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From: "David S. Miller" <davem@redhat.com>
To: hadi@cyberus.ca
Cc: kuznet@ms2.inr.ac.ru, shemminger@osdl.org, netdev@oss.sgi.com
Subject: Re: bk16 changes to cbq
Date: Sat, 3 Jul 2004 10:16:46 -0700	[thread overview]
Message-ID: <20040703101646.52ae1e01.davem@redhat.com> (raw)
In-Reply-To: <1088861810.1039.298.camel@jzny.localdomain>

On 03 Jul 2004 09:36:50 -0400
jamal <hadi@cyberus.ca> wrote:

> -               if (q->wd_expires && !netif_queue_stopped(sch->dev)) {
> +               if (q->wd_expires) {
>                         long delay = PSCHED_US2JIFFIE(q->wd_expires);
>                         if (delay <= 0)
>                                 delay = 1;
> 
> What i remember is this (4-5 years back) used to cure a bug - cant
> remember the details unfortunately, but Alexey may remember.
> I am hoping removal of the above line implies that those conditions dont
> exist anymore? 

The test is racy with drivers, on the very next line the
driver could take a TX completion interrupt and unplug the
queue invalidating the test entirely.

If the test proves wrong, that's OK because we'll try again
at the top level of packet queue dispatch.

There was a good explaination of Stephen's patch
on netdev when he posted it.

  reply	other threads:[~2004-07-03 17:16 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-07-03 13:36 bk16 changes to cbq jamal
2004-07-03 17:16 ` David S. Miller [this message]
2004-07-04  0:03   ` jamal
2004-07-04  1:21   ` jamal
2004-07-05 20:27 ` Alexey Kuznetsov
2004-07-06  1:28   ` jamal
2004-07-07  5:13   ` David S. Miller
2004-07-07 15:59     ` Alexey Kuznetsov
2004-07-07 18:11       ` jamal

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