Re: [patch 2/3] NUMA slab locking fixes - move irq disabling fromcahep->spinlock to l3 lock

[Andrew Morton]

Ravikiran G Thirumalai <kiran@xxxxxxxxxxxx> wrote:
>
> Earlier, we had to disable on chip interrupts while taking the cachep->spinlock
>  because, at cache_grow, on every addition of a slab to a slab cache, we 
>  incremented colour_next which was protected by the cachep->spinlock, and
>  cache_grow could occur at interrupt context.  Since, now we protect the 
>  per-node colour_next with the node's list_lock, we do not need to disable 
>  on chip interrupts while taking the per-cache spinlock, but we
>  just need to disable interrupts when taking the per-node kmem_list3 list_lock.

It'd be nice to have some comments describing what cachep->spinlock
actually protects.

Does __cache_shrink() need some locking to prevent nodes from going offline?
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