kern/78474 for 5.4? (kernel stack swapout problem again)

[David Xu]

Doug White wrote:

>On Thu, 21 Apr 2005, David Xu wrote:
>
>  
>
>>Sam Lawrance wrote:
>>
>>    
>>
>>>Will this problem:
>>>
>>>Swapped out procs not brought in immediately after child exits
>>>http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/78474
>>>
>>>be dealt with for the release of 5.4?
>>>
>>>Perhaps I'm the only FreeBSD user with swapped out processes ;-)
>>>
>>>-Sam
>>>
>>>
>>>
>>>
>>>      
>>>
>>I have noticed that current spinlock implementation no longer means that
>>CPU must be in critical region (critical_enter is called), even previous
>>hack TDP_WAKEPROC0 is no longer correct, :(, I think it is the time to
>>disable swapout.
>>    
>>
>
>I'm sorry, I can't parse your double negative.  On -CURRENT critical
>sections (entered with critical_enter()) no longer disable interrupts, but
>do inhibit preemption.  But spinlocks still do critical_enter() (see
>spinlock_enter()).
>
>  
>
I will commit the patch provided in the PR, it should work. I am just 
worrying
TDP_WAKEPROC0 will not work if spinlock does not entering critical region.