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=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY autolearn=ham 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 3386DC43613 for ; Mon, 24 Jun 2019 16:54:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 043C5204FD for ; Mon, 24 Jun 2019 16:54:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732274AbfFXQyR (ORCPT ); Mon, 24 Jun 2019 12:54:17 -0400 Received: from out30-44.freemail.mail.aliyun.com ([115.124.30.44]:33883 "EHLO out30-44.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726700AbfFXQyR (ORCPT ); Mon, 24 Jun 2019 12:54:17 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R101e4;CH=green;DM=||false|;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04426;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=11;SR=0;TI=SMTPD_---0TV6jVAp_1561395249; Received: from US-143344MP.local(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0TV6jVAp_1561395249) by smtp.aliyun-inc.com(127.0.0.1); Tue, 25 Jun 2019 00:54:13 +0800 Subject: Re: [v3 PATCH 2/4] mm: move mem_cgroup_uncharge out of __page_cache_release() From: Yang Shi To: "Kirill A. Shutemov" Cc: ktkhai@virtuozzo.com, kirill.shutemov@linux.intel.com, hannes@cmpxchg.org, mhocko@suse.com, hughd@google.com, shakeelb@google.com, rientjes@google.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <1560376609-113689-1-git-send-email-yang.shi@linux.alibaba.com> <1560376609-113689-3-git-send-email-yang.shi@linux.alibaba.com> <20190613113943.ahmqpezemdbwgyax@box> <2909ce59-86ba-ea0b-479f-756020fb32af@linux.alibaba.com> Message-ID: Date: Mon, 24 Jun 2019 09:54:05 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <2909ce59-86ba-ea0b-479f-756020fb32af@linux.alibaba.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/13/19 10:13 AM, Yang Shi wrote: > > > On 6/13/19 4:39 AM, Kirill A. Shutemov wrote: >> On Thu, Jun 13, 2019 at 05:56:47AM +0800, Yang Shi wrote: >>> The later patch would make THP deferred split shrinker memcg aware, but >>> it needs page->mem_cgroup information in THP destructor, which is >>> called >>> after mem_cgroup_uncharge() now. >>> >>> So, move mem_cgroup_uncharge() from __page_cache_release() to compound >>> page destructor, which is called by both THP and other compound pages >>> except HugeTLB.  And call it in __put_single_page() for single order >>> page. >> >> If I read the patch correctly, it will change behaviour for pages with >> NULL_COMPOUND_DTOR. Have you considered it? Are you sure it will not >> break >> anything? > Hi Kirill, Did this solve your concern? Any more comments on this series? Thanks, Yang > So far a quick search shows NULL_COMPOUND_DTOR is not used by any type > of compound page. The HugeTLB code sets destructor to > NULL_COMPOUND_DTOR when freeing hugetlb pages via hugetlb specific > destructor. > > The prep_new_page() would call prep_compound_page() if __GFP_COMP is > used, which sets dtor to COMPOUND_PAGE_DTOR by default.  Just hugetlb > and THP set their specific dtors. > > And, it looks __put_compound_page() doesn't check if dtor is NULL or > not at all. > >> >