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 44429C433EF for ; Mon, 22 Nov 2021 11:41:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B03686B0071; Mon, 22 Nov 2021 06:41:06 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AB29E6B0072; Mon, 22 Nov 2021 06:41:06 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9A06F6B0073; Mon, 22 Nov 2021 06:41:06 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0113.hostedemail.com [216.40.44.113]) by kanga.kvack.org (Postfix) with ESMTP id 8ED4A6B0071 for ; Mon, 22 Nov 2021 06:41:06 -0500 (EST) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 52AD087C97 for ; Mon, 22 Nov 2021 11:40:56 +0000 (UTC) X-FDA: 78836374512.22.2F27A2D Received: from gentwo.de (gentwo.de [161.97.139.209]) by imf30.hostedemail.com (Postfix) with ESMTP id CDD0CE0019A2 for ; Mon, 22 Nov 2021 11:40:50 +0000 (UTC) Received: by gentwo.de (Postfix, from userid 1001) id AFCA0B003BD; Mon, 22 Nov 2021 12:40:53 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by gentwo.de (Postfix) with ESMTP id AD1BAB0034F; Mon, 22 Nov 2021 12:40:53 +0100 (CET) Date: Mon, 22 Nov 2021 12:40:53 +0100 (CET) From: Christoph Lameter X-X-Sender: cl@gentwo.de To: Vlastimil Babka cc: Rustam Kovhaev , penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, corbet@lwn.net, djwong@kernel.org, david@fromorbit.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, gregkh@linuxfoundation.org, viro@zeniv.linux.org.uk, dvyukov@google.com Subject: Re: [PATCH v4] slob: add size header to all allocations In-Reply-To: <148d2774-77b9-bb25-c132-80b00e16ea06@suse.cz> Message-ID: References: <037227db-c869-7d9c-65e8-8f5f8682171d@suse.cz> <20211122013026.909933-1-rkovhaev@gmail.com> <3c996e22-034f-1013-3978-1f786aae38fb@suse.cz> <148d2774-77b9-bb25-c132-80b00e16ea06@suse.cz> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Stat-Signature: 9i8m8yczmn4qk8yif95deg5qsbibb8t4 X-Rspamd-Queue-Id: CDD0CE0019A2 X-Rspamd-Server: rspam07 Authentication-Results: imf30.hostedemail.com; dkim=none; spf=none (imf30.hostedemail.com: domain of cl@gentwo.org has no SPF policy when checking 161.97.139.209) smtp.mailfrom=cl@gentwo.org; dmarc=none X-HE-Tag: 1637581250-355350 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 Mon, 22 Nov 2021, Vlastimil Babka wrote: > It's no problem to have the real beginning of the object aligned, and the > prepended header not. The code already does that before this patch for the > kmalloc power-of-two alignments, where e.g. the object can be aligned to 256 > bytes, but the prepended header to a smaller ARCH_KMALLOC_MINALIGN / > ARCH_SLAB_MINALIGN. Ok but then the first object in a page may still have those issues. > > I dont know but it seems that making slob that sophisticated is counter > > productive. Remove SLOB? > > I wouldn't mind, but somebody might :) Well run a space efficiency analysis after this patch. If the memory used is larger than SLUB (with the configuration for minimal data footprint) then there is no reason for SLOB to continue.