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mem-pool: minor fix and clarification

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A comment has been added to pool_destructor() function to explain why
locks are not needed there. Also, the initialization of 'poison' field
has been moved inside a locked region for further safety and clarity.

Change-Id: Idbf23bda7f9228d60c644a1bea4b6c2cfc582090
updates: bz#1193929
Signed-off-by: Xavi Hernandez <xhernandez@redhat.com>
This commit is contained in:
Xavi Hernandez 2018-11-27 12:21:01 +01:00 committed by Amar Tumballi
parent 0a3540293b
commit 6d69a66349
1 changed files with 10 additions and 3 deletions
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13
libglusterfs/src/mem-pool.c
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@ -527,7 +527,15 @@ pool_destructor(void *arg)
{
per_thread_pool_list_t *pool_list = arg;
/* The pool-sweeper thread will take it from here. */
/* The pool-sweeper thread will take it from here.
*
* We can change 'poison' here without taking locks because the change
* itself doesn't interact with other parts of the code and a simple write
* is already atomic from the point of view of the processor.
*
* This change can modify what mem_put() does, but both possibilities are
* fine until the sweeper thread kicks in. The real synchronization must be
* between mem_put() and the sweeper thread. */
pool_list->poison = 1;
}
@ -789,9 +797,8 @@ mem_get_pool_list(void)
}
}
pool_list->poison = 0;
(void)pthread_mutex_lock(&pool_lock);
pool_list->poison = 0;
list_add(&pool_list->thr_list, &pool_threads);
(void)pthread_mutex_unlock(&pool_lock);