From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753268AbeDQML6 (ORCPT ); Tue, 17 Apr 2018 08:11:58 -0400 Received: from mailout.micron.com ([137.201.242.129]:51259 "EHLO mailout.micron.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752712AbeDQMLz (ORCPT ); Tue, 17 Apr 2018 08:11:55 -0400 From: "Bean Huo (beanhuo)" To: Bart Van Assche , "rostedt@goodmis.org" , "rajatja@google.com" CC: "linux-scsi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "mingo@redhad.com" , "linux-block@vger.kernel.org" , "martin.petersen@oracle.com" , "axboe@kernel.dk" , "jejb@linux.vnet.ibm.com" Subject: Re: [RESEND PATCH v1 1/2] trace: events: scsi: Add tag in SCSI trace events Thread-Topic: [RESEND PATCH v1 1/2] trace: events: scsi: Add tag in SCSI trace events Thread-Index: AdPWROvYwC4lEZ3QTDCERkGhwBoFPg== Date: Tue, 17 Apr 2018 12:09:26 +0000 Message-ID: Accept-Language: zh-CN, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.160.29.124] X-TM-AS-Product-Ver: SMEX-12.0.0.1782-8.200.1013-23788.005 X-TM-AS-Result: No--15.342000-0.000000-31 X-TM-AS-MatchedID: 150567-139010-700022-851106-700075-701583-704421-704425-7 07663-707163-709584-700133-703491-700107-702020-187067-105700-106230-705901 -703747-700038-703283-148004-148046-148133-148980-41000-42000-42003-29961-63 X-TM-AS-User-Approved-Sender: Yes X-TM-AS-User-Blocked-Sender: No x-mt-checkinternalsenderrule: True Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id w3HCCm0d011855 >On Mon, 2018-04-16 at 20:27 +0000, Bean Huo (beanhuo) wrote: >> By the way, these patches are not to add new feature, they are just to >> add print tag along with the other exist printed request parameters. > >Are you aware that there are two tag fields in struct request, namely "tag" >and "internal_tag"? Are you aware that how these fields are used depends on >whether or not a scheduler is attached to a request queue? Have you verified >that the "tag" field contains a meaningful value for blk-mq for every blk-mq >tracepoint? > >Thanks, > >Bart. > > Yes, I noticed and was aware, there are tag and internal_tag. One thing I was not aware is that the patches would make such a big impact on blk-mq based on Your comments. I am not expert on block layer, that is why I added block maintainer here. Please point out which line and what is problem? If there is some wrong with the patch. Which one is correct "tag" to track request? Thanks, //Bean Huo