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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, T_DKIMWL_WL_HIGH 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 0E893C433F5 for ; Thu, 30 Aug 2018 21:50:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A336520835 for ; Thu, 30 Aug 2018 21:50:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=python.org header.i=@python.org header.b="Vf0+c0LB" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A336520835 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=python.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727686AbeHaBzK (ORCPT ); Thu, 30 Aug 2018 21:55:10 -0400 Received: from mail.python.org ([188.166.95.178]:54722 "EHLO mail.python.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726674AbeHaBzK (ORCPT ); Thu, 30 Aug 2018 21:55:10 -0400 Received: from auth1-smtp.messagingengine.com (auth1-smtp.messagingengine.com [66.111.4.227]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.python.org (Postfix) with ESMTPSA id 421bld3FFvzFqry; Thu, 30 Aug 2018 17:50:53 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=python.org; s=200901; t=1535665854; bh=vP/3k/d5Q2ilr+OTdlYqCYzUUq+ug4BweZ8RHwzM6SU=; h=From:To:Cc:Date:Subject:In-Reply-To:References:From; b=Vf0+c0LBypRa0+LVXgVntyuktYkadBTRFM2MOWMZF5OyN2lWGO5oXEZVmDey48atT i038lRNLFn5vfnc3tme/MTml9i6KrFwr8B8BJyGtgfLiAWq+Cr88NYy8KDTRooonx1 GMDJ+kaj2qmCcPVAc6jzby83zKicH/XEpGncHnmg= Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailauth.nyi.internal (Postfix) with ESMTP id EEB6E21E95; Thu, 30 Aug 2018 17:50:51 -0400 (EDT) Received: from web2 ([10.202.2.212]) by compute4.internal (MEProxy); Thu, 30 Aug 2018 17:50:51 -0400 X-ME-Proxy: X-ME-Sender: Received: by mailuser.nyi.internal (Postfix, from userid 99) id 124C2621D0; Thu, 30 Aug 2018 17:50:51 -0400 (EDT) Message-Id: <1535665851.2058334.1491869472.4E860103@webmail.messagingengine.com> From: Benjamin Peterson To: Arnaldo Carvalho de Melo Cc: peterz@infradead.org, mingo@redhat.com, alexander.shishkin@linux.intel.com, jolsa@redhat.com, namhyung@kernel.org, linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" X-Mailer: MessagingEngine.com Webmail Interface - ajax-7b72137a Date: Thu, 30 Aug 2018 14:50:51 -0700 Subject: Re: [PATCH] perf trace beautify: Beautify flags of mount(2) and umount(2). In-Reply-To: <20180830182848.GE6097@kernel.org> References: <20180828035344.31500-1-benjamin@python.org> <20180830182848.GE6097@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thanks for the review. On Thu, Aug 30, 2018, at 11:28, Arnaldo Carvalho de Melo wrote: > Em Mon, Aug 27, 2018 at 08:53:44PM -0700, Benjamin Peterson escreveu: > > Example output of perf trace -e mount,umount2: > > > > 6243.930 ( 0.052 ms): mount/30976 mount(dev_name: 0x55dc541bb920, dir_name: 0x55dc541bc960, type: 0x55dc541b9c40, flags: BIND) = 0 > > 7851.821 (26.015 ms): umount/30983 umount2(name: 0x558daa82cf50, flags: MNT_FORCE ) = 0 > > > > Signed-off-by: Benjamin Peterson > > So, I tried: > > Before your patch: > > # perf trace -e *mount* mount /dev/mapper/fedora-home /s > 0.000 ( 4.335 ms): mount/3126 mount(dev_name: 0x55deecc4d480, > dir_name: 0x55deecc4d4a0, type: 0x55deecc53880, flags: 3236757504) = 0 > # > # perf trace -e *mount* umount /dev/mapper/fedora-home /s > ? ( ): umount/3138 ... [continued]: umount2()) = 0 > 11.576 (umount: 0.004 ms): /s: not mounted.umount/ > 3138 umount2(arg0: 94501956754656, arg1: 0, arg2: 1, arg3: > 140051050083104, arg4: 4, arg5: 94501956755136) = -1 EINVAL Invalid > argument > # > > After: > > [root@jouet ~]# perf trace -e *mount* mount /dev/mapper/fedora-home /s > 0.000 ( 1.213 ms): mount/5244 mount(dev_name: 0x5558c1169480, > dir_name: 0x5558c11694a0, type: 0x5558c116f880, flags: ) = 0 > [root@jouet ~]# perf trace -e *mount* umount /s > 0.000 ( 9.241 ms): umount/5251 umount2(name: > 0x55f74a986480 ) = 0 > > The flags for mount got empty? Can you pleaes check that? I.e. using the > default mount options, not specifying a 'bind' mount like you did. That comes from these lines in syscall_arg__scnprintf_mount_flags: if ((flags & MS_MGC_MSK) == MS_MGC_VAL) flags &= ~MS_MGC_MSK; The reason for this is explained in the comment for do_mount in fs/namespace.c: /* * Pre-0.97 versions of mount() didn't have a flags word. * When the flags word was introduced its top half was required * to have the magic value 0xC0ED, and this remained so until 2.4.0-test9. * Therefore, if this magic number is present, it carries no information * and must be discarded. */ (I used a bind mount for my commit message example because a "default" mount() doesn't use any flags.) > > I'm splitting this patch so that the aliasing of 'umount2' to 'umount' > gets merged now, > > Check my perf/core branch at: > > git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git LGTM. Thanks