From: Jens Axboe <jens.axboe@oracle.com>
To: Xiaoning Ding <dingxn@cse.ohio-state.edu>
Cc: linux-kernel@vger.kernel.org
Subject: Re: a bug in AS scheduler?
Date: Wed, 28 Feb 2007 13:10:40 +0100 [thread overview]
Message-ID: <20070228121040.GW3733@kernel.dk> (raw)
In-Reply-To: <45E5038F.1090200@cse.ohio-state.edu>
On Tue, Feb 27 2007, Xiaoning Ding wrote:
> Hi,
>
> I am reading the source code AS scheduler in 2.6.18(as-ioscheduler.c).
> In function as_close_req, variable delay is in millisecond, while
> ad->antic_expire is in jiffies. Doesn't the comparison of delay and
> ad->antic_expire make any problem?
> The related source code is quoted blow:
>
> if (ad->antic_status == ANTIC_OFF || !ad->ioc_finished)
> delay = 0;
> else
> delay = ((jiffies - ad->antic_start) * 1000) / HZ;
antic_start is in jiffies, the difference is here multiplied by 1000 and
divided by HZ to turn it into msecs. so delay is in msecs.
--
Jens Axboe
next prev parent reply other threads:[~2007-02-28 12:11 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-28 4:22 Xiaoning Ding
2007-02-28 12:10 ` Jens Axboe [this message]
2007-02-28 13:25 ` Benoit Boissinot
2007-02-28 13:34 ` Jens Axboe
2007-02-28 15:33 ` Xiaoning Ding
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