From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760932Ab3GSQv1 (ORCPT ); Fri, 19 Jul 2013 12:51:27 -0400 Received: from cantor2.suse.de ([195.135.220.15]:53492 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755946Ab3GSQvY (ORCPT ); Fri, 19 Jul 2013 12:51:24 -0400 From: Michal Hocko To: Andrew Morton Cc: Anton Vorontsov , Johannes Weiner , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Tejun Heo , Li Zefan , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH resend 1/3] vmpressure: change vmpressure::sr_lock to spinlock Date: Fri, 19 Jul 2013 18:51:09 +0200 Message-Id: <1374252671-11939-1-git-send-email-mhocko@suse.cz> X-Mailer: git-send-email 1.8.3.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Brought-up-by: Tejun Heo Signed-off-by: Michal Hocko --- 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 76be077..2081680 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 736a601..f4ee6a1 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); -- 1.8.3.2