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=-17.4 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,URIBL_BLOCKED, 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 68BCFC4321A for ; Fri, 28 Jun 2019 15:24:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3933B2064A for ; Fri, 28 Jun 2019 15:24:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="BtPgXcHa" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726846AbfF1PYv (ORCPT ); Fri, 28 Jun 2019 11:24:51 -0400 Received: from mail-pl1-f201.google.com ([209.85.214.201]:41840 "EHLO mail-pl1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726657AbfF1PYu (ORCPT ); Fri, 28 Jun 2019 11:24:50 -0400 Received: by mail-pl1-f201.google.com with SMTP id i3so3698695plb.8 for ; Fri, 28 Jun 2019 08:24:50 -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=ZsiRx6xvzXROMUfoU65xDsRvBFu/S3BDc/iiU2HXWv4=; b=BtPgXcHakceSysUUvvTmVSqsGhdHXi1kTosXaG1TL6r/NdCk16Kn1UZudJwQ8FryNT MqMKLaTqfEshncO9iNRq3T2l4bFQs9lSi8YCG2CnMALJaJycGYuXhHwviqJu5AP4riC8 i3YxItLgROyPMkeYXhbQ+04IIo3s28z1I4gbaqa10tstGRhTEsE7azL2mH+zTyglgFCp TB0VyCvjbF3Vt92IjWzM5k50QSqsGJtJ7QBekyVLXcBao3UchX5g5/oua87eS/1oWJUt brlC1HXwtP1z0swdd16RFVvCEJ2o2gDNUQpf/2Rc7F1tgTQ+cEGt2lKpSg+CStlr7gF1 zxUg== 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=ZsiRx6xvzXROMUfoU65xDsRvBFu/S3BDc/iiU2HXWv4=; b=aDF8IjqC1TfFabMeeRVG7sceVFMLaihUaSnsTgRamRdB8OJFLSgG8sdu0J6ohDvraC R1B9Af+Qfzvt/+2Rh85XbP+wboaqvtLve0k1FxEX0mVPmob0q6cXSy3lCXP8QfYvliIC G6JsU8/20wPVvtM59MMUcSrbWxHD+Jv+xei/fOsAsSvT+693kUHkS/Zs7mQtuCuq6wRa brHoRh5K3iVViIk8fP0Peh4W8D+Gq8kiNOa/wJXt2QNZB/T6sOBXy78f//T79DqMwN+f oTi/H7WtxPTmtJGNT+jQe9tDzf6Z+4R/M70NKPr/Tp9G1lyncg9+vKXsgkAat4PgMq1s nNLg== X-Gm-Message-State: APjAAAU1KVcCr08dPjgiP+7fUn/+LCNQRP1KPvHckptgFzswzoZ1CuYd PMYPKM/oejHdm2BMG6VA+ZnWc7vod3UH/w== X-Google-Smtp-Source: APXvYqzEojWmbhFHT2oTqcaA/Uz0vqGKl0ZGIuOIBoO2lEvVjVcxnQ2cWLOCM1OrJQdFMc9IHU4lEf3YCZuZ6w== X-Received: by 2002:a63:f953:: with SMTP id q19mr9792545pgk.367.1561735489272; Fri, 28 Jun 2019 08:24:49 -0700 (PDT) Date: Fri, 28 Jun 2019 08:24:19 -0700 Message-Id: <20190628152421.198994-1-shakeelb@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.22.0.410.gd8fdbe21b5-goog Subject: [PATCH v4 1/3] mm, oom: refactor dump_tasks for memcg OOMs From: Shakeel Butt To: Johannes Weiner , Michal Hocko , Andrew Morton , Roman Gushchin , David Rientjes Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Shakeel Butt , Tetsuo Handa , Vladimir Davydov , KOSAKI Motohiro , Paul Jackson , Nick Piggin 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 Acked-by: Roman Gushchin Cc: Johannes Weiner Cc: Tetsuo Handa Cc: Vladimir Davydov Cc: David Rientjes Cc: KOSAKI Motohiro Cc: Paul Jackson Cc: Nick Piggin Cc: Andrew Morton --- Changelog since v3: - None 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 085abc91024d..a940d2aa92d6 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -380,10 +380,38 @@ static void select_bad_process(struct oom_control *oc) } } +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 @@ -391,37 +419,21 @@ 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) @@ -453,7 +465,7 @@ 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