From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.223.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 31311236442 for ; Fri, 20 Jun 2025 13:05:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.131 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750424705; cv=none; b=C22XaPjWXWez4Di34KLXRByhnHtM7U/EIzqkvqEAAi8FRdGU1FD0S9eooN1jl1PuzpnMXoVkpMG3CU6uBqMoSBMINeFGKLL1NvS/lS9+3JiLEnfKO/kQyFQeoKzpEbSjB1C4Ezn5CyMW8igeOpqoiVCIPM4Hywrk9libkHmx2YU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750424705; c=relaxed/simple; bh=2YdG+o9yyXjFTHBMglWNk/zaHuQ+KY9OfnhjNqkzLKc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=cMpbHZbE28T6vaeTb3+a8yEUf+Tlw2n4goNVwqF/AHBfEHtVI+6xkeTxzIaHTWXZbs/BIoqdY7PT2xSd3WjdGAx52v2+5+gbBI1W9qqO6D9kAbYbBSlo26Aoh/mUgP7KxpxmjlPhuKKNM1LvuoMDR/Y22QQmDJRGQ64FbDbDmHQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz; spf=pass smtp.mailfrom=suse.cz; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b=ljyAvX6y; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b=ekurzktQ; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b=ljyAvX6y; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b=ekurzktQ; arc=none smtp.client-ip=195.135.223.131 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.cz Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b="ljyAvX6y"; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b="ekurzktQ"; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b="ljyAvX6y"; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b="ekurzktQ" Received: from imap1.dmz-prg2.suse.org (unknown [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 674641F38D; Fri, 20 Jun 2025 13:05:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1750424702; 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=g5Vh7PQtzn7ctlN5CnoQKtRomFBLSHgBU4H7pj3uRrk=; b=ljyAvX6yHma/vYwnb9hA/aUwoGPEdPzAE0Lku4ZszVg9ngpFDAAV9y8h9IOk9/8LSZifSm 2D1YskRtGmlQ6YkpvU+ClBdQUiRqb5UH13EMulrhF/hRhsc2JQS7RoavC6B5tgbgmheYKo B5d6zM8ZKu6EcooKUYv6BpDsouNS3p8= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1750424702; 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=g5Vh7PQtzn7ctlN5CnoQKtRomFBLSHgBU4H7pj3uRrk=; b=ekurzktQlwUwBQk6RQd4alsVf73brvr3Gmcz6Wms3xm2o7HFuQdO9ZSZmtgE+nYWUljY// JgD73G8wv9V2JpDA== Authentication-Results: smtp-out2.suse.de; none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1750424702; 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=g5Vh7PQtzn7ctlN5CnoQKtRomFBLSHgBU4H7pj3uRrk=; b=ljyAvX6yHma/vYwnb9hA/aUwoGPEdPzAE0Lku4ZszVg9ngpFDAAV9y8h9IOk9/8LSZifSm 2D1YskRtGmlQ6YkpvU+ClBdQUiRqb5UH13EMulrhF/hRhsc2JQS7RoavC6B5tgbgmheYKo B5d6zM8ZKu6EcooKUYv6BpDsouNS3p8= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1750424702; 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=g5Vh7PQtzn7ctlN5CnoQKtRomFBLSHgBU4H7pj3uRrk=; b=ekurzktQlwUwBQk6RQd4alsVf73brvr3Gmcz6Wms3xm2o7HFuQdO9ZSZmtgE+nYWUljY// JgD73G8wv9V2JpDA== 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 48D63136BA; Fri, 20 Jun 2025 13:05:02 +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 GIBfEX5cVWjlMgAAD6G6ig (envelope-from ); Fri, 20 Jun 2025 13:05:02 +0000 Message-ID: <8c4a4ea2-1eab-47dd-9b65-d60cfac16577@suse.cz> Date: Fri, 20 Jun 2025 15:05:02 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/5] mm/madvise: remove the visitor pattern and thread anon_vma state Content-Language: en-US To: Lorenzo Stoakes , Andrew Morton Cc: David Hildenbrand , Zi Yan , Baolin Wang , "Liam R . Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Jann Horn , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Lance Yang , SeongJae Park , Suren Baghdasaryan References: <4239e727b98763856b86cbd9eeaa0ba792eb2394.1750363557.git.lorenzo.stoakes@oracle.com> 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: <4239e727b98763856b86cbd9eeaa0ba792eb2394.1750363557.git.lorenzo.stoakes@oracle.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spamd-Result: default: False [-4.30 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_TLS_ALL(0.00)[]; RCPT_COUNT_TWELVE(0.00)[16]; MID_RHS_MATCH_FROM(0.00)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; FROM_HAS_DN(0.00)[]; FREEMAIL_CC(0.00)[redhat.com,nvidia.com,linux.alibaba.com,oracle.com,arm.com,kernel.org,google.com,kvack.org,vger.kernel.org,gmail.com]; TO_DN_SOME(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FUZZY_BLOCKED(0.00)[rspamd.com]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,oracle.com:email,suse.cz:mid] X-Spam-Level: X-Spam-Flag: NO X-Spam-Score: -4.30 On 6/19/25 22:26, Lorenzo Stoakes wrote: > Now we have the madvise_behavior helper struct we no longer need to mess > around with void* pointers in order to propagate anon_vma_name, and this > means we can get rid of the confusing and inconsistent visitor pattern > implementation in madvise_vma_anon_name(). > > This means we now have a single state object that threads through most of > madvise()'s logic and a single code path which executes the majority of > madvise() behaviour (we maintain separate logic for failure injection and > memory population for the time being). > > Note that users cannot inadvertently cause this behaviour to occur, as > madvise_behavior_valid() would reject it. This paragraph is a bit confusing. I've inferred from the code you're talking about the new internal negative values, but the preceding paragraphs don't mention them. Could you explain in more detail what the patch does? I.e. adding the new struct madvise_behavior field and the new behavior value(s). > Doing this results in a can_modify_vma_madv() check for anonymous VMA name > changes, however this will cause no issues as this operation is not > prohibited. > > We can also then reuse more code and drop the redundant > madvise_vma_anon_name() function altogether. > > Additionally separate out behaviours that update VMAs from those that do > not. > > Signed-off-by: Lorenzo Stoakes > @@ -1325,21 +1388,25 @@ static int madvise_vma_behavior(struct vm_area_struct *vma, > if (error) > goto out; > break; > - case MADV_COLLAPSE: > - return madvise_collapse(vma, prev, start, end); > - case MADV_GUARD_INSTALL: > - return madvise_guard_install(vma, prev, start, end); > - case MADV_GUARD_REMOVE: > - return madvise_guard_remove(vma, prev, start, end); > + case __MADV_SET_ANON_VMA_NAME: > + case __MADV_CLEAR_ANON_VMA_NAME: > + /* Only anonymous mappings can be named */ > + if (vma->vm_file && !vma_is_anon_shmem(vma)) > + return -EBADF; > + break; > } > > /* We cannot provide prev in this lock mode. */ > - VM_WARN_ON_ONCE(arg->lock_mode == MADVISE_VMA_READ_LOCK); > - anon_name = anon_vma_name(vma); > - anon_vma_name_get(anon_name); > + VM_WARN_ON_ONCE(madv_behavior->lock_mode == MADVISE_VMA_READ_LOCK); > + > + if (!is_anon_vma_name(behavior)) { > + anon_name = anon_vma_name(vma); > + anon_vma_name_get(anon_name); > + } > error = madvise_update_vma(vma, prev, start, end, new_flags, > anon_name); > - anon_vma_name_put(anon_name); > + if (!is_anon_vma_name(behavior)) > + anon_vma_name_put(anon_name); This is not new, but the refactoring made it very visible that we're doing get/put on anon_name exactly in cases where we're not messing with anon_name so it might look buggy. Some explanatory comment would be thus nice, otherwise people need to git blame for commit 942341dcc5748. Otherwise LGTM, will wait with tag for v2 as you replied elsewhere there will be changes. Thanks!