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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 CF29DC433DF for ; Sat, 20 Jun 2020 17:09:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A9A2A23ECF for ; Sat, 20 Jun 2020 17:09:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fieldses.org header.i=@fieldses.org header.b="HDufi5g7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728072AbgFTRJ2 (ORCPT ); Sat, 20 Jun 2020 13:09:28 -0400 Received: from fieldses.org ([173.255.197.46]:33350 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727083AbgFTRJ1 (ORCPT ); Sat, 20 Jun 2020 13:09:27 -0400 Received: by fieldses.org (Postfix, from userid 2815) id 183C614D8; Sat, 20 Jun 2020 13:09:24 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.11.0 fieldses.org 183C614D8 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fieldses.org; s=default; t=1592672964; bh=e6zYVkezLT2ct6J3M7M86Qk+qpHHQC4dPy9/qoTz7aM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HDufi5g79j2EKmPO+eAznsnT5kJ1fwhER+27gkVIii9w36rFHpo1ceaAE6OqWuIIX a4dna+XFvu1kqQdSvo3FdTHmqtHwEBD26AFXn+NPJFhwObV+ohrW1NK2bua/0SkdRw aPlJri1ySFDlaFmf3Zjrx10wbdh7TorkAgcq5plc= Date: Sat, 20 Jun 2020 13:09:24 -0400 From: "J. Bruce Fields" To: Eric Sandeen Cc: Dave Chinner , Masayoshi Mizuma , "Darrick J. Wong" , Christoph Hellwig , Theodore Ts'o , Andreas Dilger , Alexander Viro , Masayoshi Mizuma , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-xfs , jlayton@redhat.com Subject: Re: [PATCH] fs: i_version mntopt gets visible through /proc/mounts Message-ID: <20200620170924.GI1514@fieldses.org> References: <20200618034535.h5ho7pd4eilpbj3f@gabell> <20200618223948.GI2005@dread.disaster.area> <20200619022005.GA25414@fieldses.org> <20200619024455.GN2005@dread.disaster.area> <20200619204033.GB1564@fieldses.org> <20200619221044.GO2005@dread.disaster.area> <20200619222843.GB2650@fieldses.org> <20200620014957.GQ2005@dread.disaster.area> <20200620015633.GA1516@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Sat, Jun 20, 2020 at 12:00:43PM -0500, Eric Sandeen wrote: > On 6/19/20 8:56 PM, J. Bruce Fields wrote: > > On Sat, Jun 20, 2020 at 11:49:57AM +1000, Dave Chinner wrote: > > ... > > >> However, other people have different opinions on this matter (and we > >> know that from the people who considered XFS v4 -> v5 going slower > >> because iversion a major regression), and so we must acknowledge > >> those opinions even if we don't agree with them. > > > > Do you have any of those reports handy? Were there numbers? > > I can't answer that but did a little digging. MS_I_VERSION as an option > appeared here: > ... > so the optional enablement was there on day one, without any real explanation > of why. My memory is that they didn't have measurements at first, but worried that there might be a performance issue. Which later mesurements confirmed. But that Jeff Layton's work eliminated most of that. I think ext4 was the focuse of the concern, but xfs might also have had a (less serious) regression, and btrfs might have actually had it worst? But I don't have references and my memory may be wrong. --b.