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 7EDFDFAD3E2 for ; Wed, 22 Apr 2026 23:57:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4B1576B0005; Wed, 22 Apr 2026 19:57:17 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 462086B008A; Wed, 22 Apr 2026 19:57:17 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 378706B008C; Wed, 22 Apr 2026 19:57:17 -0400 (EDT) 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 27DFB6B0005 for ; Wed, 22 Apr 2026 19:57:17 -0400 (EDT) Received: from smtpin08.hostedemail.com (lb01b-stub [10.200.18.250]) by unirelay08.hostedemail.com (Postfix) with ESMTP id BF182140376 for ; Wed, 22 Apr 2026 23:57:16 +0000 (UTC) X-FDA: 84687855672.08.43D12AA Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf20.hostedemail.com (Postfix) with ESMTP id 091521C000C for ; Wed, 22 Apr 2026 23:57:14 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=mNFB+xdW; spf=pass (imf20.hostedemail.com: domain of kees@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=kees@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1776902235; 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=yJBRG6KDMW+yq2D5qxmZxyG7uq7dTMoiUt0GCZhykPk=; b=6yW3EsdMma7TSa7Z+IN3r/uC4WGJID7k/3I2NeRTLWcBFNicYNG+8UrurKqAW4dQgRTwSw QNMU6fBLYMR75t5BMiRzbm777h3UHmkruHPgu1txIPNHxfd7YaHpj/qNjWvVZKseecbPrw pVsZLl+SgYFyFSLqGuLpati4EgUdTu8= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=mNFB+xdW; spf=pass (imf20.hostedemail.com: domain of kees@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=kees@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1776902235; a=rsa-sha256; cv=none; b=ufRiNAuiwGTW4IkPJPHWOFue1CGaJvcSwgwS7RXGSn6TJA3rjIUstbDFVYivSdN3iT32sp 620IlUSLK4Poeu7d0tUcDkpW5rt55MGmbypiuKz03U4GncUe+/CeET+MV5wXsvGUMB/b/+ 3EqkyxN8AnIZKl/ELcdyR3mr4AqY7v4= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id BED7744492; Wed, 22 Apr 2026 23:57:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7CDB8C19425; Wed, 22 Apr 2026 23:57:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776902233; bh=h6ggrtCedybWSPNMwswG0DZDcNwcm7cnvs/LOyD/wNQ=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=mNFB+xdWLZKpCxXZm4/ECJ7c866xDmRQuYKee2ZmooLdAboj4IF919Yq3Iw0bINsX RA4s2JA6QITi2C8+PeIS8/KussEZgcuvkC/xnNNHlYcTPzfY/A3b0ztWYGAPRFwI7q dFrML80TrDtSrx81rSV0kIXhdCtQo7zA0q26ALnYgDR5M/YJ++seIkDSgNLESZuZoO x0ElHg5+r32UBFskPnb1kuB1/kBSU2lIvB4V/c0IfQCt5g8Tm+EL2o7hCU8m71CPuJ 558uJ+lGCcjFbOFFld46ZXtKgYDBP2LW5O7Tcc5SS8XOXouVemuXDANtK9uPhHYsdE QBLGa3JPbkmZQ== Date: Wed, 22 Apr 2026 16:57:11 -0700 From: Kees Cook To: Marco Elver CC: Vlastimil Babka , Andrew Morton , Nathan Chancellor , Nicolas Schier , Dennis Zhou , Tejun Heo , Christoph Lameter , Harry Yoo , Hao Li , David Rientjes , Roman Gushchin , "Gustavo A. R. Silva" , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Alexander Potapenko , Dmitry Vyukov , Nick Desaulniers , Bill Wendling , Justin Stitt , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-hardening@vger.kernel.org, kasan-dev@googlegroups.com, llvm@lists.linux.dev, Andrey Konovalov , Florent Revest , Jann Horn , KP Singh , Matteo Rizzo , GONG Ruiqi Subject: =?US-ASCII?Q?Re=3A_=5BPATCH_v2=5D_slab=3A_support_for_compiler-?= =?US-ASCII?Q?assisted_type-based_slab_cache_partitioning?= User-Agent: K-9 Mail for Android In-Reply-To: References: <20260415143735.2974230-1-elver@google.com> <202604210954.84C57E5E0@keescook> Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 091521C000C X-Stat-Signature: ndd1a91ahqrrtr835m9nc7wh4ayhsy1h X-Rspam-User: X-HE-Tag: 1776902234-977654 X-HE-Meta: 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 2C97OsWb ckXBcLsdUKA80X7jbMPPOjAf6KOBmocrxC91D5JxESgr6s4qwcn4j+oQb0mlYPhdE2L/iJQzwiQ/L626IJ1847a3kMD6lk2SIzmJDj8leMupU9sFWFsJZ1rWA+hHjKLTRDMfl9XiS7v5E9uaKIYh6GyED4L1TpTEDxI0vXPd26IN9RHbJieMDZdr9l34G+fNmYAHhGRAqCilHgqcH9Sm/ymDTcWU0htap890C48KXhAD6AdmG3tRuxfPjhUb70h5eROGQG0YvkUD1bXYEzXS3K47wownVtssjGg2e140S/yvCpAMO00/BzhDUdsfDSFhMQ/2uIaMyCNp/Azno0SFkTNTFUqAGjHLY+I4Phd+oBkzcNJcs4C195/iWqkai2W2b0wvw Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On April 22, 2026 8:26:30 AM PDT, Marco Elver wrote: >On Tue, Apr 21, 2026 at 09:13PM +0200, Marco Elver wrote: >[=2E=2E=2E] >> > And actually, perhaps a global rename of the options so the selection >> > naming is at the end of the CONFIG phrase, and bundle the on/off into >> > the choice: >> > >> > >> > choice >> > prompt "Partitioned slab cache mode" >> > depends on PARTITION_KMALLOC_CACHES >> > default KMALLOC_PARTITION_TYPED if !SLUB_TINY && CC_HAS_ALLOC= _TOKEN >> > default KMALLOC_PARTITION_RANDOM if !SLUB_TINY >> > default KMALLOC_PARTITION_NONE >> > >> > config KMALLOC_PARTITION_NONE >> > =2E=2E=2E >> > config KMALLOC_PARTITION_RANDOM >> > depends on !SLUB_TINY >> > =2E=2E=2E >> > config KMALLOC_PARTITION_TYPED >> > depends on !SLUB_TINY && CC_HAS_ALLOC_TOKEN >>=20 >> There was a comment somewhere else that even introducing >> PARTITION_KMALLOC_CACHES might confuse users of RANDOM_KMALLOC_CACHES= =2E >> I think completely getting rid of and renaming RANDOM_KMALLOC_CACHES >> has marginal benefit, and will cause friction for existing users (even >> moreso than already)=2E I see little benefit here, and would prefer not >> to break user configs more than needed: configs that already set >> RANDOM_KMALLOC_CACHES, upon rebuild will be prompted to enable >> PARTITION_KMALLOC_CACHES; if user says Y, then their previous >> selection (RANDOM) would already be picked and they don't have to >> rediscover that it exists under a new name=2E >>=20 >> I can make this change, but only if you're sure the benefit outweighs >> the downsides here=2E > >Upon further reflection, since the transition isn't smooth anyway, I'm >probably going to rename, but have them all use the PARTITION_KMALLOC_* >prefix so it's easy to just search for "CONFIG_PARTITION_KMALLOC_"=2E I >don't see the need for a "NONE" variant - I've seen this pattern >elsewhere, and then you end up with users reading the =2Econfig and >concluding "CONFIG_PARTITION_KMALLOC_CACHES is enabled =2E=2E=2E but oh n= ever >mind actually it isn't" which I find confusing=2E This could be useful if >we had a dynamic on/off toggle and the default is NONE, but that's not >the case here=2E There is now the "transitional" Kconfig keyword too, which should make it = easy to move to the new name=2E For the naming, I tend to prefer the noun-verb (e=2Eg=2E timer_start()) an= d noun-feature-option ordering (e=2Eg=2E CONFIG_SLAB_FREELIST_RANDOM)=2E Th= is feature isn't about partition tables, so I don't think the first word sh= ould be "partition"=2E :) As far as doing the full isolation later, yeah, that's fine, and I think w= ith this Kconfig change it's easy to add a new mode=2E -Kees --=20 Kees Cook