On 28.01.2014 [10:29:47 -0800], Nishanth Aravamudan wrote:

On 27.01.2014 [14:58:05 +0900], Joonsoo Kim wrote:

quoted

On Fri, Jan 24, 2014 at 05:10:42PM -0800, Nishanth Aravamudan wrote:

quoted

On 24.01.2014 [16:25:58 -0800], David Rientjes wrote:

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On Fri, 24 Jan 2014, Nishanth Aravamudan wrote:

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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 <redacted>
Acked-by: Nishanth Aravamudan <redacted>

with the caveat below.

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

Thanks,
Nish