Messages in this thread | | | Subject | Re: [patch 2/2] slub: add min_partial sysfs tunable | From | Pekka Enberg <> | Date | Mon, 23 Feb 2009 12:26:24 +0200 |
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Hi David,
On Mon, 23 Feb 2009, Pekka Enberg wrote: > > The patches look good but the description is bit lacking. Does this > > actually fix up something? Why don't we fix the limit calculations > > instead? > > > > I'm a sucker for numbers so I'm easily fooled into merging patches with > > statements of the form "this shaves off N bytes/kb/mb on XYZ systems".
On Mon, 2009-02-23 at 01:58 -0800, David Rientjes wrote: > The memory savings from simply moving min_partial from struct > kmem_cache_node to struct kmem_cache is obviously not significant (unless > maybe you're from SGI or something), at the largest it's > > # allocated caches * (MAX_NUMNODES - 1) * sizeof(unsigned long) > > The true savings occurs when userspace reduces the number of partial slabs > that would otherwise be wasted, especially on machines with a large > number of nodes (ia64 with CONFIG_NODES_SHIFT at 10 for default?). As > well as the kernel estimates ideal values for n->min_partial and ensures > it's within a sane range, userspace has no other input other than writing > to /sys/kernel/slab/cache/shrink.
Applied with the above explanation added to the changelog. Thanks!
Pekka
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