Please note that diffs are not public domain; they are subject to the copyright notices on the relevant files. =================================================================== RCS file: /ftp/cvs/cvsroot/src/sys/kern/kern_mutex.c,v rcsdiff: /ftp/cvs/cvsroot/src/sys/kern/kern_mutex.c,v: warning: Unknown phrases like `commitid ...;' are present. retrieving revision 1.5 retrieving revision 1.65 diff -u -p -r1.5 -r1.65 --- src/sys/kern/kern_mutex.c 2007/02/26 09:20:53 1.5 +++ src/sys/kern/kern_mutex.c 2017/05/01 21:35:25 1.65 @@ -1,7 +1,7 @@ -/* $NetBSD: kern_mutex.c,v 1.5 2007/02/26 09:20:53 yamt Exp $ */ +/* $NetBSD: kern_mutex.c,v 1.65 2017/05/01 21:35:25 pgoyette Exp $ */ /*- - * Copyright (c) 2002, 2006, 2007 The NetBSD Foundation, Inc. + * Copyright (c) 2002, 2006, 2007, 2008 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation @@ -15,13 +15,6 @@ * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. - * 3. All advertising materials mentioning features or use of this software - * must display the following acknowledgement: - * This product includes software developed by the NetBSD - * Foundation, Inc. and its contributors. - * 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED @@ -44,14 +37,13 @@ * Richard McDougall. */ -#include "opt_multiprocessor.h" - #define __MUTEX_PRIVATE #include -__KERNEL_RCSID(0, "$NetBSD: kern_mutex.c,v 1.5 2007/02/26 09:20:53 yamt Exp $"); +__KERNEL_RCSID(0, "$NetBSD: kern_mutex.c,v 1.65 2017/05/01 21:35:25 pgoyette Exp $"); #include +#include #include #include #include @@ -59,10 +51,13 @@ __KERNEL_RCSID(0, "$NetBSD: kern_mutex.c #include #include #include +#include +#include +#include #include -#include +#include /* * When not running a debug kernel, spin mutexes are not much @@ -78,16 +73,19 @@ __KERNEL_RCSID(0, "$NetBSD: kern_mutex.c */ #define MUTEX_WANTLOCK(mtx) \ - LOCKDEBUG_WANTLOCK(MUTEX_GETID(mtx), \ + LOCKDEBUG_WANTLOCK(MUTEX_DEBUG_P(mtx), (mtx), \ (uintptr_t)__builtin_return_address(0), 0) +#define MUTEX_TESTLOCK(mtx) \ + LOCKDEBUG_WANTLOCK(MUTEX_DEBUG_P(mtx), (mtx), \ + (uintptr_t)__builtin_return_address(0), -1) #define MUTEX_LOCKED(mtx) \ - LOCKDEBUG_LOCKED(MUTEX_GETID(mtx), \ + LOCKDEBUG_LOCKED(MUTEX_DEBUG_P(mtx), (mtx), NULL, \ (uintptr_t)__builtin_return_address(0), 0) #define MUTEX_UNLOCKED(mtx) \ - LOCKDEBUG_UNLOCKED(MUTEX_GETID(mtx), \ + LOCKDEBUG_UNLOCKED(MUTEX_DEBUG_P(mtx), (mtx), \ (uintptr_t)__builtin_return_address(0), 0) #define MUTEX_ABORT(mtx, msg) \ - mutex_abort(mtx, __FUNCTION__, msg) + mutex_abort(__func__, __LINE__, mtx, msg) #if defined(LOCKDEBUG) @@ -118,15 +116,39 @@ do { \ #endif /* DIAGNOSTIC */ /* + * Some architectures can't use __cpu_simple_lock as is so allow a way + * for them to use an alternate definition. + */ +#ifndef MUTEX_SPINBIT_LOCK_INIT +#define MUTEX_SPINBIT_LOCK_INIT(mtx) __cpu_simple_lock_init(&(mtx)->mtx_lock) +#endif +#ifndef MUTEX_SPINBIT_LOCKED_P +#define MUTEX_SPINBIT_LOCKED_P(mtx) __SIMPLELOCK_LOCKED_P(&(mtx)->mtx_lock) +#endif +#ifndef MUTEX_SPINBIT_LOCK_TRY +#define MUTEX_SPINBIT_LOCK_TRY(mtx) __cpu_simple_lock_try(&(mtx)->mtx_lock) +#endif +#ifndef MUTEX_SPINBIT_LOCK_UNLOCK +#define MUTEX_SPINBIT_LOCK_UNLOCK(mtx) __cpu_simple_unlock(&(mtx)->mtx_lock) +#endif + +#ifndef MUTEX_INITIALIZE_SPIN_IPL +#define MUTEX_INITIALIZE_SPIN_IPL(mtx, ipl) \ + ((mtx)->mtx_ipl = makeiplcookie((ipl))) +#endif + +/* * Spin mutex SPL save / restore. */ #define MUTEX_SPIN_SPLRAISE(mtx) \ do { \ - struct cpu_info *x__ci = curcpu(); \ + struct cpu_info *x__ci; \ int x__cnt, s; \ + s = splraiseipl(MUTEX_SPIN_IPL(mtx)); \ + x__ci = curcpu(); \ x__cnt = x__ci->ci_mtx_count--; \ - s = splraiseipl(mtx->mtx_ipl); \ + __insn_barrier(); \ if (x__cnt == 0) \ x__ci->ci_mtx_oldspl = (s); \ } while (/* CONSTCOND */ 0) @@ -136,7 +158,7 @@ do { \ struct cpu_info *x__ci = curcpu(); \ int s = x__ci->ci_mtx_oldspl; \ __insn_barrier(); \ - if (++(x__ci->ci_mtx_count) == 0) \ + if (++(x__ci->ci_mtx_count) == 0) \ splx(s); \ } while (/* CONSTCOND */ 0) @@ -151,28 +173,27 @@ do { \ #define MUTEX_OWNER(owner) \ (owner & MUTEX_THREAD) -#define MUTEX_OWNED(owner) \ - (owner != 0) #define MUTEX_HAS_WAITERS(mtx) \ (((int)(mtx)->mtx_owner & MUTEX_BIT_WAITERS) != 0) -#define MUTEX_INITIALIZE_ADAPTIVE(mtx, id) \ +#define MUTEX_INITIALIZE_ADAPTIVE(mtx, dodebug) \ + if (!dodebug) \ + (mtx)->mtx_owner |= MUTEX_BIT_NODEBUG; \ do { \ - (mtx)->mtx_id = (id); \ } while (/* CONSTCOND */ 0); -#define MUTEX_INITIALIZE_SPIN(mtx, id, ipl) \ +#define MUTEX_INITIALIZE_SPIN(mtx, dodebug, ipl) \ do { \ (mtx)->mtx_owner = MUTEX_BIT_SPIN; \ - (mtx)->mtx_ipl = makeiplcookie((ipl)); \ - (mtx)->mtx_id = (id); \ - __cpu_simple_lock_init(&(mtx)->mtx_lock); \ + if (!dodebug) \ + (mtx)->mtx_owner |= MUTEX_BIT_NODEBUG; \ + MUTEX_INITIALIZE_SPIN_IPL((mtx), (ipl)); \ + MUTEX_SPINBIT_LOCK_INIT((mtx)); \ } while (/* CONSTCOND */ 0) #define MUTEX_DESTROY(mtx) \ do { \ (mtx)->mtx_owner = MUTEX_THREAD; \ - (mtx)->mtx_id = -1; \ } while (/* CONSTCOND */ 0); #define MUTEX_SPIN_P(mtx) \ @@ -180,14 +201,26 @@ do { \ #define MUTEX_ADAPTIVE_P(mtx) \ (((mtx)->mtx_owner & MUTEX_BIT_SPIN) == 0) -#define MUTEX_GETID(mtx) ((mtx)->mtx_id) +#define MUTEX_DEBUG_P(mtx) (((mtx)->mtx_owner & MUTEX_BIT_NODEBUG) == 0) +#if defined(LOCKDEBUG) +#define MUTEX_OWNED(owner) (((owner) & ~MUTEX_BIT_NODEBUG) != 0) +#define MUTEX_INHERITDEBUG(n, o) (n) |= (o) & MUTEX_BIT_NODEBUG +#else /* defined(LOCKDEBUG) */ +#define MUTEX_OWNED(owner) ((owner) != 0) +#define MUTEX_INHERITDEBUG(n, o) /* nothing */ +#endif /* defined(LOCKDEBUG) */ static inline int MUTEX_ACQUIRE(kmutex_t *mtx, uintptr_t curthread) { int rv; - rv = MUTEX_CAS(&mtx->mtx_owner, 0UL, curthread); - MUTEX_RECEIVE(); + uintptr_t oldown = 0; + uintptr_t newown = curthread; + + MUTEX_INHERITDEBUG(oldown, mtx->mtx_owner); + MUTEX_INHERITDEBUG(newown, oldown); + rv = MUTEX_CAS(&mtx->mtx_owner, oldown, newown); + MUTEX_RECEIVE(mtx); return rv; } @@ -196,21 +229,19 @@ MUTEX_SET_WAITERS(kmutex_t *mtx, uintptr { int rv; rv = MUTEX_CAS(&mtx->mtx_owner, owner, owner | MUTEX_BIT_WAITERS); - MUTEX_RECEIVE(); + MUTEX_RECEIVE(mtx); return rv; } static inline void MUTEX_RELEASE(kmutex_t *mtx) { - MUTEX_GIVE(); - mtx->mtx_owner = 0; -} + uintptr_t newown; -static inline void -MUTEX_CLEAR_WAITERS(kmutex_t *mtx) -{ - /* nothing */ + MUTEX_GIVE(mtx); + newown = 0; + MUTEX_INHERITDEBUG(newown, mtx->mtx_owner); + mtx->mtx_owner = newown; } #endif /* __HAVE_SIMPLE_MUTEXES */ @@ -224,29 +255,27 @@ MUTEX_CLEAR_WAITERS(kmutex_t *mtx) #endif #ifndef __HAVE_MUTEX_STUBS -__strong_alias(mutex_enter, mutex_vector_enter); -__strong_alias(mutex_exit, mutex_vector_exit); +__strong_alias(mutex_enter,mutex_vector_enter); +__strong_alias(mutex_exit,mutex_vector_exit); #endif #ifndef __HAVE_SPIN_MUTEX_STUBS -__strong_alias(mutex_spin_enter, mutex_vector_enter); -__strong_alias(mutex_spin_exit, mutex_vector_exit); +__strong_alias(mutex_spin_enter,mutex_vector_enter); +__strong_alias(mutex_spin_exit,mutex_vector_exit); #endif -void mutex_abort(kmutex_t *, const char *, const char *); -void mutex_dump(volatile void *); -int mutex_onproc(uintptr_t, struct cpu_info **); -static struct lwp *mutex_getowner(wchan_t); /* XXX naming conflict */ +static void mutex_abort(const char *, size_t, kmutex_t *, const char *); +static void mutex_dump(volatile void *); lockops_t mutex_spin_lockops = { "Mutex", - 0, + LOCKOPS_SPIN, mutex_dump }; lockops_t mutex_adaptive_lockops = { "Mutex", - 1, + LOCKOPS_SLEEP, mutex_dump }; @@ -255,7 +284,7 @@ syncobj_t mutex_syncobj = { turnstile_unsleep, turnstile_changepri, sleepq_lendpri, - mutex_getowner, + (void *)mutex_owner, }; /* @@ -280,13 +309,12 @@ mutex_dump(volatile void *cookie) * generates a lot of machine code in the DIAGNOSTIC case, so * we ask the compiler to not inline it. */ -__attribute ((noinline)) __attribute ((noreturn)) void -mutex_abort(kmutex_t *mtx, const char *func, const char *msg) +void __noinline +mutex_abort(const char *func, size_t line, kmutex_t *mtx, const char *msg) { - LOCKDEBUG_ABORT(MUTEX_GETID(mtx), mtx, (MUTEX_SPIN_P(mtx) ? - &mutex_spin_lockops : &mutex_adaptive_lockops), func, msg); - /* NOTREACHED */ + LOCKDEBUG_ABORT(func, line, mtx, (MUTEX_SPIN_P(mtx) ? + &mutex_spin_lockops : &mutex_adaptive_lockops), msg); } /* @@ -301,23 +329,43 @@ mutex_abort(kmutex_t *mtx, const char *f void mutex_init(kmutex_t *mtx, kmutex_type_t type, int ipl) { - u_int id; + bool dodebug; memset(mtx, 0, sizeof(*mtx)); - if (type == MUTEX_DRIVER) - type = (ipl == IPL_NONE ? MUTEX_ADAPTIVE : MUTEX_SPIN); - switch (type) { case MUTEX_ADAPTIVE: - case MUTEX_DEFAULT: KASSERT(ipl == IPL_NONE); - id = LOCKDEBUG_ALLOC(mtx, &mutex_adaptive_lockops); - MUTEX_INITIALIZE_ADAPTIVE(mtx, id); + break; + case MUTEX_DEFAULT: + case MUTEX_DRIVER: + if (ipl == IPL_NONE || ipl == IPL_SOFTCLOCK || + ipl == IPL_SOFTBIO || ipl == IPL_SOFTNET || + ipl == IPL_SOFTSERIAL) { + type = MUTEX_ADAPTIVE; + } else { + type = MUTEX_SPIN; + } + break; + default: + break; + } + + switch (type) { + case MUTEX_NODEBUG: + dodebug = LOCKDEBUG_ALLOC(mtx, NULL, + (uintptr_t)__builtin_return_address(0)); + MUTEX_INITIALIZE_SPIN(mtx, dodebug, ipl); + break; + case MUTEX_ADAPTIVE: + dodebug = LOCKDEBUG_ALLOC(mtx, &mutex_adaptive_lockops, + (uintptr_t)__builtin_return_address(0)); + MUTEX_INITIALIZE_ADAPTIVE(mtx, dodebug); break; case MUTEX_SPIN: - id = LOCKDEBUG_ALLOC(mtx, &mutex_spin_lockops); - MUTEX_INITIALIZE_SPIN(mtx, id, ipl); + dodebug = LOCKDEBUG_ALLOC(mtx, &mutex_spin_lockops, + (uintptr_t)__builtin_return_address(0)); + MUTEX_INITIALIZE_SPIN(mtx, dodebug, ipl); break; default: panic("mutex_init: impossible type"); @@ -338,64 +386,56 @@ mutex_destroy(kmutex_t *mtx) MUTEX_ASSERT(mtx, !MUTEX_OWNED(mtx->mtx_owner) && !MUTEX_HAS_WAITERS(mtx)); } else { - MUTEX_ASSERT(mtx, mtx->mtx_lock != __SIMPLELOCK_LOCKED); + MUTEX_ASSERT(mtx, !MUTEX_SPINBIT_LOCKED_P(mtx)); } - LOCKDEBUG_FREE(mtx, MUTEX_GETID(mtx)); + LOCKDEBUG_FREE(MUTEX_DEBUG_P(mtx), mtx); MUTEX_DESTROY(mtx); } +#ifdef MULTIPROCESSOR /* - * mutex_onproc: + * mutex_oncpu: * * Return true if an adaptive mutex owner is running on a CPU in the * system. If the target is waiting on the kernel big lock, then we - * return false immediately. This is necessary to avoid deadlock - * against the big lock. - * - * Note that we can't use the mutex owner field as an LWP pointer. We - * don't have full control over the timing of our execution, and so the - * pointer could be completely invalid by the time we dereference it. - * - * XXX This should be optimised further to reduce potential cache line - * ping-ponging and skewing of the spin time while busy waiting. + * must release it. This is necessary to avoid deadlock. */ -#ifdef MULTIPROCESSOR -int -mutex_onproc(uintptr_t owner, struct cpu_info **cip) +static bool +mutex_oncpu(uintptr_t owner) { - CPU_INFO_ITERATOR cii; struct cpu_info *ci; - struct lwp *l; + lwp_t *l; - if (!MUTEX_OWNED(owner)) - return 0; - l = (struct lwp *)MUTEX_OWNER(owner); + KASSERT(kpreempt_disabled()); - if ((ci = *cip) != NULL && ci->ci_curlwp == l) { - mb_read(); /* XXXSMP Very expensive, necessary? */ - return ci->ci_biglock_wanted != l; + if (!MUTEX_OWNED(owner)) { + return false; } - for (CPU_INFO_FOREACH(cii, ci)) { - if (ci->ci_curlwp == l) { - *cip = ci; - mb_read(); /* XXXSMP Very expensive, necessary? */ - return ci->ci_biglock_wanted != l; - } + /* + * See lwp_dtor() why dereference of the LWP pointer is safe. + * We must have kernel preemption disabled for that. + */ + l = (lwp_t *)MUTEX_OWNER(owner); + ci = l->l_cpu; + + if (ci && ci->ci_curlwp == l) { + /* Target is running; do we need to block? */ + return (ci->ci_biglock_wanted != l); } - *cip = NULL; - return 0; + /* Not running. It may be safe to block now. */ + return false; } -#endif +#endif /* MULTIPROCESSOR */ /* * mutex_vector_enter: * - * Support routine for mutex_enter() that must handles all cases. In + * Support routine for mutex_enter() that must handle all cases. In * the LOCKDEBUG case, mutex_enter() is always aliased here, even if - * fast-path stubs are available. If an mutex_spin_enter() stub is + * fast-path stubs are available. If a mutex_spin_enter() stub is * not available, then it is also aliased directly here. */ void @@ -404,7 +444,6 @@ mutex_vector_enter(kmutex_t *mtx) uintptr_t owner, curthread; turnstile_t *ts; #ifdef MULTIPROCESSOR - struct cpu_info *ci = NULL; u_int count; #endif LOCKSTAT_COUNTER(spincnt); @@ -423,7 +462,7 @@ mutex_vector_enter(kmutex_t *mtx) MUTEX_SPIN_SPLRAISE(mtx); MUTEX_WANTLOCK(mtx); #ifdef FULL - if (__cpu_simple_lock_try(&mtx->mtx_lock)) { + if (MUTEX_SPINBIT_LOCK_TRY(mtx)) { MUTEX_LOCKED(mtx); return; } @@ -442,14 +481,14 @@ mutex_vector_enter(kmutex_t *mtx) do { if (panicstr != NULL) break; - while (mtx->mtx_lock == __SIMPLELOCK_LOCKED) { - SPINLOCK_BACKOFF(count); + while (MUTEX_SPINBIT_LOCKED_P(mtx)) { + SPINLOCK_BACKOFF(count); #ifdef LOCKDEBUG if (SPINLOCK_SPINOUT(spins)) MUTEX_ABORT(mtx, "spinout"); #endif /* LOCKDEBUG */ } - } while (!__cpu_simple_lock_try(&mtx->mtx_lock)); + } while (!MUTEX_SPINBIT_LOCK_TRY(mtx)); if (count != SPINLOCK_BACKOFF_MIN) { LOCKSTAT_STOP_TIMER(lsflag, spintime); @@ -469,16 +508,9 @@ mutex_vector_enter(kmutex_t *mtx) MUTEX_ASSERT(mtx, curthread != 0); MUTEX_WANTLOCK(mtx); -#ifdef LOCKDEBUG if (panicstr == NULL) { - simple_lock_only_held(NULL, "mutex_enter"); -#ifdef MULTIPROCESSOR LOCKDEBUG_BARRIER(&kernel_lock, 1); -#else - LOCKDEBUG_BARRIER(NULL, 1); -#endif } -#endif LOCKSTAT_ENTER(lsflag); @@ -487,8 +519,8 @@ mutex_vector_enter(kmutex_t *mtx) * determine that the owner is not running on a processor, * then we stop spinning, and sleep instead. */ - for (;;) { - owner = mtx->mtx_owner; + KPREEMPT_DISABLE(curlwp); + for (owner = mtx->mtx_owner;;) { if (!MUTEX_OWNED(owner)) { /* * Mutex owner clear could mean two things: @@ -501,29 +533,31 @@ mutex_vector_enter(kmutex_t *mtx) */ if (MUTEX_ACQUIRE(mtx, curthread)) break; + owner = mtx->mtx_owner; continue; } - - if (panicstr != NULL) + if (__predict_false(panicstr != NULL)) { + KPREEMPT_ENABLE(curlwp); return; - if (MUTEX_OWNER(owner) == curthread) + } + if (__predict_false(MUTEX_OWNER(owner) == curthread)) { MUTEX_ABORT(mtx, "locking against myself"); - + } #ifdef MULTIPROCESSOR /* * Check to see if the owner is running on a processor. * If so, then we should just spin, as the owner will * likely release the lock very soon. */ - if (mutex_onproc(owner, &ci)) { + if (mutex_oncpu(owner)) { LOCKSTAT_START_TIMER(lsflag, spintime); count = SPINLOCK_BACKOFF_MIN; - for (;;) { - owner = mtx->mtx_owner; - if (!mutex_onproc(owner, &ci)) - break; + do { + KPREEMPT_ENABLE(curlwp); SPINLOCK_BACKOFF(count); - } + KPREEMPT_DISABLE(curlwp); + owner = mtx->mtx_owner; + } while (mutex_oncpu(owner)); LOCKSTAT_STOP_TIMER(lsflag, spintime); LOCKSTAT_COUNT(spincnt, 1); if (!MUTEX_OWNED(owner)) @@ -540,6 +574,7 @@ mutex_vector_enter(kmutex_t *mtx) */ if (!MUTEX_SET_WAITERS(mtx, owner)) { turnstile_exit(mtx); + owner = mtx->mtx_owner; continue; } @@ -562,7 +597,7 @@ mutex_vector_enter(kmutex_t *mtx) * .. clear lock word, waiters * return success * - * There is a another race that can occur: a third CPU could + * There is another race that can occur: a third CPU could * acquire the mutex as soon as it is released. Since * adaptive mutexes are primarily spin mutexes, this is not * something that we need to worry about too much. What we @@ -577,7 +612,7 @@ mutex_vector_enter(kmutex_t *mtx) * or preempted). * * o At any given time, MUTEX_SET_WAITERS() can only ever - * be in progress on one CPU in the system - guarenteed + * be in progress on one CPU in the system - guaranteed * by the turnstile chain lock. * * o No other operations other than MUTEX_SET_WAITERS() @@ -594,7 +629,7 @@ mutex_vector_enter(kmutex_t *mtx) * completes before the modification of curlwp becomes * visible to this CPU. * - * o cpu_switch() posts a store fence before setting curlwp + * o mi_switch() posts a store fence before setting curlwp * and before resuming execution of an LWP. * * o _kernel_lock() posts a store fence before setting @@ -607,23 +642,23 @@ mutex_vector_enter(kmutex_t *mtx) * waiters field) and check the lock holder's status again. * Some of the possible outcomes (not an exhaustive list): * - * 1. The onproc check returns true: the holding LWP is + * 1. The on-CPU check returns true: the holding LWP is * running again. The lock may be released soon and * we should spin. Importantly, we can't trust the * value of the waiters flag. * - * 2. The onproc check returns false: the holding LWP is - * not running. We now have the oppertunity to check + * 2. The on-CPU check returns false: the holding LWP is + * not running. We now have the opportunity to check * if mutex_exit() has blatted the modifications made * by MUTEX_SET_WAITERS(). * - * 3. The onproc check returns false: the holding LWP may + * 3. The on-CPU check returns false: the holding LWP may * or may not be running. It has context switched at * some point during our check. Again, we have the * chance to see if the waiters bit is still set or * has been overwritten. * - * 4. The onproc check returns false: the holding LWP is + * 4. The on-CPU check returns false: the holding LWP is * running on a CPU, but wants the big lock. It's OK * to check the waiters field in this case. * @@ -637,9 +672,10 @@ mutex_vector_enter(kmutex_t *mtx) * If the waiters bit is not set it's unsafe to go asleep, * as we might never be awoken. */ - mb_read(); - if (mutex_onproc(owner, &ci) || !MUTEX_HAS_WAITERS(mtx)) { + if ((membar_consumer(), mutex_oncpu(owner)) || + (membar_consumer(), !MUTEX_HAS_WAITERS(mtx))) { turnstile_exit(mtx); + owner = mtx->mtx_owner; continue; } #endif /* MULTIPROCESSOR */ @@ -651,8 +687,9 @@ mutex_vector_enter(kmutex_t *mtx) LOCKSTAT_STOP_TIMER(lsflag, slptime); LOCKSTAT_COUNT(slpcnt, 1); - turnstile_unblock(); + owner = mtx->mtx_owner; } + KPREEMPT_ENABLE(curlwp); LOCKSTAT_EVENT(lsflag, mtx, LB_ADAPTIVE_MUTEX | LB_SLEEP1, slpcnt, slptime); @@ -677,16 +714,19 @@ mutex_vector_exit(kmutex_t *mtx) if (MUTEX_SPIN_P(mtx)) { #ifdef FULL - if (mtx->mtx_lock != __SIMPLELOCK_LOCKED) + if (__predict_false(!MUTEX_SPINBIT_LOCKED_P(mtx))) { + if (panicstr != NULL) + return; MUTEX_ABORT(mtx, "exiting unheld spin mutex"); + } MUTEX_UNLOCKED(mtx); - __cpu_simple_unlock(&mtx->mtx_lock); + MUTEX_SPINBIT_LOCK_UNLOCK(mtx); #endif MUTEX_SPIN_SPLRESTORE(mtx); return; } - if (__predict_false(panicstr != NULL) || __predict_false(cold)) { + if (__predict_false((uintptr_t)panicstr | cold)) { MUTEX_UNLOCKED(mtx); MUTEX_RELEASE(mtx); return; @@ -696,6 +736,26 @@ mutex_vector_exit(kmutex_t *mtx) MUTEX_DASSERT(mtx, curthread != 0); MUTEX_ASSERT(mtx, MUTEX_OWNER(mtx->mtx_owner) == curthread); MUTEX_UNLOCKED(mtx); +#if !defined(LOCKDEBUG) + __USE(curthread); +#endif + +#ifdef LOCKDEBUG + /* + * Avoid having to take the turnstile chain lock every time + * around. Raise the priority level to splhigh() in order + * to disable preemption and so make the following atomic. + */ + { + int s = splhigh(); + if (!MUTEX_HAS_WAITERS(mtx)) { + MUTEX_RELEASE(mtx); + splx(s); + return; + } + splx(s); + } +#endif /* * Get this lock's turnstile. This gets the interlock on @@ -748,10 +808,12 @@ int mutex_owned(kmutex_t *mtx) { + if (mtx == NULL) + return 0; if (MUTEX_ADAPTIVE_P(mtx)) return MUTEX_OWNER(mtx->mtx_owner) == (uintptr_t)curlwp; #ifdef FULL - return mtx->mtx_lock == __SIMPLELOCK_LOCKED; + return MUTEX_SPINBIT_LOCKED_P(mtx); #else return 1; #endif @@ -760,9 +822,10 @@ mutex_owned(kmutex_t *mtx) /* * mutex_owner: * - * Return the current owner of an adaptive mutex. + * Return the current owner of an adaptive mutex. Used for + * priority inheritance. */ -struct lwp * +lwp_t * mutex_owner(kmutex_t *mtx) { @@ -770,12 +833,21 @@ mutex_owner(kmutex_t *mtx) return (struct lwp *)MUTEX_OWNER(mtx->mtx_owner); } -static struct lwp * -mutex_getowner(wchan_t obj) +/* + * mutex_ownable: + * + * When compiled with DEBUG and LOCKDEBUG defined, ensure that + * the mutex is available. We cannot use !mutex_owned() since + * that won't work correctly for spin mutexes. + */ +int +mutex_ownable(kmutex_t *mtx) { - kmutex_t *mtx = (void *)(uintptr_t)obj; /* discard qualifiers */ - return mutex_owner(mtx); +#ifdef LOCKDEBUG + MUTEX_TESTLOCK(mtx); +#endif + return 1; } /* @@ -794,7 +866,7 @@ mutex_tryenter(kmutex_t *mtx) if (MUTEX_SPIN_P(mtx)) { MUTEX_SPIN_SPLRAISE(mtx); #ifdef FULL - if (__cpu_simple_lock_try(&mtx->mtx_lock)) { + if (MUTEX_SPINBIT_LOCK_TRY(mtx)) { MUTEX_WANTLOCK(mtx); MUTEX_LOCKED(mtx); return 1; @@ -851,14 +923,14 @@ mutex_spin_retry(kmutex_t *mtx) do { if (panicstr != NULL) break; - while (mtx->mtx_lock == __SIMPLELOCK_LOCKED) { - SPINLOCK_BACKOFF(count); + while (MUTEX_SPINBIT_LOCKED_P(mtx)) { + SPINLOCK_BACKOFF(count); #ifdef LOCKDEBUG if (SPINLOCK_SPINOUT(spins)) MUTEX_ABORT(mtx, "spinout"); #endif /* LOCKDEBUG */ } - } while (!__cpu_simple_lock_try(&mtx->mtx_lock)); + } while (!MUTEX_SPINBIT_LOCK_TRY(mtx)); LOCKSTAT_STOP_TIMER(lsflag, spintime); LOCKSTAT_EVENT(lsflag, mtx, LB_SPIN_MUTEX | LB_SPIN, 1, spintime); @@ -870,47 +942,3 @@ mutex_spin_retry(kmutex_t *mtx) #endif /* MULTIPROCESSOR */ } #endif /* defined(__HAVE_SPIN_MUTEX_STUBS) || defined(FULL) */ - -/* - * sched_lock_idle: - * - * XXX Ugly hack for cpu_switch(). - */ -void -sched_lock_idle(void) -{ -#ifdef FULL - kmutex_t *mtx = &sched_mutex; - - curcpu()->ci_mtx_count--; - - if (!__cpu_simple_lock_try(&mtx->mtx_lock)) { - mutex_spin_retry(mtx); - return; - } - - MUTEX_LOCKED(mtx); -#else - curcpu()->ci_mtx_count--; -#endif /* FULL */ -} - -/* - * sched_unlock_idle: - * - * XXX Ugly hack for cpu_switch(). - */ -void -sched_unlock_idle(void) -{ -#ifdef FULL - kmutex_t *mtx = &sched_mutex; - - if (mtx->mtx_lock != __SIMPLELOCK_LOCKED) - MUTEX_ABORT(mtx, "sched_unlock_idle"); - - MUTEX_UNLOCKED(mtx); - __cpu_simple_unlock(&mtx->mtx_lock); -#endif /* FULL */ - curcpu()->ci_mtx_count++; -}