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SubjectRe: [patch] slub: default min_partial to at least highest cpus per node
On Tue, 7 Apr 2009, Pekka Enberg wrote:

> Yeah, something more dynamic makes sense. But we probably need to do
> ilog2(nr_cpu_ids) or something; otherwise we will have very long partial lists
> on big iron machines (think 4096 cpus here).
>

The suggestion was to replace MAX_PARTIAL with nr_cpu_ids, not as the
default value for n->min_partial, which is ilog2(size). To exceed the
current value of MAX_PARTIAL, which is 10, size would need to be 2K or
greater.

I agree that the default n->min_partial would be better represented in
terms of cpus than object size. ilog2(nr_cpu_ids) certainly seems
appropriate and free partial slabs can always be reclaimed by utilizing
/sys/kernel/slab/cache/shrink.

The 4096 cpu example is certainly realistic, but probably not UMA.


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