Date: Fri, 16 Mar 2012 04:35:52 +0000 (UTC) From: David Xu <davidxu@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r233022 - head/lib/libthr/thread Message-ID: <201203160435.q2G4ZqhX099496@svn.freebsd.org>
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Author: davidxu Date: Fri Mar 16 04:35:52 2012 New Revision: 233022 URL: http://svn.freebsd.org/changeset/base/233022 Log: When destroying a barrier, waiting all threads exit the barrier, this makes it possible a thread received PTHREAD_BARRIER_SERIAL_THREAD immediately free memory area of the barrier. Modified: head/lib/libthr/thread/thr_barrier.c head/lib/libthr/thread/thr_private.h Modified: head/lib/libthr/thread/thr_barrier.c ============================================================================== --- head/lib/libthr/thread/thr_barrier.c Fri Mar 16 03:22:37 2012 (r233021) +++ head/lib/libthr/thread/thr_barrier.c Fri Mar 16 04:35:52 2012 (r233022) @@ -42,13 +42,34 @@ int _pthread_barrier_destroy(pthread_barrier_t *barrier) { pthread_barrier_t bar; + struct pthread *curthread; if (barrier == NULL || *barrier == NULL) return (EINVAL); + curthread = _get_curthread(); bar = *barrier; - if (bar->b_waiters > 0) + THR_UMUTEX_LOCK(curthread, &bar->b_lock); + if (bar->b_destroying) { + THR_UMUTEX_UNLOCK(curthread, &bar->b_lock); return (EBUSY); + } + bar->b_destroying = 1; + do { + if (bar->b_waiters > 0) { + bar->b_destroying = 0; + THR_UMUTEX_UNLOCK(curthread, &bar->b_lock); + return (EBUSY); + } + if (bar->b_refcount != 0) { + _thr_ucond_wait(&bar->b_cv, &bar->b_lock, NULL, 0); + THR_UMUTEX_LOCK(curthread, &bar->b_lock); + } else + break; + } while (1); + bar->b_destroying = 0; + THR_UMUTEX_UNLOCK(curthread, &bar->b_lock); + *barrier = NULL; free(bar); return (0); @@ -74,6 +95,7 @@ _pthread_barrier_init(pthread_barrier_t bar->b_cycle = 0; bar->b_waiters = 0; bar->b_count = count; + bar->b_refcount = 0; *barrier = bar; return (0); @@ -101,11 +123,14 @@ _pthread_barrier_wait(pthread_barrier_t ret = PTHREAD_BARRIER_SERIAL_THREAD; } else { cycle = bar->b_cycle; + bar->b_refcount++; do { _thr_ucond_wait(&bar->b_cv, &bar->b_lock, NULL, 0); THR_UMUTEX_LOCK(curthread, &bar->b_lock); /* test cycle to avoid bogus wakeup */ } while (cycle == bar->b_cycle); + if (--bar->b_refcount == 0 && bar->b_destroying) + _thr_ucond_broadcast(&bar->b_cv); THR_UMUTEX_UNLOCK(curthread, &bar->b_lock); ret = 0; } Modified: head/lib/libthr/thread/thr_private.h ============================================================================== --- head/lib/libthr/thread/thr_private.h Fri Mar 16 03:22:37 2012 (r233021) +++ head/lib/libthr/thread/thr_private.h Fri Mar 16 04:35:52 2012 (r233022) @@ -182,9 +182,11 @@ struct pthread_cond_attr { struct pthread_barrier { struct umutex b_lock; struct ucond b_cv; - volatile int64_t b_cycle; - volatile int b_count; - volatile int b_waiters; + int64_t b_cycle; + int b_count; + int b_waiters; + int b_refcount; + int b_destroying; }; struct pthread_barrierattr {
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