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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 6EDCAC004C9 for ; Sun, 5 May 2019 13:05:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 450D12082F for ; Sun, 5 May 2019 13:05:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727891AbfEENFf (ORCPT ); Sun, 5 May 2019 09:05:35 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:42664 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727504AbfEENFf (ORCPT ); Sun, 5 May 2019 09:05:35 -0400 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92 #3 (Red Hat Linux)) id 1hNGpd-0006Z0-4o; Sun, 05 May 2019 13:05:29 +0000 Date: Sun, 5 May 2019 14:05:29 +0100 From: Al Viro To: Amir Goldstein Cc: Jan Kara , Linus Torvalds , linux-fsdevel@vger.kernel.org, LKP Subject: Re: [PATCH] fsnotify: fix unlink performance regression Message-ID: <20190505130528.GA23075@ZenIV.linux.org.uk> References: <20190505091549.1934-1-amir73il@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190505091549.1934-1-amir73il@gmail.com> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Sun, May 05, 2019 at 12:15:49PM +0300, Amir Goldstein wrote: > __fsnotify_parent() has an optimization in place to avoid unneeded > take_dentry_name_snapshot(). When fsnotify_nameremove() was changed > not to call __fsnotify_parent(), we left out the optimization. > Kernel test robot reported a 5% performance regression in concurrent > unlink() workload. > > Reported-by: kernel test robot > Link: https://lore.kernel.org/lkml/20190505062153.GG29809@shao2-debian/ > Link: https://lore.kernel.org/linux-fsdevel/20190104090357.GD22409@quack2.suse.cz/ > Fixes: 5f02a8776384 ("fsnotify: annotate directory entry modification events") > Signed-off-by: Amir Goldstein > --- > > Jan, > > The linked 5.1-rc1 performance regression report came with bad timing. > Not sure if Linus is planning an rc8. If not, you will probably not > see this before the 5.1 release and we shall have to queue it for 5.2 > and backport to stable 5.1. > > I crafted the patch so it applies cleanly both to master and Al's > for-next branch (there are some fsnotify changes in work.dcache). Charming... What about rename() and matching regressions there?