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 15A0AC43334 for ; Mon, 4 Jul 2022 11:26:51 +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=UCT/ZEFrlPMi4CmDcTvtThTKP5JSBu0bkBMyHhZk28I=; b=XC6Rkk+HXLluy5 p5Y/j5YbVmf1++YCN79ncA3Zb0pRcDx2tzIKpQ9Prnfq1bT3w8HGWSMQWb4HPWSdcTzh7Mjsqr6sC WXkhPNKf1tzhwx0MjXUN8Q0X3CkwmZnNQ7nLu1zGVmudiJqPLM+HBpCjIMk/rdPYqla1PD/Fklzo7 2ibA6346THBIa6WWsSSVnDgYLLllWTVqJfUVzkBOcoKzCTn27Mdl7w5nvoirz8sZcuHxyK7nbu+GU dYvrVDkG4Cv+aLfW/fQSKT2YitvxUqKRCTdPCiILSTpFaM7jeknA4huX0ytgbNJBETueUC4Q4XJB5 uN48CBgHQT+gO3hTaYyw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1o8KCm-007hRJ-HH; Mon, 04 Jul 2022 11:25:29 +0000 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1o8JdC-007Dtl-VN for linux-arm-kernel@bombadil.infradead.org; Mon, 04 Jul 2022 10:48:43 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=R065WUthmqEzgKWBrKAm5cYHdmg6DG4yvVjf9aretus=; b=vIRAshX83ml6lhx5YzTLRFSdLx +/XlOOmPWFLIb8vohBG+auYtcUzx49+jp/UVKIKc1b+q+4TRRpi9MFRJpCp8ebYN0Et8QZHy7LUoH v1hXcq2aLAEcKEHtFD9x9Ef5CHAVH2Q/xVa6xKiTnDjCgzkZzLwcDj/HHblGh7e9Zzd3w9H59yu7V 1g0If6WEv5JgyNbKNzfX/x5SJQ9Rw4eIwxjLa2zd7f3ryUfy/bm79K7eJfrnNg8MT58BGR8t7eQO1 3YUW94KTxi/q/QYCE8C29s4V4ewUg75zmGTi7n0WCD3iTO3AnDRRcsG1rEyPkClQqvEvCvbxMvR77 ty9vwmUQ==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1o8Jd9-00HBz8-Pt; Mon, 04 Jul 2022 10:48:39 +0000 Date: Mon, 4 Jul 2022 11:48:39 +0100 From: Matthew Wilcox To: "Russell King (Oracle)" Cc: Andrew Morton , Arnd Bergmann , Mike Rapoport , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 15/14] arm: Rename PMD_ORDER to PMD_BITS Message-ID: References: <20220703141203.147893-1-rppt@kernel.org> <20220703211441.3981873-1-willy@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: 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 Mon, Jul 04, 2022 at 05:32:33AM +0100, Russell King (Oracle) wrote: > On Sun, Jul 03, 2022 at 10:54:49PM +0100, Matthew Wilcox wrote: > > On Sun, Jul 03, 2022 at 10:16:45PM +0100, Russell King (Oracle) wrote: > > > On Sun, Jul 03, 2022 at 10:14:41PM +0100, Matthew Wilcox (Oracle) wrote: > > > > This is the number of bits used by a PMD entry, not the order of a PMD. > > > > > > No, it's not the number of bits. A PMD entry doesn't fit in 2 or 3 bits. > > > This is even more confusing. > > > > Well, what is it then? The order of something is PAGE_SIZE << n, and > > that doesn't seem to be what this is. > > Where is it defined that "order" means "PAGE_SIZE << n" ? include/asm-generic/getorder.h: * get_order - Determine the allocation order of a memory size > "order" here is "order of magnitude" and in this case, it is 2^n, just > like order of magnitude in base 10 is 10^n. So strictly, the usage > here is completely correct, but if you describe "order" as "PAGE_SIZE << > n" that is no longer an order of magnitude, because it doesn't increase > in an order of magnitude (iow, n = 2 isn't PAGE_SIZE * PAGE_SIZE). > > Now, if you're trying to tell me that Linux has decided to define > "order" to be something non-standard, I'll accept that, but then we > shouldn't be renaming stuff that is using it in a standard way. > > -- > 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