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ITS#5364: maintain value ltp_vary_open_count

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This commit is contained in:
Hallvard Furuseth 2008-02-10 17:38:32 +00:00
parent ee73fca523
commit fe86a1cbe5
1 changed files with 40 additions and 16 deletions
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56
libraries/libldap_r/tpool.c
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@ -107,7 +107,7 @@ struct ldap_int_thread_pool_s {
* rejects new tasks. ltp_max_pending = -(its old value).
*/
int ltp_finishing;
/* Some active task needs to be the sole active task.
* Atomic variable so ldap_pvt_thread_pool_pausing() can read it.
*/
@ -123,6 +123,21 @@ struct ldap_int_thread_pool_s {
int ltp_active_count; /* Active, not paused requests */
int ltp_open_count; /* Number of threads */
int ltp_starting; /* Currenlty starting threads */
/*
* State maintained to reduce the time ltp_mutex must be locked
* in ldap_pvt_thread_pool_<submit/wrapper>().
*/
/* >0 if paused or we may open a thread, <0 if we should close a thread. */
/* Updated when ltp_<finishing/pause/max_count/open_count> change. */
int ltp_vary_open_count;
# define SET_VARY_OPEN_COUNT(pool) \
((pool)->ltp_vary_open_count = \
(pool)->ltp_pause ? 1 : \
(pool)->ltp_finishing ? -1 : \
((pool)->ltp_max_count ? (pool)->ltp_max_count : LDAP_MAXTHR) \
- (pool)->ltp_open_count)
};
static int ldap_int_has_thread_pool = 0;
@ -196,8 +211,11 @@ ldap_pvt_thread_pool_init (
return(rc);
ldap_int_has_thread_pool = 1;
pool->ltp_max_count = max_threads;
SET_VARY_OPEN_COUNT(pool);
pool->ltp_max_pending = max_pending;
LDAP_STAILQ_INIT(&pool->ltp_pending_list);
LDAP_SLIST_INIT(&pool->ltp_free_list);
ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
@ -220,6 +238,7 @@ ldap_pvt_thread_pool_init (
* lock the mutex right now, since no threads are running.
*/
pool->ltp_open_count++;
SET_VARY_OPEN_COUNT(pool);
ldap_pvt_thread_t thr;
rc = ldap_pvt_thread_create( &thr, 1, ldap_int_thread_pool_wrapper, pool );
@ -286,12 +305,13 @@ ldap_pvt_thread_pool_submit (
return(0);
}
ldap_pvt_thread_cond_signal(&pool->ltp_cond);
if (pool->ltp_open_count < pool->ltp_active_count + pool->ltp_pending_count
&& (pool->ltp_open_count <
(pool->ltp_max_count ? pool->ltp_max_count : LDAP_MAXTHR)))
if (pool->ltp_vary_open_count > 0 &&
pool->ltp_open_count < pool->ltp_active_count+pool->ltp_pending_count)
{
pool->ltp_open_count++;
pool->ltp_starting++;
pool->ltp_open_count++;
SET_VARY_OPEN_COUNT(pool);
if (0 != ldap_pvt_thread_create(
&thr, 1, ldap_int_thread_pool_wrapper, pool))
{
@ -300,6 +320,8 @@ ldap_pvt_thread_pool_submit (
*/
pool->ltp_starting--;
pool->ltp_open_count--;
SET_VARY_OPEN_COUNT(pool);
if (pool->ltp_open_count == 0) {
/* no open threads at all?!?
*/
@ -359,7 +381,10 @@ ldap_pvt_thread_pool_maxthreads(
return(-1);
ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
pool->ltp_max_count = max_threads;
SET_VARY_OPEN_COUNT(pool);
ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
return(0);
}
@ -432,7 +457,7 @@ ldap_pvt_thread_pool_query(
break;
case LDAP_PVT_THREAD_POOL_PARAM_STATE:
*((char **)value) =
*((char **)value) =
pool->ltp_pause ? "pausing" :
!pool->ltp_finishing ? "running" :
pool->ltp_pending_count ? "finishing" : "stopping";
@ -524,6 +549,7 @@ ldap_pvt_thread_pool_destroy ( ldap_pvt_thread_pool_t *tpool, int run_pending )
ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
pool->ltp_finishing = 1;
SET_VARY_OPEN_COUNT(pool);
if (pool->ltp_max_pending > 0)
pool->ltp_max_pending = -pool->ltp_max_pending;
if (!run_pending)
@ -599,16 +625,10 @@ ldap_int_thread_pool_wrapper (
task = LDAP_STAILQ_FIRST(&pool->ltp_pending_list);
if (task == NULL) {
if (pool->ltp_finishing)
break;
if (pool->ltp_open_count >
(pool->ltp_max_count ? pool->ltp_max_count : LDAP_MAXTHR))
{
/* too many threads running (can happen if the
* maximum threads value is set during ongoing
* operation using ldap_pvt_thread_pool_maxthreads)
* so let this thread die.
if (pool->ltp_vary_open_count < 0) {
/* not paused, and either finishing or too many
* threads running (can happen if ltp_max_count
* was reduced) so let this thread die.
*/
break;
}
@ -653,6 +673,7 @@ ldap_int_thread_pool_wrapper (
ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
pool->ltp_open_count--;
SET_VARY_OPEN_COUNT(pool);
/* let pool_destroy know we're all done */
if (pool->ltp_open_count < 1)
ldap_pvt_thread_cond_signal(&pool->ltp_cond);
@ -696,6 +717,8 @@ ldap_pvt_thread_pool_pause (
/* Wait for everyone else to pause or finish */
pool->ltp_pause = 1;
SET_VARY_OPEN_COUNT(pool);
while (pool->ltp_active_count > 1) {
ldap_pvt_thread_cond_wait(&pool->ltp_pcond, &pool->ltp_mutex);
}
@ -721,6 +744,7 @@ ldap_pvt_thread_pool_resume (
ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
pool->ltp_pause = 0;
SET_VARY_OPEN_COUNT(pool);
if (!pool->ltp_finishing)
ldap_pvt_thread_cond_broadcast(&pool->ltp_cond);
ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);