From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3600301-1522826723-2-15549399521541542175 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no ("Email failed DMARC policy for domain") X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.249, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, 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='org', MailFrom='org' X-Spam-charsets: X-IgnoreVacation: yes ("Email failed DMARC policy for domain") 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= 1522826722; b=hxPkn81oF7rquN8mTgYzn1QNxOj4r5qje/ItoWCPL0Si1SPFBm lvk9bS0yrOQ0gfVKZfZT/xoia0z2I9hgFtagJZxKostUvkDTM3RkTXz2YScK6iip bTgx//k0drnxGW8Usy8s1ufuXsW5+MofGYvq4EVk6Ug75nLF0iGlBI4QVjJ9fSyH FypqzKt7z4r/AdEOh0QfT4K94PoQgu9HcjVLvEDoHkrqLI8xR97VIYt0dE6Z+QK1 byD2CSHx3JRdA9xyC4a5bOUfOhdUXR80rmt7GPRO3bQFK4rqZx/mRLvIzfFgOEF0 xzqsL95oUriu3EowN7GNmYEXxDzzOhvoCfFA== 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=1522826722; bh= Eu2NMGQPs2U3R1ooG6dDfpvl8KMV31KL3B8FyYDPh6M=; b=GTdZuzzXNH5w3UfJ 9SGb+x3Qxdv8yYnvr4ppsJPWjCjnQq9mcOs67M4ORuRfnFZ/EbSKw9HOOpR40GtZ UU7ZMYnu+BsPD7Kbxe4fYJIjA708jjVsiC7glQOocHl4VTHgJ5wAmZEtG/yYDbjT GKHaY6/ET8tbaIX5sGlSqXN/iwt1e2npKJ8zJUrsCq1vhJqUOvgtPqQg2okDKRih M+cv7YmrpevBiL34c+AuWUd8I5Gdasq7Xv9hN+ejXGoKUphoZovFj90cZqo36n2S vUGLk/7ZnWtyiecNQi4fGBwhYcjiv/MY+GskUzy77tuLv+C+/YUXu2SPdhab8i4Y IoAsFQ== ARC-Authentication-Results: i=1; mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=fail (p=none,has-list-id=yes,d=none) header.from=monom.org; 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=monom.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=fail (p=none,has-list-id=yes,d=none) header.from=monom.org; 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=monom.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfAeIjbPKKWJau8ENBjlRDWs7K50m7t54xWwB465TTsNerAJ68ogns6m6Xb1Q+/36T2AMpSfK2ZixxZZhn9dZOCMfQVj4DnGrX332DJH6+WB28y2fNE3/ 22fwqYSVRVWWO7RXOJgHcFKgM1aUkco8zjsdD2mQOrVrcoZvX+OsGOmEKUBYbP0EtEYtn6o3WKBs8cnz43HcOJMdwmf4pH88ccA9lRN5WyziFRQRrg9HzYXR X-CM-Analysis: v=2.3 cv=FKU1Odgs c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=Kd1tUaAdevIA:10 a=meVymXHHAAAA:8 a=VwQbUJbxAAAA:8 a=8k6WQxmsAAAA:8 a=8cYThTpUtsaJvHBqLhIA:9 a=2JgSa4NbpEOStq-L5dxp:22 a=AjGcO6oz07-iQ99wixmX:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750938AbeDDHZV (ORCPT ); Wed, 4 Apr 2018 03:25:21 -0400 Received: from mail.monom.org ([188.138.9.77]:49772 "EHLO mail.monom.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750772AbeDDHZU (ORCPT ); Wed, 4 Apr 2018 03:25:20 -0400 X-Remote-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on mail.monom.org X-Remote-Spam-Level: X-Remote-Spam-Status: No, score=-2.5 required=5.0 tests=ALL_TRUSTED,BAYES_00 autolearn=ham autolearn_force=no version=3.4.1 From: Daniel Wagner To: linux-kernel@vger.kernel.org Cc: linux-rt-users , Steven Rostedt , Thomas Gleixner , Carsten Emde , John Kacur , Paul Gortmaker , Julia Cartwright , Daniel Wagner , tom.zanussi@linux.intel.com, stable@vger.kernel.org, Sebastian Andrzej Siewior Subject: [PATCH RT 6/7] Revert "memcontrol: Prevent scheduling while atomic in cgroup code" Date: Wed, 4 Apr 2018 09:16:51 +0200 Message-Id: <20180404071652.24196-7-wagi@monom.org> X-Mailer: git-send-email 2.14.3 In-Reply-To: <20180404071652.24196-1-wagi@monom.org> References: <20180404071652.24196-1-wagi@monom.org> 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: From: "Steven Rostedt (VMware)" The commit "memcontrol: Prevent scheduling while atomic in cgroup code" fixed this issue: refill_stock() get_cpu_var() drain_stock() res_counter_uncharge() res_counter_uncharge_until() spin_lock() <== boom But commit 3e32cb2e0a12b ("mm: memcontrol: lockless page counters") replaced the calls to res_counter_uncharge() in drain_stock() to the lockless function page_counter_uncharge(). There is no more spin lock there and no more reason to have that local lock. Cc: Reported-by: Haiyang HY1 Tan Signed-off-by: Steven Rostedt (VMware) [bigeasy: That upstream commit appeared in v3.19 and the patch in question in v3.18.7-rt2 and v3.18 seems still to be maintained. So I guess that v3.18 would need the locallocks that we are about to remove here. I am not sure if any earlier versions have the patch backported. The stable tag here is because Haiyang reported (and debugged) a crash in 4.4-RT with this patch applied (which has get_cpu_light() instead the locallocks it gained in v4.9-RT). https://lkml.kernel.org/r/05AA4EC5C6EC1D48BE2CDCFF3AE0B8A637F78A15@CNMAILEX04.lenovo.com ] Signed-off-by: Sebastian Andrzej Siewior --- mm/memcontrol.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 493b4986d5dc..56f67a15937b 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1925,17 +1925,14 @@ static void drain_local_stock(struct work_struct *dummy) */ static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages) { - struct memcg_stock_pcp *stock; - int cpu = get_cpu_light(); - - stock = &per_cpu(memcg_stock, cpu); + struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock); if (stock->cached != memcg) { /* reset if necessary */ drain_stock(stock); stock->cached = memcg; } stock->nr_pages += nr_pages; - put_cpu_light(); + put_cpu_var(memcg_stock); } /* -- 2.14.3