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=-13.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 23BDEC2BA1E for ; Mon, 6 Apr 2020 08:39:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 008E2206F5 for ; Mon, 6 Apr 2020 08:39:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726663AbgDFIjy (ORCPT ); Mon, 6 Apr 2020 04:39:54 -0400 Received: from mga17.intel.com ([192.55.52.151]:3160 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726533AbgDFIjy (ORCPT ); Mon, 6 Apr 2020 04:39:54 -0400 IronPort-SDR: 8uyouLB70ldJPHpKI1k8yDZz7c6svAAGObK62Q/ZLMNvprjvynVWuL79SvZE1QOb/K+0VfFbo2 t3UMeQRxrT+w== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Apr 2020 01:39:54 -0700 IronPort-SDR: qt9AlbJY6pdhpLaYacPMLu1YOp/T1isBbqlT1hpkWNEgvNo42KAQXDNde9k4PqIQiYNcKFw8Vs B7ycFdQOG5Zg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,350,1580803200"; d="scan'208";a="424287561" Received: from shao2-debian.sh.intel.com (HELO localhost) ([10.239.13.3]) by orsmga005.jf.intel.com with ESMTP; 06 Apr 2020 01:39:52 -0700 Date: Mon, 6 Apr 2020 16:39:30 +0800 From: kernel test robot To: Al Viro Cc: LKML , lkp@lists.01.org Subject: Re: [non] 2aa3847085: will-it-scale.per_process_ops -32.0% regression Message-ID: <20200406083930.GV8179@shao2-debian> References: <20200406012539.GR8179@shao2-debian> <20200406020451.GQ23230@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200406020451.GQ23230@ZenIV.linux.org.uk> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 06, 2020 at 03:04:51AM +0100, Al Viro wrote: > On Mon, Apr 06, 2020 at 09:25:39AM +0800, kernel test robot wrote: > > Greeting, > > > > FYI, we noticed a -32.0% regression of will-it-scale.per_process_ops due to commit: > > > > > > commit: 2aa38470853a65dc9b1b4bd0989d34cd3fc57ebd ("non-RCU analogue of the previous commit") > > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master > > Arrgghh... Could you check if vfs.git#fixes recovers that? FWIW, proposed fix > is this: > > commit d98d78cd6ac9eb5ed0506140cc43432d7c7dd480 > Author: Al Viro > Date: Sun Apr 5 21:59:55 2020 -0400 > > fix braino in legitimize_path() > > brown paperbag time... wrong order of arguments ended up confusing > the values to check dentry and mount_lock seqcounts against. > > Reported-by: kernel test robot > Fixes: 2aa38470853a ("non-RCU analogue of the previous commit") > Signed-off-by: Al Viro > > diff --git a/fs/namei.c b/fs/namei.c > index 61fdb77a7d58..a320371899cf 100644 > --- a/fs/namei.c > +++ b/fs/namei.c > @@ -610,7 +610,7 @@ static bool __legitimize_path(struct path *path, unsigned seq, unsigned mseq) > static inline bool legitimize_path(struct nameidata *nd, > struct path *path, unsigned seq) > { > - return __legitimize_path(path, nd->m_seq, seq); > + return __legitimize_path(path, seq, nd->m_seq); > } > > static bool legitimize_links(struct nameidata *nd) Hi Al, Yes, the regression can be fixed: 7ef482fa65513b18 2aa38470853a65dc9b1b4bd098 d98d78cd6ac9eb5ed0506140cc testcase/testparams/testbox ---------------- -------------------------- -------------------------- --------------------------- %stddev change %stddev change %stddev \ | \ | \ 449960 -32% 306036 450924 will-it-scale/performance-open2-ucode=0x21/lkp-ivb-d04 449959 -32% 306035 450923 GEO-MEAN will-it-scale.per_process_ops Best Regards, Rong Chen