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=-16.4 required=3.0 tests=DKIMWL_WL_MED,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_GIT, USER_IN_DEF_DKIM_WL 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 881D4C4646C for ; Mon, 24 Jun 2019 21:26:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3A44F208E3 for ; Mon, 24 Jun 2019 21:26:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="fCpgEkM3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728341AbfFXV0v (ORCPT ); Mon, 24 Jun 2019 17:26:51 -0400 Received: from mail-pf1-f202.google.com ([209.85.210.202]:52583 "EHLO mail-pf1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726331AbfFXV0v (ORCPT ); Mon, 24 Jun 2019 17:26:51 -0400 Received: by mail-pf1-f202.google.com with SMTP id a20so10324691pfn.19 for ; Mon, 24 Jun 2019 14:26:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=QuhQR2g5/6NgmqGFuivV/bpabSOVZ9f1VzuLjz/nCSs=; b=fCpgEkM3oU/q6tGjPXFgGeBjEu3hVd9yUvzw1RQH/0g25b6Jh+izus//6Javr+fxFc HH3rWllH1qzQxTgR+uHyVLDW9+cBU2XiQWne19jdSqEFYsuGN8N6hWC2lvovRusHjFPE wOHZB62oPVqhJ9vqAq/XIzj5rSF0X8WKlUCxK9TJtmCa/M1EUosulXBohIJZ5jLhOdY1 h8BIR+9sdQhMyh/BkBVU8vmep7CExj0cBDdxuKwkUdAL/uvVGbi5K1xqsja0TmlJ+1ia lsKhi4mrjMbKSfw9mgRUaLGeY9+RY5b7ciQDh312AiL6TloQaBuIZobxBEM8VNlJd5vn PPSQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=QuhQR2g5/6NgmqGFuivV/bpabSOVZ9f1VzuLjz/nCSs=; b=dHeaoeeklATdq5P7HuZKi7bEd2C75a9J6AJQkMrFsR6Rt1gbd5gZ84tCATzyHrTDRN l45d3b/speSkfTrZM9Cozp4QpU/gzmy3DR/yojE9XnrmqQvHYG9GGQ2SquoXNbyOeqgx BhIQw5YAuzHN+ldOpajBZC36ejGsHNvRZGHRz6Q4MO2try9cWhiJJGzqWc70NG9iDviI jVbrUmpflUEWFC6CuqgfczQs+ZWMoa+FgaMtUgU6t15vVyjMwTuJhzXoGnajQoa2PiMY B6xt11ETS1snzjxFsupeCN6hAkgcZ2Dk6qmPUMXCqPSCzdp3kPtUVMN3wWJ/n1Dg4u8/ LypQ== X-Gm-Message-State: APjAAAXLTQxq0H5ttLxwDaq3N7kk7ue7poKKz5Kt+IAz4Y+Y2mUtCWKD Pf1ujKs1q7ervd+tnsp8let9fD1F17aOJw== X-Google-Smtp-Source: APXvYqz5a7SZDemOpTEhQLNyJry7dI+Y4LMqToKE27cqw3yUALC3EexEf36v0Lyn6dcmeZbhLipgWCztywg1PA== X-Received: by 2002:a63:296:: with SMTP id 144mr35516171pgc.141.1561411610100; Mon, 24 Jun 2019 14:26:50 -0700 (PDT) Date: Mon, 24 Jun 2019 14:26:29 -0700 Message-Id: <20190624212631.87212-1-shakeelb@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.22.0.410.gd8fdbe21b5-goog Subject: [PATCH v3 1/3] mm, oom: refactor dump_tasks for memcg OOMs From: Shakeel Butt To: Johannes Weiner , Vladimir Davydov , Michal Hocko , Andrew Morton , Roman Gushchin , David Rientjes , KOSAKI Motohiro , Tetsuo Handa , Paul Jackson , Nick Piggin Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Shakeel Butt , Michal Hocko Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org dump_tasks() traverses all the existing processes even for the memcg OOM context which is not only unnecessary but also wasteful. This imposes a long RCU critical section even from a contained context which can be quite disruptive. Change dump_tasks() to be aligned with select_bad_process and use mem_cgroup_scan_tasks to selectively traverse only processes of the target memcg hierarchy during memcg OOM. Signed-off-by: Shakeel Butt Acked-by: Michal Hocko --- Changelog since v2: - Updated the commit message. Changelog since v1: - Divide the patch into two patches. mm/oom_kill.c | 68 ++++++++++++++++++++++++++++++--------------------- 1 file changed, 40 insertions(+), 28 deletions(-) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 05aaa1a5920b..bd80997e0969 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -385,10 +385,38 @@ static void select_bad_process(struct oom_control *oc) oc->chosen_points = oc->chosen_points * 1000 / oc->totalpages; } +static int dump_task(struct task_struct *p, void *arg) +{ + struct oom_control *oc = arg; + struct task_struct *task; + + if (oom_unkillable_task(p, NULL, oc->nodemask)) + return 0; + + task = find_lock_task_mm(p); + if (!task) { + /* + * This is a kthread or all of p's threads have already + * detached their mm's. There's no need to report + * them; they can't be oom killed anyway. + */ + return 0; + } + + pr_info("[%7d] %5d %5d %8lu %8lu %8ld %8lu %5hd %s\n", + task->pid, from_kuid(&init_user_ns, task_uid(task)), + task->tgid, task->mm->total_vm, get_mm_rss(task->mm), + mm_pgtables_bytes(task->mm), + get_mm_counter(task->mm, MM_SWAPENTS), + task->signal->oom_score_adj, task->comm); + task_unlock(task); + + return 0; +} + /** * dump_tasks - dump current memory state of all system tasks - * @memcg: current's memory controller, if constrained - * @nodemask: nodemask passed to page allocator for mempolicy ooms + * @oc: pointer to struct oom_control * * Dumps the current memory state of all eligible tasks. Tasks not in the same * memcg, not in the same cpuset, or bound to a disjoint set of mempolicy nodes @@ -396,37 +424,21 @@ static void select_bad_process(struct oom_control *oc) * State information includes task's pid, uid, tgid, vm size, rss, * pgtables_bytes, swapents, oom_score_adj value, and name. */ -static void dump_tasks(struct mem_cgroup *memcg, const nodemask_t *nodemask) +static void dump_tasks(struct oom_control *oc) { - struct task_struct *p; - struct task_struct *task; - pr_info("Tasks state (memory values in pages):\n"); pr_info("[ pid ] uid tgid total_vm rss pgtables_bytes swapents oom_score_adj name\n"); - rcu_read_lock(); - for_each_process(p) { - if (oom_unkillable_task(p, memcg, nodemask)) - continue; - task = find_lock_task_mm(p); - if (!task) { - /* - * This is a kthread or all of p's threads have already - * detached their mm's. There's no need to report - * them; they can't be oom killed anyway. - */ - continue; - } + if (is_memcg_oom(oc)) + mem_cgroup_scan_tasks(oc->memcg, dump_task, oc); + else { + struct task_struct *p; - pr_info("[%7d] %5d %5d %8lu %8lu %8ld %8lu %5hd %s\n", - task->pid, from_kuid(&init_user_ns, task_uid(task)), - task->tgid, task->mm->total_vm, get_mm_rss(task->mm), - mm_pgtables_bytes(task->mm), - get_mm_counter(task->mm, MM_SWAPENTS), - task->signal->oom_score_adj, task->comm); - task_unlock(task); + rcu_read_lock(); + for_each_process(p) + dump_task(p, oc); + rcu_read_unlock(); } - rcu_read_unlock(); } static void dump_oom_summary(struct oom_control *oc, struct task_struct *victim) @@ -458,7 +470,7 @@ static void dump_header(struct oom_control *oc, struct task_struct *p) dump_unreclaimable_slab(); } if (sysctl_oom_dump_tasks) - dump_tasks(oc->memcg, oc->nodemask); + dump_tasks(oc); if (p) dump_oom_summary(oc, p); } -- 2.22.0.410.gd8fdbe21b5-goog