From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754413AbZESRdm (ORCPT ); Tue, 19 May 2009 13:33:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751383AbZESRde (ORCPT ); Tue, 19 May 2009 13:33:34 -0400 Received: from brick.kernel.dk ([93.163.65.50]:34383 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751177AbZESRde (ORCPT ); Tue, 19 May 2009 13:33:34 -0400 Date: Tue, 19 May 2009 19:33:35 +0200 From: Jens Axboe To: FUJITA Tomonori Cc: hch@infradead.org, jmoyer@redhat.com, lizf@cn.fujitsu.com, mingo@elte.hu, rostedt@goodmis.org, fweisbec@gmail.com, tzanussi@gmail.com, tytso@mit.edu, swhiteho@redhat.com, kosaki.motohiro@jp.fujitsu.com, linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH] convert block trace points to TRACE_EVENT() Message-ID: <20090519173334.GB4140@kernel.dk> References: <4A0BB813.9080807@cn.fujitsu.com> <20090519130841.GA3801@infradead.org> <20090520004943Q.fujita.tomonori@lab.ntt.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090520004943Q.fujita.tomonori@lab.ntt.co.jp> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 20 2009, FUJITA Tomonori wrote: > On Tue, 19 May 2009 09:08:41 -0400 > Christoph Hellwig wrote: > > > On Tue, May 19, 2009 at 08:59:29AM -0400, Jeff Moyer wrote: > > > I'm not sure I'm comfortable with this. Having had to diagnose > > > performance problems using blktrace, I find the dev_t information for > > > plugs and unplugs especially interesting. Maybe we can still figure > > > this out given the context in the trace, though. Can you comment on > > > that? > > > > The problem is that right now we still allow request queues shared by > > multiple gendisks, so we can't get at the gendisk. The blktrace ioctl > > interface gets around that by doing the setup with an ioctl on the > > block device node and storing the dev_t at that point. > > > > But I don't think we actually have any drivers left sharing a queue > > that way, and I'd love to get rid of that for various reasons. > > There are still some (e.g. drivers/block/floppy.c)? I though that we > hit this when we tried to add the command filter feature though I > might be wrong (I can't recall). And mtd, iirc. But only a few. I'll fiddle up a patch to finally get rid of this, it has been pending for... years. -- Jens Axboe