diff options
Diffstat (limited to 'src/zone.c')
| -rw-r--r-- | src/zone.c | 30 |
1 files changed, 24 insertions, 6 deletions
@@ -89,6 +89,7 @@ JEMALLOC_ATTR(weak_import); static malloc_zone_t *default_zone, *purgeable_zone; static malloc_zone_t jemalloc_zone; static struct malloc_introspection_t jemalloc_zone_introspect; +static pid_t zone_force_lock_pid = -1; /******************************************************************************/ /* Function prototypes for non-inline static functions. */ @@ -270,6 +271,12 @@ zone_log(malloc_zone_t *zone, void *address) { static void zone_force_lock(malloc_zone_t *zone) { if (isthreaded) { + /* + * See the note in zone_force_unlock, below, to see why we need + * this. + */ + assert(zone_force_lock_pid == -1); + zone_force_lock_pid = getpid(); jemalloc_prefork(); } } @@ -277,14 +284,25 @@ zone_force_lock(malloc_zone_t *zone) { static void zone_force_unlock(malloc_zone_t *zone) { /* - * Call jemalloc_postfork_child() rather than - * jemalloc_postfork_parent(), because this function is executed by both - * parent and child. The parent can tolerate having state - * reinitialized, but the child cannot unlock mutexes that were locked - * by the parent. + * zone_force_lock and zone_force_unlock are the entry points to the + * forking machinery on OS X. The tricky thing is, the child is not + * allowed to unlock mutexes locked in the parent, even if owned by the + * forking thread (and the mutex type we use in OS X will fail an assert + * if we try). In the child, we can get away with reinitializing all + * the mutexes, which has the effect of unlocking them. In the parent, + * doing this would mean we wouldn't wake any waiters blocked on the + * mutexes we unlock. So, we record the pid of the current thread in + * zone_force_lock, and use that to detect if we're in the parent or + * child here, to decide which unlock logic we need. */ if (isthreaded) { - jemalloc_postfork_child(); + assert(zone_force_lock_pid != -1); + if (getpid() == zone_force_lock_pid) { + jemalloc_postfork_parent(); + } else { + jemalloc_postfork_child(); + } + zone_force_lock_pid = -1; } } |