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* preempt_disable() question
@ 2008-03-19  2:14 Rick Brown
  2008-03-19 22:27 ` Jiri Slaby
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Rick Brown @ 2008-03-19  2:14 UTC (permalink / raw)
  To: Linux Kernel

Hi,

I've asked this on kernel newbies before, but not enough responses.

Does preempt_disable() disable preemption on all the processors, or
just the local processor?

TIA,

Rick

^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: preempt_disable() question
  2008-03-19  2:14 preempt_disable() question Rick Brown
@ 2008-03-19 22:27 ` Jiri Slaby
  2008-03-19 22:46 ` Peter Zijlstra
  2008-03-20 16:23 ` Daniel Walker
  2 siblings, 0 replies; 4+ messages in thread
From: Jiri Slaby @ 2008-03-19 22:27 UTC (permalink / raw)
  To: Rick Brown; +Cc: Linux Kernel

On 03/19/2008 03:14 AM, Rick Brown wrote:
> Hi,
> 
> I've asked this on kernel newbies before, but not enough responses.
> 
> Does preempt_disable() disable preemption on all the processors, or
> just the local processor?

AFAIU preempt_disable increments preempt count of the current task, so that 
nobody will take the cpu which it is executing on (scheduler doesn't allow that) 
while the task is running until preempt count lowers to 0. How do you mean the 
"disabling preemption on local processor", how/why would you want to disable 
preemption of task potentially running on the other one?

^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: preempt_disable() question
  2008-03-19  2:14 preempt_disable() question Rick Brown
  2008-03-19 22:27 ` Jiri Slaby
@ 2008-03-19 22:46 ` Peter Zijlstra
  2008-03-20 16:23 ` Daniel Walker
  2 siblings, 0 replies; 4+ messages in thread
From: Peter Zijlstra @ 2008-03-19 22:46 UTC (permalink / raw)
  To: Rick Brown; +Cc: Linux Kernel

On Wed, 2008-03-19 at 07:44 +0530, Rick Brown wrote:
> Hi,
> 
> I've asked this on kernel newbies before, but not enough responses.
> 
> Does preempt_disable() disable preemption on all the processors, or
> just the local processor?

Just the local one


^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: preempt_disable() question
  2008-03-19  2:14 preempt_disable() question Rick Brown
  2008-03-19 22:27 ` Jiri Slaby
  2008-03-19 22:46 ` Peter Zijlstra
@ 2008-03-20 16:23 ` Daniel Walker
  2 siblings, 0 replies; 4+ messages in thread
From: Daniel Walker @ 2008-03-20 16:23 UTC (permalink / raw)
  To: Rick Brown; +Cc: Linux Kernel


On Wed, 2008-03-19 at 07:44 +0530, Rick Brown wrote:
> Hi,
> 
> I've asked this on kernel newbies before, but not enough responses.
> 
> Does preempt_disable() disable preemption on all the processors, or
> just the local processor?

Just the local processor.

Daniel


^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2008-03-20 16:23 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2008-03-19  2:14 preempt_disable() question Rick Brown
2008-03-19 22:27 ` Jiri Slaby
2008-03-19 22:46 ` Peter Zijlstra
2008-03-20 16:23 ` Daniel Walker

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