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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 7634DC11D05 for ; Thu, 20 Feb 2020 16:24:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4E6C7206F4 for ; Thu, 20 Feb 2020 16:24:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="lxTIdidZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728575AbgBTQYF (ORCPT ); Thu, 20 Feb 2020 11:24:05 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:35548 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727709AbgBTQYF (ORCPT ); Thu, 20 Feb 2020 11:24:05 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=/X+cuahXNVjwX8kIjzPU/QZUMEm+qIm+lNxfvhlX3EA=; b=lxTIdidZw2P2UO9t/Oji3FNceT +CjnxJZogq66GLHl3rhRoufVhXPoH7CxN5rw1pgrMvr7szk03lJeq2TvDL3R2ys6m86hnGj7sXBXg AQaHFo4WLWH90RnuR6backVMmU/lhsJTXMH7V42hfdxcXElLYWAoi8WkszieVn0N2xZmXUiT1EECe GJX8uJUjnaFLb7zI2vKxvhhrKwSedVafnnaMtZd9zrJbg6npgPtnxSYDtx+h9J81ITalXizKXonPp SQVVA+pyipbUonuljCpyE7+n90vEPRYltjJb/REqxUNVBonREpCV+ttQEEWV7EF1CEorahGhIHM1b 9p1J3F8g==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1j4ocO-0001zg-A1; Thu, 20 Feb 2020 16:24:04 +0000 Date: Thu, 20 Feb 2020 08:24:04 -0800 From: Matthew Wilcox To: Christoph Hellwig Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, ocfs2-devel@oss.oracle.com, linux-xfs@vger.kernel.org Subject: Re: [PATCH v7 21/24] iomap: Restructure iomap_readpages_actor Message-ID: <20200220162404.GY24185@bombadil.infradead.org> References: <20200219210103.32400-1-willy@infradead.org> <20200219210103.32400-22-willy@infradead.org> <20200220154741.GB19577@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200220154741.GB19577@infradead.org> Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Thu, Feb 20, 2020 at 07:47:41AM -0800, Christoph Hellwig wrote: > On Wed, Feb 19, 2020 at 01:01:00PM -0800, Matthew Wilcox wrote: > > From: "Matthew Wilcox (Oracle)" > > > > By putting the 'have we reached the end of the page' condition at the end > > of the loop instead of the beginning, we can remove the 'submit the last > > page' code from iomap_readpages(). Also check that iomap_readpage_actor() > > didn't return 0, which would lead to an endless loop. > > I'm obviously biassed a I wrote the original code, but I find the new > very much harder to understand (not that the previous one was easy, this > is tricky code..). Agreed, I found the original code hard to understand. I think this is easier because now cur_page doesn't leak outside this loop, so it has an obvious lifecycle. I'm kind of optimistic for Dave Howells' iov_iter addition of an ITER_MAPPING. That might simplify all of this code. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Date: Thu, 20 Feb 2020 08:24:04 -0800 Subject: [Ocfs2-devel] [PATCH v7 21/24] iomap: Restructure iomap_readpages_actor In-Reply-To: <20200220154741.GB19577@infradead.org> References: <20200219210103.32400-1-willy@infradead.org> <20200219210103.32400-22-willy@infradead.org> <20200220154741.GB19577@infradead.org> Message-ID: <20200220162404.GY24185@bombadil.infradead.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Christoph Hellwig Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, ocfs2-devel@oss.oracle.com, linux-xfs@vger.kernel.org On Thu, Feb 20, 2020 at 07:47:41AM -0800, Christoph Hellwig wrote: > On Wed, Feb 19, 2020 at 01:01:00PM -0800, Matthew Wilcox wrote: > > From: "Matthew Wilcox (Oracle)" > > > > By putting the 'have we reached the end of the page' condition at the end > > of the loop instead of the beginning, we can remove the 'submit the last > > page' code from iomap_readpages(). Also check that iomap_readpage_actor() > > didn't return 0, which would lead to an endless loop. > > I'm obviously biassed a I wrote the original code, but I find the new > very much harder to understand (not that the previous one was easy, this > is tricky code..). Agreed, I found the original code hard to understand. I think this is easier because now cur_page doesn't leak outside this loop, so it has an obvious lifecycle. I'm kind of optimistic for Dave Howells' iov_iter addition of an ITER_MAPPING. That might simplify all of this code. 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=0.5 required=3.0 tests=DATE_IN_PAST_03_06, DKIM_INVALID,DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 70671C11D1B for ; Thu, 20 Feb 2020 20:02:07 +0000 (UTC) Received: from lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (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 48F14206F4; Thu, 20 Feb 2020 20:02:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=sourceforge.net header.i=@sourceforge.net header.b="ltV5o52u"; 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Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1j4ocO-0001zg-A1; Thu, 20 Feb 2020 16:24:04 +0000 Date: Thu, 20 Feb 2020 08:24:04 -0800 From: Matthew Wilcox To: Christoph Hellwig Message-ID: <20200220162404.GY24185@bombadil.infradead.org> References: <20200219210103.32400-1-willy@infradead.org> <20200219210103.32400-22-willy@infradead.org> <20200220154741.GB19577@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200220154741.GB19577@infradead.org> X-Headers-End: 1j4s1L-00C9cy-IG Subject: Re: [f2fs-dev] [PATCH v7 21/24] iomap: Restructure iomap_readpages_actor X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, linux-mm@kvack.org, ocfs2-devel@oss.oracle.com, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-btrfs@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On Thu, Feb 20, 2020 at 07:47:41AM -0800, Christoph Hellwig wrote: > On Wed, Feb 19, 2020 at 01:01:00PM -0800, Matthew Wilcox wrote: > > From: "Matthew Wilcox (Oracle)" > > > > By putting the 'have we reached the end of the page' condition at the end > > of the loop instead of the beginning, we can remove the 'submit the last > > page' code from iomap_readpages(). Also check that iomap_readpage_actor() > > didn't return 0, which would lead to an endless loop. > > I'm obviously biassed a I wrote the original code, but I find the new > very much harder to understand (not that the previous one was easy, this > is tricky code..). Agreed, I found the original code hard to understand. I think this is easier because now cur_page doesn't leak outside this loop, so it has an obvious lifecycle. I'm kind of optimistic for Dave Howells' iov_iter addition of an ITER_MAPPING. That might simplify all of this code. _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel 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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 7AF0CC11D05 for ; Thu, 20 Feb 2020 16:24:16 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 2DB0F206F4 for ; Thu, 20 Feb 2020 16:24:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="lxTIdidZ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2DB0F206F4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 48Nfzx5Y5DzDqM0 for ; Fri, 21 Feb 2020 03:24:13 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=infradead.org (client-ip=2607:7c80:54:e::133; helo=bombadil.infradead.org; envelope-from=willy@infradead.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=bombadil.20170209 header.b=lxTIdidZ; dkim-atps=neutral Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 48Nfzq14PXzDqGc for ; Fri, 21 Feb 2020 03:24:06 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=/X+cuahXNVjwX8kIjzPU/QZUMEm+qIm+lNxfvhlX3EA=; b=lxTIdidZw2P2UO9t/Oji3FNceT +CjnxJZogq66GLHl3rhRoufVhXPoH7CxN5rw1pgrMvr7szk03lJeq2TvDL3R2ys6m86hnGj7sXBXg AQaHFo4WLWH90RnuR6backVMmU/lhsJTXMH7V42hfdxcXElLYWAoi8WkszieVn0N2xZmXUiT1EECe GJX8uJUjnaFLb7zI2vKxvhhrKwSedVafnnaMtZd9zrJbg6npgPtnxSYDtx+h9J81ITalXizKXonPp SQVVA+pyipbUonuljCpyE7+n90vEPRYltjJb/REqxUNVBonREpCV+ttQEEWV7EF1CEorahGhIHM1b 9p1J3F8g==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1j4ocO-0001zg-A1; Thu, 20 Feb 2020 16:24:04 +0000 Date: Thu, 20 Feb 2020 08:24:04 -0800 From: Matthew Wilcox To: Christoph Hellwig Subject: Re: [PATCH v7 21/24] iomap: Restructure iomap_readpages_actor Message-ID: <20200220162404.GY24185@bombadil.infradead.org> References: <20200219210103.32400-1-willy@infradead.org> <20200219210103.32400-22-willy@infradead.org> <20200220154741.GB19577@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200220154741.GB19577@infradead.org> X-BeenThere: linux-erofs@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development of Linux EROFS file system List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, linux-mm@kvack.org, ocfs2-devel@oss.oracle.com, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-btrfs@vger.kernel.org Errors-To: linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Sender: "Linux-erofs" On Thu, Feb 20, 2020 at 07:47:41AM -0800, Christoph Hellwig wrote: > On Wed, Feb 19, 2020 at 01:01:00PM -0800, Matthew Wilcox wrote: > > From: "Matthew Wilcox (Oracle)" > > > > By putting the 'have we reached the end of the page' condition at the end > > of the loop instead of the beginning, we can remove the 'submit the last > > page' code from iomap_readpages(). Also check that iomap_readpage_actor() > > didn't return 0, which would lead to an endless loop. > > I'm obviously biassed a I wrote the original code, but I find the new > very much harder to understand (not that the previous one was easy, this > is tricky code..). Agreed, I found the original code hard to understand. I think this is easier because now cur_page doesn't leak outside this loop, so it has an obvious lifecycle. I'm kind of optimistic for Dave Howells' iov_iter addition of an ITER_MAPPING. That might simplify all of this code. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Date: Thu, 20 Feb 2020 08:24:04 -0800 Subject: [Cluster-devel] [PATCH v7 21/24] iomap: Restructure iomap_readpages_actor In-Reply-To: <20200220154741.GB19577@infradead.org> References: <20200219210103.32400-1-willy@infradead.org> <20200219210103.32400-22-willy@infradead.org> <20200220154741.GB19577@infradead.org> Message-ID: <20200220162404.GY24185@bombadil.infradead.org> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Thu, Feb 20, 2020 at 07:47:41AM -0800, Christoph Hellwig wrote: > On Wed, Feb 19, 2020 at 01:01:00PM -0800, Matthew Wilcox wrote: > > From: "Matthew Wilcox (Oracle)" > > > > By putting the 'have we reached the end of the page' condition at the end > > of the loop instead of the beginning, we can remove the 'submit the last > > page' code from iomap_readpages(). Also check that iomap_readpage_actor() > > didn't return 0, which would lead to an endless loop. > > I'm obviously biassed a I wrote the original code, but I find the new > very much harder to understand (not that the previous one was easy, this > is tricky code..). Agreed, I found the original code hard to understand. I think this is easier because now cur_page doesn't leak outside this loop, so it has an obvious lifecycle. I'm kind of optimistic for Dave Howells' iov_iter addition of an ITER_MAPPING. That might simplify all of this code.