Re: [PATCH] ignore referenced pages on reclaim when OOM

Rik van Riel
2004-11-08T21:56:25Z

On Tue, 9 Nov 2004, Nikita Danilov wrote:

> > Speeds up extreme load performance on Rik's tests.
>
> I recently tested quite similar thing, the only dfference being that in
> my case references bit started being ignored when scanning priority
> reached 2 rather than 0.
>
> I found that it _degrades_ performance in the loads when there is a lot
> of file system write-back going from tail of the inactive list (like
> dirtying huge file through mmap in a loop).

Well yeah, when you reach priority 2, you've only scanned
1/4 of memory. On the other hand, when you reach priority
0, you've already scanned all pages once - beyond that point
the referenced bit really doesn't buy you much any more.

--
"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it." - Brian W. Kernighan