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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,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 57B52C433E1 for ; Mon, 24 Aug 2020 12:55:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 402F120838 for ; Mon, 24 Aug 2020 12:55:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727888AbgHXMzi (ORCPT ); Mon, 24 Aug 2020 08:55:38 -0400 Received: from out30-56.freemail.mail.aliyun.com ([115.124.30.56]:53750 "EHLO out30-56.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727839AbgHXMza (ORCPT ); Mon, 24 Aug 2020 08:55:30 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R121e4;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=21;SR=0;TI=SMTPD_---0U6k9-bl_1598273712; Received: from aliy80.localdomain(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0U6k9-bl_1598273712) by smtp.aliyun-inc.com(127.0.0.1); Mon, 24 Aug 2020 20:55:22 +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 Subject: [PATCH v18 27/32] mm/swap.c: optimizing __pagevec_lru_add lru_lock Date: Mon, 24 Aug 2020 20:55:00 +0800 Message-Id: <1598273705-69124-28-git-send-email-alex.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1598273705-69124-1-git-send-email-alex.shi@linux.alibaba.com> References: <1598273705-69124-1-git-send-email-alex.shi@linux.alibaba.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The current relock logical will change lru_lock when if found a new lruvec, so if 2 memcgs are reading file or alloc page equally, they could hold the lru_lock alternately. This patch will record the needed lru_lock and only hold them once in above scenario. That could reduce the lock contention. Suggested-by: Konstantin Khlebnikov Signed-off-by: Alex Shi Cc: Andrew Morton Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- mm/swap.c | 43 ++++++++++++++++++++++++++++++++++++------- 1 file changed, 36 insertions(+), 7 deletions(-) diff --git a/mm/swap.c b/mm/swap.c index 2ac78e8fab71..fe53449fa1b8 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -958,24 +958,53 @@ static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec) trace_mm_lru_insertion(page, lru); } +struct add_lruvecs { + struct list_head lists[PAGEVEC_SIZE]; + struct lruvec *vecs[PAGEVEC_SIZE]; +}; + /* * Add the passed pages to the LRU, then drop the caller's refcount * on them. Reinitialises the caller's pagevec. */ void __pagevec_lru_add(struct pagevec *pvec) { - int i; + int i, j, total; struct lruvec *lruvec = NULL; unsigned long flags = 0; + struct page *page; + struct add_lruvecs lruvecs; + + lruvecs.vecs[0] = NULL; + for (i = total = 0; i < pagevec_count(pvec); i++) { + page = pvec->pages[i]; + lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page)); + + /* Try to find a same lruvec */ + for (j = 0; j <= total; j++) + if (lruvec == lruvecs.vecs[j]) + break; + /* A new lruvec */ + if (j > total) { + INIT_LIST_HEAD(&lruvecs.lists[total]); + lruvecs.vecs[total] = lruvec; + j = total++; + lruvecs.vecs[total] = 0; + } - for (i = 0; i < pagevec_count(pvec); i++) { - struct page *page = pvec->pages[i]; + list_add(&page->lru, &lruvecs.lists[j]); + } - lruvec = relock_page_lruvec_irqsave(page, lruvec, &flags); - __pagevec_lru_add_fn(page, lruvec); + for (i = 0; i < total; i++) { + spin_lock_irqsave(&lruvecs.vecs[i]->lru_lock, flags); + while (!list_empty(&lruvecs.lists[i])) { + page = lru_to_page(&lruvecs.lists[i]); + list_del(&page->lru); + __pagevec_lru_add_fn(page, lruvecs.vecs[i]); + } + spin_unlock_irqrestore(&lruvecs.vecs[i]->lru_lock, flags); } - if (lruvec) - unlock_page_lruvec_irqrestore(lruvec, flags); + release_pages(pvec->pages, pvec->nr); pagevec_reinit(pvec); } -- 1.8.3.1