io-threads: Use non-default thread stack size

The default stack size on Linux is around 8 MiB for each
thread. This is clearly too high for our purpose. This commit reduces
the stack size down to 1 MiB.

Signed-off-by: Anand V. Avati <avati@amp.gluster.com>

2 files changed, 27 insertions, 1 deletions

diff --git a/xlators/performance/io-threads/src/io-threads.c b/xlators/performance/io-threads/src/io-threads.c
index b8cb633cdeb..66aec51a37e 100644
--- a/xlators/performance/io-threads/src/io-threads.c
+++ b/xlators/performance/io-threads/src/io-threads.c
@@ -1759,7 +1759,8 @@ void
 iot_startup_worker (iot_worker_t *worker, iot_worker_fn workerfunc)
 {
         worker->state = IOT_STATE_ACTIVE;
-        pthread_create (&worker->thread, NULL, workerfunc, worker);
+        pthread_create (&worker->thread, &worker->conf->w_attr, workerfunc,
+                        worker);
 }
 
 
@@ -1777,6 +1778,24 @@ iot_startup_workers (iot_worker_t **workers, int start_idx, int count,
 }
 
 static void
+set_stack_size (iot_conf_t *conf)
+{
+        int     err = 0;
+        size_t  stacksize = IOT_THREAD_STACK_SIZE;
+
+        pthread_attr_init (&conf->w_attr);
+        err = pthread_attr_setstacksize (&conf->w_attr, stacksize);
+        if (err == EINVAL) {
+                gf_log (conf->this->name, GF_LOG_WARNING,
+                                "Using default thread stack size");
+                stacksize = 0;
+        }
+
+        pthread_attr_setstacksize (&conf->w_attr, stacksize);
+
+}
+
+static void
 workers_init (iot_conf_t *conf)
 {
         /* Initialize un-ordered workers */
@@ -1787,6 +1806,7 @@ workers_init (iot_conf_t *conf)
         conf->oworkers = allocate_worker_array (conf->max_o_threads);
         allocate_workers (conf, conf->oworkers, 0, conf->max_o_threads);
 
+        set_stack_size (conf);
         iot_startup_workers (conf->oworkers, 0, conf->min_o_threads,
                         iot_worker_ordered);
         iot_startup_workers (conf->uworkers, 0, conf->min_u_threads,
diff --git a/xlators/performance/io-threads/src/io-threads.h b/xlators/performance/io-threads/src/io-threads.h
index 3bc37a67d43..3fff676f6cf 100644
--- a/xlators/performance/io-threads/src/io-threads.h
+++ b/xlators/performance/io-threads/src/io-threads.h
@@ -65,6 +65,8 @@ struct iot_request {
 #define iot_ordered_scaling_on(conf)    ((conf)->o_scaling == IOT_SCALING_ON)
 #define iot_unordered_scaling_on(conf)  ((conf)->u_scaling == IOT_SCALING_ON)
 
+#define IOT_THREAD_STACK_SIZE   ((size_t)(1024*1024))
+
 struct iot_worker {
   struct list_head rqlist;      /* List of requests assigned to me. */
   struct iot_conf *conf;
@@ -131,6 +133,10 @@ struct iot_conf {
                                    and never lets any thread exit.
                                    */
 
+  pthread_attr_t w_attr;        /* Used to reduce the stack size of the
+                                   pthread worker down from the default of
+                                   8MiB.
+                                   */
 };
 
 typedef struct iot_conf iot_conf_t;