Re: page fault scalability patch V11 [0/7]: overview

William Lee Irwin III
2004-11-20T02:41:04Z

William Lee Irwin III wrote:
>> Unprivileged triggers for full-tasklist scans are NMI oops material.

On Sat, Nov 20, 2004 at 01:25:37PM +1100, Nick Piggin wrote:
> What about pushing the per-thread rss delta back into the global atomic
> rss counter in each schedule()?
> Pros:
> This would take the task exiting problem into its stride as a matter of
> course.
> Single atomic read to get rss.
> Cons:
> would just be moving the atomic op somewhere else if we don't get
> many page faults per schedule.
> Not really nice dependancies.
> Assumes schedule (not context switch) must occur somewhat regularly.
> At present this is not true for SCHED_FIFO tasks.
> Too nasty?

This doesn't sound too hot. There's enough accounting that can't be
done anywhere but schedule(), and this can be done elsewhere. Plus,
you're moving an already too-frequent operation to a more frequent
callsite.

-- wli