Re: vm lock contention reduction

William Lee Irwin III
2002-07-08T00:59:20Z

Rik van Riel wrote:
>> But it is, mmap() and anonymous memory don't trigger writeback.

On Fri, Jul 05, 2002 at 05:48:48PM -0700, Andrew Morton wrote:
> That's different. Bill hit a problem just running tiobench.
> We can run balance_dirty_pages() when a COW copyout is performed,
> which will approximately improve things.
> But the whole idea of the dirty memory thresholds just seems bust,
> really. Because how do you pick the thresholds? 40%. Bah.

I don't know what the answer should be, but I can certainly demonstrate
this in a rather uninteresting situation (4GB, 4cpu's, 1 disk, 16 tasks).

But I can concur with that evaluation. In my esteem fixed fractions of
memory don't have a very direct relationship to what's going on.

Cheers,
Bill