Re: SLUB defrag pull request?

From: Christoph Lameter
Date: Thu Oct 23 2008 - 11:41:01 EST


On Thu, 23 Oct 2008, Eric Dumazet wrote:

At alloc time, I remember I added a prefetchw() call in SLAB in __cache_alloc(),
this could explain some differences between SLUB and SLAB too, since SLAB
gives a hint to processor to warm its cache.

SLUB touches objects by default when allocating. And it does it immediately in slab_alloc() in order to retrieve the pointer to the next object. So there is no point of hinting there right now.

If we go to the pointer arrays then the situation is similar to SLAB where the object is not touched by the allocator. Then the hint would be useful again.

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