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 CED6DC3ABC3 for ; Mon, 12 May 2025 13:44:30 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B95A16B013D; Mon, 12 May 2025 09:44:29 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B44A26B013E; Mon, 12 May 2025 09:44:29 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A0B8B6B013F; Mon, 12 May 2025 09:44:29 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 82BE56B013D for ; Mon, 12 May 2025 09:44:29 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 5EF911612BB for ; Mon, 12 May 2025 13:44:29 +0000 (UTC) X-FDA: 83434375458.13.DD0AB7F Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.223.131]) by imf14.hostedemail.com (Postfix) with ESMTP id 06D1F10000B for ; Mon, 12 May 2025 13:44:26 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=KEVMP0YM; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b="CIw/tjR6"; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=KEVMP0YM; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b="CIw/tjR6"; dmarc=none; spf=pass (imf14.hostedemail.com: domain of vbabka@suse.cz designates 195.135.223.131 as permitted sender) smtp.mailfrom=vbabka@suse.cz ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1747057467; a=rsa-sha256; cv=none; b=EETVltfPOW5AO+crkE0MubOCAW/gKKVyUwoXWVFgDaXajjUPU4n7cr6QUV2qagAcrJ43UN c3XZD8VLhbOwZvjN4paVbMdoM6JrAK2KlB2ujt1cnbnntJ8ZENGn+MaE0BGIIq2BKYAaV8 qVz+8j+bpJwtdVAS4dw/YUgMScYhxUE= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=KEVMP0YM; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b="CIw/tjR6"; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=KEVMP0YM; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b="CIw/tjR6"; dmarc=none; spf=pass (imf14.hostedemail.com: domain of vbabka@suse.cz designates 195.135.223.131 as permitted sender) smtp.mailfrom=vbabka@suse.cz ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1747057467; 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=ER+N9VpRUCzTYrWu0T2ibs7iXfF6pjRuTAOA5gVtaos=; b=bw5eyYGRgyC8ZqD/c/bnsEoxM961vXg//7MZDaAZJ2jLVvH/VAPe92WBpUUSPJ5W/7dJI2 j8+lQivlqC8b86NTFIc5coVcsv014KmaxNuZsO3PtZ7Z5wWFcNCK6bpR3vCvCTtqauSIJf NaE4eN+SjeP0slbbmg/5Wdjxx0YLVio= 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 4EE4F1F388; Mon, 12 May 2025 13:44:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1747057465; 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=ER+N9VpRUCzTYrWu0T2ibs7iXfF6pjRuTAOA5gVtaos=; b=KEVMP0YMAB0/Koaa/yIXOoWu2jE8rGQZsiZhUiIfyWcEopOWGblI0oKpHyCSYCQVZdQWno lyENY5uzG4zLANDDfWye4090Z0Fjivx0rlBN4Z0C4JawdbhWdjtmfz0hzetQSsp1dGwYLI YN5CRNSKoNgVMNLpw0bQ1ONy1x03Upo= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1747057465; 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=ER+N9VpRUCzTYrWu0T2ibs7iXfF6pjRuTAOA5gVtaos=; b=CIw/tjR6B1/nBxmjn+fePWFUr4nZvz69tvn6mJ6MahHldP/deIKIwkbOxuW+LpFzpoRpWu T003HzbPJXFIzaDw== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1747057465; 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=ER+N9VpRUCzTYrWu0T2ibs7iXfF6pjRuTAOA5gVtaos=; b=KEVMP0YMAB0/Koaa/yIXOoWu2jE8rGQZsiZhUiIfyWcEopOWGblI0oKpHyCSYCQVZdQWno lyENY5uzG4zLANDDfWye4090Z0Fjivx0rlBN4Z0C4JawdbhWdjtmfz0hzetQSsp1dGwYLI YN5CRNSKoNgVMNLpw0bQ1ONy1x03Upo= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1747057465; 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=ER+N9VpRUCzTYrWu0T2ibs7iXfF6pjRuTAOA5gVtaos=; b=CIw/tjR6B1/nBxmjn+fePWFUr4nZvz69tvn6mJ6MahHldP/deIKIwkbOxuW+LpFzpoRpWu T003HzbPJXFIzaDw== 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 32303137D2; Mon, 12 May 2025 13:44:25 +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 DJ3rCzn7IWhbLgAAD6G6ig (envelope-from ); Mon, 12 May 2025 13:44:25 +0000 Message-ID: <61badb6b-62aa-4457-900d-c280a8a41f97@suse.cz> Date: Mon, 12 May 2025 15:44:25 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 3/3] mm/vma: remove mmap() retry merge Content-Language: en-US To: Lorenzo Stoakes , Andrew Morton Cc: David Hildenbrand , "Liam R . Howlett" , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jann Horn , Pedro Falcato , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Alexander Viro , Christian Brauner , Jan Kara , Matthew Wilcox References: From: Vlastimil Babka In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Action: no action X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 06D1F10000B X-Rspam-User: X-Stat-Signature: kcqw7wgjqhk58zd87a9fdyq1kjzjfjyk X-HE-Tag: 1747057466-234977 X-HE-Meta: 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 F0vs03Dm 7N/v/tTh02lbDw1Mj4MyB/xXdJJcclHLDw8zyIEnvt6eN+XtA1iF62NB+DAzALwpd1UDID8m0d21hE19vp0GGRSxfsNqnayW0oh+NIWXQoo7V62pzaYdUulpEl1g2B/oWKXQFQjexNAB7FDQvYXDzKwq1wCzAvp3xOvJp8uz2bgM8IElFtWAUfPhPTf5eHk9iylgn7cm/YxkvlOGeoHwzTrwqpgBVZcHD4x6M5NhEmnQPex5seto0IYqzqtISVySa/wUQGJEtaY/ibcXNjqSJQMlm6evu6CfwrlrouhQRtX7YD+amzm6kPv8dAnfKdLv1fLp9mnKnkR5bxfMNQfrzJksCKA== 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 5/9/25 14:13, Lorenzo Stoakes wrote: > We have now introduced a mechanism that obviates the need for a reattempted > merge via the mmap_prepare() file hook, so eliminate this functionality > altogether. > > The retry merge logic has been the cause of a great deal of complexity in > the past and required a great deal of careful manoeuvring of code to ensure > its continued and correct functionality. > > It has also recently been involved in an issue surrounding maple tree > state, which again points to its problematic nature. > > We make it much easier to reason about mmap() logic by eliminating this and > simply writing a VMA once. This also opens the doors to future optimisation > and improvement in the mmap() logic. > > For any device or file system which encounters unwanted VMA fragmentation > as a result of this change (that is, having not implemented .mmap_prepare > hooks), the issue is easily resolvable by doing so. > > Signed-off-by: Lorenzo Stoakes > Reviewed-by: David Hildenbrand Reviewed-by: Vlastimil Babka