From: Vivek Goyal <vgoyal@redhat.com>
To: Jeff Moyer <jmoyer@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>,
linux-kernel@vger.kernel.org, guijianfeng@cn.fujitsu.com
Subject: Re: [PATCH 2/2] cfq-iosched: Take care of corner cases of group losing share due to deletion
Date: Wed, 9 Dec 2009 15:39:41 -0500 [thread overview]
Message-ID: <20091209203941.GA2738@redhat.com> (raw)
In-Reply-To: <x49bpi8nf19.fsf@segfault.boston.devel.redhat.com>
On Wed, Dec 09, 2009 at 02:06:10PM -0500, Jeff Moyer wrote:
> Vivek Goyal <vgoyal@redhat.com> writes:
>
> > Reported-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
> > Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
>
> > + /*
> > + * If think times is less than a jiffy than ttime_mean=0 and above
> > + * will not be true. It might happen that slice has not expired yet
> > + * but will expire soon (4-5 ns) during select_queue(). To cover the
>
> 4-5ns? I'm not sure why you chose these numbers. Is that what you saw
> in testing?
Yes, that was the number I observed in blktrace while I was debugging
the issue.
> Anyway, I'm ok with the change, I dislike the reference to
> time when a single jiffy could be up to 10ms.
>
> Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
next prev parent reply other threads:[~2009-12-09 20:39 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-08 22:52 [PATCH 1/2] cfq-iosched: Get rid of cfqq wait_busy_done flag Vivek Goyal
2009-12-08 22:52 ` [PATCH 2/2] cfq-iosched: Take care of corner cases of group losing share due to deletion Vivek Goyal
2009-12-09 13:56 ` Jens Axboe
2009-12-09 15:17 ` Vivek Goyal
2009-12-09 18:50 ` Jens Axboe
2009-12-09 19:06 ` Jeff Moyer
2009-12-09 20:39 ` Vivek Goyal [this message]
2009-12-09 19:03 ` [PATCH 1/2] cfq-iosched: Get rid of cfqq wait_busy_done flag Jeff Moyer
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