Re: [PATCH 1/2] mm/slob: Mark zone page state to get slab usage at /proc/meminfo

From: Ezequiel Garcia
Date: Mon Oct 22 2012 - 13:13:55 EST


Hi Christoph,

On Mon, Oct 22, 2012 at 11:41 AM, Christoph Lameter <cl@xxxxxxxxx> wrote:
> On Mon, 22 Oct 2012, Ezequiel Garcia wrote:
>
>> On page allocations, SLAB and SLUB modify zone page state counters
>> NR_SLAB_UNRECLAIMABLE or NR_SLAB_RECLAIMABLE.
>> This allows to obtain slab usage information at /proc/meminfo.
>>
>> Without this patch, /proc/meminfo will show zero Slab usage for SLOB.
>>
>> Since SLOB discards SLAB_RECLAIM_ACCOUNT flag, we always use
>> NR_SLAB_UNRECLAIMABLE zone state item.
>

... and I have a question about this.

SLUB handles large kmalloc allocations falling back
to page-size allocations (kmalloc_large, etc).
This path doesn't touch NR_SLAB_XXRECLAIMABLE zone item state.

Without fully understanding it, I've decided to implement the same
behavior for SLOB,
leaving page-size allocations unaccounted on /proc/meminfo.

Is this expected / wanted ?

SLAB, on the other side, handles every allocation through some slab cache,
so it always set the zone state.

Thanks!

Ezequiel
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