILE 2 /* Turnstile contention. */ #define SWT_SLEEPQ 3 /* Sleepq wait. */ #define SWT_RELINQUISH 4 /* yield call. */ #define SWT_NEEDRESCHED 5 /* NEEDRESCHED was set. */ #define SWT_IDLE 6 /* Switching from the idle thread. */ #define SWT_IWAIT 7 /* Waiting for interrupts. */ #define SWT_SUSPEND 8 /* Thread suspended. */ #define SWT_REMOTEPREEMPT 9 /* Remote processor preempted. */ #define SWT_REMOTEWAKEIDLE 10 /* Remote processor preempted idle. */ #define SWT_BIND 11 /* Thread bound to a new CPU. */ #define SWT_COUNT 12 /* Number of switch types. */ /* Flags */ #define SW_VOL 0x0100 /* Voluntary switch. */ #define SW_INVOL 0x0200 /* Involuntary switch. */ #define SW_PREEMPT 0x0400 /* The invol switch is a preemption */ /* How values for thread_single(). */ #define SINGLE_NO_EXIT 0 #define SINGLE_EXIT 1 #define SINGLE_BOUNDARY 2 #define SINGLE_ALLPROC 3 #ifdef MALLOC_DECLARE MALLOC_DECLARE(M_PARGS); MALLOC_DECLARE(M_SESSION); MALLOC_DECLARE(M_SUBPROC); #endif #define FOREACH_PROC_IN_SYSTEM(p) \ LIST_FOREACH((p), &allproc, p_list) #define FOREACH_THREAD_IN_PROC(p, td) \ TAILQ_FOREACH((td), &(p)->p_threads, td_plist) #define FIRST_THREAD_IN_PROC(p) TAILQ_FIRST(&(p)->p_threads) /* * We use process IDs <= pid_max <= PID_MAX; PID_MAX + 1 must also fit * in a pid_t, as it is used to represent "no process group". */ #define PID_MAX 99999 #define NO_PID 100000 #define THREAD0_TID NO_PID extern pid_t pid_max; #define SESS_LEADER(p) ((p)->p_session->s_leader == (p)) /* Lock and unlock a process. */ #define PROC_LOCK(p) mtx_lock(&(p)->p_mtx) #define PROC_TRYLOCK(p) mtx_trylock(&(p)->p_mtx) #define PROC_UNLOCK(p) mtx_unlock(&(p)->p_mtx) #define PROC_LOCKED(p) mtx_owned(&(p)->p_mtx) #define PROC_WAIT_UNLOCKED(p) mtx_wait_unlocked(&(p)->p_mtx) #define PROC_LOCK_ASSERT(p, type) mtx_assert(&(p)->p_mtx, (type)) /* Lock and unlock a process group. */ #define PGRP_LOCK(pg) mtx_lock(&(pg)->pg_mtx) #define PGRP_UNLOCK(pg) mtx_unlock(&(pg)->pg_mtx) #define PGRP_LOCKED(pg) mtx_owned(&(pg)->pg_mtx) #define PGRP_LOCK_ASSERT(pg, type) mtx_assert(&(pg)->pg_mtx, (type)) #define PGRP_LOCK_PGSIGNAL(pg) do { \ if ((pg) != NULL) \ PGRP_LOCK(pg); \ } while (0) #define PGRP_UNLOCK_PGSIGNAL(pg) do { \ if ((pg) != NULL) \ PGRP_UNLOCK(pg); \ } while (0) /* Lock and unlock a session. */ #define SESS_LOCK(s) mtx_lock(&(s)->s_mtx) #define SESS_UNLOCK(s) mtx_unlock(&(s)->s_mtx) #define SESS_LOCKED(s) mtx_owned(&(s)->s_mtx) #define SESS_LOCK_ASSERT(s, type) mtx_assert(&(s)->s_mtx, (type)) /* * Non-zero p_lock ensures that: * - exit1() is not performed until p_lock reaches zero; * - the process' threads stack are not swapped out if they are currently * not (P_INMEM). * * PHOLD() asserts that the process (except the current process) is * not exiting, increments p_lock and swaps threads stacks into memory, * if needed. * _PHOLD() is same as PHOLD(), it takes the process locked. * _PHOLD_LITE() also takes the process locked, but comparing with * _PHOLD(), it only guarantees that exit1() is not executed, * faultin() is not called. */ #define PHOLD(p) do { \ PROC_LOCK(p); \ _PHOLD(p); \ PROC_UNLOCK(p); \ } while (0) #define _PHOLD(p) do { \ PROC_LOCK_ASSERT((p), MA_OWNED); \ KASSERT(!((p)->p_flag & P_WEXIT) || (p) == curproc, \ ("PHOLD of exiting process %p", p)); \ (p)->p_lock++; \ if (((p)->p_flag & P_INMEM) == 0) \ faultin((p)); \ } while (0) #define _PHOLD_LITE(p) do { \ PROC_LOCK_ASSERT((p), MA_OWNED); \ KASSERT(!((p)->p_flag & P_WEXIT) || (p) == curproc, \ ("PHOLD of exiting process %p", p)); \ (p)->p_lock++; \ } while (0) #define PROC_ASSERT_HELD(p) do { \ KASSERT((p)->p_lock > 0, ("process %p not held", p)); \ } while (0) #define PRELE(p) do { \ PROC_LOCK((p)); \ _PRELE((p)); \ PROC_UNLOCK((p)); \ } while (0) #define _PRELE(p) do { \ PROC_LOCK_ASSERT((p), MA_OWNED); \ PROC_ASSERT_HELD(p); \ (--(p)->p_lock); \ if (((p)->p_flag & P_WEXIT) && (p)->p_lock == 0) \ wakeup(&(p)->p_lock); \ } while (0) #define PROC_ASSERT_NOT_HELD(p) do { \ KASSERT((p)->p_lock == 0, ("process %p held", p)); \ } while (0) #define PROC_UPDATE_COW(p) do { \ struct proc *_p = (p); \ PROC_LOCK_ASSERT((_p), MA_OWNED); \ atomic_store_int(&_p->p_cowgen, _p->p_cowgen + 1); \ } while (0) #define PROC_COW_CHANGECOUNT(td, p) ({ \ struct thread *_td = (td); \ struct proc *_p = (p); \ MPASS(_td == curthread); \ PROC_LOCK_ASSERT(_p, MA_OWNED); \ _p->p_cowgen - _td->td_cowgen; \ }) /* Check whether a thread is safe to be swapped out. */ #define thread_safetoswapout(td) ((td)->td_flags & TDF_CANSWAP) /* Control whether or not it is safe for curthread to sleep. */ #define THREAD_NO_SLEEPING() do { \ curthread->td_no_sleeping++; \ MPASS(curthread->td_no_sleeping > 0); \ } while (0) #define THREAD_SLEEPING_OK() do { \ MPASS(curthread->td_no_sleeping > 0); \ curthread->td_no_sleeping--; \ } while (0) #define THREAD_CAN_SLEEP() ((curthread)->td_no_sleeping == 0) +#define THREAD_CONTENDS_ON_LOCK(lo) do { \ + MPASS(curthread->td_wantedlock == NULL); \ + curthread->td_wantedlock = lo; \ +} while (0) + +#define THREAD_CONTENTION_DONE(lo) do { \ + MPASS(curthread->td_wantedlock == lo); \ + curthread->td_wantedlock = NULL; \ +} while (0) + #define PIDHASH(pid) (&pidhashtbl[(pid) & pidhash]) #define PIDHASHLOCK(pid) (&pidhashtbl_lock[((pid) & pidhashlock)]) extern LIST_HEAD(pidhashhead, proc) *pidhashtbl; extern struct sx *pidhashtbl_lock; extern u_long pidhash; extern u_long pidhashlock; #define PGRPHASH(pgid) (&pgrphashtbl[(pgid) & pgrphash]) extern LIST_HEAD(pgrphashhead, pgrp) *pgrphashtbl; extern u_long pgrphash; extern struct sx allproc_lock; extern int allproc_gen; extern struct sx proctree_lock; extern struct mtx ppeers_lock; extern struct mtx procid_lock; extern struct proc proc0; /* Process slot for swapper. */ extern struct thread0_storage thread0_st; /* Primary thread in proc0. */ #define thread0 (thread0_st.t0st_thread) extern struct vmspace vmspace0; /* VM space for proc0. */ extern int hogticks; /* Limit on kernel cpu hogs. */ extern int lastpid; extern int nprocs, maxproc; /* Current and max number of procs. */ extern int maxprocperuid; /* Max procs per uid. */ extern u_long ps_arg_cache_limit; LIST_HEAD(proclist, proc); TAILQ_HEAD(procqueue, proc); TAILQ_HEAD(threadqueue, thread); extern struct proclist allproc; /* List of all processes. */ extern struct proc *initproc, *pageproc; /* Process slots for init, pager. */ extern struct uma_zone *proc_zone; extern struct uma_zone *pgrp_zone; struct proc *pfind(pid_t); /* Find process by id. */ struct proc *pfind_any(pid_t); /* Find (zombie) process by id. */ struct proc *pfind_any_locked(pid_t pid); /* Find process by id, locked. */ struct pgrp *pgfind(pid_t); /* Find process group by id. */ void pidhash_slockall(void); /* Shared lock all pid hash lists. */ void pidhash_sunlockall(void); /* Shared unlock all pid hash lists. */ struct fork_req { int fr_flags; int fr_pages; int *fr_pidp; struct proc **fr_procp; int *fr_pd_fd; int fr_pd_flags; struct filecaps *fr_pd_fcaps; int fr_flags2; #define FR2_DROPSIG_CAUGHT 0x00000001 /* Drop caught non-DFL signals */ #define FR2_SHARE_PATHS 0x00000002 /* Invert sense of RFFDG for paths */ #define FR2_KPROC 0x00000004 /* Create a kernel process */ }; /* * pget() flags. */ #define PGET_HOLD 0x00001 /* Hold the process. */ #define PGET_CANSEE 0x00002 /* Check against p_cansee(). */ #define PGET_CANDEBUG 0x00004 /* Check against p_candebug(). */ #define PGET_ISCURRENT 0x00008 /* Check that the found process is current. */ #define PGET_NOTWEXIT 0x00010 /* Check that the process is not in P_WEXIT. */ #define PGET_NOTINEXEC 0x00020 /* Check that the process is not in P_INEXEC. */ #define PGET_NOTID 0x00040 /* Do not assume tid if pid > PID_MAX. */ #define PGET_WANTREAD (PGET_HOLD | PGET_CANDEBUG | PGET_NOTWEXIT) int pget(pid_t pid, int flags, struct proc **pp); /* ast_register() flags */ #define ASTR_ASTF_REQUIRED 0x0001 /* td_ast TDAI(TDA_X) flag set is required for call */ #define ASTR_TDP 0x0002 /* td_pflags flag set is required */ #define ASTR_KCLEAR 0x0004 /* call me on ast_kclear() */ #define ASTR_UNCOND 0x0008 /* call me always */ void ast(struct trapframe *framep); void ast_kclear(struct thread *td); void ast_register(int ast, int ast_flags, int tdp, void (*f)(struct thread *td, int asts)); void ast_deregister(int tda); void ast_sched_locked(struct thread *td, int tda); void ast_sched_mask(struct thread *td, int ast); void ast_sched(struct thread *td, int tda); void ast_unsched_locked(struct thread *td, int tda); struct thread *choosethread(void); int cr_bsd_visible(struct ucred *u1, struct ucred *u2); int cr_cansee(struct ucred *u1, struct ucred *u2); int cr_canseesocket(struct ucred *cred, struct socket *so); int cr_cansignal(struct ucred *cred, struct proc *proc, int signum); int enterpgrp(struct proc *p, pid_t pgid, struct pgrp *pgrp, struct session *sess); int enterthispgrp(struct proc *p, struct pgrp *pgrp); void faultin(struct proc *p); int fork1(struct thread *, struct fork_req *); void fork_exit(void (*)(void *, struct trapframe *), void *, struct trapframe *); void fork_return(struct thread *, struct trapframe *); int inferior(struct proc *p); void itimer_proc_continue(struct proc *p); void kqtimer_proc_continue(struct proc *p); void kern_proc_vmmap_resident(struct vm_map *map, struct vm_map_entry *entry, int *resident_count, bool *super); void kern_yield(int); void kick_proc0(void); void killjobc(void); int leavepgrp(struct proc *p); int maybe_preempt(struct thread *td); void maybe_yield(void); void mi_switch(int flags); int p_candebug(struct thread *td, struct proc *p); int p_cansee(struct thread *td, struct proc *p); int p_cansched(struct thread *td, struct proc *p); int p_cansignal(struct thread *td, struct proc *p, int signum); int p_canwait(struct thread *td, struct proc *p); struct pargs *pargs_alloc(int len); void pargs_drop(struct pargs *pa); void pargs_hold(struct pargs *pa); void proc_add_orphan(struct proc *child, struct proc *parent); int proc_get_binpath(struct proc *p, char *binname, char **fullpath, char **freepath); int proc_getargv(struct thread *td, struct proc *p, struct sbuf *sb); int proc_getauxv(struct thread *td, struct proc *p, struct sbuf *sb); int proc_getenvv(struct thread *td, struct proc *p, struct sbuf *sb); void procinit(void); int proc_iterate(int (*cb)(struct proc *, void *), void *cbarg); void proc_linkup0(struct proc *p, struct thread *td); void proc_linkup(struct proc *p, struct thread *td); struct proc *proc_realparent(struct proc *child); void proc_reap(struct thread *td, struct proc *p, int *status, int options); void proc_reparent(struct proc *child, struct proc *newparent, bool set_oppid); void proc_set_p2_wexit(struct proc *p); void proc_set_traced(struct proc *p, bool stop); void proc_wkilled(struct proc *p); struct pstats *pstats_alloc(void); void pstats_fork(struct pstats *src, struct pstats *dst); void pstats_free(struct pstats *ps); void proc_clear_orphan(struct proc *p); void reaper_abandon_children(struct proc *p, bool exiting); int securelevel_ge(struct ucred *cr, int level); int securelevel_gt(struct ucred *cr, int level); void sess_hold(struct session *); void sess_release(struct session *); int setrunnable(struct thread *, int); void setsugid(struct proc *p); bool should_yield(void); int sigonstack(size_t sp); void stopevent(struct proc *, u_int, u_int); struct thread *tdfind(lwpid_t, pid_t); void threadinit(void); void tidhash_add(struct thread *); void tidhash_remove(struct thread *); void cpu_idle(int); int cpu_idle_wakeup(int); extern void (*cpu_idle_hook)(sbintime_t); /* Hook to machdep CPU idler. */ void cpu_switch(struct thread *, struct thread *, struct mtx *); void cpu_sync_core(void); void cpu_throw(struct thread *, struct thread *) __dead2; bool curproc_sigkilled(void); void userret(struct thread *, struct trapframe *); void cpu_exit(struct thread *); void exit1(struct thread *, int, int) __dead2; void cpu_copy_thread(struct thread *td, struct thread *td0); bool cpu_exec_vmspace_reuse(struct proc *p, struct vm_map *map); int cpu_fetch_syscall_args(struct thread *td); void cpu_fork(struct thread *, struct proc *, struct thread *, int); void cpu_fork_kthread_handler(struct thread *, void (*)(void *), void *); int cpu_procctl(struct thread *td, int idtype, id_t id, int com, void *data); void cpu_set_syscall_retval(struct thread *, int); void cpu_set_upcall(struct thread *, void (*)(void *), void *, stack_t *); int cpu_set_user_tls(struct thread *, void *tls_base); void cpu_thread_alloc(struct thread *); void cpu_thread_clean(struct thread *); void cpu_thread_exit(struct thread *); void cpu_thread_free(struct thread *); void cpu_thread_swapin(struct thread *); void cpu_thread_swapout(struct thread *); struct thread *thread_alloc(int pages); int thread_alloc_stack(struct thread *, int pages); int thread_check_susp(struct thread *td, bool sleep); void thread_cow_get_proc(struct thread *newtd, struct proc *p); void thread_cow_get(struct thread *newtd, struct thread *td); void thread_cow_free(struct thread *td); void thread_cow_update(struct thread *td); void thread_cow_synced(struct thread *td); int thread_create(struct thread *td, struct rtprio *rtp, int (*initialize_thread)(struct thread *, void *), void *thunk); void thread_exit(void) __dead2; void thread_free(struct thread *td); void thread_link(struct thread *td, struct proc *p); void thread_reap_barrier(void); int thread_single(struct proc *p, int how); void thread_single_end(struct proc *p, int how); void thread_stash(struct thread *td); void thread_stopped(struct proc *p); void childproc_stopped(struct proc *child, int reason); void childproc_continued(struct proc *child); void childproc_exited(struct proc *child); void thread_run_flash(struct thread *td); int thread_suspend_check(int how); bool thread_suspend_check_needed(void); void thread_suspend_switch(struct thread *, struct proc *p); void thread_suspend_one(struct thread *td); void thread_unlink(struct thread *td); void thread_unsuspend(struct proc *p); void thread_wait(struct proc *p); bool stop_all_proc_block(void); void stop_all_proc_unblock(void); void stop_all_proc(void); void resume_all_proc(void); static __inline int curthread_pflags_set(int flags) { struct thread *td; int save; td = curthread; save = ~flags | (td->td_pflags & flags); td->td_pflags |= flags; return (save); } static __inline void curthread_pflags_restore(int save) { curthread->td_pflags &= save; } static __inline int curthread_pflags2_set(int flags) { struct thread *td; int save; td = curthread; save = ~flags | (td->td_pflags2 & flags); td->td_pflags2 |= flags; return (save); } static __inline void curthread_pflags2_restore(int save) { curthread->td_pflags2 &= save; } static __inline __pure2 struct td_sched * td_get_sched(struct thread *td) { return ((struct td_sched *)&td[1]); } #define PROC_ID_PID 0 #define PROC_ID_GROUP 1 #define PROC_ID_SESSION 2 #define PROC_ID_REAP 3 void proc_id_set(int type, pid_t id); void proc_id_set_cond(int type, pid_t id); void proc_id_clear(int type, pid_t id); EVENTHANDLER_LIST_DECLARE(process_ctor); EVENTHANDLER_LIST_DECLARE(process_dtor); EVENTHANDLER_LIST_DECLARE(process_init); EVENTHANDLER_LIST_DECLARE(process_fini); EVENTHANDLER_LIST_DECLARE(process_exit); EVENTHANDLER_LIST_DECLARE(process_fork); EVENTHANDLER_LIST_DECLARE(process_exec); EVENTHANDLER_LIST_DECLARE(thread_ctor); EVENTHANDLER_LIST_DECLARE(thread_dtor); EVENTHANDLER_LIST_DECLARE(thread_init); #endif /* _KERNEL */ #endif /* !_SYS_PROC_H_ */