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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4B691C433EF for ; Sat, 20 Nov 2021 07:59:01 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C00056B0071; Sat, 20 Nov 2021 02:58:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id BE3BF6B0072; Sat, 20 Nov 2021 02:58:45 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A9F206B0073; Sat, 20 Nov 2021 02:58:45 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0254.hostedemail.com [216.40.44.254]) by kanga.kvack.org (Postfix) with ESMTP id 9A23A6B0071 for ; Sat, 20 Nov 2021 02:58:45 -0500 (EST) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 5524480C7BC0 for ; Sat, 20 Nov 2021 07:58:35 +0000 (UTC) X-FDA: 78828556590.04.C7C56E9 Received: from mail-lf1-f51.google.com (mail-lf1-f51.google.com [209.85.167.51]) by imf01.hostedemail.com (Postfix) with ESMTP id 9E3475092ED9 for ; Sat, 20 Nov 2021 07:58:32 +0000 (UTC) Received: by mail-lf1-f51.google.com with SMTP id y26so54156756lfa.11 for ; Fri, 19 Nov 2021 23:58:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=QDPBsHcfNzrPZpXm7j+tJ6FtAT1aH1QKACsXUwu2lsU=; b=PDIEkVRE4lRmmix6/kxfmiSW4LoI0BO2oI5eeIooXPPBVyf65uczSyS7/ryrSS30TB yxTiLtqZPEhw/QJsG03QilaLw0yxveHy4FdQKSADKfOQeZ+PzgAjKkAAMZ9fTG2X7PHy q3PcsDO1p59bhbLyWub0/L3p8OfhhttrwOAZUm4+ltQQgUTSY9rOrbMNacNSIAxYb07s Pt9fk8i0hGIcYGImn6ufTyobVPEffh3xY4MdR7gl7Eu8nyqzLZKq+TnidX1MqXLynmwH iiRf2LJpIO+G67HLqgqO+zKYKIscIpBouV5K55umtQPZenddR0fPFdAUpe1yoLJuk4WU nAVw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=QDPBsHcfNzrPZpXm7j+tJ6FtAT1aH1QKACsXUwu2lsU=; b=qIxpCbdLc+Gt4ZsazUm6b8KcDYj9sMQoKjuPpCVYRCJtwQk7KSJva5rtQ/QwSS20YA zC8e32yy2x5lFNsJI5lLyKud1I0Wk9TtgVDu6dvkU4KhUZqONPrlclTZgWx3pQd1aopB bX18u68cEbMvFoMSxrvWvtZg69b/JgZuPiBdoaQ3e+Ugsna5cPhXZL8w9hAilxXm2cQw 2bxATo3Dwk2AstnOWkD76oqtNG+mJJQz9y4y6M6037Map1+XdbOFThTJJOdRJsDfFr3B 672Pi9CoP09ik0wfQ1oyVQrRJ8VyRazcr/eGAlgFCgWq3qFMUmL1Bgnq7v5KtPuay1sm V7CA== X-Gm-Message-State: AOAM533Pwl3eTej5KssL0/9YZ4Uk2OHuhCEjNIe1q/uiHi16NDaifGdS toqvDvixNeQ7RTvm+5RnrJHo6S49fhaGF+bZSKWgzQ== X-Google-Smtp-Source: ABdhPJw+OYVb4seahyrAiDFYKQkciHblBbjBsl9XGIXlNspD805fH4RQ2gSTe1cRC2JQc8l1JxWEgxNl8G9bQKbPpYo= X-Received: by 2002:a2e:a314:: with SMTP id l20mr34005249lje.86.1637395113126; Fri, 19 Nov 2021 23:58:33 -0800 (PST) MIME-Version: 1.0 References: <20211120045011.3074840-1-almasrymina@google.com> <20211120045011.3074840-3-almasrymina@google.com> In-Reply-To: <20211120045011.3074840-3-almasrymina@google.com> From: Shakeel Butt Date: Fri, 19 Nov 2021 23:58:21 -0800 Message-ID: Subject: Re: [PATCH v4 2/4] mm/oom: handle remote ooms To: Mina Almasry Cc: Johannes Weiner , Michal Hocko , Vladimir Davydov , Andrew Morton , Jonathan Corbet , Alexander Viro , Hugh Dickins , Shuah Khan , Greg Thelen , Dave Chinner , Matthew Wilcox , Roman Gushchin , "Theodore Ts'o" , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 9E3475092ED9 X-Stat-Signature: 1ef57jim6detq4rkyrreztfpt4h39xan Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=PDIEkVRE; spf=pass (imf01.hostedemail.com: domain of shakeelb@google.com designates 209.85.167.51 as permitted sender) smtp.mailfrom=shakeelb@google.com; dmarc=pass (policy=reject) header.from=google.com X-HE-Tag: 1637395112-942551 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 Fri, Nov 19, 2021 at 8:50 PM Mina Almasry wrote: > [...] > +/* > + * Returns true if current's mm is a descendant of the memcg_under_oom (or > + * equal to it). False otherwise. This is used by the oom-killer to detect > + * ooms due to remote charging. > + */ > +bool is_remote_oom(struct mem_cgroup *memcg_under_oom) > +{ > + struct mem_cgroup *current_memcg; > + bool is_remote_oom; > + > + if (!memcg_under_oom) > + return false; > + > + rcu_read_lock(); > + current_memcg = mem_cgroup_from_task(current); > + if (current_memcg && !css_tryget_online(¤t_memcg->css)) No need to grab a reference. You can call mem_cgroup_is_descendant() within rcu. > + current_memcg = NULL; > + rcu_read_unlock(); > + > + if (!current_memcg) > + return false; > + > + is_remote_oom = > + !mem_cgroup_is_descendant(current_memcg, memcg_under_oom); > + css_put(¤t_memcg->css); > + > + return is_remote_oom; > +} > +