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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,URIBL_BLOCKED,USER_AGENT_GIT 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 31EC5C5ACD7 for ; Wed, 18 Mar 2020 03:02:45 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EE86F20738 for ; Wed, 18 Mar 2020 03:02:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EE86F20738 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 9E5206B0006; Tue, 17 Mar 2020 23:02:44 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 996F26B0007; Tue, 17 Mar 2020 23:02:44 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8AABB6B0008; Tue, 17 Mar 2020 23:02:44 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0151.hostedemail.com [216.40.44.151]) by kanga.kvack.org (Postfix) with ESMTP id 740476B0006 for ; Tue, 17 Mar 2020 23:02:44 -0400 (EDT) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 81F60181AEF00 for ; Wed, 18 Mar 2020 03:02:44 +0000 (UTC) X-FDA: 76606985448.16.club06_52059555fa604 X-HE-Tag: club06_52059555fa604 X-Filterd-Recvd-Size: 2932 Received: from out30-44.freemail.mail.aliyun.com (out30-44.freemail.mail.aliyun.com [115.124.30.44]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Wed, 18 Mar 2020 03:02:43 +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=e01e07417;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0TsvBh-R_1584500549; Received: from localhost(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0TsvBh-R_1584500549) by smtp.aliyun-inc.com(127.0.0.1); Wed, 18 Mar 2020 11:02:37 +0800 From: Yang Shi To: shakeelb@google.com, vbabka@suse.cz, willy@infradead.org, akpm@linux-foundation.org Cc: yang.shi@linux.alibaba.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [v4 PATCH 2/2] mm: swap: use smp_mb__after_atomic() to order LRU bit set Date: Wed, 18 Mar 2020 11:02:21 +0800 Message-Id: <1584500541-46817-2-git-send-email-yang.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1584500541-46817-1-git-send-email-yang.shi@linux.alibaba.com> References: <1584500541-46817-1-git-send-email-yang.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: Memory barrier is needed after setting LRU bit, but smp_mb() is too strong. Some architectures, i.e. x86, imply memory barrier with atomic operations, so replacing it with smp_mb__after_atomic() sounds better, which is nop on strong ordered machines, and full memory barriers on others. With this change the vm-scalability cases would perform better on x86, I saw total 6% improvement with this patch and previous inline fix. The test data (lru-file-readtwice throughput) against v5.6-rc4: mainline w/ inline fix w/ both (adding this) 150MB 154MB 159MB Fixes: 9c4e6b1a7027 ("mm, mlock, vmscan: no more skipping pagevecs") Acked-by: Vlastimil Babka Reviewed-and-Tested-by: Shakeel Butt Signed-off-by: Yang Shi --- v3: * Added Shakeel's review-and-test signature. v2: * Solved the comment from Vlastimil and added his Ack. mm/swap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/swap.c b/mm/swap.c index cf39d24..74ea08a 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -931,7 +931,6 @@ static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec, VM_BUG_ON_PAGE(PageLRU(page), page); - SetPageLRU(page); /* * Page becomes evictable in two ways: * 1) Within LRU lock [munlock_vma_page() and __munlock_pagevec()]. @@ -958,7 +957,8 @@ static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec, * looking at the same page) and the evictable page will be stranded * in an unevictable LRU. */ - smp_mb(); + SetPageLRU(page); + smp_mb__after_atomic(); if (page_evictable(page)) { lru = page_lru(page); -- 1.8.3.1