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=FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 2B3B2C3F2CE for ; Wed, 4 Mar 2020 03:13:53 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9313A208C3 for ; Wed, 4 Mar 2020 03:13:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9313A208C3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=sina.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 375416B0003; Tue, 3 Mar 2020 22:13:51 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 2FE8E6B0005; Tue, 3 Mar 2020 22:13:51 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1EDD16B0006; Tue, 3 Mar 2020 22:13:51 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0025.hostedemail.com [216.40.44.25]) by kanga.kvack.org (Postfix) with ESMTP id 0178C6B0003 for ; Tue, 3 Mar 2020 22:13:50 -0500 (EST) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id D28923A91 for ; Wed, 4 Mar 2020 03:13:50 +0000 (UTC) X-FDA: 76556210220.19.rose45_5b9494be84f5d X-HE-Tag: rose45_5b9494be84f5d X-Filterd-Recvd-Size: 5025 Received: from r3-18.sinamail.sina.com.cn (r3-18.sinamail.sina.com.cn [202.108.3.18]) by imf30.hostedemail.com (Postfix) with SMTP for ; Wed, 4 Mar 2020 03:13:48 +0000 (UTC) Received: from unknown (HELO localhost.localdomain)([114.246.226.1]) by sina.com with ESMTP id 5E5F1CE80001616E; Wed, 4 Mar 2020 11:13:46 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com X-SMAIL-MID: 16357215073474 From: Hillf Danton To: Alex Shi Cc: cgroups@vger.kernel.org, akpm@linux-foundation.org, mgorman@techsingularity.net, tj@kernel.org, hughd@google.com, khlebnikov@yandex-team.ru, daniel.m.jordan@oracle.com, yang.shi@linux.alibaba.com, willy@infradead.org, hannes@cmpxchg.org, lkp@intel.com, Michal Hocko , Vladimir Davydov , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v9 02/20] mm/memcg: fold lock_page_lru into commit_charge Date: Wed, 4 Mar 2020 11:13:35 +0800 Message-Id: <20200304031335.9784-1-hdanton@sina.com> In-Reply-To: <1583146830-169516-1-git-send-email-alex.shi@linux.alibaba.com> References: <1583146830-169516-1-git-send-email-alex.shi@linux.alibaba.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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 Mon, 2 Mar 2020 19:00:12 +0800 Alex Shi wrote: >=20 > As Konstantin Khlebnikov mentioned: >=20 > Also I don't like these functions: > - called lock/unlock but actually also isolates > - used just once > - pgdat evaluated twice >=20 > Cleanup and fold these functions into commit_charge. It also reduces > lock time while lrucare && !PageLRU. >=20 > Signed-off-by: Alex Shi > Cc: Johannes Weiner > Cc: Michal Hocko > Cc: Konstantin Khlebnikov > Cc: Vladimir Davydov > Cc: Andrew Morton > Cc: cgroups@vger.kernel.org > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > --- > mm/memcontrol.c | 57 ++++++++++++++++++++-----------------------------= -------- > 1 file changed, 20 insertions(+), 37 deletions(-) >=20 > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index d09776cd6e10..875e2aebcde7 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2572,41 +2572,11 @@ static void cancel_charge(struct mem_cgroup *me= mcg, unsigned int nr_pages) > css_put_many(&memcg->css, nr_pages); > } > =20 > -static void lock_page_lru(struct page *page, int *isolated) > -{ > - pg_data_t *pgdat =3D page_pgdat(page); > - > - spin_lock_irq(&pgdat->lru_lock); > - if (PageLRU(page)) { > - struct lruvec *lruvec; > - > - lruvec =3D mem_cgroup_page_lruvec(page, pgdat); > - ClearPageLRU(page); > - del_page_from_lru_list(page, lruvec, page_lru(page)); > - *isolated =3D 1; > - } else > - *isolated =3D 0; > -} > - > -static void unlock_page_lru(struct page *page, int isolated) > -{ > - pg_data_t *pgdat =3D page_pgdat(page); > - > - if (isolated) { > - struct lruvec *lruvec; > - > - lruvec =3D mem_cgroup_page_lruvec(page, pgdat); > - VM_BUG_ON_PAGE(PageLRU(page), page); > - SetPageLRU(page); > - add_page_to_lru_list(page, lruvec, page_lru(page)); > - } > - spin_unlock_irq(&pgdat->lru_lock); > -} > - > static void commit_charge(struct page *page, struct mem_cgroup *memcg, > bool lrucare) > { > - int isolated; > + struct lruvec *lruvec =3D NULL; > + pg_data_t *pgdat; > =20 > VM_BUG_ON_PAGE(page->mem_cgroup, page); > =20 > @@ -2614,9 +2584,17 @@ static void commit_charge(struct page *page, str= uct mem_cgroup *memcg, > * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page > * may already be on some other mem_cgroup's LRU. Take care of it. > */ > - if (lrucare) > - lock_page_lru(page, &isolated); > - > + if (lrucare) { > + pgdat =3D page_pgdat(page); > + spin_lock_irq(&pgdat->lru_lock); > + > + if (PageLRU(page)) { > + lruvec =3D mem_cgroup_page_lruvec(page, pgdat); > + ClearPageLRU(page); > + del_page_from_lru_list(page, lruvec, page_lru(page)); > + } else > + spin_unlock_irq(&pgdat->lru_lock); > + } > /* > * Nobody should be changing or seriously looking at > * page->mem_cgroup at this point: > @@ -2633,8 +2611,13 @@ static void commit_charge(struct page *page, str= uct mem_cgroup *memcg, > */ > page->mem_cgroup =3D memcg; > =20 Well it is likely to update memcg for page without lru_lock held even if more care is required, which is a change added in the current semantic an= d worth a line of words in log. > - if (lrucare) > - unlock_page_lru(page, isolated); > + if (lrucare && lruvec) { > + lruvec =3D mem_cgroup_page_lruvec(page, pgdat); > + VM_BUG_ON_PAGE(PageLRU(page), page); > + SetPageLRU(page); > + add_page_to_lru_list(page, lruvec, page_lru(page)); > + spin_unlock_irq(&pgdat->lru_lock); > + } > } > =20 > #ifdef CONFIG_MEMCG_KMEM > --=20 > 1.8.3.1 >=20 >=20