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 00769C3F68F for ; Tue, 24 Dec 2019 11:28:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C9DAF20706 for ; Tue, 24 Dec 2019 11:28:48 +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="C4msNrpO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726140AbfLXL2s (ORCPT ); Tue, 24 Dec 2019 06:28:48 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:48630 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726102AbfLXL2s (ORCPT ); Tue, 24 Dec 2019 06:28:48 -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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=eeGktmG27cS6ntegZtja6DJNcWGUSKxmq9N11h/xcOM=; b=C4msNrpOXv31pMiNNgpW4ZgB4 Lm7yhvWsCHRM1MXDpX4A8DUYNdJtmO4DP3QTL0Zs+1eIUMBSHT9cc9No2+ehPiQoPtDT/nng5qQu0 asrnoCi5MW4glQjszVRu1m/+Dwgqqj1TGWwlQGMIT2rSrhMMG24Ksl/PGlw8NLn8MjouPC3I3KOFn OZ9+u+YMAoNL7g3S7plq2Cq7hAPZjf7PLZRVay8H1l1nwS25YecZ/XcPXzq3wNrk1rDnZKvelTEuB Z3fRlzuFHDKf5Xq7Vmf0BpSqKXQzqF8wBctSUkWnKnvM2+X1RNtavXZszyCyKSrPpCbVhTksKq+l7 0MEvjGh0Q==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1ijiMn-0001pn-VG; Tue, 24 Dec 2019 11:28:45 +0000 Date: Tue, 24 Dec 2019 03:28:45 -0800 From: Christoph Hellwig To: "Darrick J. Wong" Cc: Brian Foster , linux-xfs@vger.kernel.org Subject: Re: [PATCH 2/3] xfs: rework insert range into an atomic operation Message-ID: <20191224112845.GC24663@infradead.org> References: <20191213171258.36934-1-bfoster@redhat.com> <20191213171258.36934-3-bfoster@redhat.com> <20191218023726.GH12765@magnolia> <20191218121033.GA63809@bfoster> <20191218211540.GB7489@magnolia> <20191219115550.GA6995@bfoster> <20191220201717.GQ7489@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191220201717.GQ7489@magnolia> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Fri, Dec 20, 2019 at 12:17:17PM -0800, Darrick J. Wong wrote: > I think directio completions might suffer from the same class of problem > though, since we allow concurrent dio writes and dio doesn't do any of > the ioend batching that we do with buffered write ioends. OTOH direct I/O completions are per-I/O, and not per-extent like buffered I/O completions. Moreover for the case where we don't update i_size and don't need a separate log force (overwrites without O_SYNC or using fua) we could actually avoid the workqueue entirely with just a little work. > It might also be nice to find a way to unify the ioend paths since they > both do "convert unwritten and do cow remapping" on the entire range, > and diverge only once that's done. They were common a while ago and it was a complete mess. That is why I split them.