From 22f2020f84c6da2dd0acb2dce12e39e59ff7c8be Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Wed, 31 Jul 2013 13:53:48 -0700 Subject: 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 Reported-by: Tejun Heo Cc: Anton Vorontsov Cc: Johannes Weiner Cc: KAMEZAWA Hiroyuki Cc: KOSAKI Motohiro Cc: Li Zefan Reviewed-by: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/vmpressure.h | 2 +- mm/vmpressure.c | 10 +++++----- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/include/linux/vmpressure.h b/include/linux/vmpressure.h index 76be077340ea..2081680e015d 100644 --- 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 index 736a6011c2c8..f4ee6a190a4d 100644 --- 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); -- cgit v1.2.3-59-g8ed1b