Re: [PATCH -mm] slub: update cpu after new_slab()

[Christoph Lameter]

On Wed, 25 Apr 2007, Hugh Dickins wrote:

> > Right. local_irq_save does not switch off preemption as I thought.
> 
> Strange comment.  Preemption is not possible while IRQs are disabled,
> but new_slab() rightly reenables them within itself in the __GFP_WAIT
> case, since it's going off to do a page allocation and may need to wait.

Yes I expected local_irq_save to increase the preempt count and then 
local_irq_enable to simply enable interrupts without affecting the preempt 
count. Thus the process should stay on the same processor.

Never thought it would be possible to move to a different processor in mid 
flight.
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