From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752210AbZIHEKy (ORCPT ); Tue, 8 Sep 2009 00:10:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751412AbZIHEKy (ORCPT ); Tue, 8 Sep 2009 00:10:54 -0400 Received: from mail-yw0-f173.google.com ([209.85.211.173]:55936 "EHLO mail-yw0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751394AbZIHEKx convert rfc822-to-8bit (ORCPT ); Tue, 8 Sep 2009 00:10:53 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=UTM8k39MQPQJEuEJxPt5giskW/ekJgPWWxEhCMD05iWY0iLSECl+AbhN6MSJfQdQsJ vyiy7cVV35NdQQyAIDFwOMuuGARkXdqGrQbNwt1Mqs51frV8ycpb3Jkz4ee0jSHJSBQk 6ZbYkW8obyIRbrTOSJZ6d7eksxZFL35eUzHmc= MIME-Version: 1.0 In-Reply-To: <4AA5BB3E.4050808@cn.fujitsu.com> References: <20090908093416.5a2f98b6.minchan.kim@barrios-desktop> <20090908005520.GA7967@localhost> <4AA5BB3E.4050808@cn.fujitsu.com> Date: Tue, 8 Sep 2009 13:10:55 +0900 Message-ID: <28c262360909072110j8ef5962h7231be5c03d68da3@mail.gmail.com> Subject: Re: [PATCH] trace bio queueing trial only when it occurs From: Minchan Kim To: Li Zefan Cc: Wu Fengguang , Andrew Morton , lkml , Jens Axboe Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 8, 2009 at 11:02 AM, Li Zefan wrote: > Wu Fengguang wrote: >> Minchan, >> >> I tend to agree with the change, but somehow confused by blkparse(1): >> >>         Q -- queued   This notes *intent* to queue i/o at the given location.  No real requests exists yet. >> >> Li Zefan has been working on blktrace and he can tell more. >> > > I work on ftrace-plugin blktrace and blk TRACE_EVENT, but don't know > much about the old blktrace history. ;) > > I think the manpage says it's called before ->make_request_fn(), so > "No real requests exist yet". > > Actually the trace was called just before make_request at first: >        2056a782f8e7e65fd4bfd027506b4ce1c5e9ccd4 > > And then 2 patches added some checks between them: >        5ddfe9691c91a244e8d1be597b6428fcefd58103 >        51fd77bd9f512ab6cc9df0733ba1caaab89eb957 > > It seems to me it makes sense to have this patch. Thanks for good information. Yes. It seems above 2 patches seem to break the rule. Could I add your ACK? >> Thanks, >> Fengguang >> >> On Tue, Sep 08, 2009 at 08:34:16AM +0800, Minchan Kim wrote: >>> It got lost in LKML mail storm. >>> I resend this. >>> Wu, Could you review this patch, please? >>> >>> == CUT_HERE == >>> >>> If BIO is discarded or cross over end of device, >>> BIO queueing trial doesn't occur. >>> >>> Let's trace it only when it happens. >>> >>> Signed-off-by: Minchan Kim >>> --- >>>  block/blk-core.c |    4 ++-- >>>  1 files changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/block/blk-core.c b/block/blk-core.c >>> index 5b59592..1a0cfd5 100644 >>> --- a/block/blk-core.c >>> +++ b/block/blk-core.c >>> @@ -1463,8 +1463,6 @@ static inline void __generic_make_request(struct bio *bio) >>>              if (old_sector != -1) >>>                      trace_block_remap(q, bio, old_dev, old_sector); >>> >>> -            trace_block_bio_queue(q, bio); >>> - >>>              old_sector = bio->bi_sector; >>>              old_dev = bio->bi_bdev->bd_dev; >>> >>> @@ -1477,6 +1475,8 @@ static inline void __generic_make_request(struct bio *bio) >>>                      goto end_io; >>>              } >>> >>> +            trace_block_bio_queue(q, bio); >>> + >>>              ret = q->make_request_fn(q, bio); >>>      } while (ret); >>> >>> -- >>> 1.6.4 >>> >>> >>> > -- Kind regards, Minchan Kim