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=-8.5 required=3.0 tests=INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT 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 2947AC31E51 for ; Tue, 18 Jun 2019 12:25:04 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DFC842082C for ; Tue, 18 Jun 2019 12:25:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DFC842082C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7B8328E0002; Tue, 18 Jun 2019 08:25:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 767528E0001; Tue, 18 Jun 2019 08:25:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 62EB08E0002; Tue, 18 Jun 2019 08:25:03 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-ed1-f72.google.com (mail-ed1-f72.google.com [209.85.208.72]) by kanga.kvack.org (Postfix) with ESMTP id 127398E0001 for ; Tue, 18 Jun 2019 08:25:03 -0400 (EDT) Received: by mail-ed1-f72.google.com with SMTP id o13so21083638edt.4 for ; Tue, 18 Jun 2019 05:25:03 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:date:from:to :cc:subject:message-id:references:mime-version:content-disposition :in-reply-to:user-agent; bh=kWVRrUQj9mWoqQlvFFTdbBytWIYtInyZrJjLe8l2Oqs=; b=I1ov0sfSfV+pDtYpRfJ25rww29S18+wrxLmyKZiCIPPJKFqw75d4MAyTDFwXvs+E2u TyFcEvnbWOJNK06U6IuPlXYRjjfsRzESW4TKcJd/iA04dmC5SwrxvQ+dTqAIIhGR/FmO A9UHvlEFZIaZtIkeDQjUO+dzU0iOvwfxngMUEW/ScB/Eu1El5k8U5UUXuGvuhDFIbP4R SGtRKmRw4krMac/u8Iihw6O30l9jcVbCOlmLkaUSV0K8em119HnwW36VJ8/jBqXwKBRb hYDCN4U6Qy0nTNAOPVDGoD5bTGIMfqufE2w921DjpOnOHPVEsteQcqOL4iOTqUKKsFaz gSrA== X-Original-Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) smtp.mailfrom=mhocko@kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org X-Gm-Message-State: APjAAAUmR8QueKzQHyqhgPFnBOZIxVB1YTsTCAZDH4z/CYBm6sEGq+Ti QMVRTqTUHUNnw8N0cPzNMd09sLFCVNjjbLLb5YTMrK/zoet18YlQmOfIt4/iBJSseRwGcc7sYM6 rqmw8R2pWJmQgJ40EvP5BKK275oGGnnAnThYtQ+BeAe+Y6xf15E2umjkSN3TAgRg= X-Received: by 2002:a50:9273:: with SMTP id j48mr98120018eda.285.1560860702597; Tue, 18 Jun 2019 05:25:02 -0700 (PDT) X-Google-Smtp-Source: APXvYqwDGc0IjzBXcoCOGu1/znWEVzDAqWFgd5SlGeYtCjU/L3CD137OVKg8Npc2c0R5OX8auWdU X-Received: by 2002:a50:9273:: with SMTP id j48mr98119938eda.285.1560860701811; Tue, 18 Jun 2019 05:25:01 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1560860701; cv=none; d=google.com; s=arc-20160816; b=JJqA9GeC64JTmah7kM9/ROFPFYBSjAfrDIsQB5A4w4JV4Dc4idE7s0HIAxcnq78gKR rAtHJaICX50Cnjc2Ibd9liCUNvIMb1N8PgReXMYoqMfLT4AiG7kvmKIyej6kLIRr6VuN /xOgox8h7LhQBdo0LDy5NJ5GV6tYZHGz42DgDpxdGeOgjpG/q6mqveJashIhGW8XI+wb 8ITvSPfvBnt9Co4K97i7zUu/zOB/XpDvKZGTlZ8BHb3r9sbLJdYllvaCqtrOmPGC1rjM adFC/+68QhX0a4d5MaqDobZO5xZm2v6r5vRJBHvlL3/4ru1oBiimkCvfsIaZ4tXfmFDz yXLw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date; bh=kWVRrUQj9mWoqQlvFFTdbBytWIYtInyZrJjLe8l2Oqs=; b=QZ9hytDQoTu3UhGBgdEyM4IW76ru2vqrMlIZLIyveH8uq7TsRPYHUzkm0pzFZY1EDL yqb+pI1QpgKVbMWnvrq4lucR+4XrzsO0FjcufNbY6E35HvYUnkFa8afw5x/avgNFCD+p yIMuOIBE4xl5HoL4o0VPEkmw1IkYNRXlTymKIaAlneVS3vwzlVIsoj2cClP1G8CQk5UR /aM0D9+5lGdjvW7n/GUlnBe0KFxquw3SLl6ln1A4WKkXofptjiztU6PPo3rzFP6w1EnX OToKbYRRkOVPK/pPMMbvAto1kf2IndKik5zdiEPbkTbOse8Naw/xY8y8qm2NER6O7QIW ocRg== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) smtp.mailfrom=mhocko@kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id p26si8920300eju.361.2019.06.18.05.25.01 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 18 Jun 2019 05:25:01 -0700 (PDT) Received-SPF: softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) client-ip=195.135.220.15; Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) smtp.mailfrom=mhocko@kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 4181EAF49; Tue, 18 Jun 2019 12:25:01 +0000 (UTC) Date: Tue, 18 Jun 2019 14:24:57 +0200 From: Michal Hocko To: Shakeel Butt Cc: Johannes Weiner , Roman Gushchin , Tetsuo Handa , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/2] mm, oom: refactor dump_tasks for memcg OOMs Message-ID: <20190618122457.GD3318@dhcp22.suse.cz> References: <20190617231207.160865-1-shakeelb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190617231207.160865-1-shakeelb@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon 17-06-19 16:12:06, Shakeel Butt wrote: > dump_tasks() currently goes through all the processes present on the > system even for memcg OOMs. Change dump_tasks() similar to > select_bad_process() and use mem_cgroup_scan_tasks() to selectively > traverse the processes of the memcgs during memcg OOM. The changelog is quite modest to be honest. I would go with " 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 Thanks! > --- > 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 > -- Michal Hocko SUSE Labs