Re: [PATCH] Allocate memory cgroup structures in local nodes v2

From: Michal Hocko
Date: Thu May 05 2011 - 02:39:23 EST


On Wed 04-05-11 23:38:50, Johannes Weiner wrote:
> On Wed, May 04, 2011 at 01:26:23PM -0700, Andi Kleen wrote:
> > diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
> > index 9905501..a362215 100644
> > --- a/mm/page_cgroup.c
> > +++ b/mm/page_cgroup.c
> > @@ -134,7 +134,7 @@ static void *__init_refok alloc_page_cgroup(size_t size, int nid)
> > {
> > void *addr = NULL;
> >
> > - addr = alloc_pages_exact(size, GFP_KERNEL | __GFP_NOWARN);
> > + addr = alloc_pages_exact_node(nid, GFP_KERNEL | __GFP_NOWARN, size);
>
> alloc_pages_exact_node is not the 'specify node as well'-version of
> alloc_pages_exact, it refers to 'exact node'. Thus the
> free_pages_exact call is no longer the right counter-part.
>
> alloc_pages_exact_node takes an order, not a size argument.
>
> alloc_pages_exact_node returns a pointer to the struct page, not to
> the allocated memory, like all other alloc_pages* functions with the
> exception of alloc_pages_exact.
>
> I don't think any of those mistakes even triggers a compiler warning.
> Wow. This API is so thoroughly fscked beyond belief that I think the
> only way to top this is to have one of the functions invert the bits
> of its return value depending on the parity of the uptime counter.

I think Dave Hansen is doing a cleanup in that area
(https://lkml.org/lkml/2011/4/11/337).

--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
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