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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 201F5C4646B for ; Thu, 20 Jun 2019 17:22:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F06872084A for ; Thu, 20 Jun 2019 17:22:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726934AbfFTRWW (ORCPT ); Thu, 20 Jun 2019 13:22:22 -0400 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:32922 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726637AbfFTRWW (ORCPT ); Thu, 20 Jun 2019 13:22:22 -0400 Received: from callcc.thunk.org (guestnat-104-133-0-109.corp.google.com [104.133.0.109] (may be forged)) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id x5KHM8mu014348 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 20 Jun 2019 13:22:09 -0400 Received: by callcc.thunk.org (Postfix, from userid 15806) id 528DC420484; Thu, 20 Jun 2019 13:22:08 -0400 (EDT) Date: Thu, 20 Jun 2019 13:22:08 -0400 From: "Theodore Ts'o" To: Ross Zwisler Cc: Jan Kara , Ross Zwisler , linux-kernel@vger.kernel.org, Alexander Viro , Andreas Dilger , Jan Kara , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Fletcher Woodruff , Justin TerAvest Subject: Re: [PATCH 2/3] jbd2: introduce jbd2_inode dirty range scoping Message-ID: <20190620172208.GB4650@mit.edu> Mail-Followup-To: Theodore Ts'o , Ross Zwisler , Jan Kara , Ross Zwisler , linux-kernel@vger.kernel.org, Alexander Viro , Andreas Dilger , Jan Kara , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Fletcher Woodruff , Justin TerAvest References: <20190619172156.105508-1-zwisler@google.com> <20190619172156.105508-3-zwisler@google.com> <20190620110454.GL13630@quack2.suse.cz> <20190620150911.GA4488@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190620150911.GA4488@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu, Jun 20, 2019 at 09:09:11AM -0600, Ross Zwisler wrote: > We could definitely keep separate dirty ranges for each of the current and > next transaction. I think the case where you would see a difference would be > if you had multiple transactions in a row which grew the dirty range for a > given jbd2_inode, and then had a random I/O workload which kept dirtying pages > inside that enlarged dirty range. > > I'm not sure how often this type of workload would be a problem. For the > workloads I've been testing which purely append to the inode, having a single > dirty range per jbd2_inode is sufficient. My inclination would be to keep things simple for now, unless we have a real workload that tickles this. In the long run I'm hoping to remove the need to do writebacks from the journal thread altogether, by always updating the metadata blocks *after* the I/O completes, instead of before we submit the I/O. - Ted