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_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 F19DEC3F68F for ; Wed, 4 Dec 2019 23:41:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C89942073C for ; Wed, 4 Dec 2019 23:41:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728321AbfLDXlS (ORCPT ); Wed, 4 Dec 2019 18:41:18 -0500 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:52555 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728011AbfLDXlS (ORCPT ); Wed, 4 Dec 2019 18:41:18 -0500 Received: from callcc.thunk.org (guestnat-104-133-0-111.corp.google.com [104.133.0.111] (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 xB4Nf7k9030083 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 4 Dec 2019 18:41:08 -0500 Received: by callcc.thunk.org (Postfix, from userid 15806) id E0197421A48; Wed, 4 Dec 2019 18:41:06 -0500 (EST) Date: Wed, 4 Dec 2019 18:41:06 -0500 From: "Theodore Y. Ts'o" To: Andreas Dilger Cc: Daniel Phillips , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, OGAWA Hirofumi Subject: Re: [RFC] Thing 1: Shardmap fox Ext4 Message-ID: <20191204234106.GC5641@mit.edu> References: <176a1773-f5ea-e686-ec7b-5f0a46c6f731@phunq.net> <20191127142508.GB5143@mit.edu> <20191128022817.GE22921@mit.edu> <3b5f28e5-2b88-47bb-1b32-5c2fed989f0b@phunq.net> <20191130175046.GA6655@mit.edu> <76ddbdba-55ba-3426-2e29-0fa17db9b6d8@phunq.net> <23F33101-065E-445A-AE5C-D05E35E2B78B@dilger.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <23F33101-065E-445A-AE5C-D05E35E2B78B@dilger.ca> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, Dec 04, 2019 at 11:31:50AM -0700, Andreas Dilger wrote: > One important use case that we have for Lustre that is not yet in the > upstream ext4[*] is the ability to do parallel directory operations. > This means we can create, lookup, and/or unlink entries in the same > directory concurrently, to increase parallelism for large directories. > > > [*] we've tried to submit the pdirops patch a couple of times, but the > main blocker is that the VFS has a single directory mutex and couldn't > use the added functionality without significant VFS changes. > Patch at https://git.whamcloud.com/?p=fs/lustre-release.git;f=ldiskfs/kernel_patches/patches/rhel8/ext4-pdirop.patch;hb=HEAD > The XFS folks recently added support for parallel directory operations into the VFS, for the benefit of XFS has this feature. So it should be possible adjust the patch so it will work with the upstream kernel now. Cheers, - Ted