Re: [PATCH 02/10] mm: system wide ALLOC_NO_WATERMARK

Daniel Phillips
2007-08-13T12:33:06Z

On Friday 10 August 2007 10:46, Christoph Lameter wrote:
> On Fri, 10 Aug 2007, Daniel Phillips wrote:
> > It is quite clear what is in your patch. Instead of just grabbing
> > a page off the buddy free lists in a critical allocation situation
> > you go invoke shrink_caches. Why oh why? All the memory needed to
> > get
>
> Because we get to the code of interest when we have no memory on the
> buddy free lists...

Ah wait, that statement is incorrect and may well be the crux of your
misunderstanding. Buddy free lists are not exhausted until the entire
memalloc reserve has been depleted, which would indicate a kernel bug
and imminent system death.

> ...and need to reclaim memory to fill them up again.

That we do, but we satisfy the allocations in the vm writeout path
first, without waiting for shrink_caches to do its thing.

Regards,

Daniel