From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 05836C433E0 for ; Fri, 12 Jun 2020 17:44:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D85C1207F7 for ; Fri, 12 Jun 2020 17:44:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chrisdown.name header.i=@chrisdown.name header.b="ExSMmNiI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726391AbgFLRol (ORCPT ); Fri, 12 Jun 2020 13:44:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57780 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726085AbgFLRol (ORCPT ); Fri, 12 Jun 2020 13:44:41 -0400 Received: from mail-ej1-x642.google.com (mail-ej1-x642.google.com [IPv6:2a00:1450:4864:20::642]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EDCCBC03E96F for ; Fri, 12 Jun 2020 10:44:40 -0700 (PDT) Received: by mail-ej1-x642.google.com with SMTP id w16so10363568ejj.5 for ; Fri, 12 Jun 2020 10:44:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chrisdown.name; s=google; h=date:from:to:cc:subject:message-id:mime-version:content-disposition :content-transfer-encoding:user-agent; bh=El2ZhOBNpOphhFc1XzfVOf5zdV0ZOf8ZqDSCzO0pdXQ=; b=ExSMmNiIU7w2dNRKqM6HiRU9brV5dI+iTGVf+mxt7q63rlToikgj3nMb1iq3YADJBF ev3ed8upaGQ+qe9wjcso2C9F45/3Ud5jGOhB8d1Zvs+Wj38uxrM0oQtF8lKK95/K5WGi 81VPI2Bpm1n5W2VpKPUy+7srzOYLycHM1Rup4= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition:content-transfer-encoding:user-agent; bh=El2ZhOBNpOphhFc1XzfVOf5zdV0ZOf8ZqDSCzO0pdXQ=; b=kATwbaUCIk2p63ZXM5mtG5/9a88i2h3k4tjD8VNUkmn41N8ejeNIwretKuyFBgqfg4 dPfHD0BcTwrIHcHjiWPv4ZPW71AvfReX3PFMt+RKWsp+MKjb8nDNHJbpnQQL8h1Ia4fd Zy2wqACDiEGdBr1PEvDv/8s0KYiNYmO5NAGO6ihzJN2NF18y60g05YMcVfzNTFKGyaGI LU4VcIQA2g9nFFJeD/ImDHw8rBLRi4l1HWiWOXrApFX/vmbXnJSWbO/gSCS2MZcBaRxb kfUvwcGsKbPlNOHslSgNxpyhcgSb4SsRy2Ai+vwMi7leYv7p6QpHtOSMgjbBECqXSbTr EGBA== X-Gm-Message-State: AOAM530IonXKv8xSDOZdEft0P22i2GXz36cLjP3e5Umhtdic3F3Cut7v 6xsbm8MdkfiEDqcZry8BBW6HoywCxqWQPg== X-Google-Smtp-Source: ABdhPJxjGBObU+iuR5VFNURPaq/Kot+BO1JubX/YelHlAX2HwCoqdG4luT5UYW9Jpmd9kPxVsKQr+w== X-Received: by 2002:a17:906:c952:: with SMTP id fw18mr13976047ejb.505.1591983878004; Fri, 12 Jun 2020 10:44:38 -0700 (PDT) Received: from localhost ([2620:10d:c093:400::5:18e1]) by smtp.gmail.com with ESMTPSA id d35sm3443742edc.40.2020.06.12.10.44.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 12 Jun 2020 10:44:37 -0700 (PDT) Date: Fri, 12 Jun 2020 18:44:37 +0100 From: Chris Down To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michal =?iso-8859-1?Q?Koutn=FD?= Subject: [PATCH] mm, memcg: prevent missed memory.low load tears Message-ID: <20200612174437.GA391453@chrisdown.name> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit User-Agent: Mutt/1.14.2 (2020-05-25) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Looks like one of these got missed when massaging in f86b810c2610 ("mm, memcg: prevent memory.low load/store tearing") with other linux-mm changes. Reported-by: Michal Koutný Signed-off-by: Chris Down --- mm/memcontrol.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 0b38b6ad547d..f7cc66a80348 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6416,7 +6416,7 @@ enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root, if (parent == root) { memcg->memory.emin = READ_ONCE(memcg->memory.min); - memcg->memory.elow = memcg->memory.low; + memcg->memory.elow = READ_ONCE(memcg->memory.low); goto out; } @@ -6428,7 +6428,8 @@ enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root, atomic_long_read(&parent->memory.children_min_usage))); WRITE_ONCE(memcg->memory.elow, effective_protection(usage, parent_usage, - memcg->memory.low, READ_ONCE(parent->memory.elow), + READ_ONCE(memcg->memory.low), + READ_ONCE(parent->memory.elow), atomic_long_read(&parent->memory.children_low_usage))); out: -- 2.27.0