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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 C9BA0C433E1 for ; Tue, 25 Aug 2020 00:09:07 +0000 (UTC) Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (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 A65D4207D3 for ; Tue, 25 Aug 2020 00:09:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A65D4207D3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=fromorbit.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvdimm-bounces@lists.01.org Received: from ml01.vlan13.01.org (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 58132137DB2B1; Mon, 24 Aug 2020 17:09:07 -0700 (PDT) Received-SPF: Pass (helo) identity=helo; client-ip=211.29.132.97; helo=mail110.syd.optusnet.com.au; envelope-from=david@fromorbit.com; receiver= Received: from mail110.syd.optusnet.com.au (mail110.syd.optusnet.com.au [211.29.132.97]) by ml01.01.org (Postfix) with ESMTP id E657A1307C9E0 for ; Mon, 24 Aug 2020 17:09:04 -0700 (PDT) Received: from dread.disaster.area (pa49-181-146-199.pa.nsw.optusnet.com.au [49.181.146.199]) by mail110.syd.optusnet.com.au (Postfix) with ESMTPS id 5E3E5108D79; Tue, 25 Aug 2020 10:09:03 +1000 (AEST) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1kAMWM-0005k3-RG; Tue, 25 Aug 2020 10:09:02 +1000 Date: Tue, 25 Aug 2020 10:09:02 +1000 From: Dave Chinner To: "Matthew Wilcox (Oracle)" Subject: Re: [PATCH 6/9] iomap: Convert read_count to byte count Message-ID: <20200825000902.GG12131@dread.disaster.area> References: <20200824145511.10500-1-willy@infradead.org> <20200824145511.10500-7-willy@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200824145511.10500-7-willy@infradead.org> X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.3 cv=QKgWuTDL c=1 sm=1 tr=0 cx=a_idp_d a=GorAHYkI+xOargNMzM6qxQ==:117 a=GorAHYkI+xOargNMzM6qxQ==:17 a=kj9zAlcOel0A:10 a=y4yBn9ojGxQA:10 a=7-415B0cAAAA:8 a=n1aMJpBO7yNg7y_OdF8A:9 a=CjuIK1q_8ugA:10 a=biEYGPWJfzWAr4FL6Ov7:22 Message-ID-Hash: DQSKNY7LK7FD3CBZZ62MJQ6OW7ETHPQY X-Message-ID-Hash: DQSKNY7LK7FD3CBZZ62MJQ6OW7ETHPQY X-MailFrom: david@fromorbit.com X-Mailman-Rule-Hits: nonmember-moderation X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation CC: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, "Darrick J . Wong" , linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org X-Mailman-Version: 3.1.1 Precedence: list List-Id: "Linux-nvdimm developer list." Archived-At: List-Archive: List-Help: List-Post: List-Subscribe: List-Unsubscribe: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Mon, Aug 24, 2020 at 03:55:07PM +0100, Matthew Wilcox (Oracle) wrote: > Instead of counting bio segments, count the number of bytes submitted. > This insulates us from the block layer's definition of what a 'same page' > is, which is not necessarily clear once THPs are involved. I'd like to see a comment on the definition of struct iomap_page to indicate that read_count (and write count) reflect the byte count of IO currently in flight on the page, not an IO count, because THP makes tracking this via bio state hard. Otherwise it is not at all obvious why it is done and why it is intentional... Otherwise the code looks OK. Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org 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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 02C7BC433DF for ; Tue, 25 Aug 2020 00:09:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E0713206BE for ; Tue, 25 Aug 2020 00:09:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727111AbgHYAJI (ORCPT ); Mon, 24 Aug 2020 20:09:08 -0400 Received: from mail110.syd.optusnet.com.au ([211.29.132.97]:39354 "EHLO mail110.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726189AbgHYAJG (ORCPT ); Mon, 24 Aug 2020 20:09:06 -0400 Received: from dread.disaster.area (pa49-181-146-199.pa.nsw.optusnet.com.au [49.181.146.199]) by mail110.syd.optusnet.com.au (Postfix) with ESMTPS id 5E3E5108D79; Tue, 25 Aug 2020 10:09:03 +1000 (AEST) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1kAMWM-0005k3-RG; Tue, 25 Aug 2020 10:09:02 +1000 Date: Tue, 25 Aug 2020 10:09:02 +1000 From: Dave Chinner To: "Matthew Wilcox (Oracle)" Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, "Darrick J . Wong" , linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 6/9] iomap: Convert read_count to byte count Message-ID: <20200825000902.GG12131@dread.disaster.area> References: <20200824145511.10500-1-willy@infradead.org> <20200824145511.10500-7-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200824145511.10500-7-willy@infradead.org> X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.3 cv=QKgWuTDL c=1 sm=1 tr=0 cx=a_idp_d a=GorAHYkI+xOargNMzM6qxQ==:117 a=GorAHYkI+xOargNMzM6qxQ==:17 a=kj9zAlcOel0A:10 a=y4yBn9ojGxQA:10 a=7-415B0cAAAA:8 a=n1aMJpBO7yNg7y_OdF8A:9 a=CjuIK1q_8ugA:10 a=biEYGPWJfzWAr4FL6Ov7:22 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 24, 2020 at 03:55:07PM +0100, Matthew Wilcox (Oracle) wrote: > Instead of counting bio segments, count the number of bytes submitted. > This insulates us from the block layer's definition of what a 'same page' > is, which is not necessarily clear once THPs are involved. I'd like to see a comment on the definition of struct iomap_page to indicate that read_count (and write count) reflect the byte count of IO currently in flight on the page, not an IO count, because THP makes tracking this via bio state hard. Otherwise it is not at all obvious why it is done and why it is intentional... Otherwise the code looks OK. Cheers, Dave. -- Dave Chinner david@fromorbit.com