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 E19AEC282C1 for ; Fri, 28 Feb 2025 16:30:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 763B5280002; Fri, 28 Feb 2025 11:30:55 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 713CB280001; Fri, 28 Feb 2025 11:30:55 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5B5D0280002; Fri, 28 Feb 2025 11:30:55 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id F299D280001 for ; Fri, 28 Feb 2025 11:30:54 -0500 (EST) Received: from smtpin25.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 227AB140EB5 for ; Fri, 28 Feb 2025 16:30:54 +0000 (UTC) X-FDA: 83169892428.25.BBCA17A Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.223.131]) by imf02.hostedemail.com (Postfix) with ESMTP id 8539B80002 for ; Fri, 28 Feb 2025 16:30:50 +0000 (UTC) Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=ih+SG9gR; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=CRzw+XNC; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=ih+SG9gR; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=CRzw+XNC; spf=pass (imf02.hostedemail.com: domain of vbabka@suse.cz designates 195.135.223.131 as permitted sender) smtp.mailfrom=vbabka@suse.cz; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1740760251; 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=CXe2ViHaxm0CEH2BkdyBu6aQbOLlCqhLToGAXJkbj/A=; b=PGlBy4pX5oVmVS2H99L2C6gB2L54fjDT7YdW0glw3dc9O/T1VmXsfA3NQXTmjR9AYAS2IZ FgnWahk5cvCnFL/SWt6Pt9u4keGBGzgfRPxOTfD0W98huzSZ05cxdSrRy8pFXSouEdhoty vfekkP74CoIwoyelSB6UZpFg9Ql2WPg= ARC-Authentication-Results: i=1; imf02.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=ih+SG9gR; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=CRzw+XNC; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=ih+SG9gR; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=CRzw+XNC; spf=pass (imf02.hostedemail.com: domain of vbabka@suse.cz designates 195.135.223.131 as permitted sender) smtp.mailfrom=vbabka@suse.cz; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1740760251; a=rsa-sha256; cv=none; b=yaTaTqW/0ZwaS/cDeII5G/T2ZDHUW4KJHIpzqkQCzoTHicZ1RP0gh/MJ7/PVKnaEA5wUl8 JDz1IB/ge2dW+d+gjBn+hCECf72bXEPVTIDHrT+2mmmxR+oxn0k7wTSjxBs73joQHT8Uy/ ap9T+INErXvo16X0hHcpITDzk5DQm+U= Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 91D171F38F; Fri, 28 Feb 2025 16:30:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1740760248; h=from:from:reply-to: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; bh=CXe2ViHaxm0CEH2BkdyBu6aQbOLlCqhLToGAXJkbj/A=; b=ih+SG9gRtPJTVuSfcSC/Z5GmDkwqh8nyp5t/lKkc8RnLwINfGsylCAbdHJPyhPeGRa9Ow5 76u1Fgt74Nd34jN8jhhZyU3bAYYOiacNZl0Hbeu7t0lJofvFf5Q5u2QXyfv7lsQEad4QPZ JtOLKxlbqygPYTjQ1/srMXgL8DPf9LY= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1740760248; h=from:from:reply-to: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; bh=CXe2ViHaxm0CEH2BkdyBu6aQbOLlCqhLToGAXJkbj/A=; b=CRzw+XNCZ7TjsK4TQMUE8vuSroJ1pN5xR6OAAr4ICGWjk1pIK3VhIDTKJbA98QqyJMMWM/ ybK9eh6YtTqsamCA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1740760248; h=from:from:reply-to: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; bh=CXe2ViHaxm0CEH2BkdyBu6aQbOLlCqhLToGAXJkbj/A=; b=ih+SG9gRtPJTVuSfcSC/Z5GmDkwqh8nyp5t/lKkc8RnLwINfGsylCAbdHJPyhPeGRa9Ow5 76u1Fgt74Nd34jN8jhhZyU3bAYYOiacNZl0Hbeu7t0lJofvFf5Q5u2QXyfv7lsQEad4QPZ JtOLKxlbqygPYTjQ1/srMXgL8DPf9LY= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1740760248; h=from:from:reply-to: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; bh=CXe2ViHaxm0CEH2BkdyBu6aQbOLlCqhLToGAXJkbj/A=; b=CRzw+XNCZ7TjsK4TQMUE8vuSroJ1pN5xR6OAAr4ICGWjk1pIK3VhIDTKJbA98QqyJMMWM/ ybK9eh6YtTqsamCA== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 6F71C137AC; Fri, 28 Feb 2025 16:30:48 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id 6gzdGrjkwWdfYAAAD6G6ig (envelope-from ); Fri, 28 Feb 2025 16:30:48 +0000 Message-ID: Date: Fri, 28 Feb 2025 17:30:48 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm/list_lru: make the case where mlru is NULL as unlikely Content-Language: en-US To: Shakeel Butt , Jingxiang Zeng Cc: linux-mm@kvack.org, akpm@linux-foundation.org, hannes@cmpxchg.org, mhocko@kernel.org, roman.gushchin@linux.dev, muchun.song@linux.dev, chengming.zhou@linux.dev, kasong@tencent.com, kernel test robot References: <20250225153020.2514685-1-jingxiangzeng.cas@gmail.com> From: Vlastimil Babka In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Action: no action X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 8539B80002 X-Stat-Signature: 7baye5nrwtpiiuzykipratu63g8feiiz X-HE-Tag: 1740760250-161682 X-HE-Meta: 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 zh9+hrpP 1V/9Fi7ezbUQew29vaKXx4MCvHzFZUsQeWJLrRQqkd73e8/7V8xkwIaG5Uc+t8uFRAbugQUS5LNJX1Uvy77MzHTnkxsB8E2KXyHyRvlWYzdS0mItQ/pQOZq4A3uE1qMQ3uOXl/8z50xLvWKs2jYQ8KwM1mlurxGhNtGtSSjVFnHz1MIrg5Z3sTx7TIigMAWmknR10pm5yKIxINUplN/Kwwwj8VaKfAhzCyZ2FtOmQLrgJHrN8SAkCy+lXRG6H8dbECPYm6fWoicUSo6iLvUhX4Bk0NOCf4Zx2Nm7cGZR/y2ggRTNnELHdRZAIZVsMhGBnI6SK3ICeSq/1lcA= 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: List-Subscribe: List-Unsubscribe: On 2/25/25 17:23, Shakeel Butt wrote: > On Tue, Feb 25, 2025 at 11:30:20PM +0800, Jingxiang Zeng wrote: >> mm/list_lru.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/mm/list_lru.c b/mm/list_lru.c >> index 064d2018e265..e7e13513ff8e 100644 >> --- a/mm/list_lru.c >> +++ b/mm/list_lru.c >> @@ -552,7 +552,7 @@ static int memcg_list_lru_alloc(struct mem_cgroup *memcg, struct list_lru *lru) >> } >> xas_unlock_irqrestore(&xas, flags); >> } while (xas_nomem(&xas, GFP_KERNEL)); >> - if (mlru) >> + if (unlikely(mlru)) >> kfree(mlru); > > The report is saying not to check at all. So, just remove the check and > simply call kfree(mlru) as it handles the NULL check efficiently. BTW, if it's unlikely to be !NULL then it's not really efficient to call kfree() unconditionally as it's a function call and those are more expensive than inline check (especially with spectre mitigations).