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 9B0FDC4332F for ; Wed, 19 Oct 2022 15:09:21 +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:MIME-Version:References: Message-ID:Subject:Cc: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=w2qet7Vk+7zzc2QQUnYOGnAEgXksMJq+s0vmslva3/4=; b=sn1aqH3LXhhliv ehQz6bMcGJuhD4VwFksGrOnj3Qp2v1a9xETkIUXHpGhhM2ivARirWVjO+eVJ3PWWzRJzCBkTrxIoC sbE2kXZWjtPuydW6wSzlV1HFsOPAf2c8BK4SlMisDdb2/Byi9Xjfn49+vwVsV4zpcCTYGsB8y2248 DVlM7FzcOEY3uKQPf/90MWsBUscEvWB3KkEV7FaPMQIiI2cdRMWs3CTJyzXAnAMNi8Kh9CpVqNyGi FyXUjEa0vOOfe4u5UwGc0RWKUNPdX25T7LioNjQspgoTD99xyyp22QK2OszM0KkSY13y/qGCo0xMD lYKTWaaY4qi2pf9O6EOw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1olAfQ-0033Ot-1i; Wed, 19 Oct 2022 15:07:36 +0000 Received: from pandora.armlinux.org.uk ([2001:4d48:ad52:32c8:5054:ff:fe00:142]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1olAJS-002rTA-Qd for linux-arm-kernel@lists.infradead.org; Wed, 19 Oct 2022 14:44:56 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=5mYsxjFeGKpcm5KRoXtnujxHXSvElTxW7YBXE+XahDo=; b=GYpzJ4IZIEfobfw2od09Tue2PV 4elW8HRHpOe79w1JijJ0TPTMFxGt3XDEFxytqo1o4IEXBn0Jl6GG1UAN5ndNpIdibD+jcICdO8hi1 itO01Z3AXa1DzUKuW6CQUdmH0SvB+9jnoZL3lqzkbXW3+VJGaXLkPzaEw0o7KN8qJdm2NzTHuBhfS BYnmWChb87rwU/Hn2dZilJdNHidtz4w9EcQudXpnm+nxGNe+/QS4TVsuFq9LRSfdlzyzO5mY/ExNK wcmVKKRtjnBBWonp0yslD/t5D6O0ynqDxw0n05xcJkhUpvATyFzFnczZmeY/95wkr6ilgN9jh8VqL 13yPXzsg==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:34806) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1olAJL-0005qQ-Aa; Wed, 19 Oct 2022 15:44:47 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1olAJH-0002Ea-5V; Wed, 19 Oct 2022 15:44:43 +0100 Date: Wed, 19 Oct 2022 15:44:43 +0100 From: "Russell King (Oracle)" To: Giulio Benetti Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Anshuman Khandual , Andrew Morton , Kefeng Wang , Arnd Bergmann , Will Deacon Subject: Re: [PATCH v2 2/2] ARM: mm: convert empty_zero_page to array for consistency Message-ID: References: <20221018222503.90118-1-giulio.benetti@benettiengineering.com> <20221018222503.90118-2-giulio.benetti@benettiengineering.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20221018222503.90118-2-giulio.benetti@benettiengineering.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221019_074454_893884_0AC6CAD7 X-CRM114-Status: GOOD ( 14.11 ) 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 Wed, Oct 19, 2022 at 12:25:03AM +0200, Giulio Benetti wrote: > ARM architecture is the only one to have empty_zero_page to be a > struct page pointer, while in all other implementations empty_zero_page is > a data pointer or directly an array(the zero page itself). So let's convert > empty_zero_page to an array for consistency and to avoid an early > allocation+dcache flush. Being the array in .bss it will be cleared earlier > in a more linear way(and a bit faster) way. > > Suggested-by: Arnd Bergmann > Signed-off-by: Giulio Benetti I'm completely against this approach. It introduces inefficiencies in paths we don't need, and also means that the zero page is at a fixed location relative to the kernel, neither of which I like in the slightest. Thanks. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last! _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel