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 407C3C77B6E for ; Fri, 14 Apr 2023 16:31:14 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DBFF7280002; Fri, 14 Apr 2023 12:31:13 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D704B280001; Fri, 14 Apr 2023 12:31:13 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C8712280002; Fri, 14 Apr 2023 12:31:13 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id BCC41280001 for ; Fri, 14 Apr 2023 12:31:13 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 8BAB9403E3 for ; Fri, 14 Apr 2023 16:31:13 +0000 (UTC) X-FDA: 80680536426.12.A49F5C7 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf02.hostedemail.com (Postfix) with ESMTP id 5A4A28002C for ; Fri, 14 Apr 2023 16:31:11 +0000 (UTC) Authentication-Results: imf02.hostedemail.com; dkim=none; spf=pass (imf02.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1681489871; a=rsa-sha256; cv=none; b=VSacF7yD7dGlp/9xgqkEnIckmsYgztGOyk9iZiZSd0SKpsJdbqc44wry9TZ8CIYtaukalq KYO0c1S+NUYUsixuRmVaIEDCzZfu/pCEJgpTYAZxymiMVICU1rjCxOxPBmBf0Xa8LWZQf5 soYhD33kSU5JwuDcpU4FZWiIbb4IoIg= ARC-Authentication-Results: i=1; imf02.hostedemail.com; dkim=none; spf=pass (imf02.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1681489871; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=HSzwu8ecCAcH9Z8/amlXmda8Ydv1qi7a5c9gB1PD5R4=; b=y2UpxrdPmPd/V3LHomDpNbUbAs8gHtTcUTfHcUwMTTQK3WgIq5G585E/xHP6pLtOVR5bpy zt2CreyArNN7RfiowLVvNlDHRoXZPLpKdjJJWsZPvsliIIs7ZxMYfOuDsqJZILDpZUvC+D EC8379mfMX2OGVmZT/m+HRs+Kygofy0= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id DBBB74B3; Fri, 14 Apr 2023 09:31:54 -0700 (PDT) Received: from [10.57.68.227] (unknown [10.57.68.227]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5AE133F6C4; Fri, 14 Apr 2023 09:31:09 -0700 (PDT) Message-ID: <9f879f29-e642-ef9c-9f6f-612d552b9116@arm.com> Date: Fri, 14 Apr 2023 17:31:07 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.9.1 Subject: Re: [RFC v2 PATCH 05/17] mm: Routines to determine max anon folio allocation order Content-Language: en-US To: Matthew Wilcox Cc: "Kirill A. Shutemov" , Andrew Morton , Yu Zhao , "Yin, Fengwei" , linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org References: <20230414130303.2345383-1-ryan.roberts@arm.com> <20230414130303.2345383-6-ryan.roberts@arm.com> <20230414140948.7pcaz6niyr2tpa7s@box.shutemov.name> <2b76ee7e-06d1-94ca-d22e-46b6302b7c30@arm.com> <20230414153747.n5kyhvb5a726lvrz@box.shutemov.name> From: Ryan Roberts In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: 5A4A28002C X-Rspamd-Server: rspam01 X-Stat-Signature: gi99ehba6ypeczswyx115numqjiw64x8 X-HE-Tag: 1681489871-716396 X-HE-Meta: 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 eYWw28kD sQRwRMkyhE0h/jQl0n2d67yvTpY/wEaoK/88kZPUUbK6gSS+KQJb3BM0yH4HOS/5PDHvavaBg5BFC+qOfUQ88CPB/296BzgC2kJo6xVS9N406bzbop5jyAt635VguCLCnUsWr 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 14/04/2023 17:18, Matthew Wilcox wrote: > On Fri, Apr 14, 2023 at 05:06:49PM +0100, Ryan Roberts wrote: >> The point I'm thinking about is for 4K pages, we need to allocate 64K blocks to >> use the contig bit. Roughly I guess that means going from average of 2K wastage >> per anon VMA to 32K. Perhaps you can get away with that for a decent perf uplift. >> >> But for 64K pages, we need to allocate 2M blocks to use the contig bit. So that >> takes average wastage from 32K to 1M. That feels a bit harder to justify. >> Perhaps here, we should make a decision based on MADV_HUGEPAGE? >> >> So perhaps we actually want 2 values: one for if MADV_HUGEPAGE is not set on the >> VMA, and one if it is? (with 64K pages I'm guessing there are many cases where >> we won't PMD-map THPs - its 512MB). > > I'm kind of hoping that all this work takes away the benefit from > CONFIG_PAGE_SIZE_64K, and we can just use 4k pages everywhere. That sounds great. I'm not sure I share your confidence though ;-)