vmpressure: change vmpressure::sr_lock to spinlock

There is nothing that can sleep inside critical sections protected by this lock and those sections are really small so there doesn't make much sense to use mutex for them. Change the log to a spinlock Signed-off-by: Michal Hocko <[email protected]> Reported-by: Tejun Heo <[email protected]> Cc: Anton Vorontsov <[email protected]> Cc: Johannes Weiner <[email protected]> Cc: KAMEZAWA Hiroyuki <[email protected]> Cc: KOSAKI Motohiro <[email protected]> Cc: Li Zefan <[email protected]> Reviewed-by: Tejun Heo <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
rtvt123 · Jul 31, 2013 · 22f2020 · 22f2020
1 parent 62e32ac
commit 22f2020
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Showing 2 changed files with 6 additions and 6 deletions.
diff --git a/include/linux/vmpressure.h b/include/linux/vmpressure.h
@@ -12,7 +12,7 @@ struct vmpressure {
 	unsigned long scanned;
 	unsigned long reclaimed;
 	/* The lock is used to keep the scanned/reclaimed above in sync. */
-	struct mutex sr_lock;
+	struct spinlock sr_lock;
 
 	/* The list of vmpressure_event structs. */
 	struct list_head events;

diff --git a/mm/vmpressure.c b/mm/vmpressure.c
@@ -180,12 +180,12 @@ static void vmpressure_work_fn(struct work_struct *work)
 	if (!vmpr->scanned)
 		return;
 
-	mutex_lock(&vmpr->sr_lock);
+	spin_lock(&vmpr->sr_lock);
 	scanned = vmpr->scanned;
 	reclaimed = vmpr->reclaimed;
 	vmpr->scanned = 0;
 	vmpr->reclaimed = 0;
-	mutex_unlock(&vmpr->sr_lock);
+	spin_unlock(&vmpr->sr_lock);
 
 	do {
 		if (vmpressure_event(vmpr, scanned, reclaimed))
@@ -240,11 +240,11 @@ void vmpressure(gfp_t gfp, struct mem_cgroup *memcg,
 	if (!scanned)
 		return;
 
-	mutex_lock(&vmpr->sr_lock);
+	spin_lock(&vmpr->sr_lock);
 	vmpr->scanned += scanned;
 	vmpr->reclaimed += reclaimed;
 	scanned = vmpr->scanned;
-	mutex_unlock(&vmpr->sr_lock);
+	spin_unlock(&vmpr->sr_lock);
 
 	if (scanned < vmpressure_win || work_pending(&vmpr->work))
 		return;
@@ -367,7 +367,7 @@ void vmpressure_unregister_event(struct cgroup *cg, struct cftype *cft,
  */
 void vmpressure_init(struct vmpressure *vmpr)
 {
-	mutex_init(&vmpr->sr_lock);
+	spin_lock_init(&vmpr->sr_lock);
 	mutex_init(&vmpr->events_lock);
 	INIT_LIST_HEAD(&vmpr->events);
 	INIT_WORK(&vmpr->work, vmpressure_work_fn);