Revert revision 214007, I realized that MySQL wants to resolve
a silly rwlock deadlock problem, the deadlock is caused by writer waiters, if a thread has already locked a reader lock, and wants to acquire another reader lock, it will be blocked by writer waiters, but we had already fixed it years ago.
This commit is contained in:
parent
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commit
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Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=214093
@ -177,10 +177,8 @@
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#define pthread_rwlock_unlock _pthread_rwlock_unlock
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#define pthread_rwlock_wrlock _pthread_rwlock_wrlock
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#define pthread_rwlockattr_destroy _pthread_rwlockattr_destroy
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#define pthread_rwlockattr_getkind_np _pthread_rwlockattr_getkind_np
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#define pthread_rwlockattr_getpshared _pthread_rwlockattr_getpshared
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#define pthread_rwlockattr_init _pthread_rwlockattr_init
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#define pthread_rwlockattr_setkind_np _pthread_rwlockattr_setkind_np
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#define pthread_rwlockattr_setpshared _pthread_rwlockattr_setpshared
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#define pthread_self _pthread_self
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#define pthread_set_name_np _pthread_set_name_np
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@ -158,10 +158,8 @@
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#undef pthread_rwlock_unlock
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#undef pthread_rwlock_wrlock
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#undef pthread_rwlockattr_destroy
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#undef pthread_rwlockattr_getkind_np
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#undef pthread_rwlockattr_getpshared
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#undef pthread_rwlockattr_init
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#undef pthread_rwlockattr_setkind_np
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#undef pthread_rwlockattr_setpshared
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#undef pthread_self
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#undef pthread_set_name_np
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@ -318,9 +318,7 @@ FBSDprivate_1.0 {
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_pthread_rwlock_wrlock;
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_pthread_rwlockattr_destroy;
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_pthread_rwlockattr_getpshared;
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_pthread_rwlockattr_getkind_np;
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_pthread_rwlockattr_init;
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_pthread_rwlockattr_setkind_np;
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_pthread_rwlockattr_setpshared;
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_pthread_self;
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_pthread_set_name_np;
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@ -403,8 +401,6 @@ FBSD_1.1 {
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FBSD_1.2 {
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openat;
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pthread_rwlockattr_getkind_np;
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pthread_rwlockattr_setkind_np;
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setcontext;
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swapcontext;
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};
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@ -285,14 +285,11 @@ struct pthread_prio {
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struct pthread_rwlockattr {
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int pshared;
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int kind;
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};
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struct pthread_rwlock {
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struct urwlock lock;
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struct pthread *owner;
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int recurse;
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int kind;
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};
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/*
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@ -63,19 +63,13 @@ __weak_reference(_pthread_rwlock_timedwrlock, pthread_rwlock_timedwrlock);
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*/
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static int
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rwlock_init(pthread_rwlock_t *rwlock, const pthread_rwlockattr_t *attr)
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rwlock_init(pthread_rwlock_t *rwlock, const pthread_rwlockattr_t *attr __unused)
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{
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pthread_rwlock_t prwlock;
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prwlock = (pthread_rwlock_t)calloc(1, sizeof(struct pthread_rwlock));
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if (prwlock == NULL)
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return (ENOMEM);
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if (attr != NULL)
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prwlock->kind = (*attr)->kind;
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else
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prwlock->kind = PTHREAD_RWLOCK_DEFAULT_NP;
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if (prwlock->kind == PTHREAD_RWLOCK_PREFER_READER_NP)
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prwlock->lock.rw_flags |= URWLOCK_PREFER_READER;
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*rwlock = prwlock;
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return (0);
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}
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@ -118,7 +112,7 @@ init_static(struct pthread *thread, pthread_rwlock_t *rwlock)
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}
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int
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_pthread_rwlock_init(pthread_rwlock_t *rwlock, const pthread_rwlockattr_t *attr)
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_pthread_rwlock_init (pthread_rwlock_t *rwlock, const pthread_rwlockattr_t *attr)
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{
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*rwlock = NULL;
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return (rwlock_init(rwlock, attr));
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@ -266,14 +260,6 @@ rwlock_wrlock_common (pthread_rwlock_t *rwlock, const struct timespec *abstime)
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CHECK_AND_INIT_RWLOCK
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if (__predict_false(prwlock->owner == curthread)) {
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if (__predict_false(
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prwlock->kind == PTHREAD_RWLOCK_PREFER_WRITER_NP)) {
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prwlock->recurse++;
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return (0);
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}
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}
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/*
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* POSIX said the validity of the abstimeout parameter need
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* not be checked if the lock can be immediately acquired.
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@ -349,13 +335,6 @@ _pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
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if (state & URWLOCK_WRITE_OWNER) {
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if (__predict_false(prwlock->owner != curthread))
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return (EPERM);
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if (__predict_false(
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prwlock->kind == PTHREAD_RWLOCK_PREFER_WRITER_NP)) {
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if (prwlock->recurse > 0) {
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prwlock->recurse--;
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return (0);
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}
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}
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prwlock->owner = NULL;
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}
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@ -36,10 +36,8 @@
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__weak_reference(_pthread_rwlockattr_destroy, pthread_rwlockattr_destroy);
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__weak_reference(_pthread_rwlockattr_getpshared, pthread_rwlockattr_getpshared);
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__weak_reference(_pthread_rwlockattr_getkind_np, pthread_rwlockattr_getkind_np);
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__weak_reference(_pthread_rwlockattr_init, pthread_rwlockattr_init);
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__weak_reference(_pthread_rwlockattr_setpshared, pthread_rwlockattr_setpshared);
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__weak_reference(_pthread_rwlockattr_setkind_np, pthread_rwlockattr_setkind_np);
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int
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_pthread_rwlockattr_destroy(pthread_rwlockattr_t *rwlockattr)
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@ -83,7 +81,6 @@ _pthread_rwlockattr_init(pthread_rwlockattr_t *rwlockattr)
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return(ENOMEM);
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prwlockattr->pshared = PTHREAD_PROCESS_PRIVATE;
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prwlockattr->kind = PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP;
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*rwlockattr = prwlockattr;
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return(0);
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@ -100,22 +97,3 @@ _pthread_rwlockattr_setpshared(pthread_rwlockattr_t *rwlockattr, int pshared)
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return(0);
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}
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int
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_pthread_rwlockattr_setkind_np(pthread_rwlockattr_t *attr, int kind)
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{
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if (kind != PTHREAD_RWLOCK_PREFER_READER_NP &&
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kind != PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP &&
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kind != PTHREAD_RWLOCK_PREFER_WRITER_NP) {
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return (EINVAL);
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}
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(*attr)->kind = kind;
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return (0);
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}
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int
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_pthread_rwlockattr_getkind_np(const pthread_rwlockattr_t *attr, int *kind)
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{
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*kind = (*attr)->kind;
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return (0);
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}
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