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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_SANE_1 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 438B8C0044D for ; Tue, 17 Mar 2020 02:06:10 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B87FB20674 for ; Tue, 17 Mar 2020 02:06:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B87FB20674 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 3E5166B0005; Mon, 16 Mar 2020 22:06:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 396376B0006; Mon, 16 Mar 2020 22:06:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2AC596B0007; Mon, 16 Mar 2020 22:06:09 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0127.hostedemail.com [216.40.44.127]) by kanga.kvack.org (Postfix) with ESMTP id 10DEE6B0005 for ; Mon, 16 Mar 2020 22:06:09 -0400 (EDT) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id CDB47180AD815 for ; Tue, 17 Mar 2020 02:06:08 +0000 (UTC) X-FDA: 76603214016.29.oven94_6f6c92f49d116 X-HE-Tag: oven94_6f6c92f49d116 X-Filterd-Recvd-Size: 4440 Received: from out30-45.freemail.mail.aliyun.com (out30-45.freemail.mail.aliyun.com [115.124.30.45]) by imf39.hostedemail.com (Postfix) with ESMTP for ; Tue, 17 Mar 2020 02:06:05 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R101e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07488;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_---0Tsp8nCr_1584410758; Received: from US-143344MP.local(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0Tsp8nCr_1584410758) by smtp.aliyun-inc.com(127.0.0.1); Tue, 17 Mar 2020 10:06:00 +0800 Subject: Re: [v2 PATCH 1/2] mm: swap: make page_evictable() inline To: Shakeel Butt Cc: Vlastimil Babka , Matthew Wilcox , Andrew Morton , Linux MM , LKML References: <1584397455-28701-1-git-send-email-yang.shi@linux.alibaba.com> From: Yang Shi Message-ID: Date: Mon, 16 Mar 2020 19:05:58 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US 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 3/16/20 4:46 PM, Shakeel Butt wrote: > On Mon, Mar 16, 2020 at 3:24 PM Yang Shi wrote: >> When backporting commit 9c4e6b1a7027 ("mm, mlock, vmscan: no more >> skipping pagevecs") to our 4.9 kernel, our test bench noticed around 10% >> down with a couple of vm-scalability's test cases (lru-file-readonce, >> lru-file-readtwice and lru-file-mmap-read). I didn't see that much down >> on my VM (32c-64g-2nodes). It might be caused by the test configuration, >> which is 32c-256g with NUMA disabled and the tests were run in root memcg, >> so the tests actually stress only one inactive and active lru. It >> sounds not very usual in mordern production environment. >> >> That commit did two major changes: >> 1. Call page_evictable() >> 2. Use smp_mb to force the PG_lru set visible >> >> It looks they contribute the most overhead. The page_evictable() is a >> function which does function prologue and epilogue, and that was used by >> page reclaim path only. However, lru add is a very hot path, so it >> sounds better to make it inline. However, it calls page_mapping() which >> is not inlined either, but the disassemble shows it doesn't do push and >> pop operations and it sounds not very straightforward to inline it. >> >> Other than this, it sounds smp_mb() is not necessary for x86 since >> SetPageLRU is atomic which enforces memory barrier already, replace it >> with smp_mb__after_atomic() in the following patch. >> >> With the two fixes applied, the tests can get back around 5% on that >> test bench and get back normal on my VM. Since the test bench >> configuration is not that usual and I also saw around 6% up on the >> latest upstream, so it sounds good enough IMHO. >> >> The below is test data (lru-file-readtwice throughput) against the v5.6-rc4: >> mainline w/ inline fix >> 150MB 154MB >> >> With this patch the throughput gets 2.67% up. The data with using >> smp_mb__after_atomic() is showed in the following patch. >> >> Fixes: 9c4e6b1a7027 ("mm, mlock, vmscan: no more skipping pagevecs") >> Cc: Shakeel Butt >> Cc: Vlastimil Babka >> Cc: Matthew Wilcox >> Signed-off-by: Yang Shi > > So, I tested on a real machine with limiting the 'dd' on a single node > and reading 100 GiB sparse file (less than a single node). I just ran > a single instance to not cause the lru lock contention. The cmd I used > is "dd if=file-100GiB of=/dev/null bs=4k". I ran the cmd 10 times with > drop_caches in between and measured the time it took. > > Without patch: 56.64143 +- 0.672 sec > > With patches: 56.10 +- 0.21 sec > > Reviewed-and-Tested-by: Shakeel Butt Thanks Shakeel. It'd better to add your test result in the commit log too.