From 4bcffe41e193bfa03f54f77e2158b3d989a001d0 Mon Sep 17 00:00:00 2001 From: Rickard Green Date: Mon, 27 Feb 2012 18:45:47 +0100 Subject: Optimize process state changes --- erts/emulator/beam/erl_alloc_util.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) (limited to 'erts/emulator/beam/erl_alloc_util.c') diff --git a/erts/emulator/beam/erl_alloc_util.c b/erts/emulator/beam/erl_alloc_util.c index e0d525bdde..62225d3572 100644 --- a/erts/emulator/beam/erl_alloc_util.c +++ b/erts/emulator/beam/erl_alloc_util.c @@ -832,14 +832,14 @@ init_dd_queue(ErtsAllctrDDQueue_t *ddq) static ERTS_INLINE erts_aint_t ddq_managed_thread_enqueue(ErtsAllctrDDQueue_t *ddq, void *ptr) { - erts_aint_t ilast, itmp; + erts_aint_t first_ilast, ilast, itmp; ErtsAllctrDDBlock_t *this = ptr; erts_atomic_init_nob(&this->atmc_next, ERTS_AINT_NULL); /* Enqueue at end of list... */ - ilast = erts_atomic_read_nob(&ddq->tail.data.last); + first_ilast = ilast = erts_atomic_read_nob(&ddq->tail.data.last); while (1) { ErtsAllctrDDBlock_t *last = (ErtsAllctrDDBlock_t *) ilast; itmp = erts_atomic_cmpxchg_mb(&last->atmc_next, @@ -853,8 +853,11 @@ ddq_managed_thread_enqueue(ErtsAllctrDDQueue_t *ddq, void *ptr) /* Move last pointer forward... */ while (1) { if (erts_atomic_read_rb(&this->atmc_next) != ERTS_AINT_NULL) { - /* Someone else will move it forward */ - return erts_atomic_read_rb(&ddq->tail.data.last); + ilast = erts_atomic_read_rb(&ddq->tail.data.last); + if (first_ilast != ilast) { + /* Someone else will move it forward */ + return ilast; + } } itmp = erts_atomic_cmpxchg_mb(&ddq->tail.data.last, (erts_aint_t) this, -- cgit v1.2.3