From patchwork Thu Oct 29 10:45:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Shi X-Patchwork-Id: 11866019 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id ADAE361C for ; Thu, 29 Oct 2020 10:46:13 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 674C820731 for ; Thu, 29 Oct 2020 10:46:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 674C820731 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 3FE186B0085; Thu, 29 Oct 2020 06:45:53 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 26F276B0087; Thu, 29 Oct 2020 06:45:53 -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 10D576B0088; Thu, 29 Oct 2020 06:45:53 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0111.hostedemail.com [216.40.44.111]) by kanga.kvack.org (Postfix) with ESMTP id C33086B0085 for ; Thu, 29 Oct 2020 06:45:52 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 6ADBC33CD for ; Thu, 29 Oct 2020 10:45:52 +0000 (UTC) X-FDA: 77424632544.25.peace84_04067062728c Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin25.hostedemail.com (Postfix) with ESMTP id 4A86B1804E3A0 for ; Thu, 29 Oct 2020 10:45:52 +0000 (UTC) X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,alex.shi@linux.alibaba.com,,RULES_HIT:30012:30054:30064:30070:30090,0,RBL:47.88.44.36:@linux.alibaba.com:.lbl8.mailshell.net-64.10.201.10 62.18.0.100;04yryf486oxsd7uqwqufec8y9xkzdyctke4fs6bekms3zscntofo5xngpj94x98.kjdzxtx9xntf8yatpszdn7xga1imtszwrnzeaedj1pwyns3etwps4gst5b68weq.r-lbl8.mailshell.net-223.238.255.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:69,LUA_SUMMARY:none X-HE-Tag: peace84_04067062728c X-Filterd-Recvd-Size: 8456 Received: from out4436.biz.mail.alibaba.com (out4436.biz.mail.alibaba.com [47.88.44.36]) by imf12.hostedemail.com (Postfix) with ESMTP for ; Thu, 29 Oct 2020 10:45:51 +0000 (UTC) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R901e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04407;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=22;SR=0;TI=SMTPD_---0UDXwDyN_1603968328; Received: from aliy80.localdomain(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0UDXwDyN_1603968328) by smtp.aliyun-inc.com(127.0.0.1); Thu, 29 Oct 2020 18:45:35 +0800 From: Alex Shi To: 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, hannes@cmpxchg.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 Cc: Michal Hocko Subject: [PATCH v20 15/20] mm/lru: introduce TestClearPageLRU Date: Thu, 29 Oct 2020 18:45:00 +0800 Message-Id: <1603968305-8026-16-git-send-email-alex.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1603968305-8026-1-git-send-email-alex.shi@linux.alibaba.com> References: <1603968305-8026-1-git-send-email-alex.shi@linux.alibaba.com> 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: Currently lru_lock still guards both lru list and page's lru bit, that's ok. but if we want to use specific lruvec lock on the page, we need to pin down the page's lruvec/memcg during locking. Just taking lruvec lock first may be undermined by the page's memcg charge/migration. To fix this problem, we could clear the lru bit out of locking and use it as pin down action to block the page isolation in memcg changing. So now a standard steps of page isolation is following: 1, get_page(); #pin the page avoid to be free 2, TestClearPageLRU(); #block other isolation like memcg change 3, spin_lock on lru_lock; #serialize lru list access 4, delete page from lru list; The step 2 could be optimzed/replaced in scenarios which page is unlikely be accessed or be moved between memcgs. This patch start with the first part: TestClearPageLRU, which combines PageLRU check and ClearPageLRU into a macro func TestClearPageLRU. This function will be used as page isolation precondition to prevent other isolations some where else. Then there are may !PageLRU page on lru list, need to remove BUG() checking accordingly. There 2 rules for lru bit now: 1, the lru bit still indicate if a page on lru list, just in some temporary moment(isolating), the page may have no lru bit when it's on lru list. but the page still must be on lru list when the lru bit set. 2, have to remove lru bit before delete it from lru list. As Andrew Morton mentioned this change would dirty cacheline for page isn't on LRU. But the lost would be acceptable in Rong Chen report: https://lore.kernel.org/lkml/20200304090301.GB5972@shao2-debian/ Suggested-by: Johannes Weiner Signed-off-by: Alex Shi Acked-by: Hugh Dickins Cc: Hugh Dickins Cc: Johannes Weiner Cc: Michal Hocko Cc: Vladimir Davydov Cc: Andrew Morton Cc: linux-kernel@vger.kernel.org Cc: cgroups@vger.kernel.org Cc: linux-mm@kvack.org Acked-by: Johannes Weiner --- include/linux/page-flags.h | 1 + mm/mlock.c | 3 +-- mm/vmscan.c | 39 +++++++++++++++++++-------------------- 3 files changed, 21 insertions(+), 22 deletions(-) diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 4f6ba9379112..14a0cac9e099 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -335,6 +335,7 @@ static inline void page_init_poison(struct page *page, size_t size) PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD) __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD) PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD) + TESTCLEARFLAG(LRU, lru, PF_HEAD) PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD) TESTCLEARFLAG(Active, active, PF_HEAD) PAGEFLAG(Workingset, workingset, PF_HEAD) diff --git a/mm/mlock.c b/mm/mlock.c index d487aa864e86..7b0e6334be6f 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -276,10 +276,9 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone) * We already have pin from follow_page_mask() * so we can spare the get_page() here. */ - if (PageLRU(page)) { + if (TestClearPageLRU(page)) { struct lruvec *lruvec; - ClearPageLRU(page); lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page)); del_page_from_lru_list(page, lruvec, diff --git a/mm/vmscan.c b/mm/vmscan.c index 845733afccde..ce4ab932805c 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1542,7 +1542,7 @@ unsigned int reclaim_clean_pages_from_list(struct zone *zone, */ int __isolate_lru_page(struct page *page, isolate_mode_t mode) { - int ret = -EINVAL; + int ret = -EBUSY; /* Only take pages on the LRU. */ if (!PageLRU(page)) @@ -1552,8 +1552,6 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode) if (PageUnevictable(page) && !(mode & ISOLATE_UNEVICTABLE)) return ret; - ret = -EBUSY; - /* * To minimise LRU disruption, the caller can indicate that it only * wants to isolate pages it will be able to operate on without @@ -1600,8 +1598,10 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode) * sure the page is not being freed elsewhere -- the * page release code relies on it. */ - ClearPageLRU(page); - ret = 0; + if (TestClearPageLRU(page)) + ret = 0; + else + put_page(page); } return ret; @@ -1667,8 +1667,6 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, page = lru_to_page(src); prefetchw_prev_lru_page(page, src, flags); - VM_BUG_ON_PAGE(!PageLRU(page), page); - nr_pages = compound_nr(page); total_scan += nr_pages; @@ -1765,21 +1763,18 @@ int isolate_lru_page(struct page *page) VM_BUG_ON_PAGE(!page_count(page), page); WARN_RATELIMIT(PageTail(page), "trying to isolate tail page"); - if (PageLRU(page)) { + if (TestClearPageLRU(page)) { pg_data_t *pgdat = page_pgdat(page); struct lruvec *lruvec; - spin_lock_irq(&pgdat->lru_lock); + get_page(page); lruvec = mem_cgroup_page_lruvec(page, pgdat); - if (PageLRU(page)) { - int lru = page_lru(page); - get_page(page); - ClearPageLRU(page); - del_page_from_lru_list(page, lruvec, lru); - ret = 0; - } + spin_lock_irq(&pgdat->lru_lock); + del_page_from_lru_list(page, lruvec, page_lru(page)); spin_unlock_irq(&pgdat->lru_lock); + ret = 0; } + return ret; } @@ -4289,6 +4284,10 @@ void check_move_unevictable_pages(struct pagevec *pvec) nr_pages = thp_nr_pages(page); pgscanned += nr_pages; + /* block memcg migration during page moving between lru */ + if (!TestClearPageLRU(page)) + continue; + if (pagepgdat != pgdat) { if (pgdat) spin_unlock_irq(&pgdat->lru_lock); @@ -4297,10 +4296,7 @@ void check_move_unevictable_pages(struct pagevec *pvec) } lruvec = mem_cgroup_page_lruvec(page, pgdat); - if (!PageLRU(page) || !PageUnevictable(page)) - continue; - - if (page_evictable(page)) { + if (page_evictable(page) && PageUnevictable(page)) { enum lru_list lru = page_lru_base_type(page); VM_BUG_ON_PAGE(PageActive(page), page); @@ -4309,12 +4305,15 @@ void check_move_unevictable_pages(struct pagevec *pvec) add_page_to_lru_list(page, lruvec, lru); pgrescued += nr_pages; } + SetPageLRU(page); } if (pgdat) { __count_vm_events(UNEVICTABLE_PGRESCUED, pgrescued); __count_vm_events(UNEVICTABLE_PGSCANNED, pgscanned); spin_unlock_irq(&pgdat->lru_lock); + } else if (pgscanned) { + count_vm_events(UNEVICTABLE_PGSCANNED, pgscanned); } } EXPORT_SYMBOL_GPL(check_move_unevictable_pages);