Re: [PATCH] slub: Don't throw away partial remote slabs if there is no local memory

Nishanth Aravamudan
2014-01-24T23:29:26Z

On 24.01.2014 [13:03:13 -0800], David Rientjes wrote:
> On Fri, 24 Jan 2014, Christoph Lameter wrote:
>
> > On Fri, 24 Jan 2014, Wanpeng Li wrote:
> >
> > > >
> > > >diff --git a/mm/slub.c b/mm/slub.c
> > > >index 545a170..a1c6040 100644
> > > >--- a/mm/slub.c
> > > >+++ b/mm/slub.c
> > > >@@ -1700,6 +1700,9 @@ static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
> > > > void *object;
> > > > int searchnode = (node == NUMA_NO_NODE) ? numa_node_id() : node;
> >
> > This needs to be numa_mem_id() and numa_mem_id would need to be
> > consistently used.
> >
> > > >
> > > >+ if (!node_present_pages(searchnode))
> > > >+ searchnode = numa_mem_id();
> >
> > Probably wont need that?
> >
>
> I think the problem is a memoryless node being used for kmalloc_node() so
> we need to decide where to enforce node_present_pages(). __slab_alloc()
> seems like the best candidate when !node_match().

Actually, this is effectively what Anton's patch does, except with
Wanpeng's adjustment to use node_present_pages(). Does that seem
sufficient to you?

It does only cover the memoryless node case (not the exhausted node
case), but I think that shouldn't block the fix (and it does fix the
issue we've run across in our testing).

-Nish