diff options
Diffstat (limited to 'libpthread/nptl/pthread_mutex_lock.c')
| -rw-r--r-- | libpthread/nptl/pthread_mutex_lock.c | 436 |
1 files changed, 406 insertions, 30 deletions
diff --git a/libpthread/nptl/pthread_mutex_lock.c b/libpthread/nptl/pthread_mutex_lock.c index faa5391dd..47e4d4158 100644 --- a/libpthread/nptl/pthread_mutex_lock.c +++ b/libpthread/nptl/pthread_mutex_lock.c @@ -1,4 +1,4 @@ -/* Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc. +/* Copyright (C) 2002-2007, 2008, 2009 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. @@ -19,27 +19,52 @@ #include <assert.h> #include <errno.h> +#include <stdlib.h> +#include <unistd.h> +#include <not-cancel.h> #include "pthreadP.h" #include <lowlevellock.h> #ifndef LLL_MUTEX_LOCK -# define LLL_MUTEX_LOCK(mutex) lll_mutex_lock (mutex) -# define LLL_MUTEX_TRYLOCK(mutex) lll_mutex_trylock (mutex) +# define LLL_MUTEX_LOCK(mutex) \ + lll_lock ((mutex)->__data.__lock, PTHREAD_MUTEX_PSHARED (mutex)) +# define LLL_MUTEX_TRYLOCK(mutex) \ + lll_trylock ((mutex)->__data.__lock) +# define LLL_ROBUST_MUTEX_LOCK(mutex, id) \ + lll_robust_lock ((mutex)->__data.__lock, id, \ + PTHREAD_ROBUST_MUTEX_PSHARED (mutex)) #endif +static int __pthread_mutex_lock_full (pthread_mutex_t *mutex) + __attribute_noinline__; + + int -__pthread_mutex_lock (pthread_mutex_t *mutex) +__pthread_mutex_lock ( + pthread_mutex_t *mutex) { assert (sizeof (mutex->__size) >= sizeof (mutex->__data)); + unsigned int type = PTHREAD_MUTEX_TYPE (mutex); + if (__builtin_expect (type & ~PTHREAD_MUTEX_KIND_MASK_NP, 0)) + return __pthread_mutex_lock_full (mutex); + pid_t id = THREAD_GETMEM (THREAD_SELF, tid); - switch (__builtin_expect (mutex->__data.__kind, PTHREAD_MUTEX_TIMED_NP)) + if (__builtin_expect (type, PTHREAD_MUTEX_TIMED_NP) + == PTHREAD_MUTEX_TIMED_NP) + { + simple: + /* Normal mutex. */ + LLL_MUTEX_LOCK (mutex); + assert (mutex->__data.__owner == 0); + } + else if (__builtin_expect (type == PTHREAD_MUTEX_RECURSIVE_NP, 1)) { /* Recursive mutex. */ - case PTHREAD_MUTEX_RECURSIVE_NP: + /* Check whether we already hold the mutex. */ if (mutex->__data.__owner == id) { @@ -54,32 +79,17 @@ __pthread_mutex_lock (pthread_mutex_t *mutex) } /* We have to get the mutex. */ - LLL_MUTEX_LOCK (mutex->__data.__lock); + LLL_MUTEX_LOCK (mutex); + assert (mutex->__data.__owner == 0); mutex->__data.__count = 1; - break; - - /* Error checking mutex. */ - case PTHREAD_MUTEX_ERRORCHECK_NP: - /* Check whether we already hold the mutex. */ - if (mutex->__data.__owner == id) - return EDEADLK; - - /* FALLTHROUGH */ - - default: - /* Correct code cannot set any other type. */ - case PTHREAD_MUTEX_TIMED_NP: - simple: - /* Normal mutex. */ - LLL_MUTEX_LOCK (mutex->__data.__lock); - break; - - case PTHREAD_MUTEX_ADAPTIVE_NP: + } + else if (__builtin_expect (type == PTHREAD_MUTEX_ADAPTIVE_NP, 1)) + { if (! __is_smp) goto simple; - if (LLL_MUTEX_TRYLOCK (mutex->__data.__lock) != 0) + if (LLL_MUTEX_TRYLOCK (mutex) != 0) { int cnt = 0; int max_cnt = MIN (MAX_ADAPTIVE_COUNT, @@ -88,7 +98,7 @@ __pthread_mutex_lock (pthread_mutex_t *mutex) { if (cnt++ >= max_cnt) { - LLL_MUTEX_LOCK (mutex->__data.__lock); + LLL_MUTEX_LOCK (mutex); break; } @@ -96,15 +106,362 @@ __pthread_mutex_lock (pthread_mutex_t *mutex) BUSY_WAIT_NOP; #endif } - while (LLL_MUTEX_TRYLOCK (mutex->__data.__lock) != 0); + while (LLL_MUTEX_TRYLOCK (mutex) != 0); mutex->__data.__spins += (cnt - mutex->__data.__spins) / 8; } + assert (mutex->__data.__owner == 0); + } + else + { + assert (type == PTHREAD_MUTEX_ERRORCHECK_NP); + /* Check whether we already hold the mutex. */ + if (__builtin_expect (mutex->__data.__owner == id, 0)) + return EDEADLK; + goto simple; + } + + /* Record the ownership. */ + mutex->__data.__owner = id; +#ifndef NO_INCR + ++mutex->__data.__nusers; +#endif + + return 0; +} + +static int +__pthread_mutex_lock_full (pthread_mutex_t *mutex) +{ + int oldval; + pid_t id = THREAD_GETMEM (THREAD_SELF, tid); + + switch (PTHREAD_MUTEX_TYPE (mutex)) + { + case PTHREAD_MUTEX_ROBUST_RECURSIVE_NP: + case PTHREAD_MUTEX_ROBUST_ERRORCHECK_NP: + case PTHREAD_MUTEX_ROBUST_NORMAL_NP: + case PTHREAD_MUTEX_ROBUST_ADAPTIVE_NP: + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, + &mutex->__data.__list.__next); + + oldval = mutex->__data.__lock; + do + { + again: + if ((oldval & FUTEX_OWNER_DIED) != 0) + { + /* The previous owner died. Try locking the mutex. */ + int newval = id; +#ifdef NO_INCR + newval |= FUTEX_WAITERS; +#else + newval |= (oldval & FUTEX_WAITERS); +#endif + + newval + = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, + newval, oldval); + + if (newval != oldval) + { + oldval = newval; + goto again; + } + + /* We got the mutex. */ + mutex->__data.__count = 1; + /* But it is inconsistent unless marked otherwise. */ + mutex->__data.__owner = PTHREAD_MUTEX_INCONSISTENT; + + ENQUEUE_MUTEX (mutex); + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); + + /* Note that we deliberately exit here. If we fall + through to the end of the function __nusers would be + incremented which is not correct because the old + owner has to be discounted. If we are not supposed + to increment __nusers we actually have to decrement + it here. */ +#ifdef NO_INCR + --mutex->__data.__nusers; +#endif + + return EOWNERDEAD; + } + + /* Check whether we already hold the mutex. */ + if (__builtin_expect ((oldval & FUTEX_TID_MASK) == id, 0)) + { + int kind = PTHREAD_MUTEX_TYPE (mutex); + if (kind == PTHREAD_MUTEX_ROBUST_ERRORCHECK_NP) + { + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, + NULL); + return EDEADLK; + } + + if (kind == PTHREAD_MUTEX_ROBUST_RECURSIVE_NP) + { + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, + NULL); + + /* Just bump the counter. */ + if (__builtin_expect (mutex->__data.__count + 1 == 0, 0)) + /* Overflow of the counter. */ + return EAGAIN; + + ++mutex->__data.__count; + + return 0; + } + } + + oldval = LLL_ROBUST_MUTEX_LOCK (mutex, id); + + if (__builtin_expect (mutex->__data.__owner + == PTHREAD_MUTEX_NOTRECOVERABLE, 0)) + { + /* This mutex is now not recoverable. */ + mutex->__data.__count = 0; + lll_unlock (mutex->__data.__lock, + PTHREAD_ROBUST_MUTEX_PSHARED (mutex)); + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); + return ENOTRECOVERABLE; + } + } + while ((oldval & FUTEX_OWNER_DIED) != 0); + + mutex->__data.__count = 1; + ENQUEUE_MUTEX (mutex); + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); + break; + + case PTHREAD_MUTEX_PI_RECURSIVE_NP: + case PTHREAD_MUTEX_PI_ERRORCHECK_NP: + case PTHREAD_MUTEX_PI_NORMAL_NP: + case PTHREAD_MUTEX_PI_ADAPTIVE_NP: + case PTHREAD_MUTEX_PI_ROBUST_RECURSIVE_NP: + case PTHREAD_MUTEX_PI_ROBUST_ERRORCHECK_NP: + case PTHREAD_MUTEX_PI_ROBUST_NORMAL_NP: + case PTHREAD_MUTEX_PI_ROBUST_ADAPTIVE_NP: + { + int kind = mutex->__data.__kind & PTHREAD_MUTEX_KIND_MASK_NP; + int robust = mutex->__data.__kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP; + + if (robust) + /* Note: robust PI futexes are signaled by setting bit 0. */ + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, + (void *) (((uintptr_t) &mutex->__data.__list.__next) + | 1)); + + oldval = mutex->__data.__lock; + + /* Check whether we already hold the mutex. */ + if (__builtin_expect ((oldval & FUTEX_TID_MASK) == id, 0)) + { + if (kind == PTHREAD_MUTEX_ERRORCHECK_NP) + { + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); + return EDEADLK; + } + + if (kind == PTHREAD_MUTEX_RECURSIVE_NP) + { + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); + + /* Just bump the counter. */ + if (__builtin_expect (mutex->__data.__count + 1 == 0, 0)) + /* Overflow of the counter. */ + return EAGAIN; + + ++mutex->__data.__count; + + return 0; + } + } + + int newval = id; +#ifdef NO_INCR + newval |= FUTEX_WAITERS; +#endif + oldval = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, + newval, 0); + + if (oldval != 0) + { + /* The mutex is locked. The kernel will now take care of + everything. */ + int private = (robust + ? PTHREAD_ROBUST_MUTEX_PSHARED (mutex) + : PTHREAD_MUTEX_PSHARED (mutex)); + INTERNAL_SYSCALL_DECL (__err); + int e = INTERNAL_SYSCALL (futex, __err, 4, &mutex->__data.__lock, + __lll_private_flag (FUTEX_LOCK_PI, + private), 1, 0); + + if (INTERNAL_SYSCALL_ERROR_P (e, __err) + && (INTERNAL_SYSCALL_ERRNO (e, __err) == ESRCH + || INTERNAL_SYSCALL_ERRNO (e, __err) == EDEADLK)) + { + assert (INTERNAL_SYSCALL_ERRNO (e, __err) != EDEADLK + || (kind != PTHREAD_MUTEX_ERRORCHECK_NP + && kind != PTHREAD_MUTEX_RECURSIVE_NP)); + /* ESRCH can happen only for non-robust PI mutexes where + the owner of the lock died. */ + assert (INTERNAL_SYSCALL_ERRNO (e, __err) != ESRCH || !robust); + + /* Delay the thread indefinitely. */ + while (1) + pause_not_cancel (); + } + + oldval = mutex->__data.__lock; + + assert (robust || (oldval & FUTEX_OWNER_DIED) == 0); + } + + if (__builtin_expect (oldval & FUTEX_OWNER_DIED, 0)) + { + atomic_and (&mutex->__data.__lock, ~FUTEX_OWNER_DIED); + + /* We got the mutex. */ + mutex->__data.__count = 1; + /* But it is inconsistent unless marked otherwise. */ + mutex->__data.__owner = PTHREAD_MUTEX_INCONSISTENT; + + ENQUEUE_MUTEX_PI (mutex); + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); + + /* Note that we deliberately exit here. If we fall + through to the end of the function __nusers would be + incremented which is not correct because the old owner + has to be discounted. If we are not supposed to + increment __nusers we actually have to decrement it here. */ +#ifdef NO_INCR + --mutex->__data.__nusers; +#endif + + return EOWNERDEAD; + } + + if (robust + && __builtin_expect (mutex->__data.__owner + == PTHREAD_MUTEX_NOTRECOVERABLE, 0)) + { + /* This mutex is now not recoverable. */ + mutex->__data.__count = 0; + + INTERNAL_SYSCALL_DECL (__err); + INTERNAL_SYSCALL (futex, __err, 4, &mutex->__data.__lock, + __lll_private_flag (FUTEX_UNLOCK_PI, + PTHREAD_ROBUST_MUTEX_PSHARED (mutex)), + 0, 0); + + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); + return ENOTRECOVERABLE; + } + + mutex->__data.__count = 1; + if (robust) + { + ENQUEUE_MUTEX_PI (mutex); + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); + } + } break; + + case PTHREAD_MUTEX_PP_RECURSIVE_NP: + case PTHREAD_MUTEX_PP_ERRORCHECK_NP: + case PTHREAD_MUTEX_PP_NORMAL_NP: + case PTHREAD_MUTEX_PP_ADAPTIVE_NP: + { + int kind = mutex->__data.__kind & PTHREAD_MUTEX_KIND_MASK_NP; + + oldval = mutex->__data.__lock; + + /* Check whether we already hold the mutex. */ + if (mutex->__data.__owner == id) + { + if (kind == PTHREAD_MUTEX_ERRORCHECK_NP) + return EDEADLK; + + if (kind == PTHREAD_MUTEX_RECURSIVE_NP) + { + /* Just bump the counter. */ + if (__builtin_expect (mutex->__data.__count + 1 == 0, 0)) + /* Overflow of the counter. */ + return EAGAIN; + + ++mutex->__data.__count; + + return 0; + } + } + + int oldprio = -1, ceilval; + do + { + int ceiling = (oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) + >> PTHREAD_MUTEX_PRIO_CEILING_SHIFT; + + if (__pthread_current_priority () > ceiling) + { + if (oldprio != -1) + __pthread_tpp_change_priority (oldprio, -1); + return EINVAL; + } + + int retval = __pthread_tpp_change_priority (oldprio, ceiling); + if (retval) + return retval; + + ceilval = ceiling << PTHREAD_MUTEX_PRIO_CEILING_SHIFT; + oldprio = ceiling; + + oldval + = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, +#ifdef NO_INCR + ceilval | 2, +#else + ceilval | 1, +#endif + ceilval); + + if (oldval == ceilval) + break; + + do + { + oldval + = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, + ceilval | 2, + ceilval | 1); + + if ((oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) != ceilval) + break; + + if (oldval != ceilval) + lll_futex_wait (&mutex->__data.__lock, ceilval | 2, + PTHREAD_MUTEX_PSHARED (mutex)); + } + while (atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, + ceilval | 2, ceilval) + != ceilval); + } + while ((oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) != ceilval); + + assert (mutex->__data.__owner == 0); + mutex->__data.__count = 1; + } + break; + + default: + /* Correct code cannot set any other type. */ + return EINVAL; } /* Record the ownership. */ - assert (mutex->__data.__owner == 0); mutex->__data.__owner = id; #ifndef NO_INCR ++mutex->__data.__nusers; @@ -116,3 +473,22 @@ __pthread_mutex_lock (pthread_mutex_t *mutex) strong_alias (__pthread_mutex_lock, pthread_mutex_lock) strong_alias (__pthread_mutex_lock, __pthread_mutex_lock_internal) #endif + + +#ifdef NO_INCR +void +__pthread_mutex_cond_lock_adjust ( + pthread_mutex_t *mutex) +{ + assert ((mutex->__data.__kind & PTHREAD_MUTEX_PRIO_INHERIT_NP) != 0); + assert ((mutex->__data.__kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP) == 0); + assert ((mutex->__data.__kind & PTHREAD_MUTEX_PSHARED_BIT) == 0); + + /* Record the ownership. */ + pid_t id = THREAD_GETMEM (THREAD_SELF, tid); + mutex->__data.__owner = id; + + if (mutex->__data.__kind == PTHREAD_MUTEX_PI_RECURSIVE_NP) + ++mutex->__data.__count; +} +#endif |