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authorShehjar Tikoo <shehjart@zresearch.com>2009-04-03 02:06:25 -0700
committerAnand V. Avati <avati@amp.gluster.com>2009-04-08 11:57:09 +0530
commitfe1cedc1a960493337676885881018e4687c12a2 (patch)
tree61c89060d8812f03adeea7b3b4a15ae40b12f014 /xlators
parent3acd56bec5afef9db673ae8d7dbe52bc7943b298 (diff)
io-threads: Refactor ordered worker exit path
This patch re-factors the exit path of an ordered worker on a time-out. Earlier we're checking for exit permission in such a way that required us to release and acquire the worker lock a second time in the worker loop opening a window wherein a new request could've been appended to the request queue. This patch makes the decision to exit while still holding on to the worker lock. Signed-off-by: Anand V. Avati <avati@amp.gluster.com>
Diffstat (limited to 'xlators')
-rw-r--r--xlators/performance/io-threads/src/io-threads.c59
1 files changed, 25 insertions, 34 deletions
diff --git a/xlators/performance/io-threads/src/io-threads.c b/xlators/performance/io-threads/src/io-threads.c
index 83d0d7089..a361def9f 100644
--- a/xlators/performance/io-threads/src/io-threads.c
+++ b/xlators/performance/io-threads/src/io-threads.c
@@ -1490,46 +1490,33 @@ iot_destroy_request (iot_request_t * req)
}
/* Must be called with worker lock held. */
-int
+gf_boolean_t
iot_can_ordered_exit (iot_worker_t * worker)
{
- int allow_exit = 0;
+ gf_boolean_t allow_exit = _gf_false;
iot_conf_t *conf = NULL;
conf = worker->conf;
- if (worker->queue_size > 0)
- goto decided;
-
/* We dont want this thread to exit if its index is
* below the min thread count.
*/
if (worker->thread_idx >= conf->min_o_threads)
- allow_exit = 1;
+ allow_exit = _gf_true;
-decided:
return allow_exit;
}
-int
+/* Must be called with worker lock held. */
+gf_boolean_t
iot_ordered_exit (iot_worker_t *worker)
{
- int allow_exit = 0;
-
- /* It is possible that since the last time we timed out while
- * waiting for a request, a new request has been added to this
- * worker's request queue. Before we really exit, we must
- * check for those requests.
- */
- pthread_mutex_lock (&worker->qlock);
- {
- allow_exit = iot_can_ordered_exit (worker);
+ gf_boolean_t allow_exit = _gf_false;
- if (allow_exit) {
- worker->state = IOT_STATE_DEAD;
- worker->thread = 0;
- }
- }
- pthread_mutex_unlock (&worker->qlock);
+ allow_exit = iot_can_ordered_exit (worker);
+ if (allow_exit) {
+ worker->state = IOT_STATE_DEAD;
+ worker->thread = 0;
+ }
return allow_exit;
}
@@ -1537,9 +1524,10 @@ iot_ordered_exit (iot_worker_t *worker)
int
iot_ordered_request_wait (iot_worker_t * worker)
{
- struct timeval tv;
+ struct timeval tv;
struct timespec ts;
- int waitres = 0;
+ int waitres = 0;
+ int retstat = 0;
gettimeofday (&tv, NULL);
ts.tv_sec = tv.tv_sec + worker->conf->o_idle_time;
@@ -1551,9 +1539,10 @@ iot_ordered_request_wait (iot_worker_t * worker)
waitres = pthread_cond_timedwait (&worker->dq_cond, &worker->qlock,
&ts);
if (waitres == ETIMEDOUT)
- return -1;
+ if (iot_ordered_exit (worker))
+ retstat = -1;
- return 0;
+ return retstat;
}
call_stub_t *
@@ -1568,6 +1557,9 @@ iot_dequeue_ordered (iot_worker_t *worker)
while (!worker->queue_size) {
waitstat = 0;
waitstat = iot_ordered_request_wait (worker);
+ /* We must've timed out and are now required to
+ * exit.
+ */
if (waitstat == -1)
goto out;
}
@@ -1596,12 +1588,11 @@ iot_worker_ordered (void *arg)
while (1) {
stub = iot_dequeue_ordered (worker);
- if (stub == NULL) {
- if (iot_ordered_exit (worker))
- break;
- else
- continue;
- }
+ /* If stub is NULL, we must've timed out waiting for a
+ * request and have now been allowed to exit.
+ */
+ if (stub == NULL)
+ break;
call_resume (stub);
}