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 5FE7AC4332F for ; Wed, 9 Nov 2022 15:50:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 58D5B6B0072; Wed, 9 Nov 2022 10:50:17 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 53D606B0073; Wed, 9 Nov 2022 10:50:17 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 405316B0074; Wed, 9 Nov 2022 10:50:17 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 2EAED6B0072 for ; Wed, 9 Nov 2022 10:50:17 -0500 (EST) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id C3B0512085A for ; Wed, 9 Nov 2022 15:50:16 +0000 (UTC) X-FDA: 80114340432.23.3327E74 Received: from meesny.iki.fi (meesny.iki.fi [195.140.195.201]) by imf10.hostedemail.com (Postfix) with ESMTP id C350DC0004 for ; Wed, 9 Nov 2022 15:50:15 +0000 (UTC) Received: from darkstar.musicnaut.iki.fi (85-76-49-22-nat.elisa-mobile.fi [85.76.49.22]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: aaro.koskinen) by meesny.iki.fi (Postfix) with ESMTPSA id 5065B20092; Wed, 9 Nov 2022 17:50:10 +0200 (EET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=iki.fi; s=meesny; t=1668009012; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=BHna4eOsJNa6jYXmw+tDBqgbBaWjKPKSATnmoXtvD6E=; b=jVqp7WR1xNj9cQVnjX26nQIa0sIJ7CIYmIKDCdmml8y0lg2hYRKNMhoCWhGvaG9xi20Q7Z vJCEKKIY2Ip2/zQw5wC3JuCMVFnqVCBlU2GjzIg3OvldqapenUvhOoRb4yvP6546HFOGHC R20IBBqDUumCQggds467xH3mhuzOB8k= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=iki.fi; s=meesny; t=1668009012; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=BHna4eOsJNa6jYXmw+tDBqgbBaWjKPKSATnmoXtvD6E=; b=iHrt/OPqY6xXFjullaYr2tdte4CnFKRPP/Qv9sI1/eV6eyFCRudApCF0y9xE9HyjG9CrJ/ GXTjlex8eS4bD+EEoXcJDgSLHDg7OS1E9S1Aruo/b2DONAWedPhitDNQncR7xYDAL5BGok lacxDr15fvQajVKMJ2Fqdt7GnI9N1aE= ARC-Authentication-Results: i=1; ORIGINATING; auth=pass smtp.auth=aaro.koskinen smtp.mailfrom=aaro.koskinen@iki.fi ARC-Seal: i=1; s=meesny; d=iki.fi; t=1668009012; a=rsa-sha256; cv=none; b=UTFdz4Eys6UJMnuJ1tki0FsSrCtGO9PLelwNKipGe+wWFE3KzecrcbdWpKG/2765JqlV6k MaTTRfw1yV0mijWeIwe5jnXrgfu3LnOwBdunfs5BMitsHuvF9O1N1NAxEJhHt4R0cIG0H7 6LLpguKVNzSAV4wkUxWys5Y35sSz8fU= Date: Wed, 9 Nov 2022 17:50:08 +0200 From: Aaro Koskinen To: Vlastimil Babka Cc: Pasha Tatashin , Christoph Lameter , David Rientjes , Joonsoo Kim , Pekka Enberg , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Matthew Wilcox , Roman Gushchin , Linus Torvalds , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Catalin Marinas , Rustam Kovhaev , Andrew Morton , Josh Triplett , Arnd Bergmann , Russell King , Alexander Shiyan , Janusz Krzysztofik , Tony Lindgren , Yoshinori Sato , Rich Felker , Jonas Bonn , Stefan Kristiansson , Stafford Horne , "linux-arm-kernel@lists.infradead.org" , openrisc@lists.librecores.org, linux-riscv@lists.infradead.org, linux-sh@vger.kernel.org Subject: Re: Deprecating and removing SLOB Message-ID: <20221109155008.GC307514@darkstar.musicnaut.iki.fi> References: <87187c52-ae48-130b-6479-ae1023915bc1@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87187c52-ae48-130b-6479-ae1023915bc1@suse.cz> ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1668009016; 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=BHna4eOsJNa6jYXmw+tDBqgbBaWjKPKSATnmoXtvD6E=; b=kthROSJHZQqDQ5ypHIkJnHla1Th9oXYp/B7DuEcGXHMymyAvFv9bcuBh2I+Ki6l5pPeC2m Ldsmt5bGxej3gKih94/jTLYIUNSqPOeNFFjHADBqDBqF5wCWsirg5nOzAVzgqWn46fvP3Z +1hBmxlioxHMWp7OZEgOfHbCKCOLj/8= ARC-Authentication-Results: i=2; imf10.hostedemail.com; dkim=pass header.d=iki.fi header.s=meesny header.b=jVqp7WR1; arc=pass ("iki.fi:s=meesny:i=1"); spf=pass (imf10.hostedemail.com: domain of aaro.koskinen@iki.fi designates 195.140.195.201 as permitted sender) smtp.mailfrom=aaro.koskinen@iki.fi; dmarc=none ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1668009016; a=rsa-sha256; cv=pass; b=zf09pOw5e6fqPVh5+wPJMrJZ51il1hWnoq4d1c7DKAvXyQI2OQMW7QzBc/zAA36KfcOysM zlhPtCWT0qzzRZWxffqj6taRC9xW1m2uh2szFzqwD5+0YtcasFye+l9AVU4nNx2cHEQ7yM Z4Br8WvMKctbyz1kSVZnp5is3glmPRE= X-Rspamd-Queue-Id: C350DC0004 Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=iki.fi header.s=meesny header.b=jVqp7WR1; arc=pass ("iki.fi:s=meesny:i=1"); spf=pass (imf10.hostedemail.com: domain of aaro.koskinen@iki.fi designates 195.140.195.201 as permitted sender) smtp.mailfrom=aaro.koskinen@iki.fi; dmarc=none X-Rspamd-Server: rspam10 X-Rspam-User: X-Stat-Signature: 3t3e4tuz4gaocba3r76c811xcddi4dbs X-HE-Tag: 1668009015-279864 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: Hi, On Wed, Nov 09, 2022 at 10:00:25AM +0100, Vlastimil Babka wrote: > > On Tue, Nov 8, 2022 at 10:55 AM Vlastimil Babka wrote: > >> I believe SLOB can be removed because: > >> > >> - AFAIK nobody really uses it? It strives for minimal memory footprint > >> by putting all objects together, which has its CPU performance costs > >> (locking, lack of percpu caching, searching for free space...). I'm not > >> aware of any "tiny linux" deployment that opts for this. For example, > >> OpenWRT seems to use SLUB and the devices these days have e.g. 128MB > >> RAM, not up to 16 MB anymore. I've heard anecdotes that the performance > >> SLOB impact is too much for those who tried. Googling for > >> "CONFIG_SLOB=y" yielded nothing useful. > > > > I am all for removing SLOB. > > > > There are some devices with configs where SLOB is enabled by default. > > Perhaps, the owners/maintainers of those devices/configs should be > > included into this thread: [...] > > arch/arm/configs/omap1_defconfig:CONFIG_SLOB=y I have been using SLUB on my OMAP1 boards with 32 MB RAM, because of better debugging features and the memory footprint difference doesn't really matter for my use cases. Looking at history why SLOB was added there, it seems it came from 6cfce27c14aa ("omap1: Add omap1_defconfig") when separate boards configs were merged, and SX1 board happened to have SLOB in there. This board is nowadays only used in QEMU anyway. There are OMAP1 boards with only 16 MB, but support for those boards will be removed. So from OMAP1 side, I don't think there is any real need for SLOB anymore. A.