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=-6.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,UNPARSEABLE_RELAY autolearn=unavailable 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 64918C04AB1 for ; Fri, 10 May 2019 02:25:40 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 24F9D217F5 for ; Fri, 10 May 2019 02:25:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 24F9D217F5 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 BA6546B0003; Thu, 9 May 2019 22:25:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B2F516B0006; Thu, 9 May 2019 22:25:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9F87D6B0007; Thu, 9 May 2019 22:25:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-pl1-f197.google.com (mail-pl1-f197.google.com [209.85.214.197]) by kanga.kvack.org (Postfix) with ESMTP id 62A706B0003 for ; Thu, 9 May 2019 22:25:39 -0400 (EDT) Received: by mail-pl1-f197.google.com with SMTP id y9so2734331plt.11 for ; Thu, 09 May 2019 19:25:39 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:subject:to:cc :references:from:message-id:date:user-agent:mime-version:in-reply-to :content-transfer-encoding:content-language; bh=uS9/ksYuUIT8ZBiKQL05bD/A38ycreIcjG1GMtHRHuU=; b=PTkFbeE76mC0WPQKzSa9zhKkklDhfE/9Rw66Q0FqpgfUVcwKhjVbeIOY6rkdNonzBY gIZBlOMdk0tkQWsXGocVFruQfgyH2qlY3nAW1rOEC7JFCM4mzcp4GsHp5so1d4BoxVF0 h/pGNcZKLXTDCT945biJmPCd5+oyum/ArqHSiMw5rW725xR2OK1BKbFIm+PvxTOa0oZp Ge8p3gcz7W6/lbuWk4iqw8t0+HRBC+miG2iLlw9nv7AWlriqZNqiLJydt0EOtFKGiY3o aaOn8FtCxb1M9ZIKzenYZW/Z1KkrxA0rySmcp3ttlfQr+tknNKfiPIoa+65irrCQxpYB 3v6g== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of yang.shi@linux.alibaba.com designates 47.88.44.37 as permitted sender) smtp.mailfrom=yang.shi@linux.alibaba.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=alibaba.com X-Gm-Message-State: APjAAAXZOniKTjp9OfEDG3knKHR0DZcqqzXGTxJ+0TiFOzXkRYB8PTso NPYZzyE+phBu/P2eEZ/RWqMm7v/olO9IMCc+3dyjo1QTdXNo1S2c6uUmn9PBgp626EaM1Ae9Iaj qca6JNGvDI33qLFQV4olLKiz+h63dKH0omowh2+OLjA45eDQemee0Mbk0I3fJu71drQ== X-Received: by 2002:a17:902:8ec8:: with SMTP id x8mr9667564plo.21.1557455139063; Thu, 09 May 2019 19:25:39 -0700 (PDT) X-Google-Smtp-Source: APXvYqzj36LB9ozsgEcsB3UoKgvo025raqMkEaQ3RA2QsDgEr5XIzeJOzEaEDFe2AxW0tZNrQ+/S X-Received: by 2002:a17:902:8ec8:: with SMTP id x8mr9667487plo.21.1557455138313; Thu, 09 May 2019 19:25:38 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1557455138; cv=none; d=google.com; s=arc-20160816; b=Oah0nYjoFziPeAcHDekQjcnJS7brgqu7qkaNDardM1weToHZTWRIKsTIuG3QW42f5z qDy+ii8ZTufnO7OqWvBpT3otzENzb9hvZAyW03I1eimZOUhTHwTdWf3rtsIch5taOlNO fULG16izZwsUPpTevKiBqVl9RMaW/fp2xjhMLsdmMzJpAd8dWPZrF2PtLxd4+yxgjXa7 b5a8XD5B2ORcOKUHTVYqTb4541pZmfahu1764gbHipBLWSGwzh4StbKf6yNwOuNhVnLB fLDD0TXnzIq3n1x9Xf1gPTCCiV68RTTmRSCEUYxZcj0tp/7hHjWp3Pgj+V+nX+EU+HpU 5Hpw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-language:content-transfer-encoding:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject; bh=uS9/ksYuUIT8ZBiKQL05bD/A38ycreIcjG1GMtHRHuU=; b=LBBMHpYxGqk+yTfbzV1tWSVSj2op97YUqP3wczDzmlcFF8nf9wn9cE2G1JtowNnDHq ajuSmnzxD4cskhDXxeSz2nTP/A7ZLfh0a0X3FV/7xE/LWX7wyTFr6GIKZKtd6puyt2+U ISlF/PwAaXNMaYhqstROPyXSUdbhOLonHnFRqcaBv+2YNH+jeVcFTuW6goeM3ju1cz30 f8OC2b7KpWY+9CEPukfbB4WnCFJwlEx3bcNX1kn/WXrxvFeS+yoDrFjnbTxZZ3N7KupB aZog/nD0s66lJUbYiNqIJj1Y4IKwQsbtQ6VPIFG3lQX/DIkT92NZKSJIii8b2ikyat4s 9OGw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of yang.shi@linux.alibaba.com designates 47.88.44.37 as permitted sender) smtp.mailfrom=yang.shi@linux.alibaba.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=alibaba.com Received: from out4437.biz.mail.alibaba.com (out4437.biz.mail.alibaba.com. [47.88.44.37]) by mx.google.com with ESMTPS id d62si5783293pfa.72.2019.05.09.19.25.37 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 09 May 2019 19:25:38 -0700 (PDT) Received-SPF: pass (google.com: domain of yang.shi@linux.alibaba.com designates 47.88.44.37 as permitted sender) client-ip=47.88.44.37; Authentication-Results: mx.google.com; spf=pass (google.com: domain of yang.shi@linux.alibaba.com designates 47.88.44.37 as permitted sender) smtp.mailfrom=yang.shi@linux.alibaba.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=alibaba.com X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R151e4;CH=green;DM=||false|;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04394;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0TRIa4cz_1557455120; Received: from US-143344MP.local(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0TRIa4cz_1557455120) by smtp.aliyun-inc.com(127.0.0.1); Fri, 10 May 2019 10:25:23 +0800 Subject: Re: [PATCH] mm: vmscan: correct nr_reclaimed for THP To: "Huang, Ying" Cc: hannes@cmpxchg.org, mhocko@suse.com, mgorman@techsingularity.net, kirill.shutemov@linux.intel.com, hughd@google.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <1557447392-61607-1-git-send-email-yang.shi@linux.alibaba.com> <87y33fjbvr.fsf@yhuang-dev.intel.com> From: Yang Shi Message-ID: <1fb73973-f409-1411-423b-c48895d3dde8@linux.alibaba.com> Date: Thu, 9 May 2019 19:25:20 -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: <87y33fjbvr.fsf@yhuang-dev.intel.com> Content-Type: text/plain; charset=windows-1252; 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 5/9/19 7:12 PM, Huang, Ying wrote: > Yang Shi writes: > >> Since commit bd4c82c22c36 ("mm, THP, swap: delay splitting THP after >> swapped out"), THP can be swapped out in a whole. But, nr_reclaimed >> still gets inc'ed by one even though a whole THP (512 pages) gets >> swapped out. >> >> This doesn't make too much sense to memory reclaim. For example, direct >> reclaim may just need reclaim SWAP_CLUSTER_MAX pages, reclaiming one THP >> could fulfill it. But, if nr_reclaimed is not increased correctly, >> direct reclaim may just waste time to reclaim more pages, >> SWAP_CLUSTER_MAX * 512 pages in worst case. >> >> This change may result in more reclaimed pages than scanned pages showed >> by /proc/vmstat since scanning one head page would reclaim 512 base pages. >> >> Cc: "Huang, Ying" >> Cc: Johannes Weiner >> Cc: Michal Hocko >> Cc: Mel Gorman >> Cc: "Kirill A . Shutemov" >> Cc: Hugh Dickins >> Signed-off-by: Yang Shi >> --- >> I'm not quite sure if it was the intended behavior or just omission. I tried >> to dig into the review history, but didn't find any clue. I may miss some >> discussion. >> >> mm/vmscan.c | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/mm/vmscan.c b/mm/vmscan.c >> index fd9de50..7e026ec 100644 >> --- a/mm/vmscan.c >> +++ b/mm/vmscan.c >> @@ -1446,7 +1446,11 @@ static unsigned long shrink_page_list(struct list_head *page_list, >> >> unlock_page(page); >> free_it: >> - nr_reclaimed++; >> + /* >> + * THP may get swapped out in a whole, need account >> + * all base pages. >> + */ >> + nr_reclaimed += (1 << compound_order(page)); >> >> /* >> * Is there need to periodically free_page_list? It would > Good catch! Thanks! > > How about to change this to > > > nr_reclaimed += hpage_nr_pages(page); Either is fine to me. Is this faster than "1 << compound_order(page)"? > > Best Regards, > Huang, Ying