Re: [slub p4 6/7] slub: per cpu cache for partial pages

From: Christoph Lameter
Date: Wed Aug 24 2011 - 09:58:05 EST


On Wed, 24 Aug 2011, Lin Ming wrote:

> > Potential future enhancements:
> >
> > 1. The pickup from the partial list could be perhaps be done without disabling
> > interrupts with some work. The free path already puts the page into the
> > per cpu partial list without disabling interrupts.
>
> Nice patches!
>
> Could you share possible ways for this potential enhancement?

In order to avoid disabling interrupts in the allocation paths the state
that has to be kept in kmem_cache_cpu needs to be minimized so that it can
be swapped atomically using a this_cpu_cmpxchg. This means getting rid of
the node and slab fields I guess. Working on some patches to that effect.

Once that is done one can with a this_cpu_cmpxchg_double take over the per
cpu slab and then use that information to update the slab page etc.

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