From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id D51C1606A324 for ; Tue, 27 Oct 2026 18:31:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=jjxHiqsF Received: by kanga.kvack.org (Postfix) id E05B56B088A; Tue, 27 Oct 2026 14:31:42 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DB6ED6B088B; Tue, 27 Oct 2026 14:31:42 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C7F946B088C; Tue, 27 Oct 2026 14:31:42 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id A7AAE6B088A for ; Tue, 27 Oct 2026 14:31:42 -0400 (EDT) Received: from smtpin09.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 0F07180AB3 for ; Tue, 27 Oct 2026 18:31:42 +0000 (UTC) X-FDA: 85369249644.09.186C7B9 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf07.hostedemail.com (Postfix) with ESMTP id 7E07A40006 for ; Tue, 27 Oct 2026 18:31:40 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=jjxHiqsF; spf=pass (imf07.hostedemail.com: domain of harry@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=harry@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=1793125900; 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:dkim-signature; bh=Zy1XjAvFE8Nfo7sM1UI6Kgc6ORVuqVDmnIjZZndivXA=; b=8ZC7g3GmW9GyewZVtbw8+OCTwfpVnL66ijfXmUtqWXUy/ruSTX/xUgmbnVbw5lCVX6W1Mq MJdHyI3/Jb0warTTG7tJCLydizbLeu73w/WY/NfJMBFvfdWe1T2uYqZNdm29eQYiF28TcD ECXVkiC7OCbPFtmDaB+7MPLW4YxFlD8= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1793125900; b=UKqzqYvppzWiR8rgA89A6GaplorXB9rNlJpBTH1VmEgcK/bbZIFgj1doccUQkCTqHjYik2 t4+lGW10h18t3/aJZM5WjXQVOFDTC6jNP0Llq0KOqcwxQy0n/KNXi9jlFwv2z/KeBE8faa 55DDg9HGE+zHrY/lqPporgkSPc76XBc= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=jjxHiqsF; spf=pass (imf07.hostedemail.com: domain of harry@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=harry@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 0A4E760136; Tue, 27 Oct 2026 18:31:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 475FC1F01825; Tue, 27 Oct 2026 18:31:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793125899; bh=Zy1XjAvFE8Nfo7sM1UI6Kgc6ORVuqVDmnIjZZndivXA=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=jjxHiqsFMUljw0mFy0rB3mF05wn357Z5Avshsq+h6/XJ+4wWpRHRWyb4blIhsmyOa dEjfVWkOOtDn+MAlzmBhiqXt0FR7Tb86gkV3rz6HYv/N9xl5s7FL7x3pZ2gYnFFR6b mQj/RcQBOlggEz0Zfy34bACS6vwVemN8bDvDSmV7pv987yMD47L4Oio9ssZsVtO/Tu ErnOaGJU62MD/T7ZIaOUvVr8vlxFjJCDq5Mxh/bd2y2XzlTd7O1kvt+fme80GsO+ZD o/Qh4uVMfZy6tTb1oGCG8dJewg/YoXn8q4Fg9UVrfKnSoq7V63IBZJFwMENsHqxfSv pvp0q9nw2hWww== Date: Tue, 27 Oct 2026 18:31:37 +0000 From: Harry Yoo To: "Vlastimil Babka (SUSE)" Cc: Chris Down , Andrew Morton , Hao Li , Christoph Lameter , David Rientjes , Roman Gushchin , Kees Cook , Marco Elver , GONG Ruiqi , Jan Kiszka , Kieran Bingham , Jonathan Corbet , linux-mm@kvack.org, linux-hardening@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH 0/8] mm/slab: Support selecting slab hardening features at boot Message-ID: <179312451613.474906.1475329637924619088@kernel.org> References: <16121542-acd5-4727-b64c-f8d519145b63@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <16121542-acd5-4727-b64c-f8d519145b63@kernel.org> X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 7E07A40006 X-Stat-Signature: a8oef3jtfsurdoebs6wkp64dka3da6ba X-Rspam-User: X-Spam-Status: No, score=-6.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-HE-Tag: 1793125900-597123 X-HE-Meta: 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 96GK9Hs3 B1+t0O5CJ83uIIOPDLWAQaUNmSLz6KPXGyBv1bOEwDPPk1RVlQESoXD62va+C4nC/7JroKFg8TBfZTWEGm5KveIACoqf5UxzGG+0NnjfojXE+IpgO/cBbtunVs7K8qNpTw3tKiV/kmWYQdkL7jSysGqG6eXnumMFfvo3TBh79uF5MUlMZ2q020CK2BGxYyH6YnhWI78FooNurT6qMkHMI2KbRZvzVXXEIafHADU4GHAeKielc4ZcGTuXwr61tr847PqqG Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Tue, Oct 27, 2026 at 08:10:40AM +0100, Vlastimil Babka (SUSE) wrote: > These two should be only a small cpu overhead, which is why distros > generally enable them [1]. Yeah I'd expect the impact on them to be small enough. > > slab_buckets= > > kmalloc_partition= > > These are more valid as there's a memory overhead tradeoff. quickly measuring it on a VM with 64 CPUs and 64 GiB RAM: w/ partitioned kmalloc: 94.0 MiB (235 kmalloc caches) w/o partitioned kmalloc: 76.1 MiB (~17.9 MiB diff) (40 kmalloc caches) Mostly due to a large number number of under-utilized slabs after boot. (per memalloc profiling) slab_buckets had relately smaller impact, about ~1MiB after boot. (Of course this is just after boot, and actual bloat depends on memory usage and fragmentation on production) -- Cheers, Harry / Hyeonggon