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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 34C14C77B72 for ; Fri, 14 Apr 2023 16:32:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To: Subject:MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=+c4Jvs1v1Z64b+QxLKjElFg/oA5M4FsRVdWuZbcr3cM=; b=PDqF+E3SKMMGeK wIPjBdKSuSzxJEe4BaAjIVhLBcktYuE6+rAhD/o3oSA0rBzn2g8ZLNX1yem9dzW+idORqTfYrzRsR jzCyOcMQsfzKp/lInHoVr8y6q5V1apGe8/JJdPvYEnbKWOOr/TlG4Xexhx+6y4TOnKiPDSOuKcrSB 62SKf15bQwCxzN6JLJQo3ABLubfKdKMBBLs4XbavGRFhq7lz3TKIYE/4T2sjDRjyYO7wAI+qSZX7u PmmrJ5xc+MFpeusCK5P+YA868lbyh4RNHNrSeEllk9hVCn2riDu3d9UF9oSuUh8rIzioPll2osWkc bS/RBJJ4lhw744crpDBw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pnMKS-00A78E-1V; Fri, 14 Apr 2023 16:31:16 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pnMKP-00A776-2d for linux-arm-kernel@lists.infradead.org; Fri, 14 Apr 2023 16:31:15 +0000 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: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230414_093113_900506_FF44C7D0 X-CRM114-Status: GOOD ( 13.10 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 ;-) _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel