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 10FD4C433EF for ; Fri, 29 Apr 2022 09:56:34 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6C3DD6B0071; Fri, 29 Apr 2022 05:56:34 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6734A6B0073; Fri, 29 Apr 2022 05:56:34 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 53AB06B0074; Fri, 29 Apr 2022 05:56:34 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.28]) by kanga.kvack.org (Postfix) with ESMTP id 455DD6B0071 for ; Fri, 29 Apr 2022 05:56:34 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 1DDA3619E9 for ; Fri, 29 Apr 2022 09:56:34 +0000 (UTC) X-FDA: 79409461908.10.9232CFB Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by imf22.hostedemail.com (Postfix) with ESMTP id 84D9CC0028 for ; Fri, 29 Apr 2022 09:56:32 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 5490D21877; Fri, 29 Apr 2022 09:56:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1651226192; 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=c50DF01aKj1CW75/eNJw3BumKm0+zPFfK1oMV+pk24I=; b=ljEEUfWi+6AlnTjiGF2lXCRDMgkNjliDgjPWetyY+nd74sn+YGHonn9886TLfklgiG1Eat DSYulZuWGa2xq+hcCPLEelsND8zgJnIRz+9VDspmPP+l5JPH5zdZpwKdUC8dDQis8LpyMR jAyfVZvCsll3yoOySi9ivmCpGhpb3yU= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1651226192; 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=c50DF01aKj1CW75/eNJw3BumKm0+zPFfK1oMV+pk24I=; b=UlkbKJTmkK1VV7foFZ1hx56oPs3gI/iSyBC26ypSERws2k1zWZtumF/0xPCUkTeccf+3n1 YUtvmPSo87fjHXBw== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 1953C13AE0; Fri, 29 Apr 2022 09:56:32 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id UNF3BVC2a2IZEQAAMHmgww (envelope-from ); Fri, 29 Apr 2022 09:56:32 +0000 Message-ID: <2408e290-e016-250c-9e54-350fb923d162@suse.cz> Date: Fri, 29 Apr 2022 11:56:31 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Subject: Re: [PATCH v5 2/2] mm: make minimum slab alignment a runtime property Content-Language: en-US To: Peter Collingbourne , Andrey Konovalov , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Andrew Morton , Catalin Marinas Cc: Linux ARM , Linux Memory Management List , Linux Kernel Mailing List , penberg@kernel.org, roman.gushchin@linux.dev, iamjoonsoo.kim@lge.com, rientjes@google.com, Herbert Xu , Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , kasan-dev , Eric Biederman , Kees Cook References: <20220427195820.1716975-1-pcc@google.com> <20220427195820.1716975-2-pcc@google.com> From: Vlastimil Babka In-Reply-To: <20220427195820.1716975-2-pcc@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 84D9CC0028 X-Stat-Signature: aspsmmqdoic3xoqtyynhf8tqp61wiaf9 X-Rspam-User: Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=ljEEUfWi; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=UlkbKJTm; spf=pass (imf22.hostedemail.com: domain of vbabka@suse.cz designates 195.135.220.28 as permitted sender) smtp.mailfrom=vbabka@suse.cz; dmarc=none X-HE-Tag: 1651226192-575689 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: On 4/27/22 21:58, Peter Collingbourne wrote: > When CONFIG_KASAN_HW_TAGS is enabled we currently increase the minimum > slab alignment to 16. This happens even if MTE is not supported in > hardware or disabled via kasan=off, which creates an unnecessary > memory overhead in those cases. Eliminate this overhead by making > the minimum slab alignment a runtime property and only aligning to > 16 if KASAN is enabled at runtime. > > On a DragonBoard 845c (non-MTE hardware) with a kernel built with > CONFIG_KASAN_HW_TAGS, waiting for quiescence after a full Android > boot I see the following Slab measurements in /proc/meminfo (median > of 3 reboots): > > Before: 169020 kB > After: 167304 kB > > Link: https://linux-review.googlesource.com/id/I752e725179b43b144153f4b6f584ceb646473ead > Signed-off-by: Peter Collingbourne > Reviewed-by: Andrey Konovalov > Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> > Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> > Acked-by: David Rientjes > Reviewed-by: Catalin Marinas Acked-by: Vlastimil Babka Andrew's fixup LGTM too.