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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7148DC433FE for ; Wed, 9 Nov 2022 21:17:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231501AbiKIVRL (ORCPT ); Wed, 9 Nov 2022 16:17:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36246 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231185AbiKIVRH (ORCPT ); Wed, 9 Nov 2022 16:17:07 -0500 Received: from mail-pl1-x62a.google.com (mail-pl1-x62a.google.com [IPv6:2607:f8b0:4864:20::62a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EA8523134D; Wed, 9 Nov 2022 13:17:05 -0800 (PST) Received: by mail-pl1-x62a.google.com with SMTP id p21so18273186plr.7; Wed, 09 Nov 2022 13:17:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=6o0JaodUdCinHCuijBKMPPDh4qNhM3W4CwZTMs5pShU=; b=b7JdsqL98tFczElrzx45zPQRQqT+FLWQdW7GQ21VMf1VWbVkWvdPT7fPQVW9/YYGhj fsJmZVTrJHZqpF5nrGm5JKasB3diwCu2Hs5yNW2C9n/rEZiCH7R7PnAEwZ/MGa/qzyIG zfiOnumXidobU0/zuy474imLQWsj+TNcT1BwOR4wCZrc7nj9wEle1ahDUDnwTkt6UQJ1 bZGNJ9fqbFCNFUTDQDZYUF5tjtiVt+POwV9J5xnlurRxP4GFYN8l+xbrN6OKbV0N8j6j kPz632gUkLxrLhg+OI3WB7b7hny2T7RaIKSOWnHn8CvNieatf9SjrSo7u+FU7dyzH4Jo RWzQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=6o0JaodUdCinHCuijBKMPPDh4qNhM3W4CwZTMs5pShU=; b=b3PLisN7Ncx58rTaBNLUZpurK7Peo+EAojgr7iioQ2yIi6iizKS3V22O63r4gOy4kb o4CfwbvlQhkpMutY7JA9f7+paUGVPlSSVnSsK1mib/FVf/ojjqLqh2MfYRUP9xk/ylWW CiS56JEg/zNqT5FKe7HNF+wcTuOCuLHfGs9cNia2P52wqsRHAjySRHMTYfX6Bt5MVITu W2/72nLb+cT5EBJ5uuZ/YZKudNtbfejQNK8UI3p9hMVbog6gaMvUkj1OsyCmxJgrbFuR RYUTP2km9yaJR2ivSvJ3VgpVX1O0t1JLoWgH+OBwTYEcek8NnGKcFTxJJCOgME983Rp9 daWQ== X-Gm-Message-State: ACrzQf0K+DeZsk1e++GTBesJ4+5GYDzHBL3XncL5yFdA5ge0zPOjJg/c R11ujVEZewBDVJNQT1mSPe5tfQhfcJwZGIdqGig= X-Google-Smtp-Source: AMsMyM5vTjPHFhQ2vYKc1ap+Gnz9Xnoi5f6pFtOuhyEULsih6osIQH75MdocdJksgvBY7Bht8TwzxWn0ElldlUKBtUU= X-Received: by 2002:a17:902:da82:b0:186:ee5a:47c7 with SMTP id j2-20020a170902da8200b00186ee5a47c7mr63072929plx.82.1668028625070; Wed, 09 Nov 2022 13:17:05 -0800 (PST) MIME-Version: 1.0 References: <87187c52-ae48-130b-6479-ae1023915bc1@suse.cz> <20221109155008.GC307514@darkstar.musicnaut.iki.fi> In-Reply-To: <20221109155008.GC307514@darkstar.musicnaut.iki.fi> From: Janusz Krzysztofik Date: Wed, 9 Nov 2022 22:16:53 +0100 Message-ID: Subject: Re: Deprecating and removing SLOB To: Vlastimil Babka , Aaro Koskinen 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 , 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 Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org On Wednesday, 9 November 2022 16:50:08 CET Aaro Koskinen wrote: > 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. Moreover, I always had issues with availability of socket buffers during USB device setup when trying to use SLOB on Amstrad Delta based on OMAP1510, the least powerful OMAP1. Then, +1 for SLOB removal. Thanks, Janusz