lkml.org 
[lkml]   [2006]   [Jul]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch] Reorganize the cpufreq cpu hotplug locking to not be totally bizare
On Wed, Jul 26, 2006 at 01:22:24PM -0700, Linus Torvalds wrote:
>
> Of course, that's why people want recursive locks in the first place, and
> it's also why we've (largely successfully) have avoided them - it allows
> for people being way too lazy about locking, and allows for really broken
> schenarios like this.
>
> I wonder if we could just make the workqueue code just run with preemption
> disabled - that should also automatically protect against any CPU hotplug

Its probably ok for this case.

before introducing the ugly recursion we did try the preempt_disable()
for cpufreq, and it worked for most all governers with preempt_disable(),
but powernowk8 called set_cpus_allowed() in the callback path that
threw out a scheduling while in atomic BUG().

http://lkml.org/lkml/2005/10/31/239


> events on the local CPU (and I think "local CPU" is all that the wq code
> cares about, no?)
>
> Linus

--
Cheers,
Ashok Raj
- Open Source Technology Center
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-07-26 23:43    [W:1.374 / U:1.312 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site