From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753797Ab2A2TYx (ORCPT ); Sun, 29 Jan 2012 14:24:53 -0500 Received: from mail-pw0-f46.google.com ([209.85.160.46]:57601 "EHLO mail-pw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752882Ab2A2TYw (ORCPT ); Sun, 29 Jan 2012 14:24:52 -0500 Date: Sun, 29 Jan 2012 11:24:47 -0800 From: Tejun Heo To: Namhyung Kim Cc: Jens Axboe , linux-kernel@vger.kernel.org, Steven Rostedt , dm-devel@redhat.com Subject: Re: [PATCH] block: add missing block_bio_complete() tracepoint Message-ID: <20120129192447.GB17211@htj.dyndns.org> References: <1327830093-12130-1-git-send-email-namhyung@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1327830093-12130-1-git-send-email-namhyung@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jan 29, 2012 at 06:41:33PM +0900, Namhyung Kim wrote: > The block_bio_complete() TP has been missed so long, so that bio-based > drivers haven't been able to trace its IO behavior. Add it. > > In some rare cases, such as loop_switch, @bio->bi_bdev can be NULL. > Thus convert it to TRACE_EVENT_CONDITION() as Steven suggested. > > From now on, request-based drivers will also get BLK_TA_COMPLETEs for > all bio's in requests. This needs to be handled in userland properly. > > Also remove external use of the TP in DM and unexport it. > > Signed-off-by: Namhyung Kim > Cc: Tejun Heo > Cc: Steven Rostedt > Cc: dm-devel@redhat.com I like the smiplicity change but do we know how we can filter this out from userland? Also, what's the reason not to do it from blktrace.c? What would be the downside of doing that? Thanks. -- tejun