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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 83585C33CB3 for ; Thu, 30 Jan 2020 22:52:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 328AC214D8 for ; Thu, 30 Jan 2020 22:52:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Xw5+tmp+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 328AC214D8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 900D26B039D; Thu, 30 Jan 2020 17:52:26 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 8B3336B039E; Thu, 30 Jan 2020 17:52:26 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7A0E26B039F; Thu, 30 Jan 2020 17:52:26 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0021.hostedemail.com [216.40.44.21]) by kanga.kvack.org (Postfix) with ESMTP id 628876B039D for ; Thu, 30 Jan 2020 17:52:26 -0500 (EST) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 2181421EA for ; Thu, 30 Jan 2020 22:52:26 +0000 (UTC) X-FDA: 76435801092.12.top64_6c820fd572f27 X-HE-Tag: top64_6c820fd572f27 X-Filterd-Recvd-Size: 4587 Received: from mail-ot1-f65.google.com (mail-ot1-f65.google.com [209.85.210.65]) by imf05.hostedemail.com (Postfix) with ESMTP for ; Thu, 30 Jan 2020 22:52:25 +0000 (UTC) Received: by mail-ot1-f65.google.com with SMTP id 66so4740483otd.9 for ; Thu, 30 Jan 2020 14:52:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=XSsZcaTfXOTFMqkKy3ZnZWZbmKJX0x/xuamjtfc8mfk=; b=Xw5+tmp+ErELACNDrM55VJgVQo5HyMVRPz03mHg0bvUr1o3WLBt2ztpTwqWNQ4C0cz wpoBqQ73TseKUZ8LDU9ET88Pi5YITbV03hAd07uV++wHLHZXPZGx4VKWxGVexrtMY6Yz 72uHZ7V4nOvxWxQGxD5tABvYW95KNOzueJQ34cQIwX8QbpwuSVeby9/H0+Jq2KuXH59V o5aDsxn/mdcpXjXG0Crki9njtDgVbCcKHaFxxDG456PtfNHslwX+4+KOyHiAHZiPpjs6 sbj1cQrJvOPRU9kmKgkGMdkR4NpB4AAaGF8xwA6EMAY5B9cnggQJj2OJ8ijfZjCFPx2/ z0eQ== 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=XSsZcaTfXOTFMqkKy3ZnZWZbmKJX0x/xuamjtfc8mfk=; b=qAuPI4Br7QQ2sbHWJo4fegB4L6vIJXMK5E3vGSJkDnHaOV1SW483JgfgVWY9Dp7RDq VNF4B+uHoSpo7nhlzXC9mJrNGsXEum+RyU+NAihBs5zHDkzt1gjYewe6pRJ4CZilKFeL AKZcR92CN4U6Wr51T+ARkJjHRlrWhw2tMuflZ7Db88wyhtfLOcIByWbzWhBtr5+aOF3W qMLrDo8u/2dev/FVD/qjAiN2E4wAxX/666o2zweOcQ5ecbU7+h1Wj/TRnXdTL0eS+kH7 LoLnQfLGZTb4ihC14sHuPI2oLIHjUH+lnjgs5ROULMULCUqH7N6Xn97ia5rZ0NBukpRV aaaA== X-Gm-Message-State: APjAAAWXggIPaRQPeTzMSFmJYoynV7ZIRaWOlBQiiSjhiDJc8ZFmX5ls P9GJ5dm+FZ0BJNn6Bz066MzeiH/mhvxRaE5jXlA= X-Google-Smtp-Source: APXvYqzXCCLiZwpASK2AHyFBUFB9uZN8F9l7IZ/XQxgSwk9nTjL6WYsOgvdFWnodSKcVaoUZ3cKLGDFGwHqEBfi4Xdc= X-Received: by 2002:a05:6830:1e64:: with SMTP id m4mr5653105otr.244.1580424744732; Thu, 30 Jan 2020 14:52:24 -0800 (PST) MIME-Version: 1.0 References: <20200121090048.GG29276@dhcp22.suse.cz> <20200126233935.GA11536@bombadil.infradead.org> <20200127150024.GN1183@dhcp22.suse.cz> <20200127190653.GA8708@bombadil.infradead.org> <20200128081712.GA18145@dhcp22.suse.cz> <20200128083044.GB6615@bombadil.infradead.org> <20200128091352.GC18145@dhcp22.suse.cz> <20200128104857.GC6615@bombadil.infradead.org> <20200128113953.GA24244@dhcp22.suse.cz> In-Reply-To: From: Cong Wang Date: Thu, 30 Jan 2020 14:52:13 -0800 Message-ID: Subject: Re: [PATCH] mm: avoid blocking lock_page() in kcompactd To: Michal Hocko Cc: Matthew Wilcox , LKML , Andrew Morton , linux-mm , Mel Gorman , Vlastimil Babka Content-Type: text/plain; charset="UTF-8" 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 Tue, Jan 28, 2020 at 11:44 AM Cong Wang wrote: > > On Tue, Jan 28, 2020 at 3:39 AM Michal Hocko wrote: > > > > On Tue 28-01-20 02:48:57, Matthew Wilcox wrote: > > > Doesn't the stack trace above indicate that we're doing migration as > > > the result of an allocation in add_to_page_cache_lru()? > > > > Which stack trace do you refer to? Because the one above doesn't show > > much more beyond mem_cgroup_iter and likewise others in this email > > thread. I do not really remember any stack with lock_page on the trace. > > I think the page is locked in add_to_page_cache_lru() by > __SetPageLocked(), as the stack trace shows __add_to_page_cache_locked(). > It is not yet unlocked, as it is still looping inside try_charge(). > > I will write a script to see if I can find the longest time spent in reclaim > as you suggested. After digging the changelog, I believe the following commit could fix the problem: commit f9c645621a28e37813a1de96d9cbd89cde94a1e4 Author: Tetsuo Handa Date: Mon Sep 23 15:37:08 2019 -0700 memcg, oom: don't require __GFP_FS when invoking memcg OOM killer which is not yet in our 4.19 branch yet. We will sync with 4.19 stable soon. Thanks.