From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH] net: sched: dev_deactivate_many(): use msleep(1)
 instead of yield() to wait for outstanding qdisc_run callsb
Date: Fri, 04 Apr 2014 11:26:28 -0400 (EDT)
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From: Peter Zijlstra <peterz@infradead.org>
Date: Fri, 4 Apr 2014 17:19:42 +0200

> The proper way to fix the dev_deactivate_many() is to use wait_event(),
> polling for that state is just daft. Afaict there is no reason the qdisc
> code could not do a wakeup whenever that condition changes.

I actually looked into this, and it's going to add expensive checks
to the fast paths of packet processing.

If it was so easy we'd be doing it that way already.