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 X-Spam-Level: X-Spam-Status: No, score=-5.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3A2F7C433DB for ; Thu, 21 Jan 2021 17:47:55 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DA02221973 for ; Thu, 21 Jan 2021 17:47:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DA02221973 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=qWP4ldaotR5GYSY2Fae7JvVNTE7/KDnpLLjKdgrWy6k=; b=hv4WgKqGMRpGufRbslpvtyOus WdwEKCzCbNXP/6nGFn6l0q83lSoXrtpNOeIAM1Dog4iVcFZHXnbmX4BOBFCgTcU0JS3wCxuyM3QP/ ZRbiA/OVMQavADUdqEjpEpWENLwLx0iCzBkOw8dnzEKp7XRVxZdoUbTTW2pILLTNTDHjHv+IbNuKw QUcsnyU4mI3fgJ3RXZ+dgadgeOydCRxyvWXbG+Bq8iwzqxwxceVuuGF6jwVkoxEQENUbTjWgEpFUk Nw+RzlrW0N2KLpHH7Rg8ysBTBX04bRsT2oUiHPFXV8LQ2lqWsmlCOx+JMsc2eTSnvWEesWR6lXO1l fO7bVX0vQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l2e2N-0005eR-0V; Thu, 21 Jan 2021 17:46:27 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l2e2J-0005dM-Fz for linux-arm-kernel@lists.infradead.org; Thu, 21 Jan 2021 17:46:24 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6BE78207C5; Thu, 21 Jan 2021 17:46:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1611251182; bh=MqX1kerCnT40Z0xUUgTg70OGnK4xYYiDNavID8LlQrY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=NGspuxFUB31C87kP59HWiHNPgyq/YeRGDTPlXo8XWQtnyPGQgSfZBEmO69dZUZ1zS tXU+b8PaH4/ecjgOk4iL7UdtFg9GLMPwhGoBWHRkIzImvJfs8fQlUdSjdZDpBXJhAR vGEfEWujxyFISdtdYeu0d/ewV5zvrM2pD01Dqn/uLWbXa/6tST84Qd72JoQ0A1MjbH ggp8y0yeznRsAIdM5eVd8cTMTSHxgm+4Z778aHW3A5CuMmXBQx4P/OkLaHPWjaIupk xAEtdnV69D0RGFgYLwBYnu8UXTVilbn24R/dbRvrTSegnUN+maQITF9F4JAMMQdZh3 ZotB5XHRCj0YQ== Date: Thu, 21 Jan 2021 17:46:16 +0000 From: Will Deacon To: Prathu Baronia Subject: Re: [PATCH 0/1] mm: Optimizing hugepage zeroing in arm64 Message-ID: <20210121174616.GA22740@willie-the-truck> References: <20210121165153.17828-1-prathu.baronia@oneplus.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210121165153.17828-1-prathu.baronia@oneplus.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210121_124623_644628_2F433FA9 X-CRM114-Status: GOOD ( 12.96 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Prathu Baronia , Catalin Marinas , Anshuman Khandual , linux-kernel@vger.kernel.org, chintan.pandya@oneplus.com, "glider@google.com" , Andrey Konovalov , Geert Uytterhoeven , Andrew Morton , Vincenzo Frascino , linux-arm-kernel@lists.infradead.org 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 Thu, Jan 21, 2021 at 10:21:50PM +0530, Prathu Baronia wrote: > This patch removes the unnecessary kmap calls in the hugepage zeroing path and > improves the timing by 62%. > > I had proposed a similar change in Apr-May'20 timeframe in memory.c where I > proposed to clear out a hugepage by directly calling a memset over the whole > hugepage but got the opposition that the change was not architecturally neutral. > > Upon revisiting this now I see significant improvement by removing around 2k > barrier calls from the zeroing path. So hereby I propose an arm64 specific > definition of clear_user_highpage(). Given that barrier() is purely a thing for the compiler, wouldn't the same change yield a benefit on any other architecture without HIGHMEM? In which case, I think this sort of change belongs in the core code if it's actually worthwhile. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel