Re: Major regression on hackbench with SLUB

Christoph Lameter
2007-12-13T22:11:37Z

On Fri, 7 Dec 2007, Linus Torvalds wrote:

> The biggest cost of __slab_alloc() in my profile is the "slab_lock()", but
> that may not be the one that causes problems in a 64-cpu setup, so it
> would be good to have that verified.

Hmmmm.. This would indicate lock contention on a slab.

> [ The whole node match thing is likely totally bogus. I suspect we pay
> *more* in trying to match nodes than we'd ever likely pay in just
> returning the wrong node for an allocation, but that's neither here nor
> there ]

Node match is necessary in order to make the allocator able to get memory
for the node that the caller requested.