Messages in this thread | | | Subject | Re: [patch] SLQB slab allocator (try 2) | From | Pekka Enberg <> | Date | Thu, 19 Feb 2009 11:16:07 +0200 |
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On Wed, 2009-02-18 at 09:48 +0900, KOSAKI Motohiro wrote: > > > In addition, if pekka patch (SLAB_LIMIT = 8K) run on ia64, 16K allocation > > > always fallback to page allocator and using 64K (4 times memory consumption!). > > > > Yes, correct, but SLUB does that already by passing all allocations over > > 4K to the page allocator. > > hmhm > OK. my mail was pointless. > > but why? In my understanding, slab framework mainly exist for efficient > sub-page allocation. > the fallbacking of 4K allocation in 64K page-sized architecture seems > inefficient.
I don't think any of the slab allocators are known for memory efficiency. That said, the original patch description sums up the rationale for page allocator pass-through:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=aadb4bc4a1f9108c1d0fbd121827c936c2ed4217
Interesting enough, there seems to be some performance gain from it as well as seen by Mel Gorman's recent slab allocator benchmarks.
Pekka
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