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=-6.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 79C63C00A89 for ; Mon, 2 Nov 2020 15:19:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2637B22258 for ; Mon, 2 Nov 2020 15:19:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=cmpxchg-org.20150623.gappssmtp.com header.i=@cmpxchg-org.20150623.gappssmtp.com header.b="Nb21Rwzj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726437AbgKBPTz (ORCPT ); Mon, 2 Nov 2020 10:19:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56546 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726171AbgKBPTy (ORCPT ); Mon, 2 Nov 2020 10:19:54 -0500 Received: from mail-qk1-x742.google.com (mail-qk1-x742.google.com [IPv6:2607:f8b0:4864:20::742]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 81730C061A04 for ; Mon, 2 Nov 2020 07:19:53 -0800 (PST) Received: by mail-qk1-x742.google.com with SMTP id 12so7842173qkl.8 for ; Mon, 02 Nov 2020 07:19:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=A7azf0b6L3Ni0+kWxhbDe/aVVrrIHnecUUge6+Ge8lA=; b=Nb21RwzjjoHwgcCRnJW1DYf7eJoR32b1MqtBGslTFLn/e8GgtInbyDQYC+nYumNmv4 d/xV0YK1F4tPpdIl/ZecTav+F2G6Q/LJvmV6X3FPJIY7tkqJ+BXt7NXTD7Q2yJcF8MUX 5jA+vbiysm50Woe6xvq9XafPtlKHvoGBZQq4qkyfBF1D77R1kl+BwdMFU9WGgyvA5qXc 9CmpAx6Rq79YWITccoqYewpoxxG162YRQ85qbJkhDMGz4qHpaVxwhGLwfAS8vxWGlomm z/7x7YoUNtBYJk5ZAwVAUdWoC4JMEUUUSXvjufaAjA+DzyYKmw/rk0YExgOYrMhlcpvH AjZg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=A7azf0b6L3Ni0+kWxhbDe/aVVrrIHnecUUge6+Ge8lA=; b=BYbxUSkqcFJFYigavkaCnOwG+HqG6Ya+UBGYZF+uJdJSWJnWXn+uo82S4gZeUNzgzB 2LDP8fXm6AAbm0szGWT17YnPtgl474krme3Pq/tD9C4RrlSZhRrh/RSK2i1uDNNjPJTT oi8GBXqxnfASBHQRuNgN+SbKTNJ15CumAIO97q/cKTdacorf2fPMn71BG6nh/xMThHEZ eHDbrQxxEV32C9e7+beyQm1pSjXC4wWb2HykuAOS7y8DD30OyYiu5enT/HFGc9+/7j6V fdxprrBLpKsipLmXxNFPhVMSJ+f/NGn2sNjP25ohVi6lMnTnRKQe3srz4D0gbXy47J9S 9yDw== X-Gm-Message-State: AOAM531yOY3CjM1ZSQCFTMrDiwgiMBZok9JywSeJ0cragE/zSM2E+AUY dVSeicqDpsarWW1dfw5yMgg5xQ== X-Google-Smtp-Source: ABdhPJzVBHUKjjrMXG4VpTx2UbsLQUvS0o0fqC4fierNozFF1Lesa0lxUtR56DK7XfMrHu3tRkHVSg== X-Received: by 2002:a05:620a:408f:: with SMTP id f15mr1600176qko.276.1604330392791; Mon, 02 Nov 2020 07:19:52 -0800 (PST) Received: from localhost ([163.114.130.6]) by smtp.gmail.com with ESMTPSA id 6sm8183809qks.51.2020.11.02.07.19.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 02 Nov 2020 07:19:52 -0800 (PST) Date: Mon, 2 Nov 2020 10:18:07 -0500 From: Johannes Weiner To: Alex Shi Cc: akpm@linux-foundation.org, mgorman@techsingularity.net, tj@kernel.org, hughd@google.com, khlebnikov@yandex-team.ru, daniel.m.jordan@oracle.com, willy@infradead.org, lkp@intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, shakeelb@google.com, iamjoonsoo.kim@lge.com, richard.weiyang@gmail.com, kirill@shutemov.name, alexander.duyck@gmail.com, rong.a.chen@intel.com, mhocko@suse.com, vdavydov.dev@gmail.com, shy828301@gmail.com Subject: Re: [PATCH v20 16/20] mm/compaction: do page isolation first in compaction Message-ID: <20201102151807.GI724984@cmpxchg.org> References: <1603968305-8026-1-git-send-email-alex.shi@linux.alibaba.com> <1603968305-8026-17-git-send-email-alex.shi@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1603968305-8026-17-git-send-email-alex.shi@linux.alibaba.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 29, 2020 at 06:45:01PM +0800, Alex Shi wrote: > Currently, compaction would get the lru_lock and then do page isolation > which works fine with pgdat->lru_lock, since any page isoltion would > compete for the lru_lock. If we want to change to memcg lru_lock, we > have to isolate the page before getting lru_lock, thus isoltion would > block page's memcg change which relay on page isoltion too. Then we > could safely use per memcg lru_lock later. > > The new page isolation use previous introduced TestClearPageLRU() + > pgdat lru locking which will be changed to memcg lru lock later. > > Hugh Dickins fixed following bugs in this patch's > early version: > > Fix lots of crashes under compaction load: isolate_migratepages_block() > must clean up appropriately when rejecting a page, setting PageLRU again > if it had been cleared; and a put_page() after get_page_unless_zero() > cannot safely be done while holding locked_lruvec - it may turn out to > be the final put_page(), which will take an lruvec lock when PageLRU. > And move __isolate_lru_page_prepare back after get_page_unless_zero to > make trylock_page() safe: > trylock_page() is not safe to use at this time: its setting PG_locked > can race with the page being freed or allocated ("Bad page"), and can > also erase flags being set by one of those "sole owners" of a freshly > allocated page who use non-atomic __SetPageFlag(). > > Suggested-by: Johannes Weiner > Signed-off-by: Alex Shi > Acked-by: Hugh Dickins > Cc: Andrew Morton > Cc: Matthew Wilcox > Cc: linux-kernel@vger.kernel.org > Cc: linux-mm@kvack.org Acked-by: Johannes Weiner