Fallback to 32-bit when 8-bit atomics are missing for TSD.

When it happens, this might cause a slowdown on the fast path operations.
However such case is very rare.
This commit is contained in:
Qi Wang
2019-03-07 16:01:55 -08:00
committed by Qi Wang
parent 06f0850427
commit b804d0f019
2 changed files with 24 additions and 8 deletions

View File

@@ -113,9 +113,9 @@ tsd_force_recompute(tsdn_t *tsdn) {
malloc_mutex_lock(tsdn, &tsd_nominal_tsds_lock);
tsd_t *remote_tsd;
ql_foreach(remote_tsd, &tsd_nominal_tsds, TSD_MANGLE(tcache).tsd_link) {
assert(atomic_load_u8(&remote_tsd->state, ATOMIC_RELAXED)
assert(tsd_atomic_load(&remote_tsd->state, ATOMIC_RELAXED)
<= tsd_state_nominal_max);
atomic_store_u8(&remote_tsd->state, tsd_state_nominal_recompute,
tsd_atomic_store(&remote_tsd->state, tsd_state_nominal_recompute,
ATOMIC_RELAXED);
}
malloc_mutex_unlock(tsdn, &tsd_nominal_tsds_lock);
@@ -172,7 +172,7 @@ tsd_slow_update(tsd_t *tsd) {
uint8_t old_state;
do {
uint8_t new_state = tsd_state_compute(tsd);
old_state = atomic_exchange_u8(&tsd->state, new_state,
old_state = tsd_atomic_exchange(&tsd->state, new_state,
ATOMIC_ACQUIRE);
} while (old_state == tsd_state_nominal_recompute);
}
@@ -181,14 +181,14 @@ void
tsd_state_set(tsd_t *tsd, uint8_t new_state) {
/* Only the tsd module can change the state *to* recompute. */
assert(new_state != tsd_state_nominal_recompute);
uint8_t old_state = atomic_load_u8(&tsd->state, ATOMIC_RELAXED);
uint8_t old_state = tsd_atomic_load(&tsd->state, ATOMIC_RELAXED);
if (old_state > tsd_state_nominal_max) {
/*
* Not currently in the nominal list, but it might need to be
* inserted there.
*/
assert(!tsd_in_nominal_list(tsd));
atomic_store_u8(&tsd->state, new_state, ATOMIC_RELAXED);
tsd_atomic_store(&tsd->state, new_state, ATOMIC_RELAXED);
if (new_state <= tsd_state_nominal_max) {
tsd_add_nominal(tsd);
}
@@ -201,7 +201,8 @@ tsd_state_set(tsd_t *tsd, uint8_t new_state) {
assert(tsd_in_nominal_list(tsd));
if (new_state > tsd_state_nominal_max) {
tsd_remove_nominal(tsd);
atomic_store_u8(&tsd->state, new_state, ATOMIC_RELAXED);
tsd_atomic_store(&tsd->state, new_state,
ATOMIC_RELAXED);
} else {
/*
* This is the tricky case. We're transitioning from