Changing p_swtime and td_slptime to ticks

[Jeff Roberson]

On Tue, 18 Sep 2007, Kostik Belousov wrote:

> On Mon, Sep 17, 2007 at 05:05:57PM -0700, Jeff Roberson wrote:
>> Enclosed is a patch that fixes swapping with ULE.  ULE has never properly
>> set p_swtime and td_slptime which are used by the swapout/swapin code to
>> select the appropriate thread to swap.
>>
>> In 4BSD these two variables are increment once per-second as schedcpu()
>> iterates over all threads.  ULE does not have a once per-second loop
>> iterating over all threads.  So I have changed p_swtime to p_swtick and
>> td_slptime to td_slptick.  These record the value of 'ticks' when the
>> thread slept or was last swapped in or out.
>>
>> For backwards compatibility I leave the values in kinfo_proc with the
>> legacy meaning by subtracting from ticks and dividing by hz.  I perform a
>> similar transformation in the swapout code to convert to seconds.  This
>> change does make it possible to use sub-second granular decisions in the
>> swap code, however I'm not sure if that's really necessary.
>>
>> So that I did not disturb the 4BSD mechanism I kept the original
>> td_slptime in the td_sched area.  It should be possible to use td_slptick
>> directly but especially this close to release I did not want to change
>> 4BSD.
>>
>> Feedback and testing welcome.
>
> Purely cosmetic request: please make the ticks and hz variables in the
> libkvm/kvm_proc.c static. Or, even better, move it into the struct __kvm.
>

Thanks, will do.

Jeff