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 4C15BC433FE for ; Mon, 28 Feb 2022 10:59:00 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CFD678D0002; Mon, 28 Feb 2022 05:58:59 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id CAD868D0001; Mon, 28 Feb 2022 05:58:59 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BC3F28D0002; Mon, 28 Feb 2022 05:58:59 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0133.hostedemail.com [216.40.44.133]) by kanga.kvack.org (Postfix) with ESMTP id ABD308D0001 for ; Mon, 28 Feb 2022 05:58:59 -0500 (EST) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 567AF9CD44 for ; Mon, 28 Feb 2022 10:58:59 +0000 (UTC) X-FDA: 79191891198.21.C63617E Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [78.32.30.218]) by imf04.hostedemail.com (Postfix) with ESMTP id 6372C40002 for ; Mon, 28 Feb 2022 10:57:30 +0000 (UTC) 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=DM3iere1mz4IiAwYCVyOTU3E+xuCTYR85Md0nHyvzDc=; b=QSz7tR2zlZoaBSWZGCaio7Oilq VwpNbxcqDPOH5Kt8OjbQhKwhks/heDAW4JFpmDfExgUTPmIf+TJ10GIXRaXS+m7eIwuh+Zrmg7ard JKb4cBAyp9suGksD5aOyDCbwX+GG/5CmBp/gJRuLB3YTEup0rKS6dKesQIWN1THmbCdg+fDs9npwW 3G62kcQtbbdR93/Yp8xWQeqnioTzargs6Wc3dgV6A9bObOsm+8HNJnnVTRueD5kTaHC4WKRDrKhk3 sYEtwY/WuFW1YR5ryQKZcakT/DA1fRo7nFdF8mglYtoE5o2X2pzfPHjvtIcfU/vD9UYjeVFBIOfpb OWrBs5aQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:57554) 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 1nOdiU-00087R-Ua; Mon, 28 Feb 2022 10:57:22 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1nOdiQ-00064t-9z; Mon, 28 Feb 2022 10:57:18 +0000 Date: Mon, 28 Feb 2022 10:57:18 +0000 From: "Russell King (Oracle)" To: Anshuman Khandual Cc: linux-mm@kvack.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, geert@linux-m68k.org, Christoph Hellwig , linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, sparclinux@vger.kernel.org, linux-mips@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-s390@vger.kernel.org, linux-riscv@lists.infradead.org, linux-alpha@vger.kernel.org, linux-sh@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-csky@vger.kernel.org, linux-xtensa@linux-xtensa.org, linux-parisc@vger.kernel.org, openrisc@lists.librecores.org, linux-um@lists.infradead.org, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-arch@vger.kernel.org, Arnd Bergmann Subject: Re: [PATCH V3 09/30] arm/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT Message-ID: References: <1646045273-9343-1-git-send-email-anshuman.khandual@arm.com> <1646045273-9343-10-git-send-email-anshuman.khandual@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1646045273-9343-10-git-send-email-anshuman.khandual@arm.com> X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 6372C40002 X-Stat-Signature: njwwqyzfo7ytiz7kx9zuqsmg5g8fu7b9 Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=armlinux.org.uk header.s=pandora-2019 header.b=QSz7tR2z; spf=none (imf04.hostedemail.com: domain of "linux+linux-mm=kvack.org@armlinux.org.uk" has no SPF policy when checking 78.32.30.218) smtp.mailfrom="linux+linux-mm=kvack.org@armlinux.org.uk"; dmarc=pass (policy=none) header.from=armlinux.org.uk X-Rspam-User: X-HE-Tag: 1646045850-933377 X-Bogosity: Ham, tests=bogofilter, spamicity=0.141280, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Feb 28, 2022 at 04:17:32PM +0530, Anshuman Khandual wrote: > This defines and exports a platform specific custom vm_get_page_prot() via > subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX > macros can be dropped which are no longer needed. What I would really like to know is why having to run _code_ to work out what the page protections need to be is better than looking it up in a table. Not only is this more expensive in terms of CPU cycles, it also brings additional code size with it. I'm struggling to see what the benefit is. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!