Re: [PATCH 0/5] make slab gfp fair

Andrew Morton
2007-05-14T19:46:00Z

On Mon, 14 May 2007 11:12:24 -0500
Matt Mackall <mpm@selenic.com> wrote:

> If I understand this correctly:
>
> privileged thread unprivileged greedy process
> kmem_cache_alloc(...)
> adds new slab page from lowmem pool
> do_io()
> kmem_cache_alloc(...)
> kmem_cache_alloc(...)
> kmem_cache_alloc(...)
> kmem_cache_alloc(...)
> kmem_cache_alloc(...)
> ...
> eats it all
> kmem_cache_alloc(...) -> ENOMEM
> who ate my donuts?!

Yes, that's my understanding also.

I can see why it's a problem in theory, but I don't think Peter has yet
revealed to us why it's a problem in practice. I got all excited when
Christoph asked "I am not sure what the point of all of this is.", but
Peter cunningly avoided answering that ;)

What observed problem is being fixed here?