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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 479DFC433EF for ; Wed, 13 Apr 2022 16:00:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231436AbiDMQC4 (ORCPT ); Wed, 13 Apr 2022 12:02:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60056 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229528AbiDMQCy (ORCPT ); Wed, 13 Apr 2022 12:02:54 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1F3C826556 for ; Wed, 13 Apr 2022 09:00:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1649865631; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+wn7w2vF9MQR+lrDQeY4ZU+D9MJrKuaExJ1DdBANLOc=; b=TWLhu71QLLrDX8iNt9yoGH/pfi3R41UGJHrmSszLZc8rfjtKXt04UpzHMbBun94Qv88BRU TQIz6HrVzVPRWttIJvb8N/2A7KXVeApKCYIhbG6b/5GHf+9xy78QqR65l18oV8rssqf929 MUgkaRy5Gh6SmHBfrNuWrh/xrEH0cT4= Received: from mail-qv1-f72.google.com (mail-qv1-f72.google.com [209.85.219.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-203-ICqAjVd9NWyOZBymKjYSBw-1; Wed, 13 Apr 2022 12:00:30 -0400 X-MC-Unique: ICqAjVd9NWyOZBymKjYSBw-1 Received: by mail-qv1-f72.google.com with SMTP id o1-20020a0c9001000000b00440e415a3a2so2093421qvo.13 for ; Wed, 13 Apr 2022 09:00:30 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=+wn7w2vF9MQR+lrDQeY4ZU+D9MJrKuaExJ1DdBANLOc=; b=k9WdnJ8c49t3BU/J7G9uroB9AV8U8qO/SJ5eYMGpT0Eh2CMDeOxr21hOirsDsx3f5m SDvLJ5BJTl9EaxzyN1mitxy9NqTHHGjeZVa5sBJIcBMctujES4vqnLFvv34ThdF+3Xwb zhlTXfKoYBYpGzI2WH06WI84CRlrcDFUIk8xsoC3sDeje7nR7QPjY5LivmkWBT3oy3ZG 5fM8w1PncveWbLqXzUq3EAgCOW72d+BmjFLQjYVNToFzEKl9PfYGpgF5vcYeZwO1/jGc 7sP0mYljNEsZr0UpDeGKicA+9WF7rJXqiHEPd/nuUSLbhX5gt5pZj8unU3ISP4VctBaI T1Xg== X-Gm-Message-State: AOAM530/uKAiatGNOpFTOxv0n+usT7D9pjgq+/2eH5tpffYuGCMNOu9/ 9IU1ASugq3Un6DhofgHLURKdlvyCUnuUK7RCUNYO/BeWYjg4KkXlW5r08i8Bx1yexs0B45QGzIs yJb6wdTKMlZyfSEfK0uY4IGc7 X-Received: by 2002:a37:9b91:0:b0:69a:48d:54f2 with SMTP id d139-20020a379b91000000b0069a048d54f2mr7313002qke.476.1649865628963; Wed, 13 Apr 2022 09:00:28 -0700 (PDT) X-Google-Smtp-Source: ABdhPJw2UEdFboFqgF3H4gDkx/Vl+TBWQAfu1ZXxNGKAvk/rIbXKTFIzr1SNtSN9XvcHOKM0HyG1Pg== X-Received: by 2002:a37:9b91:0:b0:69a:48d:54f2 with SMTP id d139-20020a379b91000000b0069a048d54f2mr7312965qke.476.1649865628373; Wed, 13 Apr 2022 09:00:28 -0700 (PDT) Received: from [192.168.0.188] ([24.48.139.231]) by smtp.gmail.com with ESMTPSA id f18-20020a05622a1a1200b002eef655b3e3sm5901469qtb.94.2022.04.13.09.00.26 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 13 Apr 2022 09:00:27 -0700 (PDT) Message-ID: <97a04805-120c-abc1-4e34-01cfdc5ef8fb@redhat.com> Date: Wed, 13 Apr 2022 12:00:25 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH v8] oom_kill.c: futex: Don't OOM reap the VMA containing the robust_list_head Content-Language: en-US To: Michal Hocko Cc: Joel Savitz , Peter Zijlstra , linux-mm@kvack.org, linux-kernel , Rafael Aquini , Waiman Long , Baoquan He , Christoph von Recklinghausen , Don Dutile , "Herton R . Krzesinski" , David Rientjes , Andrea Arcangeli , Andrew Morton , Davidlohr Bueso , Ingo Molnar , Darren Hart , stable@kernel.org, Thomas Gleixner References: <20220408032809.3696798-1-npache@redhat.com> <20220408081549.GM2731@worktop.programming.kicks-ass.net> <87k0bzk7e5.ffs@tglx> <87sfqni77s.ffs@tglx> <87wnfwf4e5.ffs@tglx> From: Nico Pache In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > index 7ec38194f8e1..be6d65ead7ec 100644 > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -632,7 +632,7 @@ static void oom_reap_task(struct task_struct *tsk) > */ > set_bit(MMF_OOM_SKIP, &mm->flags); > > - /* Drop a reference taken by wake_oom_reaper */ > + /* Drop a reference taken by queue_oom_repaer */ > put_task_struct(tsk); > } > > @@ -644,12 +644,12 @@ static int oom_reaper(void *unused) > struct task_struct *tsk = NULL; > > wait_event_freezable(oom_reaper_wait, oom_reaper_list != NULL); > - spin_lock(&oom_reaper_lock); > + spin_lock_irq(&oom_reaper_lock); > if (oom_reaper_list != NULL) { > tsk = oom_reaper_list; > oom_reaper_list = tsk->oom_reaper_list; > } > - spin_unlock(&oom_reaper_lock); > + spin_unlock_irq(&oom_reaper_lock); > > if (tsk) > oom_reap_task(tsk); > @@ -658,22 +658,50 @@ static int oom_reaper(void *unused) > return 0; > } > > -static void wake_oom_reaper(struct task_struct *tsk) > +static void wake_oom_reaper_fn(struct timer_list *timer) > { > - /* mm is already queued? */ > - if (test_and_set_bit(MMF_OOM_REAP_QUEUED, &tsk->signal->oom_mm->flags)) > - return; > + struct task_struct *tsk = container_of(timer, struct task_struct, oom_reaper_timer); > + struct mm_struct *mm = tsk->signal->oom_mm; > + unsigned long flags; > > - get_task_struct(tsk); > + /* The victim managed to terminate on its own - see exit_mmap */ > + if (test_bit(MMF_OOM_SKIP, &mm->flags)) { > + put_task_struct(tsk); > + return; > + } > > - spin_lock(&oom_reaper_lock); > + spin_lock_irqsave(&oom_reaper_lock, flags); > tsk->oom_reaper_list = oom_reaper_list; > oom_reaper_list = tsk; > - spin_unlock(&oom_reaper_lock); > + spin_unlock_irqrestore(&oom_reaper_lock, flags); > trace_wake_reaper(tsk->pid); > wake_up(&oom_reaper_wait); > } > > +/* > + * Give OOM victims some head room to exit themselves. If they do not exit > + * on their own the oom reaper is invoked. > + * The timeout is basically arbitrary and there is no best value to use. > + * The longer it will be the longer the worst case scenario OOM can > + * take. The smaller the timeout the more likely the oom_reaper can get > + * into the way and release resources which could be needed during the > + * exit path - e.g. futex robust lists can sit in the anonymous memory > + * which could be reaped and the exit path won't be able to let waiters > + * know the holding task has terminated. > + */ > +#define OOM_REAPER_DELAY (2*HZ) > +static void queue_oom_repaer(struct task_struct *tsk) > +{ > + /* mm is already queued? */ > + if (test_and_set_bit(MMF_OOM_REAP_QUEUED, &tsk->signal->oom_mm->flags)) > + return; > + > + get_task_struct(tsk); > + timer_setup(&tsk->oom_reaper_timer, wake_oom_reaper_fn, 0); > + tsk->oom_reaper_timer.expires = jiffies + OOM_REAPER_DELAY; > + add_timer(&tsk->oom_reaper_timer); > +} > + > static int __init oom_init(void) > { > oom_reaper_th = kthread_run(oom_reaper, NULL, "oom_reaper"); > @@ -681,7 +709,7 @@ static int __init oom_init(void) > } > subsys_initcall(oom_init) > #else > -static inline void wake_oom_reaper(struct task_struct *tsk) > +static inline void queue_oom_repaer(struct task_struct *tsk) > { > } > #endif /* CONFIG_MMU */ > @@ -932,7 +960,7 @@ static void __oom_kill_process(struct task_struct *victim, const char *message) > rcu_read_unlock(); > > if (can_oom_reap) > - wake_oom_reaper(victim); > + queue_oom_repaer(victim); > > mmdrop(mm); > put_task_struct(victim); > @@ -968,7 +996,7 @@ static void oom_kill_process(struct oom_control *oc, const char *message) > task_lock(victim); > if (task_will_free_mem(victim)) { > mark_oom_victim(victim); > - wake_oom_reaper(victim); > + queue_oom_repaer(victim); > task_unlock(victim); > put_task_struct(victim); > return; > @@ -1067,7 +1095,7 @@ bool out_of_memory(struct oom_control *oc) > */ > if (task_will_free_mem(current)) { > mark_oom_victim(current); > - wake_oom_reaper(current); > + queue_oom_repaer(current); > return true; > } Thanks for the code Michal-- It does seem to fix our issue! I will post it after I finish running it through a few more test cases, and our internal testing suites. Cheers, -- Nico