diff options
Diffstat (limited to 'src/os_posix/os_mtx_cond.c')
| -rw-r--r-- | src/os_posix/os_mtx_cond.c | 28 |
1 files changed, 22 insertions, 6 deletions
diff --git a/src/os_posix/os_mtx_cond.c b/src/os_posix/os_mtx_cond.c index be8b1abda31..a5ee78f9e3e 100644 --- a/src/os_posix/os_mtx_cond.c +++ b/src/os_posix/os_mtx_cond.c @@ -13,8 +13,7 @@ * Allocate and initialize a condition variable. */ int -__wt_cond_alloc(WT_SESSION_IMPL *session, - const char *name, bool is_signalled, WT_CONDVAR **condp) +__wt_cond_alloc(WT_SESSION_IMPL *session, const char *name, WT_CONDVAR **condp) { WT_CONDVAR *cond; WT_DECL_RET; @@ -27,7 +26,7 @@ __wt_cond_alloc(WT_SESSION_IMPL *session, WT_ERR(pthread_cond_init(&cond->cond, NULL)); cond->name = name; - cond->waiters = is_signalled ? -1 : 0; + cond->waiters = 0; *condp = cond; return (0); @@ -42,8 +41,8 @@ err: __wt_free(session, cond); * out period expires, let the caller know. */ void -__wt_cond_wait_signal( - WT_SESSION_IMPL *session, WT_CONDVAR *cond, uint64_t usecs, bool *signalled) +__wt_cond_wait_signal(WT_SESSION_IMPL *session, WT_CONDVAR *cond, + uint64_t usecs, bool (*run_func)(WT_SESSION_IMPL *), bool *signalled) { struct timespec ts; WT_DECL_RET; @@ -62,6 +61,23 @@ __wt_cond_wait_signal( WT_ERR(pthread_mutex_lock(&cond->mtx)); locked = true; + /* + * It's possible to race with threads waking us up. That's not a problem + * if there are multiple wakeups because the next wakeup will get us, or + * if we're only pausing for a short period. It's a problem if there's + * only a single wakeup, our waker is likely waiting for us to exit. + * After acquiring the mutex (so we're guaranteed to be awakened by any + * future wakeup call), optionally check if we're OK to keep running. + * This won't ensure our caller won't just loop and call us again, but + * at least it's not our fault. + * + * Assert we're not waiting longer than a second if not checking the + * run status. + */ + WT_ASSERT(session, run_func != NULL || usecs <= WT_MILLION); + if (run_func != NULL && !run_func(session)) + goto skipping; + if (usecs > 0) { __wt_epoch(session, &ts); ts.tv_sec += (time_t) @@ -81,7 +97,7 @@ __wt_cond_wait_signal( ret == ETIME || #endif ret == ETIMEDOUT) { - *signalled = false; +skipping: *signalled = false; ret = 0; } |