From patchwork Fri Jul 31 03:34:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Shi X-Patchwork-Id: 11693947 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 8311713B6 for ; Fri, 31 Jul 2020 03:35:06 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 59BAC20829 for ; Fri, 31 Jul 2020 03:35:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 59BAC20829 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 518438D0011; Thu, 30 Jul 2020 23:35:05 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 4CC4E8D000B; Thu, 30 Jul 2020 23:35:05 -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 3B8F08D0011; Thu, 30 Jul 2020 23:35:05 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0003.hostedemail.com [216.40.44.3]) by kanga.kvack.org (Postfix) with ESMTP id 26C318D000B for ; Thu, 30 Jul 2020 23:35:05 -0400 (EDT) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id A8C7A180AD817 for ; Fri, 31 Jul 2020 03:35:04 +0000 (UTC) X-FDA: 77096954928.01.land60_0513b3d26f80 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin01.hostedemail.com (Postfix) with ESMTP id 3CF521004BE3C for ; Fri, 31 Jul 2020 03:35:04 +0000 (UTC) X-Spam-Summary: 1,0,0,ff21e65460a5dd25,d41d8cd98f00b204,alex.shi@linux.alibaba.com,,RULES_HIT:41:69:355:379:541:800:960:966:973:988:989:1260:1261:1345:1431:1437:1534:1542:1711:1730:1747:1777:1792:2194:2196:2199:2200:2393:2559:2562:2693:3138:3139:3140:3141:3142:3353:3865:3867:3868:3870:3871:4321:4385:5007:6119:6261:7514:7875:9592:10004:11026:11473:11658:11914:12043:12296:12297:12438:12555:12895:12986:13846:14096:14181:14394:14721:21060:21080:21451:21627:21795:21990:30051:30054:30070,0,RBL:115.124.30.45:@linux.alibaba.com:.lbl8.mailshell.net-62.20.2.100 64.201.201.201;04yg8sf5ksnkg9iak6sz8y5ux96ryopkg1gds9ugnnghzxcde8kqn16r7c6a5tq.ho6hfxt8mnh4fz8jo6gprdjmkgyypufppgq7cq1ybqnwj1ty63mfftskjuqsnjb.h-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:none,Custom_rules:0:0:0,LFtime:24,LUA_SUMMARY:none X-HE-Tag: land60_0513b3d26f80 X-Filterd-Recvd-Size: 3314 Received: from out30-45.freemail.mail.aliyun.com (out30-45.freemail.mail.aliyun.com [115.124.30.45]) by imf23.hostedemail.com (Postfix) with ESMTP for ; Fri, 31 Jul 2020 03:35:00 +0000 (UTC) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R131e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01358;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0U4HxHq._1596166492; Received: from aliy8.localdomain(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0U4HxHq._1596166492) by smtp.aliyun-inc.com(127.0.0.1); Fri, 31 Jul 2020 11:34:53 +0800 From: Alex Shi To: Johannes Weiner Cc: Michal Hocko , Vladimir Davydov , Andrew Morton , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] mm/memcg: remove useless check on page->mem_cgroup Date: Fri, 31 Jul 2020 11:34:40 +0800 Message-Id: <1596166480-22814-1-git-send-email-alex.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 X-Rspamd-Queue-Id: 3CF521004BE3C X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 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: Since readahead page will be charged on memcg too. We don't need to check this exception now. Rmove them is safe as all user pages are charged before use. Signed-off-by: Alex Shi Cc: Johannes Weiner Cc: Michal Hocko Cc: Vladimir Davydov Cc: Andrew Morton Cc: cgroups@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Alex Shi Signed-off-by: Alex Shi Signed-off-by: Alex Shi Signed-off-by: Alex Shi Reviewed-by: Roman Gushchin Signed-off-by: Alex Shi Acked-by: Michal Hocko Acked-by: Michal Hocko --- mm/memcontrol.c | 21 ++++----------------- 1 file changed, 4 insertions(+), 17 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e84c2b5596f2..9e44ae22d591 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1322,12 +1322,7 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgd } memcg = page->mem_cgroup; - /* - * Swapcache readahead pages are added to the LRU - and - * possibly migrated - before they are charged. - */ - if (!memcg) - memcg = root_mem_cgroup; + VM_BUG_ON_PAGE(!memcg, page); mz = mem_cgroup_page_nodeinfo(memcg, page); lruvec = &mz->lruvec; @@ -6897,10 +6892,8 @@ void mem_cgroup_migrate(struct page *oldpage, struct page *newpage) if (newpage->mem_cgroup) return; - /* Swapcache readahead pages can get replaced before being charged */ memcg = oldpage->mem_cgroup; - if (!memcg) - return; + VM_BUG_ON_PAGE(!memcg, oldpage); /* Force-charge the new page. The old one will be freed soon */ nr_pages = thp_nr_pages(newpage); @@ -7094,10 +7087,7 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry) return; memcg = page->mem_cgroup; - - /* Readahead page, never charged */ - if (!memcg) - return; + VM_BUG_ON_PAGE(!memcg, page); /* * In case the memcg owning these pages has been offlined and doesn't @@ -7158,10 +7148,7 @@ int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry) return 0; memcg = page->mem_cgroup; - - /* Readahead page, never charged */ - if (!memcg) - return 0; + VM_BUG_ON_PAGE(!memcg, page); if (!entry.val) { memcg_memory_event(memcg, MEMCG_SWAP_FAIL);