Re: page fault fastpath: Increasing SMP scalability by introducing pte locks?

William Lee Irwin III
2004-08-16T16:19:25Z

On Mon, 16 Aug 2004, Ray Bryant wrote:
>> Something else to worry about here is mm->rss. Previously, this was updated
>> only with the page_table_lock held, so concurrent increments were not a
>> problem. rss may need to converted be an atomic_t if you use pte_locks.
>> It may be that an approximate value for rss is good enough, but I'm not sure
>> how to bound the error that could be introduced by a couple of hundred
>> processers handling page faults in parallel and updating rss without locking
>> it or making it an atomic_t.

On Mon, Aug 16, 2004 at 08:18:11AM -0700, Christoph Lameter wrote:
> Correct. There are a number of issues that may have to be addressed but
> first we need to agree on a general idea how to proceed.

I'd favor a per-cpu counter so the cacheline doesn't bounce.

-- wli