Re: Kernel WARNING: at net/core/dev.c:1330 __netif_schedule+0x2c/0x98()

Peter Zijlstra
2008-07-24T10:09:31Z

On Thu, 2008-07-24 at 02:32 -0700, David Miller wrote:
> From: Peter Zijlstra <peterz@infradead.org>
> Date: Thu, 24 Jul 2008 11:27:05 +0200
>
> > Well, not only lockdep, taking a very large number of locks is expensive
> > as well.
>
> Right now it would be on the order of 16 or 32 for
> real hardware.
>
> Much less than the scheduler currently takes on some
> of my systems, so currently you are the pot calling the
> kettle black. :-)

One nit, and then I'll let this issue rest :-)

The scheduler has a long lock dependancy chain (nr_cpu_ids rq locks),
but it never takes all of them at the same time. Any one code path will
at most hold two rq locks.