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ITS#5364, reduce work with ltp_mutex locked:

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Negate ltp_open_count when paused, avoids an ltp_pause test in pool_submit().
This commit is contained in:
Hallvard Furuseth 2008-02-10 18:16:44 +00:00
parent 8afd0b05c1
commit 650aaee3a5
1 changed files with 21 additions and 9 deletions
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30
libraries/libldap_r/tpool.c
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@ -112,6 +112,8 @@ struct ldap_int_thread_pool_s {
/* Some active task needs to be the sole active task.
* Atomic variable so ldap_pvt_thread_pool_pausing() can read it.
* Note: Pauses adjust ltp_<open_count/vary_open_count/work_list>,
* so pool_<submit/wrapper>() mostly can avoid testing ltp_pause.
*/
volatile sig_atomic_t ltp_pause;
@ -123,7 +125,7 @@ struct ldap_int_thread_pool_s {
int ltp_pending_count; /* Pending or paused requests */
int ltp_active_count; /* Active, not paused requests */
int ltp_open_count; /* Number of threads */
int ltp_open_count; /* Number of threads, negated when ltp_pause */
int ltp_starting; /* Currenlty starting threads */
/*
@ -310,14 +312,14 @@ ldap_pvt_thread_pool_submit (
pool->ltp_pending_count++;
LDAP_STAILQ_INSERT_TAIL(&pool->ltp_pending_list, task, ltt_next.q);
if (pool->ltp_pause) {
ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
return(0);
}
ldap_pvt_thread_cond_signal(&pool->ltp_cond);
/* true if ltp_pause != 0 or we should open (create) a thread */
if (pool->ltp_vary_open_count > 0 &&
pool->ltp_open_count < pool->ltp_active_count+pool->ltp_pending_count)
{
if (pool->ltp_pause)
goto done;
pool->ltp_starting++;
pool->ltp_open_count++;
SET_VARY_OPEN_COUNT(pool);
@ -357,12 +359,12 @@ ldap_pvt_thread_pool_submit (
}
/* there is another open thread, so this
* task will be handled eventually.
* continue on, we have signalled that
* the task is waiting.
*/
}
}
ldap_pvt_thread_cond_signal(&pool->ltp_cond);
done:
ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
return(0);
@ -435,6 +437,8 @@ ldap_pvt_thread_pool_query(
case LDAP_PVT_THREAD_POOL_PARAM_OPEN:
count = pool->ltp_open_count;
if (count < 0)
count = -count;
break;
case LDAP_PVT_THREAD_POOL_PARAM_STARTING:
@ -671,6 +675,8 @@ ldap_int_thread_pool_wrapper (
ldap_pvt_thread_cond_signal(&pool->ltp_pcond);
}
assert(!pool->ltp_pause); /* thread_keys writable, ltp_open_count >= 0 */
/* The ltp_mutex lock protects ctx->ltu_key from pool_purgekey()
* during this call, since it prevents new pauses. */
ldap_pvt_thread_pool_context_reset(&ctx);
@ -682,7 +688,7 @@ ldap_int_thread_pool_wrapper (
pool->ltp_open_count--;
SET_VARY_OPEN_COUNT(pool);
/* let pool_destroy know we're all done */
if (pool->ltp_open_count < 1)
if (pool->ltp_open_count == 0)
ldap_pvt_thread_cond_signal(&pool->ltp_cond);
ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
@ -724,6 +730,9 @@ ldap_pvt_thread_pool_pause (
/* Wait for everyone else to pause or finish */
pool->ltp_pause = 1;
/* Let ldap_pvt_thread_pool_submit() through to its ltp_pause test,
* and do not finish threads in ldap_pvt_thread_pool_wrapper() */
pool->ltp_open_count = -pool->ltp_open_count;
SET_VARY_OPEN_COUNT(pool);
/* Hide pending tasks from ldap_pvt_thread_pool_wrapper() */
pool->ltp_work_list = &empty_pending_list;
@ -753,7 +762,10 @@ ldap_pvt_thread_pool_resume (
ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
assert(pool->ltp_pause);
pool->ltp_pause = 0;
if (pool->ltp_open_count <= 0) /* true when paused, but be paranoid */
pool->ltp_open_count = -pool->ltp_open_count;
SET_VARY_OPEN_COUNT(pool);
pool->ltp_work_list = &pool->ltp_pending_list;