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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id A5791C61DA3 for ; Tue, 21 Feb 2023 10:29:50 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 400A56B0075; Tue, 21 Feb 2023 05:29:50 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 3B0156B0078; Tue, 21 Feb 2023 05:29:50 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 29FD16B007B; Tue, 21 Feb 2023 05:29:50 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 18F5E6B0075 for ; Tue, 21 Feb 2023 05:29:50 -0500 (EST) Received: from smtpin25.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id AB085C1258 for ; Tue, 21 Feb 2023 10:29:49 +0000 (UTC) X-FDA: 80490928098.25.5D32D5F Received: from mail-pl1-f169.google.com (mail-pl1-f169.google.com [209.85.214.169]) by imf09.hostedemail.com (Postfix) with ESMTP id BB21A14000B for ; Tue, 21 Feb 2023 10:29:46 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=shopee.com header.s=shopee.com header.b=cTvBJZUX; spf=pass (imf09.hostedemail.com: domain of haifeng.xu@shopee.com designates 209.85.214.169 as permitted sender) smtp.mailfrom=haifeng.xu@shopee.com; dmarc=pass (policy=reject) header.from=shopee.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1676975386; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=A6bq0cNZ1AfAVAWRtxraIczrguYU6xxumxI1OimKFcQ=; b=kX9zlGrWn80nHroGBe1Bd6I+Xoo5mfTXod5hRCzTFjwmHhkk28f34SSrl1WyVUAx1wGwRF m1O3wNbHdxAvKqrLNELyInjOSkt/5LRBez2jfHuN2WmQuId1IwqjnPPUpf9h8bhZ26+oIX KmCOHtdCgNkImNkfwFEwkPzaK39jdt8= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=shopee.com header.s=shopee.com header.b=cTvBJZUX; spf=pass (imf09.hostedemail.com: domain of haifeng.xu@shopee.com designates 209.85.214.169 as permitted sender) smtp.mailfrom=haifeng.xu@shopee.com; dmarc=pass (policy=reject) header.from=shopee.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1676975386; a=rsa-sha256; cv=none; b=LK6D8l/xk1I32HAp0CQwOmN2hXQvciBlWDE336RSsgSdemUCzfqtlRHYhwcgapxyVClnAd MZ2FXypceAEAWojTgYzSoQZayLkpkj0arzmTsX+mmhNCOWrid+PwClpLnAoAXnBinah5R3 j3g690/FtDwJQp66zKiHuVXt+L1YEDo= Received: by mail-pl1-f169.google.com with SMTP id e5so5550929plg.8 for ; Tue, 21 Feb 2023 02:29:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shopee.com; s=shopee.com; h=in-reply-to:from:references:cc:to:subject:user-agent:mime-version :date:message-id:from:to:cc:subject:date:message-id:reply-to; bh=A6bq0cNZ1AfAVAWRtxraIczrguYU6xxumxI1OimKFcQ=; b=cTvBJZUXrr8VeSPaAd/OQA+aC9rJ1ogQGfjpWHh5OAYclK7SrwdWvEquQUueynfkvQ a3efwTPEAnGZBc0WnVX/Sf/cIN+IQouc4MrvflZTyKcv7Wume1MEDzSGxZcZysDAl+sE SVWMotA2T640xagoe44Qxr516z/1JAgBGMCO6Yp6ztVQcG3cGpzJlaeEmGcuk8WubaJW M/ALr4Xy17oe3KDqnqcWC5HaLx4BGaYDFhLCc7a7Fnivk1b9R9AqoyS65x3kUBhySLhF xVsCampZ1JzrKo55JLoUti7ABpU3exb9EdtbLC8mylSTrCs0xQaJfHgG7jYo3KA9dnEV MzYg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:from:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=A6bq0cNZ1AfAVAWRtxraIczrguYU6xxumxI1OimKFcQ=; b=JvB+WC54KrpnNNFTu5PXIMY4fKNnYZg9DqcLnXfdcI/Spxzhju42g5LUDyGWH/8pNg IclieQxGLZZCg7ECeZZQrQPRZk/lM+vf6ZEHOp0s1vAbw5IsikQpyRudTv3dAgMNtnlO 3VU3RoN+ot6cwkKIGSR4HrR5IO8XZy5h6dF8HFKYE5LrG5ZcFXFXtD+6AC2RgHzqhnlU 0v3Ay0n8k/4TnCWiGT7Kd9IR7tsod2bR2lXCZr3XtNAHbfH4WgpcWlTEos/qN4YIjbTW xZ4PtmJR2Dqz2/MvXKmVHQC1b9crqQ5NtV4T1nrtg+FUKSdxEh+0cKUoWFO7o6wqoYtY hjxw== X-Gm-Message-State: AO0yUKXJ89OVZQ3jhmtCroBUTysAezfsC2GNcWwmE61msbo3z8aCYLFd hQ+fP4OPduidaT7yt+y4enEH8w== X-Google-Smtp-Source: AK7set9wbCdH/nkJCOJHU3fJsl2GLKwTo19qpBlknnmESPkg0QqEOEjup5dFLBvBGufj4aVLSHmoEQ== X-Received: by 2002:a17:90b:4b86:b0:234:106a:34ab with SMTP id lr6-20020a17090b4b8600b00234106a34abmr6031142pjb.6.1676975385411; Tue, 21 Feb 2023 02:29:45 -0800 (PST) Received: from [10.54.24.141] ([143.92.118.3]) by smtp.gmail.com with ESMTPSA id z4-20020a17090acb0400b00234a2f6d9c0sm2722126pjt.57.2023.02.21.02.29.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 21 Feb 2023 02:29:44 -0800 (PST) Content-Type: multipart/mixed; boundary="------------Spvi9DJXN5O0V9DKveeK2Vsh" Message-ID: <82918a12-d83e-10c0-0e04-eec26657b699@shopee.com> Date: Tue, 21 Feb 2023 18:29:39 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Subject: Re: [PATCH] mm/memcg: Skip high limit check in root memcg To: Michal Hocko Cc: hannes@cmpxchg.org, shakeelb@google.com, muchun.song@linux.dev, akpm@linux-foundation.org, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20230210094550.5125-1-haifeng.xu@shopee.com> From: Haifeng Xu In-Reply-To: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: BB21A14000B X-Stat-Signature: aii7mgdcs5wi7ja5d6ziu61cgxsyqz1r X-Rspam-User: X-HE-Tag: 1676975386-207440 X-HE-Meta: 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 ZtXi9Hga GD+aEj5Wx9MwZ2J4JrTOOfrMeOHQI5Sk8Jf0oWP4Z3IKPG5kkt2IjvWk5kyEqPcBoxx+/jtmWNp8u/zvt6ht0CaocBk30czMyY9goGC3IH8Dop7bFkn8EYsjEDu88gRJIJn64m7tbX+uX1ud9UaFMcy6vWXfbU7y8z/OyaQCKeBBKQl0dckDMzMyZEfkYYlvSx31gUR7kjkx1zhz2g9BPG6RV0X1SPWOZSJkvq5ujb1T17GCRVIbeKyrrQfzUJQYjgewIkxVJ7StlgiNOa8Q7YAl16jKh0YM7UC2EIOjYH1dY2zkyQK5am5oTarwo/VKzU1UiRJJvy33un2BH+j+fqdl121/j4ooEtVPr6XWE+UPgJ7salabF8oAbpeJc2VPvnjngFJAUgKQ8Jp/t6pDhXmRBOy4Jn4mt0T9bd3eV1XLuLkvWJWmWdA3ES+F8325ADfqc82yuuYfcxqTgsyrN+kIjw4IoswxsSsQDSLXgXgcVHTVx0IfDuNgY5ItTKgr8PNHzFdHAJyfMoqJGHdMqzYGwBpj1u0xJL0Ce1td5Zoq9dmBzcA5Q1vqxk/4Bh1v40zTWN8M85dR+HgSpyfixwuq0FSBsuHco7dD7JvL9z68dhPygXYHElnMMhPvUhjuTA+nW8mkG+LkXCT0= 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: This is a multi-part message in MIME format. --------------Spvi9DJXN5O0V9DKveeK2Vsh Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2023/2/14 23:56, Michal Hocko wrote: > On Fri 10-02-23 09:45:50, Haifeng Xu wrote: >> The high limit checks the memory usage from given memcg to root memcg. >> However, there is no limit in root memcg. So this check makes no sense >> and we can ignore it. > > Is this check actually addining any benefit? Have you measured aby > performance gains by this change? > >> Signed-off-by: Haifeng Xu >> --- >> mm/memcontrol.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/mm/memcontrol.c b/mm/memcontrol.c >> index 73afff8062f9..a31a56598f29 100644 >> --- a/mm/memcontrol.c >> +++ b/mm/memcontrol.c >> @@ -2780,6 +2780,10 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask, >> do { >> bool mem_high, swap_high; >> >> + /* There is no need for root memcg to check high limit */ >> + if (mem_cgroup_is_root(memcg)) >> + break; >> + >> mem_high = page_counter_read(&memcg->memory) > >> READ_ONCE(memcg->memory.high); >> swap_high = page_counter_read(&memcg->swap) > >> -- >> 2.25.1 > test steps: 1. mkdir -p /sys/fs/cgroup/memory/test 2. echo $$ > /sys/fs/cgroup/memory/test/cgroup.procs 3. ./mmap_test The test result show that with or without the patch, the time taken is almost the same. --------------Spvi9DJXN5O0V9DKveeK2Vsh Content-Type: text/plain; charset=UTF-8; name="mmap_test.c" Content-Disposition: attachment; filename="mmap_test.c" Content-Transfer-Encoding: base64 I2luY2x1ZGUgPHN5cy9tbWFuLmg+CiNpbmNsdWRlIDxzeXMvdHlwZXMuaD4KI2luY2x1ZGUg PHVuaXN0ZC5oPgojaW5jbHVkZSA8c3RkbGliLmg+CiNpbmNsdWRlIDxzdGRpby5oPgojaW5j bHVkZSA8ZmNudGwuaD4KI2luY2x1ZGUgPGN0eXBlLmg+CiNpbmNsdWRlIDxzdHJpbmcuaD4K I2luY2x1ZGUgPGludHR5cGVzLmg+CgojZGVmaW5lIFNJWkUgKDUgKiAxMDI0ICogMTAyNCAq IDEwMjQpCgppbnQ2NF90IGN1cnJlbnRfdGltZV9tcygpIHsKICAgICBzdHJ1Y3QgdGltZXZh bCB0aW1lOwogICAgIGdldHRpbWVvZmRheSgmdGltZSwgTlVMTCk7CiAgICAgaW50NjRfdCBz MSA9IChpbnQ2NF90KSh0aW1lLnR2X3NlYykgKiAxMDAwOwogICAgIGludDY0X3QgczIgPSAo dGltZS50dl91c2VjIC8gMTAwMCk7CiAgICAgcmV0dXJuIHMxICsgczI7Cn0KCmludCBtYWlu KGludCBhcmdjLCBjaGFyKiBhcmd2W10pCnsKICAgICAgICB2b2lkICogYnVmOwogICAgICAg IHNpemVfdCBzaXplID0gU0laRTsKICAgICAgICBpbnQ2NF90IHN0YXJ0LCBjb3N0OwoKICAg ICAgICBidWYgPSBtbWFwKE5VTEwsIHNpemUsIFBST1RfUkVBRCB8IFBST1RfV1JJVEUsIE1B UF9QUklWQVRFIHwgTUFQX0FOT04sIDAsIDApOwogICAgICAgIGlmIChidWYgPCAwICkgewog ICAgICAgICAgICAgICAgcHJpbnRmKCJtbWFwIGZhaWxlZFxuIik7CiAgICAgICAgICAgICAg ICBleGl0KC0xKTsKICAgICAgICB9CgogICAgICAgIHN0YXJ0ID0gY3VycmVudF90aW1lX21z KCk7CgogICAgICAgIG1sb2NrKGJ1Ziwgc2l6ZSk7CgogICAgICAgIGNvc3QgPSBjdXJyZW50 X3RpbWVfbXMoKSAtIHN0YXJ0OwogICAgICAgIHByaW50ZigiY29zdDogJSIgUFJJZDY0ICIg bXNcbiIsIGNvc3QpOwoKICAgICAgICBtdW5tYXAoYnVmLCBzaXplKTsKCiAgICAgICAgcmV0 dXJuIDA7Cn0K --------------Spvi9DJXN5O0V9DKveeK2Vsh--