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 1D71EC4167B for ; Thu, 14 Dec 2023 20:14:44 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A1B788D00E6; Thu, 14 Dec 2023 15:14:43 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 9CB448D00C7; Thu, 14 Dec 2023 15:14:43 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 86D728D00E6; Thu, 14 Dec 2023 15:14:43 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 757798D00C7 for ; Thu, 14 Dec 2023 15:14:43 -0500 (EST) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 51A95C0417 for ; Thu, 14 Dec 2023 20:14:43 +0000 (UTC) X-FDA: 81566526846.09.07474E2 Received: from gentwo.org (gentwo.org [62.72.0.81]) by imf22.hostedemail.com (Postfix) with ESMTP id A7A46C0006 for ; Thu, 14 Dec 2023 20:14:41 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=linux.com (policy=none); spf=softfail (imf22.hostedemail.com: 62.72.0.81 is neither permitted nor denied by domain of cl@linux.com) smtp.mailfrom=cl@linux.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1702584881; 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; bh=iNKVLqK3XOPH3dLna4uOMTsaPzFt7/yZ9FkYu9F8DMU=; b=F6hoBifZ/ma+W5prOgpB63wfI7xNNaadbI+eIELsYAwkfmEU3scqshMz7MXfjdBoWnO7Zi jyH23b6mgIvgAmRTz5vOfkMOFaNVB+G2aK4bfT927Dn0XTulPQnT/oc2QrUP97NoyGJYqj f8BjJYRbmR4cJjXknwQi9l4A34rUc28= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=linux.com (policy=none); spf=softfail (imf22.hostedemail.com: 62.72.0.81 is neither permitted nor denied by domain of cl@linux.com) smtp.mailfrom=cl@linux.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1702584881; a=rsa-sha256; cv=none; b=FNpL8e7TkDmX4bleFmF0CX2ZF7VlYXa5kST3v5lyAVFWjVJvsYyJVZ91MCvMxScowolN4j 2I6p88XsPqMHt5Y+LrkQZxFyqkWTkP7uGy2kjqf5MJQKp0N6nd6nM3eE8h8TV9gdcW+i/R NrLzckVKBkBDScGZhb+M8C/3fBFsjGE= Received: by gentwo.org (Postfix, from userid 1003) id 2451240E8E; Thu, 14 Dec 2023 12:14:40 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by gentwo.org (Postfix) with ESMTP id 23BBB40E89; Thu, 14 Dec 2023 12:14:40 -0800 (PST) Date: Thu, 14 Dec 2023 12:14:40 -0800 (PST) From: "Christoph Lameter (Ampere)" To: Matthew Wilcox cc: Vlastimil Babka , Pekka Enberg , David Rientjes , Joonsoo Kim , "Liam R. Howlett" , Andrew Morton , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Alexander Potapenko , Marco Elver , Dmitry Vyukov , linux-mm@kvack.org, linux-kernel@vger.kernel.org, maple-tree@lists.infradead.org, kasan-dev@googlegroups.com Subject: Re: [PATCH RFC v3 0/9] SLUB percpu array caches and maple tree nodes In-Reply-To: Message-ID: <146558f5-9f5c-e65f-0177-5f736fe663cd@linux.com> References: <20231129-slub-percpu-caches-v3-0-6bcf536772bc@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed X-Rspamd-Queue-Id: A7A46C0006 X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: xi9xfbfydc8smrpwpimkjtrs7ocdqmh8 X-HE-Tag: 1702584881-20527 X-HE-Meta: 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 OisMtrA0 QlO+sP2FpHcLpAvGDG5nIV/UOCti2CW1xZQM3XRYcAceH6Q+PSY2zxnbMtyS0REAy140yfpweQpYBw+S0ftYggSElXHGecDP/J0Ca58FP/fajJeRIBBsolTBASC2C5mMYugKg2rVkJv7aKr4SWGYoav214TJoc6ymkKF0a9v3JpeCSnr/tva4XXEqkTl26yhm+Hs3ndVyfYboH+MoRWgjx1GI9aH3QOiAnVjYcfwODycNNI4= 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: List-Subscribe: List-Unsubscribe: On Wed, 29 Nov 2023, Matthew Wilcox wrote: >> In order to make the SLUB in page freelists work better you need to have >> larger freelist and that comes with larger page sizes. I.e. boot with >> slub_min_order=5 or so to increase performance. > > That comes with its own problems, of course. Well I thought you were solving those with the folios? >> Also this means increasing TLB pressure. The in page freelists of SLUB cause >> objects from the same page be served. The SLAB queueing approach >> results in objects being mixed from any address and thus neighboring objects >> may require more TLB entries. > > Is that still a concern for modern CPUs? We're using 1GB TLB entries > these days, and there are usually thousands of TLB entries. This feels > like more of a concern for a 90s era CPU. ARM kernel memory is mapped by 4K entries by default since rodata=full is the default. Security concerns screw it up.