cvs commit: src/sys/kern kern_switch.c sched_4bsd.c

Nate Lawson nate at
Fri Jun 10 01:46:49 GMT 2005

Stephan Uphoff wrote:
> On Thu, 2005-06-09 at 19:25, John Baldwin wrote:
>>On Jun 9, 2005, at 12:43 PM, Stephan Uphoff wrote:
>>>ups         2005-06-09 19:43:08 UTC
>>>  FreeBSD src repository
>>>  Modified files:
>>>    sys/kern             kern_switch.c sched_4bsd.c
>>>  Log:
>>>  Lots of whitespace cleanup.
>>>  Fix for broken if condition.
>>>  Submitted by:   nate@
>>What was broken about the if test?  The intention was that when 
>>FULL_PREEMPTION was off, we only preempt if the destination thread is 
>>an ithread or if the current thread is an idle priority thread. 
> I was under the impression that we never preempt the idle thread but did
> not investigate closer.
> Is it save to preempt the idle thread on x86 when it does its ACPI
> C-state magic?

I agree that the idle thread should be pre-empted before the Cx sleep.


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