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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, URIBL_BLOCKED,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 5581AC43441 for ; Wed, 10 Oct 2018 12:55:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0DE4821479 for ; Wed, 10 Oct 2018 12:55:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="WWXFWIaZ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0DE4821479 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.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 S1726983AbeJJURO (ORCPT ); Wed, 10 Oct 2018 16:17:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:40754 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726617AbeJJURO (ORCPT ); Wed, 10 Oct 2018 16:17:14 -0400 Received: from jouet.infradead.org (unknown [179.97.41.186]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4C73F20870; Wed, 10 Oct 2018 12:55:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1539176110; bh=RGqt/6Ys5JqeCROojocnaV/+aVQBt2TABZzqbiuHCnU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=WWXFWIaZZguR9BENGWJv/7NyAeHJkic7ycVDt7rG0jvt2qBTVILlrlIOeVMyA3Il5 o/1Dt9DYrEcpivzKbpxOvjT8TqtH+BpolHFtWYr7T98CKBWZ00voKhm6lJ8Ea97vWf ahVAd+84HDnbdgbz0/bseNo73CasBZYpzTwVraN8= Received: by jouet.infradead.org (Postfix, from userid 1000) id 69397142C5E; Wed, 10 Oct 2018 09:55:06 -0300 (-03) Date: Wed, 10 Oct 2018 09:55:06 -0300 From: Arnaldo Carvalho de Melo To: Benjamin Peterson Cc: peterz@infradead.org, mingo@redhat.com, alexander.shishkin@linux.intel.com, jolsa@redhat.com, namhyung@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] perf trace beautify: Beautify flags of mount(2) and umount(2). Message-ID: <20181010125506.GH10775@kernel.org> References: <20180828035344.31500-1-benjamin@python.org> <20180830182848.GE6097@kernel.org> <1535665851.2058334.1491869472.4E860103@webmail.messagingengine.com> <1539143546.2716467.1536750504.65ADF11A@webmail.messagingengine.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1539143546.2716467.1536750504.65ADF11A@webmail.messagingengine.com> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Tue, Oct 09, 2018 at 08:52:26PM -0700, Benjamin Peterson escreveu: > Hi Arnaldo, > Did you get a chance to look at this again? Thanks, for pinging me about it, will check. - Arnaldo > On Thu, Aug 30, 2018, at 14:50, Benjamin Peterson wrote: > > 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 > >