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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5CE31EA3F22 for ; Tue, 10 Feb 2026 16:18:51 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4C7816B0005; Tue, 10 Feb 2026 11:18:50 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 475766B0089; Tue, 10 Feb 2026 11:18:50 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 32CC26B008A; Tue, 10 Feb 2026 11:18:50 -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 2073D6B0005 for ; Tue, 10 Feb 2026 11:18:50 -0500 (EST) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id CDBF813B587 for ; Tue, 10 Feb 2026 16:18:49 +0000 (UTC) X-FDA: 84429055578.20.E33ECC6 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.223.131]) by imf23.hostedemail.com (Postfix) with ESMTP id 5730A140016 for ; Tue, 10 Feb 2026 16:18:47 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=J6tIx6D9; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=8aX6TdNe; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=J6tIx6D9; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=8aX6TdNe; spf=pass (imf23.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=1770740327; 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=AWAHMKXyBrxfBf69pBcoJZiRyKZIcjQ3u+E8dpyzTIw=; b=5c7Ox0NAiAYhiC6TxQMrPt6zK498wKswFUmeUXmYZhYwTn2YLeVwLPctvEXN12OGRBbnDH 7lFFlyfLqZjuEEUpExgZeCoVgMWBp1AID6fKpIV8s0YvFimg4EVZTSKbBwrl6VwD1anKdT EO/RhtxfHx3u0jQ/tw1VkXD1GvTc/rQ= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=J6tIx6D9; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=8aX6TdNe; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=J6tIx6D9; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=8aX6TdNe; spf=pass (imf23.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=1770740327; a=rsa-sha256; cv=none; b=Sq+cF1NDi7Xg9+dxiJ3IwYzZ6fzjBIWI8VIgmF+WtrXHu08FwRIkAoIe3I6uzWbl8S5kmo qCEjMEBJG+au8AmxfryagDDSBwzQVkgzq0Ibx39sGiKJu8ZZL+uPbglmKUMIGZBo2OhKG1 dLS7wGnn9E1t3l1Q9lQTzbjuy/FpGVs= 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 72BB55BD70; Tue, 10 Feb 2026 16:18:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1770740325; 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:autocrypt:autocrypt; bh=AWAHMKXyBrxfBf69pBcoJZiRyKZIcjQ3u+E8dpyzTIw=; b=J6tIx6D95KB80m9fGTh2TvNmjCHG5fxuWYA++kYdpTF5CUPzEPE6Y27ROec8++ZKiXC8jc BTW7YpEmAOjK4wIlGKE65+gpazYd22/8sW2kEXc0qzTZppdYi9rb9ZwHxwmnpZGT4bcWnZ EetyOrJ4f3DWGqJuoYCozdnZpH4eVHM= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1770740325; 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:autocrypt:autocrypt; bh=AWAHMKXyBrxfBf69pBcoJZiRyKZIcjQ3u+E8dpyzTIw=; b=8aX6TdNeeQQlCcrkh2WiCDuyS2sI6CHZ6ha1b8LqZjvmgmakt1EWA0RCl51+boIW2xcNir s1WXULnmB7OOI7CQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1770740325; 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:autocrypt:autocrypt; bh=AWAHMKXyBrxfBf69pBcoJZiRyKZIcjQ3u+E8dpyzTIw=; b=J6tIx6D95KB80m9fGTh2TvNmjCHG5fxuWYA++kYdpTF5CUPzEPE6Y27ROec8++ZKiXC8jc BTW7YpEmAOjK4wIlGKE65+gpazYd22/8sW2kEXc0qzTZppdYi9rb9ZwHxwmnpZGT4bcWnZ EetyOrJ4f3DWGqJuoYCozdnZpH4eVHM= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1770740325; 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:autocrypt:autocrypt; bh=AWAHMKXyBrxfBf69pBcoJZiRyKZIcjQ3u+E8dpyzTIw=; b=8aX6TdNeeQQlCcrkh2WiCDuyS2sI6CHZ6ha1b8LqZjvmgmakt1EWA0RCl51+boIW2xcNir s1WXULnmB7OOI7CQ== 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 2D77F3EA62; Tue, 10 Feb 2026 16:18:45 +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 0ryiCWVai2lJYgAAD6G6ig (envelope-from ); Tue, 10 Feb 2026 16:18:45 +0000 Message-ID: Date: Tue, 10 Feb 2026 17:18:44 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCHv6 12/17] mm: Drop fake head checks Content-Language: en-US To: Kiryl Shutsemau , Andrew Morton , Muchun Song , David Hildenbrand , Matthew Wilcox , Usama Arif , Frank van der Linden Cc: Oscar Salvador , Mike Rapoport , Lorenzo Stoakes , Zi Yan , Baoquan He , Michal Hocko , Johannes Weiner , Jonathan Corbet , Huacai Chen , WANG Xuerui , Palmer Dabbelt , Paul Walmsley , Albert Ou , Alexandre Ghiti , kernel-team@meta.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org References: <20260202155634.650837-1-kas@kernel.org> <20260202155634.650837-13-kas@kernel.org> From: Vlastimil Babka Autocrypt: addr=vbabka@suse.cz; keydata= xsFNBFZdmxYBEADsw/SiUSjB0dM+vSh95UkgcHjzEVBlby/Fg+g42O7LAEkCYXi/vvq31JTB KxRWDHX0R2tgpFDXHnzZcQywawu8eSq0LxzxFNYMvtB7sV1pxYwej2qx9B75qW2plBs+7+YB 87tMFA+u+L4Z5xAzIimfLD5EKC56kJ1CsXlM8S/LHcmdD9Ctkn3trYDNnat0eoAcfPIP2OZ+ 9oe9IF/R28zmh0ifLXyJQQz5ofdj4bPf8ecEW0rhcqHfTD8k4yK0xxt3xW+6Exqp9n9bydiy tcSAw/TahjW6yrA+6JhSBv1v2tIm+itQc073zjSX8OFL51qQVzRFr7H2UQG33lw2QrvHRXqD Ot7ViKam7v0Ho9wEWiQOOZlHItOOXFphWb2yq3nzrKe45oWoSgkxKb97MVsQ+q2SYjJRBBH4 8qKhphADYxkIP6yut/eaj9ImvRUZZRi0DTc8xfnvHGTjKbJzC2xpFcY0DQbZzuwsIZ8OPJCc LM4S7mT25NE5kUTG/TKQCk922vRdGVMoLA7dIQrgXnRXtyT61sg8PG4wcfOnuWf8577aXP1x 6mzw3/jh3F+oSBHb/GcLC7mvWreJifUL2gEdssGfXhGWBo6zLS3qhgtwjay0Jl+kza1lo+Cv BB2T79D4WGdDuVa4eOrQ02TxqGN7G0Biz5ZLRSFzQSQwLn8fbwARAQABzSBWbGFzdGltaWwg QmFia2EgPHZiYWJrYUBzdXNlLmN6PsLBlAQTAQoAPgIbAwULCQgHAwUVCgkICwUWAgMBAAIe AQIXgBYhBKlA1DSZLC6OmRA9UCJPp+fMgqZkBQJnyBr8BQka0IFQAAoJECJPp+fMgqZkqmMQ AIbGN95ptUMUvo6aAdhxaOCHXp1DfIBuIOK/zpx8ylY4pOwu3GRe4dQ8u4XS9gaZ96Gj4bC+ jwWcSmn+TjtKW3rH1dRKopvC07tSJIGGVyw7ieV/5cbFffA8NL0ILowzVg8w1ipnz1VTkWDr 2zcfslxJsJ6vhXw5/npcY0ldeC1E8f6UUoa4eyoskd70vO0wOAoGd02ZkJoox3F5ODM0kjHu Y97VLOa3GG66lh+ZEelVZEujHfKceCw9G3PMvEzyLFbXvSOigZQMdKzQ8D/OChwqig8wFBmV QCPS4yDdmZP3oeDHRjJ9jvMUKoYODiNKsl2F+xXwyRM2qoKRqFlhCn4usVd1+wmv9iLV8nPs 2Db1ZIa49fJet3Sk3PN4bV1rAPuWvtbuTBN39Q/6MgkLTYHb84HyFKw14Rqe5YorrBLbF3rl M51Dpf6Egu1yTJDHCTEwePWug4XI11FT8lK0LNnHNpbhTCYRjX73iWOnFraJNcURld1jL1nV r/LRD+/e2gNtSTPK0Qkon6HcOBZnxRoqtazTU6YQRmGlT0v+rukj/cn5sToYibWLn+RoV1CE Qj6tApOiHBkpEsCzHGu+iDQ1WT0Idtdynst738f/uCeCMkdRu4WMZjteQaqvARFwCy3P/jpK uvzMtves5HvZw33ZwOtMCgbpce00DaET4y/UzsBNBFsZNTUBCACfQfpSsWJZyi+SHoRdVyX5 J6rI7okc4+b571a7RXD5UhS9dlVRVVAtrU9ANSLqPTQKGVxHrqD39XSw8hxK61pw8p90pg4G /N3iuWEvyt+t0SxDDkClnGsDyRhlUyEWYFEoBrrCizbmahOUwqkJbNMfzj5Y7n7OIJOxNRkB IBOjPdF26dMP69BwePQao1M8Acrrex9sAHYjQGyVmReRjVEtv9iG4DoTsnIR3amKVk6si4Ea X/mrapJqSCcBUVYUFH8M7bsm4CSxier5ofy8jTEa/CfvkqpKThTMCQPNZKY7hke5qEq1CBk2 wxhX48ZrJEFf1v3NuV3OimgsF2odzieNABEBAAHCwXwEGAEKACYCGwwWIQSpQNQ0mSwujpkQ PVAiT6fnzIKmZAUCZ8gcVAUJFhTonwAKCRAiT6fnzIKmZLY8D/9uo3Ut9yi2YCuASWxr7QQZ lJCViArjymbxYB5NdOeC50/0gnhK4pgdHlE2MdwF6o34x7TPFGpjNFvycZqccSQPJ/gibwNA zx3q9vJT4Vw+YbiyS53iSBLXMweeVV1Jd9IjAoL+EqB0cbxoFXvnjkvP1foiiF5r73jCd4PR rD+GoX5BZ7AZmFYmuJYBm28STM2NA6LhT0X+2su16f/HtummENKcMwom0hNu3MBNPUOrujtW khQrWcJNAAsy4yMoJ2Lw51T/5X5Hc7jQ9da9fyqu+phqlVtn70qpPvgWy4HRhr25fCAEXZDp xG4RNmTm+pqorHOqhBkI7wA7P/nyPo7ZEc3L+ZkQ37u0nlOyrjbNUniPGxPxv1imVq8IyycG AN5FaFxtiELK22gvudghLJaDiRBhn8/AhXc642/Z/yIpizE2xG4KU4AXzb6C+o7LX/WmmsWP Ly6jamSg6tvrdo4/e87lUedEqCtrp2o1xpn5zongf6cQkaLZKQcBQnPmgHO5OG8+50u88D9I rywqgzTUhHFKKF6/9L/lYtrNcHU8Z6Y4Ju/MLUiNYkmtrGIMnkjKCiRqlRrZE/v5YFHbayRD dJKXobXTtCBYpLJM4ZYRpGZXne/FAtWNe4KbNJJqxMvrTOrnIatPj8NhBVI0RSJRsbilh6TE m6M14QORSWTLRg== In-Reply-To: <20260202155634.650837-13-kas@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Action: no action X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 5730A140016 X-Stat-Signature: z6sm76jawh8cuixdj18yijaimbptk164 X-Rspam-User: X-HE-Tag: 1770740327-848136 X-HE-Meta: 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 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 2/2/26 16:56, Kiryl Shutsemau wrote: > With fake head pages eliminated in the previous commit, remove the > supporting infrastructure: > > - page_fixed_fake_head(): no longer needed to detect fake heads; > - page_is_fake_head(): no longer needed; > - page_count_writable(): no longer needed for RCU protection; > - RCU read_lock in page_ref_add_unless(): no longer needed; > > This substantially simplifies compound_head() and page_ref_add_unless(), > removing both branches and RCU overhead from these hot paths. > > Signed-off-by: Kiryl Shutsemau > Reviewed-by: Muchun Song Reviewed-by: Vlastimil Babka