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=-13.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=no 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 3EE33C432BE for ; Mon, 2 Aug 2021 22:16:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2442960EBC for ; Mon, 2 Aug 2021 22:16:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232590AbhHBWQv (ORCPT ); Mon, 2 Aug 2021 18:16:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52730 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231651AbhHBWQu (ORCPT ); Mon, 2 Aug 2021 18:16:50 -0400 Received: from mail-yb1-xb2a.google.com (mail-yb1-xb2a.google.com [IPv6:2607:f8b0:4864:20::b2a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 17F3CC061764 for ; Mon, 2 Aug 2021 15:16:40 -0700 (PDT) Received: by mail-yb1-xb2a.google.com with SMTP id k65so9079928yba.13 for ; Mon, 02 Aug 2021 15:16:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=aVGojMx+DUr0Bkpg2GauKzHjG+QgnSZtH0f6WVA+GT0=; b=By54SS2dwDkwJGwhuIY8NsqezsY4v2SSiJz/qQ9prW1GHhN67KM613ArcrnWbfN29w 66vJKXYIXsQWnaTR7h1Zg/CFtOpvRzaM6jlIwcaNF46QV77I8s1SYBSas/aRaxTzZw9Q r5kcuWovT3l/xOkysf+JSJWN36GqoJxKjj8NvWoeAnhIirN6HY4zI3YG1GX4M6EB0jLA /n+GC3iP+r/Rv7q99K2vr6rxpb/M6LHy6+9m/dE7gM9Pa6wvZ262dyGCi6FvoYRW7OZi VuDuagjPRdTAPq4VP9znMB0RCmC61qRMholJzB5mVVtKwzz41MR9B6NTx5+ss6GAmQ3K QCsw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=aVGojMx+DUr0Bkpg2GauKzHjG+QgnSZtH0f6WVA+GT0=; b=X/k9dg4LUG3vAdBBbnGdcm4/ZX0QZJkdBqWOnbDjkcLRPLliQ1xOJRSO2R+qYUs3TR lkux83X5ME7ufeiirMBP+p2FBbdRG7C4QeudZ9LrN/2vrk72A6v8dDF5oM1WAk+zbsyB GVqnnDAzvqSm5+G/rdsqb1dTMVlnWxyVwAK7G5tqOd2nxh5LGfKtajrZzSbY1CkyreeV /FC3yI62RfHytbsE4F4u9JTe1ZULeKu7M2imDI6WztUCDLuo0w8ibs7XShbzhpvzvL7d xW8C+OmuUg2JdudlxkSRj0Sy2GP4SOaJL1uafbG5EtSr6My2zU9/nODQdcaCvkiCu9oh eUHQ== X-Gm-Message-State: AOAM53235gaKRGkRDjd3dfsg7k8vD3OFYKtVuJGQ1z6ZEs1/2++m2bCs KD2yIdpD+haYnw9thnzHS4X2aYaYPx+g8DFqArMToQ== X-Google-Smtp-Source: ABdhPJznsVErJkSBK2mP8Pgp6BYYOZiuyhX+5Nzyp4ctrjdWEjLWT0m8oePoA6y1TBwFp0C7H8pMMC76CRg5lw9NzP0= X-Received: by 2002:a25:7ec4:: with SMTP id z187mr24318844ybc.136.1627942599134; Mon, 02 Aug 2021 15:16:39 -0700 (PDT) MIME-Version: 1.0 References: <20210723011436.60960-1-surenb@google.com> In-Reply-To: From: Suren Baghdasaryan Date: Mon, 2 Aug 2021 15:16:27 -0700 Message-ID: Subject: Re: [PATCH v3 1/2] mm: introduce process_mrelease system call To: Shakeel Butt Cc: Michal Hocko , Andrew Morton , David Rientjes , Matthew Wilcox , Johannes Weiner , Roman Gushchin , Rik van Riel , Minchan Kim , Christian Brauner , Christoph Hellwig , Oleg Nesterov , David Hildenbrand , Jann Horn , Andy Lutomirski , Christian Brauner , Florian Weimer , Jan Engelhardt , Tim Murray , Linux API , Linux MM , LKML , kernel-team Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 2, 2021 at 1:08 PM Suren Baghdasaryan wrote: > > On Mon, Aug 2, 2021 at 1:05 PM Shakeel Butt wrote: > > > > On Mon, Aug 2, 2021 at 12:54 PM Suren Baghdasaryan wrote: > > > > > > On Mon, Jul 26, 2021 at 6:44 AM Shakeel Butt wrote: > > > > > > > > On Mon, Jul 26, 2021 at 12:27 AM Michal Hocko wrote: > > > > > > > > > [...] > > > > > > > > > > Is process_mrelease on all of them really necessary? I thought that the > > > > > primary reason for the call is to guarantee a forward progress in cases > > > > > where the userspace OOM victim cannot die on SIGKILL. That should be > > > > > more an exception than a normal case, no? > > > > > > > > > > > > > I am thinking of using this API in this way: On user-defined OOM > > > > condition, kill a job/cgroup and unconditionally reap all of its > > > > processes. Keep monitoring the situation and if it does not improve go > > > > for another kill and reap. > > > > > > > > I can add additional logic in between kill and reap to see if reap is > > > > necessary but unconditionally reaping is more simple. > > > > > > > > > > > > > > > An alternative would be to have a cgroup specific interface for > > > > > > reaping similar to cgroup.kill. > > > > > > > > > > Could you elaborate? > > > > > > > > > > > > > I mentioned this in [1] where I was thinking if it makes sense to > > > > overload cgroup.kill to also add the SIGKILLed processes in > > > > oom_reaper_list. The downside would be that there will be one thread > > > > doing the reaping and the syscall approach allows userspace to reap in > > > > multiple threads. I think for now, I would go with whatever Suren is > > > > proposing and we can always add more stuff if need arises. > > > > > > > > [1] https://lore.kernel.org/containers/CALvZod4jsb6bFzTOS4ZRAJGAzBru0oWanAhezToprjACfGm+ew@mail.gmail.com/ > > > > > > Hi Folks, > > > So far I don't think there was any request for further changes. > > > Anything else you would want me to address or are we in a good shape > > > wrt this feature? > > > If so, would people who had a chance to review this patchset be > > > willing to endorse it with their Reviewed-by or Acked-by? > > > > I think with Michal's suggestion to use a killable mmap lock, at least > > I am good with the patch. > > Ah, yes. Thanks for pointing this out! I'll replace mmap_read_lock() > with mmap_read_lock_killable(). Will post an updated version later > today. Posted the next version at https://lore.kernel.org/patchwork/patch/1471403/