From patchwork Tue Jul 3 14:25:08 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tetsuo Handa X-Patchwork-Id: 10504177 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 13C6760532 for ; Tue, 3 Jul 2018 14:26:28 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0272C28700 for ; Tue, 3 Jul 2018 14:26:28 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id EA71328C55; Tue, 3 Jul 2018 14:26:27 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 70BB528949 for ; Tue, 3 Jul 2018 14:26:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0C6966B026A; Tue, 3 Jul 2018 10:26:22 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 0566D6B026B; Tue, 3 Jul 2018 10:26:21 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E34DD6B026C; Tue, 3 Jul 2018 10:26:21 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from mail-io0-f198.google.com (mail-io0-f198.google.com [209.85.223.198]) by kanga.kvack.org (Postfix) with ESMTP id B5E576B026A for ; Tue, 3 Jul 2018 10:26:21 -0400 (EDT) Received: by mail-io0-f198.google.com with SMTP id t23-v6so1694507ioa.9 for ; Tue, 03 Jul 2018 07:26:21 -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:from:to:cc :subject:date:message-id:in-reply-to:references; bh=7KAOyWQIKV8tGkL3H5o5crSpipCWkVFfZVxMvKp0qys=; b=Tw5sUjpDb05KvSGmK0EMSdjCxAEVHqju3y/7q7CiRroDEmchCoaPQOPGq3/cZmPKL8 FQo6KkrVzRY1ydJwRzjNil+/IsKVXlTl+EpXXIf5vPLPnZEvJ0vJmVgA9gJIsJsfFY2d xCKdZIXn6cMl4HDmAhYpzFPjF+CBPiUxbcVL8gcHH++az0Cop1DMSDpfE2+ks0Pxizn1 uqwrexwNdD2xLbUAQgKjkZhC4mCbUmihrnO05ZQ5TF83xqQHmW0dyMs8jCp0D7Z7eOce qyRbyzpVEVkDJ8V2jLawM8HhMOSLbNOs7/m9JL7AlD+jl4SUYLkFTc3qkKBXHKo9yRCV l4sg== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of penguin-kernel@i-love.sakura.ne.jp designates 202.181.97.72 as permitted sender) smtp.mailfrom=penguin-kernel@i-love.sakura.ne.jp X-Gm-Message-State: APt69E3DnuXnGlua3EB7LgI77ydrk0q/IQ97AQLhssrHa8LzCuMkI18U a1c02SpZb1pGR9ud2xxHgQUqCAfQIC2GmW6ewXBTTG1Ph4BAMwllvVsr+QIkSuDONCwmYN1c9jI Br4210FcKybFXEwm4G6ut62LU/LfrhcW+cZfEJPXkeri1TxSuiV3rojaMVihT167EVw== X-Received: by 2002:a6b:821e:: with SMTP id e30-v6mr25021068iod.110.1530627981532; Tue, 03 Jul 2018 07:26:21 -0700 (PDT) X-Google-Smtp-Source: AAOMgpcsHWzD49pxmOPW2x+FQ8fMCWuCcLI/Jp5eaTVMRpKQG3Gz3K419XXYaU4T3n/oJ78jns8/ X-Received: by 2002:a6b:821e:: with SMTP id e30-v6mr25021019iod.110.1530627980719; Tue, 03 Jul 2018 07:26:20 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1530627980; cv=none; d=google.com; s=arc-20160816; b=iZTxFnKwnBlYqrIJ8N/yPg+E9vZfjSb/1xoJg2QADvAS9fXt7CcpyXZfzBjIc+fSBF 7F69amifPL9eb0tpVrOw2LAxX5ImkTgVc5OBlr0eIf1tZhXC+lxNmMapQUI7Yy2+1XGt kJ8IJBbd86w3CHvW9mfXWBk1tRfXwRxvgIQRXnjOaC7jltsv//SUSdQ1a7B14sG8kzHn iTv4UnplEAE4EefAultNhpow/QXtg1rItoihNi9bSChY+WJylMrpWphJRRbf8RvA+l8S zuUPHU3czubdm3etxy/4ykf8rXafK16DDbI79jXp/+S558s7d7pFFarsZSRqmK7rijGr rrxg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=references:in-reply-to:message-id:date:subject:cc:to:from :arc-authentication-results; bh=7KAOyWQIKV8tGkL3H5o5crSpipCWkVFfZVxMvKp0qys=; b=rJtg0BiQg2QsqFHPRgY6keg/EsvOStTHqXPAN3zyqi9fFly/miKonmZLLHLrFYfMnY Iq//KqPOiWd7eVoNI16CI+Ae/Ai2tBS4zLfc9II4o6g1Z/AUz5mHmwSfIH9hEFG5yzUp WeH+2f9XtUgVBAtCxH6NJk8FhCsWMKsvCNytdlaquLrb6X6l/4gWNykPL4Sl7iHVr35d qNZKcT+0sZV92Kvu9mcHpU+9rRjBoM8ifbSf6vaBD4hb1LzEtVNR2Z6mEB5wUF/HMjN3 zXoiY+/cV56+ysftLOSQ6I/48p2G7s63J2gV9E71/luA/RbHXvIMSavwaMSiPtHCkDOc 0uKg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of penguin-kernel@i-love.sakura.ne.jp designates 202.181.97.72 as permitted sender) smtp.mailfrom=penguin-kernel@i-love.sakura.ne.jp Received: from www262.sakura.ne.jp (www262.sakura.ne.jp. [202.181.97.72]) by mx.google.com with ESMTPS id j10-v6si840466ioa.125.2018.07.03.07.26.20 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 03 Jul 2018 07:26:20 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of penguin-kernel@i-love.sakura.ne.jp designates 202.181.97.72 as permitted sender) client-ip=202.181.97.72; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of penguin-kernel@i-love.sakura.ne.jp designates 202.181.97.72 as permitted sender) smtp.mailfrom=penguin-kernel@i-love.sakura.ne.jp Received: from fsav105.sakura.ne.jp (fsav105.sakura.ne.jp [27.133.134.232]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id w63EPq1m063920; Tue, 3 Jul 2018 23:25:52 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav105.sakura.ne.jp (F-Secure/fsigk_smtp/530/fsav105.sakura.ne.jp); Tue, 03 Jul 2018 23:25:52 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/530/fsav105.sakura.ne.jp) Received: from ccsecurity.localdomain (softbank126074194044.bbtec.net [126.74.194.44]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id w63EPbJB063838 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Tue, 3 Jul 2018 23:25:51 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) From: Tetsuo Handa To: linux-mm@kvack.org, akpm@linux-foundation.org Cc: torvalds@linux-foundation.org, Tetsuo Handa , David Rientjes , Johannes Weiner , Michal Hocko , Roman Gushchin , Tejun Heo , Vladimir Davydov Subject: [PATCH 7/8] mm,oom: Do not sleep with oom_lock held. Date: Tue, 3 Jul 2018 23:25:08 +0900 Message-Id: <1530627910-3415-8-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1530627910-3415-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> References: <1530627910-3415-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> 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: X-Virus-Scanned: ClamAV using ClamSMTP Since oom_reap_mm() might take quite long time, it is not a good thing to block other threads in different OOM domains. This patch allows calling oom_reap_mm() from multiple concurrently allocating threads. By this change, the page allocator can spend CPU resource for oom_reap_mm() in their interested OOM domains. Also, out_of_memory() no longer holds oom_lock which might sleep (except cond_resched() and CONFIG_PREEMPT=y cases), for both OOM notifiers and oom_reap_mm() are called outside of oom_lock. This means that oom_lock is almost a spinlock now. But this patch does not convert oom_lock, for saving CPU resources for selecting OOM victims, printk() etc. is a still good thing to do. Signed-off-by: Tetsuo Handa Fixes: CVE-2016-10723 Cc: Roman Gushchin Cc: Michal Hocko Cc: Johannes Weiner Cc: Vladimir Davydov Cc: David Rientjes Cc: Tejun Heo --- mm/oom_kill.c | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index a1d3616..d534684 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -921,11 +921,18 @@ static bool oom_has_pending_victims(struct oom_control *oc) struct task_struct *p, *tmp; bool ret = false; bool gaveup = false; + unsigned int pos = 0; + unsigned int last_pos = 0; + retry: lockdep_assert_held(&oom_lock); list_for_each_entry_safe(p, tmp, &oom_victim_list, oom_victim_list) { struct mm_struct *mm = p->signal->oom_mm; + if (pos++ < last_pos) + continue; + last_pos = pos; + /* Skip OOM victims which current thread cannot select. */ if (oom_unkillable_task(p, oc->memcg, oc->nodemask)) continue; @@ -937,8 +944,23 @@ static bool oom_has_pending_victims(struct oom_control *oc) */ if (down_read_trylock(&mm->mmap_sem)) { if (!test_bit(MMF_OOM_SKIP, &mm->flags) && - !mm_has_blockable_invalidate_notifiers(mm)) + !mm_has_blockable_invalidate_notifiers(mm)) { + get_task_struct(p); + mmgrab(mm); + mutex_unlock(&oom_lock); oom_reap_mm(mm); + up_read(&mm->mmap_sem); + mmdrop(mm); + put_task_struct(p); + mutex_lock(&oom_lock); + /* + * Since ret == true, skipping some OOM victims + * by racing with exit_oom_mm() will not cause + * premature OOM victim selection. + */ + pos = 0; + goto retry; + } up_read(&mm->mmap_sem); } #endif