On Mon, Jul 06, 2015 at 08:14:37AM +0530, Afzal Mohammed wrote:
> scaled down weight 'fact' would not be > u32 rather than unlikely as the
> values being passed for delta is either NICE_O_LOAD or the weight of the
> 'se' which would be a value that can be accomodated in a u32.
This needs a bit more on why se->load.weight must fit u32 (its true, but
not evident from this text).
> Remove the initial > u32 handling on 'fact'.
>
> 9dbdb15553239 ("sched/fair: Rework sched_fair time accounting") in
> addition to fixing the original issue of time moving backwards elsewhere
> in the code, handled delta > u32 case (due to NO_HZ_FULL) which brought
> in as it's part the change changed here.
Because the unsigned long weight is a u64 on 64bit..
Now as long as we never call __calc_delta() on a rq weight -- which is a
sum of weights and can indeed be larger than u32, we can indeed remove
this.
And I think we already assume such, see this story on why shift will
remain positive.
> The hunk being removed here
> would not make a difference to it as this is on scaled weight > u32.
> And pre-"9dbdb15553239" doesn't seem to have logical equivalent of hunk
> removed here either.
-ENOPARSE.
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