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 B04C7D1CA05 for ; Mon, 4 Nov 2024 22:22:45 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 466CE6B008A; Mon, 4 Nov 2024 17:22:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 416B56B0093; Mon, 4 Nov 2024 17:22:45 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 304CB6B0098; Mon, 4 Nov 2024 17:22:45 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 1936C6B008A for ; Mon, 4 Nov 2024 17:22:45 -0500 (EST) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id CC98A1C6B85 for ; Mon, 4 Nov 2024 22:22:44 +0000 (UTC) X-FDA: 82749837660.11.49B75F4 Received: from nyc.source.kernel.org (nyc.source.kernel.org [147.75.193.91]) by imf29.hostedemail.com (Postfix) with ESMTP id 7AEE512001C for ; Mon, 4 Nov 2024 22:21:59 +0000 (UTC) Authentication-Results: imf29.hostedemail.com; dkim=none; spf=pass (imf29.hostedemail.com: domain of cmarinas@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=cmarinas@kernel.org; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none) ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1730758879; 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: in-reply-to:in-reply-to:references:references; bh=4U/Zip5VH+u3SpsU3E46sjs3IQMnKmQFFvTkmSSmkpk=; b=lzo9hVa4kCk+jan/9LMPvWRmldj+/4kSeb89lLIck3OuNwyuxQlh+ii2QwbIcxAQeR8T7o f1/moyVSXGfRH7KhswZ4/oTWxVKfkUrMjjfBvbDKyJAbM0t9SAz8j9V39GANbMwPxiSHgx 8gPyJatGKoN9RtXZFGRn3Cd+d1xsiyY= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1730758879; a=rsa-sha256; cv=none; b=yudMD4ONsdG5UOS/EdS3pBBRMQ5psmDiou+rLKyWvweuN/mrPnmmb+ntfFzsFBIoVcYnpg wCnQXTjinNOQf8SiMnXCwn95zEOI3mzt1l0+eIMbWOhpWd+AYf+Ca6AfP4YTOl/vNlvSgZ G+NdQBJQ/cVkDfuy/uiUnXWd4U7XHhg= ARC-Authentication-Results: i=1; imf29.hostedemail.com; dkim=none; spf=pass (imf29.hostedemail.com: domain of cmarinas@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=cmarinas@kernel.org; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 3C95DA419AB; Mon, 4 Nov 2024 22:20:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5B7ECC4CECE; Mon, 4 Nov 2024 22:22:39 +0000 (UTC) Date: Mon, 4 Nov 2024 22:22:37 +0000 From: Catalin Marinas To: Vlastimil Babka Cc: Matthew Wilcox , Koichiro Den , Peter Collingbourne , cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, roman.gushchin@linux.dev, 42.hyeyoo@gmail.com, kees@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] mm/slab: fix warning caused by duplicate kmem_cache creation in kmem_buckets_create Message-ID: References: <20241104150837.2756047-1-koichiro.den@gmail.com> <8202821f-05bc-41f8-9de3-bf78899a7c7b@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8202821f-05bc-41f8-9de3-bf78899a7c7b@suse.cz> X-Rspamd-Server: rspam10 X-Stat-Signature: yuscftsc9ieapjks3h4k5mcbbszugay1 X-Rspamd-Queue-Id: 7AEE512001C X-Rspam-User: X-HE-Tag: 1730758919-513492 X-HE-Meta: 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 wi8Nu8Tk v/M6NbRc1N0sgRyyJNEY75jS73CumDn0Z29G01J2iW6UcXKrPoZbIVnZltpeICSbrP/G4Lnq7Xzo4eF7yGGrn7w+z63Kr7EXSeBVxhjhH6vp8XHuOaBl5o1SuGKyziT1S1jJgS8J7EHiQqtolZTjxMAZpPpRlV2Usnqmrq/lcBTK39DS5YeGRx5suUHePZPUyKwzIJAQanw5JsBUaxXq9EsXtQGPsrDvCGsNQQsJBKyUk84fmYtBJvVWX0elly8Q58fWQRn7J8AJQUlujUX1mBQoiNI99o9Mkr9KaEwZxFTHnWNanjYtZ2tbjwy3aGFs2k/7cga7/oHWzAoacGjaYRQXqDDUm8oRB8frwzvHzz/zKASiFYQHp8BdSyvKnzq1CH36LVRYQ724sB1DphyF4g+ye23xbKgyQ0m1NsCKWmD4im367+ewbxjq9GYG7jCx0kiTvSPT9/7nESwPdleiWe/DAlA== 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 Mon, Nov 04, 2024 at 07:16:20PM +0100, Vlastimil Babka wrote: > On 11/4/24 19:00, Matthew Wilcox wrote: > > On Tue, Nov 05, 2024 at 12:08:37AM +0900, Koichiro Den wrote: > >> Commit b035f5a6d852 ("mm: slab: reduce the kmalloc() minimum alignment > >> if DMA bouncing possible") reduced ARCH_KMALLOC_MINALIGN to 8 on arm64. > >> However, with KASAN_HW_TAGS enabled, arch_slab_minalign() becomes 16. > >> This causes kmalloc_caches[*][8] to be aliased to kmalloc_caches[*][16], > >> resulting in kmem_buckets_create() attempting to create a kmem_cache for > >> size 16 twice. This duplication triggers warnings on boot: > > > > Wouldn't this be easier? > > They wanted it to depend on actual HW capability / kernel parameter, see > d949a8155d13 ("mm: make minimum slab alignment a runtime property") > > Also Catalin's commit referenced above was part of the series that made the > alignment more dynamic for other cases IIRC. So I doubt we can simply reduce > it back to a build-time constant. I principle, I wouldn't reduce it back to constant though the 8 vs 16 difference is not significant. It matter if one enables KASAN_HW_TAGS and wants to run it on hardware without MTE, getting the *-8 caches back. That said, I haven't managed to trigger this warning yet. Do I need other config options than KASAN_HW_TAGS and DEBUG_VM? -- Catalin