Messages in this thread |  | | Date | Fri, 9 Nov 2001 06:45:40 +0100 | From | Andi Kleen <> | Subject | Re: speed difference between using hard-linked and modular drives? |
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On Fri, Nov 09, 2001 at 11:05:32AM +1100, Anton Blanchard wrote: > We also need a way to satisfy very large allocations for the hashes (eg > the pagecache hash). On a 32G machine we get awful performance on the > pagecache hash because we can only get an order 9 allocation out of > get_free_pages: > > http://samba.org/~anton/linux/pagecache/pagecache_before.png > > When switching to vmalloc the hash is large enough to be useful: > > http://samba.org/~anton/linux/pagecache/pagecache_after.png > > As pointed out by Davem and Ingo we should try and avoid vmalloc here > due to tlb trashing.
Sounds like you need a better hash function instead.
-Andi
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