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 03201C61DA4 for ; Tue, 7 Mar 2023 02:37:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2BD736B0071; Mon, 6 Mar 2023 21:37:02 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 26D036B0072; Mon, 6 Mar 2023 21:37:02 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 134C36B0073; Mon, 6 Mar 2023 21:37:02 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 03BAD6B0071 for ; Mon, 6 Mar 2023 21:37:02 -0500 (EST) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id CFC2916095A for ; Tue, 7 Mar 2023 02:37:01 +0000 (UTC) X-FDA: 80540539842.21.ED58E6B Received: from mail-pf1-f180.google.com (mail-pf1-f180.google.com [209.85.210.180]) by imf16.hostedemail.com (Postfix) with ESMTP id E5685180004 for ; Tue, 7 Mar 2023 02:36:59 +0000 (UTC) Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=shopee.com header.s=shopee.com header.b=TgcoMgRa; spf=pass (imf16.hostedemail.com: domain of haifeng.xu@shopee.com designates 209.85.210.180 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=1678156620; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=HDKMtd6lom5Ib4tE02IeIT4xLjwj2prJfYqYEwpnO5I=; b=0QwDp6dVU1XzXnhY/JbW5DGiZBDCEYbW3hEM9V0O1u8lSkEzNAuRY213cyZZKB5Kr2Gz/l 706EiUsfXfQQF1kTXhTdGK6z6o47SSoTGALPlfjRiy3mq/SCXSvYIpLkJ9ZKBIe6qohnrR xb+A9HTkL/zKM3HXWYsf+nGISDhItcA= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=pass header.d=shopee.com header.s=shopee.com header.b=TgcoMgRa; spf=pass (imf16.hostedemail.com: domain of haifeng.xu@shopee.com designates 209.85.210.180 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=1678156620; a=rsa-sha256; cv=none; b=II0eYegPVZvloc4/FfSZCN24ZYg3y7ZOBjVYrNd2+dy9iiQ7B7siljn4MZv1p2/gzZNIng 32vEOfM9VijxhOCo8GFzqrmb9B5GbIcSN85RUu6X4oxuz5tBG0u2ZqvrPe6YJVNP6mPsMa sKSAThGGSV9ROTSSVUVgf2ITTl4I2RE= Received: by mail-pf1-f180.google.com with SMTP id fd25so7198883pfb.1 for ; Mon, 06 Mar 2023 18:36:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shopee.com; s=shopee.com; t=1678156619; h=content-transfer-encoding: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=HDKMtd6lom5Ib4tE02IeIT4xLjwj2prJfYqYEwpnO5I=; b=TgcoMgRaq9SieKQosaCeju55ChEd6LMI5sdcrzGWP7Ujloyn2tO+uke1WUD3+9WZu7 mTW6qlr0UH+5K7pPYbbYKhs116Gbu2tp0N9DbW3+2P5XD4/S5z3GVyPQWw5ygl7XvgsF Z95rFJsQlqrPTcI+1zgY+BXiJY1CYU84v0RQErmiGOqrhnmEhWPKxVyRu7a7Ck3mEdIP NQgtdqybd78YZVKKh/PoBSY3G7FRIX9dY+Alx0k0a/1rcStJuLKCCaMtCfqDvFisGmq3 vuKj0I8UvA6CDMfNH76O+fzij/IxyfsJdhJcg0gqsouGNKMZJFGy9h72i5r3AvUrOLqz Y8Ew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678156619; h=content-transfer-encoding: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=HDKMtd6lom5Ib4tE02IeIT4xLjwj2prJfYqYEwpnO5I=; b=Uk/yE/nL51YKJJzBA8szyvC/5xAB1QXgE7/X6YKbf7Jt/Z5d2YGe7W7aNVbION1UTF JFbygi8cefDvnoerNDjbZxxFQ1CjYLDdkLJ3WshG0t5Qf2IdwRH32k1ISmE4OqtTiDsD TwQgTwb6efc1R6zd/hwJHcKjoUfLDQznQjns4w7hgug2LRhK5vJfzRQGxJA2Uls/XnOK VyWHqdxS7csMEaky1KsXrgYuwoth4CdQ5FyiR+j6/g1tkpRAqK4a37AZGmVHF7vmSgTG eWVUR6piXwMsqQFw1sCp+h9WyW+soNQgbBThLjMg1waly1u3B7+uzZ1qSLwK3Ja5e6+Z J/Mg== X-Gm-Message-State: AO0yUKVLXnaarXWUfabANUvQZ3Zg+87d+EzHSriAOojrBsxKH+9VwwAE wFtTgBopPtvBcZY4Mt+DPk3wwA== X-Google-Smtp-Source: AK7set8kDPXt0cKCbfbOc/EhXLxBzIiQFM/s0cVQfpqnEqKOV0jli1fL8m3XLc/7K+o0dhyr8RD/rQ== X-Received: by 2002:a62:8489:0:b0:5a9:bf42:fcc5 with SMTP id k131-20020a628489000000b005a9bf42fcc5mr15842166pfd.0.1678156618674; Mon, 06 Mar 2023 18:36:58 -0800 (PST) Received: from [10.54.24.141] (static-ip-147-99-134-202.rev.dyxnet.com. [202.134.99.147]) by smtp.gmail.com with ESMTPSA id q19-20020a62e113000000b005dd98927cc5sm6944453pfh.76.2023.03.06.18.36.57 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 06 Mar 2023 18:36:58 -0800 (PST) Message-ID: <354360d5-dce6-a11c-ee61-d41e615bfa05@shopee.com> Date: Tue, 7 Mar 2023 10:36:55 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Subject: Re: [PATCH] mm: remove redundant check in handle_mm_fault To: David Hildenbrand , akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20230306024959.131468-1-haifeng.xu@shopee.com> From: Haifeng Xu In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: E5685180004 X-Stat-Signature: 6tppu5by137xqpn9rr8uws81pk1psjuf X-Rspam-User: X-HE-Tag: 1678156619-521690 X-HE-Meta: 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 9SDAgztr FaBoneYaC/iT10LqYraKIRL5OQu6mokmsPz6eZyR8VnJTlCZkWHJh4UYAOkaWUnCEOrlWdLaGfxw+q4qjf4q/p7MzAmH7s8peyNMg2Gqxyn5yQanjXQNI4x+HNeHFDt3HnlBAfT9K0WlMcKta6mizyTS61pSKIxQwT/i/Sr+chxDgKZzxt4EkEz3+Ou9aYanyFQl2JjL9uU1gaYqW7tS0WIRzFr+YfIB7DC7QLVRBYrg9dgt0TnRGb66wkhAvhCpuCFwYSSySoQ9GdAPZmbXE/WKggUoRWZnHqtOA8eE3o9kDRBM0TdSGxR9vqRe3TZJcJhDogdMw2ZV8mFGbuBnzqNMftJ/N8fRGi+7SRHdErwQeC+naI6klvvzz467IESCfqf6afeytFiAue6jUtuq1nODufomBuI6EwCV/0RDW8N+oeRw= 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 2023/3/6 21:49, David Hildenbrand wrote: > On 06.03.23 03:49, Haifeng Xu wrote: >> mem_cgroup_oom_synchronize() has checked whether current memcg_in_oom is >> set or not, so remove the check in handle_mm_fault(). > > "mem_cgroup_oom_synchronize() will returned immediately if memcg_in_oom is not set, so remove the check from handle_mm_fault()". > > However, that requires now always an indirect function call -- do we care about dropping that optimization? > > If memcg_in_oom is set, we will check it twice, one is from handle_mm_fault(), the other is from mem_cgroup_oom_synchronize(). That seems a bit redundant. if memcg_in_oom is not set, mem_cgroup_oom_synchronize() returns directly. Though it's an indirect function call, but the time spent can be negligible compare to the whole mm user falut preocess. And that won't cause stack overflow error. Thanks.