Messages in this thread | | | Date | Fri, 7 Mar 2008 03:32:23 +0100 | From | Nick Piggin <> | Subject | Re: [rfc][patch 1/3] slub: fix small HWCACHE_ALIGN alignment |
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On Thu, Mar 06, 2008 at 06:26:49PM -0800, Christoph Lameter wrote: > On Fri, 7 Mar 2008, Nick Piggin wrote: > > > That's just because you (apparently still) have a misconception about what > > the flag is supposed to be for. It is not for aligning things to the start > > of a cacheline boundary. It is not for avoiding false sharing on SMP. It > > The alignment of the object to the start of a cacheline is the obvious > meaning and that is also reflected in the comment in slab.h.
It doesn't say start of cache line. It says align them *on* cachelines. 2 32 byte objects on a 64 byte cacheline are aligned on the cacheline. 2.67 24 bytes objects on a 64 byte cacheline are not aligned on the cacheline.
Anyway, if you want to be myopic about it, then good luck with that.
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