From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1779982-1523430028-2-12305653550126774650 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, MAILING_LIST_MULTI -1, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='cz', MailFrom='org' X-Spam-charsets: X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=fm2; t= 1523430027; b=K+G60rbWM10reOvGuLT4PcBuJd4E+p0LtXhBfFmb8Cu3YclZVK gojL6NDTRUs7QF9UrbfjAQLoDBMDH/4vmfXvB3zVGTpL0vRgJMzsgqWeFB8SC417 uaAcJklwqWB6XDjR8OVypkq+4g6pjbkh5pq8atpyBNSBSg+zM3MbWEVA9rFT3sGH VxBYX/a8LeJElDLSAWr/3CHmdI79GzvlCqzjAvd2aqSPZD/A0WjTzJ0aOCQane2I tTKoLPs3g0v4GT/r+pmGxY6faAsUGBf6Q3zU9qpQCmr35jI+Vz4TXce3uD1gXugf IPUNuKZapTWfmCA+zRfANlP4KdFejU3CPKTQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:sender:list-id; s=fm2; t=1523430027; bh= 3y2iVUIvBEMNCw8psB0BnENo0owZjnjZ25ENiXYr1mM=; b=urONqvsykVGFTsuh 8E2I7umxwQsnZJ1CNfHdKqTXi2IEU51wIqBlKQJmhhYTaCdPF9Q5N4d0ikcMtREq ooSFZxniiXXshim/c5Z6W48rAuqHSQfitOQUX1yvCY2yomytwn1WZLZfTqwXDzBe Rgo34gb6ykCAhhFiUSgG6ZsgG01B9ikPH3mXXAdsjS07iYuthGLc2Hp6Vr+Ls3am 16fR77PlSMs8CLQc07z9QgZPkwjvrdkCbtEV+jHaGGjsJPsCbzM3tknsyVOMGjvK 5NtiY7kFe8kA6C6CoAU93nccxnqebbgsaAGxpP3kHtBBm5mTYMp2QDcqnlHSggWu d09ACw== ARC-Authentication-Results: i=1; mx3.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=suse.cz; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=suse.cz header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx3.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=suse.cz; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=suse.cz header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfG99BmHGVpRbkLW8tH9pvb36uMUA6DouJvS6+VK8C819GVtW2nLYJYYOfdmpw6eSCjSEFfTPb89AuDg9WmPcemqiOOpfWbwRgyHNKaNlh8exHvkkRFnq xg8KchrJiLsY+JOoubjYepjYY7p96CUMprYb3qv/DoKVJYbkItO/at7XWjnN/+k/Gs5yjRHJXR+8O+dXOPczCGUpBEyLrd+2jt1cK3ae9lS12mkgUCEmuTZ4 X-CM-Analysis: v=2.3 cv=Tq3Iegfh c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=Kd1tUaAdevIA:10 a=VwQbUJbxAAAA:8 a=57SyGIRnAAAA:8 a=1XWaLZrsAAAA:8 a=NufY4J3AAAAA:8 a=pGLkceISAAAA:8 a=KKAkSRfTAAAA:8 a=zPZknKe_xf31IkCjsZUA:9 a=AjGcO6oz07-iQ99wixmX:22 a=YzT4AsKTxtEdF6UtD8mD:22 a=TPcZfFuj8SYsoCJAFAiX:22 a=cvBusfyB2V15izCimMoJ:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752282AbeDKHAY (ORCPT ); Wed, 11 Apr 2018 03:00:24 -0400 Received: from mx2.suse.de ([195.135.220.15]:46217 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751983AbeDKHAX (ORCPT ); Wed, 11 Apr 2018 03:00:23 -0400 From: Vlastimil Babka To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vlastimil Babka , stable@vger.kernel.org, Joonsoo Kim , David Rientjes , Pekka Enberg , Christoph Lameter , Tejun Heo , Lai Jiangshan , John Stultz , Thomas Gleixner , Stephen Boyd Subject: [PATCH] mm, slab: reschedule cache_reap() on the same CPU Date: Wed, 11 Apr 2018 09:00:07 +0200 Message-Id: <20180411070007.32225-1-vbabka@suse.cz> X-Mailer: git-send-email 2.16.3 In-Reply-To: <20180410081531.18053-1-vbabka@suse.cz> References: <20180410081531.18053-1-vbabka@suse.cz> Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: cache_reap() is initially scheduled in start_cpu_timer() via schedule_delayed_work_on(). But then the next iterations are scheduled via schedule_delayed_work(), i.e. using WORK_CPU_UNBOUND. Thus since commit ef557180447f ("workqueue: schedule WORK_CPU_UNBOUND work on wq_unbound_cpumask CPUs") there is no guarantee the future iterations will run on the originally intended cpu, although it's still preferred. I was able to demonstrate this with /sys/module/workqueue/parameters/debug_force_rr_cpu. IIUC, it may also happen due to migrating timers in nohz context. As a result, some cpu's would be calling cache_reap() more frequently and others never. This patch uses schedule_delayed_work_on() with the current cpu when scheduling the next iteration. Signed-off-by: Vlastimil Babka Fixes: ef557180447f ("workqueue: schedule WORK_CPU_UNBOUND work on wq_unbound_cpumask CPUs") CC: Cc: Joonsoo Kim Cc: David Rientjes Cc: Pekka Enberg Cc: Christoph Lameter Cc: Tejun Heo Cc: Lai Jiangshan Cc: John Stultz Cc: Thomas Gleixner Cc: Stephen Boyd --- mm/slab.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/slab.c b/mm/slab.c index 9095c3945425..a76006aae857 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -4074,7 +4074,8 @@ static void cache_reap(struct work_struct *w) next_reap_node(); out: /* Set up the next iteration */ - schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_AC)); + schedule_delayed_work_on(smp_processor_id(), work, + round_jiffies_relative(REAPTIMEOUT_AC)); } void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo) -- 2.16.3