Messages in this thread | | | Date | Mon, 3 Mar 2008 21:06:13 +0100 | From | Nick Piggin <> | Subject | Re: [rfc][patch 1/3] slub: fix small HWCACHE_ALIGN alignment |
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On Mon, Mar 03, 2008 at 11:08:44AM -0800, Christoph Lameter wrote: > On Mon, 3 Mar 2008, Nick Piggin wrote: > > > SLUB should pack even small objects nicely into cachelines if that is what > > has been asked for. Use the same algorithm as SLAB for this. > > Why? SLAB does not cacheline align objects smaller than cache_line_size() > /2.
It still doesn't after this patch.
> If they are already not cache line aligned then we can make them as > dense as possible. That is what SLUB does.
Because when you specify HWCACHE_ALIGN, it means that you want the object not to cross cacheline boundaries for at least cache_line_size() bytes. SLAB does this. SLUB does not without this patch.
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