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

Nishanth Aravamudan
2014-02-03T23:00:55Z

On 28.01.2014 [10:29:47 -0800], Nishanth Aravamudan wrote:
> On 27.01.2014 [14:58:05 +0900], Joonsoo Kim wrote:
> > On Fri, Jan 24, 2014 at 05:10:42PM -0800, Nishanth Aravamudan wrote:
> > > On 24.01.2014 [16:25:58 -0800], David Rientjes wrote:
> > > > On Fri, 24 Jan 2014, Nishanth Aravamudan wrote:
> > > >
> > > > > Thank you for clarifying and providing a test patch. I ran with this on
> > > > > the system showing the original problem, configured to have 15GB of
> > > > > memory.
> > > > >
> > > > > With your patch after boot:
> > > > >
> > > > > MemTotal: 15604736 kB
> > > > > MemFree: 8768192 kB
> > > > > Slab: 3882560 kB
> > > > > SReclaimable: 105408 kB
> > > > > SUnreclaim: 3777152 kB
> > > > >
> > > > > With Anton's patch after boot:
> > > > >
> > > > > MemTotal: 15604736 kB
> > > > > MemFree: 11195008 kB
> > > > > Slab: 1427968 kB
> > > > > SReclaimable: 109184 kB
> > > > > SUnreclaim: 1318784 kB
> > > > >
> > > > >
> > > > > I know that's fairly unscientific, but the numbers are reproducible.
> > > > >
> >
> > Hello,
> >
> > I think that there is one mistake on David's patch although I'm not sure
> > that it is the reason for this result.
> >
> > With David's patch, get_partial() in new_slab_objects() doesn't work
> > properly, because we only change node id in !node_match() case. If we
> > meet just !freelist case, we pass node id directly to
> > new_slab_objects(), so we always try to allocate new slab page
> > regardless existence of partial pages. We should solve it.
> >
> > Could you try this one?
>
> This helps about the same as David's patch -- but I found the reason
> why! ppc64 doesn't set CONFIG_HAVE_MEMORYLESS_NODES :) Expect a patch
> shortly for that and one other case I found.
>
> This patch on its own seems to help on our test system by saving around
> 1.5GB of slab.
>
> Tested-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
> Acked-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
>
> with the caveat below.

So what's the status of this patch? Christoph, do you think this is fine
as it is?

Thanks,
Nish