From: Jens Axboe <axboe@suse.de>
To: Warren Togami <wtogami@redhat.com>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>,
Arjan van de Ven <arjanv@redhat.com>,
linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
Alan Cox <alan@redhat.com>
Subject: Re: [PATCH] i2o_block Fix, possible CFQ elevator problem?
Date: Tue, 20 Apr 2004 13:34:29 +0200 [thread overview]
Message-ID: <20040420113429.GL25806@suse.de> (raw)
In-Reply-To: <40850987.1080603@redhat.com>
On Tue, Apr 20 2004, Warren Togami wrote:
> Jens Axboe wrote:
> >>>
> >>>Repeat the tests that made it crash. The last patch I sent should work
> >>>for you, at least until the real issue is found.
> >>>
> >>
> >>Tested your patch, it indeed does seem to keep the system stable. If I
> >>am understanding it right, the patch disables merging in the case where
> >>it would have caused a BUG condition? (Less efficiency.)
> >
> >
>
> Bad news... much later during the test the system locked up. During
> this test we did not use "sync" but just let all four bonnie++'s run.
>
> http://togami.com/~warren/archive/2004/i2o_cfq_quad_bonnie3.txt
> ----------- [cut here ] --------- [please bite here ] ---------
> Kernel BUG at cfq_iosched:404
> invalid operand: 0000 [1] SMP
Sorry about that, that's actually expected when we know this bug
exists. You need to move the cfq_remove_merge_hints(q, crq) before the
BUG_ON(q->last_merge == rq) check, or (better) just remove it
completely. There's no way that q->last_merge could be set to this
request after cfq_remove_merge_hints() was called.
--
Jens Axboe
next prev parent reply other threads:[~2004-04-20 11:34 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-04-19 11:37 [PATCH] i2o_block Fix, possible CFQ elevator problem? Warren Togami
2004-04-19 12:12 ` Jens Axboe
2004-04-20 0:42 ` Warren Togami
[not found] ` <40848159.7090605@togami.com>
2004-04-20 7:08 ` Jens Axboe
2004-04-20 7:58 ` Warren Togami
2004-04-20 8:03 ` Jens Axboe
2004-04-20 8:59 ` Warren Togami
2004-04-20 9:05 ` Jens Axboe
2004-04-20 10:53 ` Warren Togami
2004-04-20 10:56 ` Jens Axboe
2004-04-20 11:29 ` Warren Togami
2004-04-20 11:34 ` Jens Axboe [this message]
2004-04-20 11:38 ` Jens Axboe
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