Re: [PATCH] powerpc/mm: Make sure a local_irq_disable prevent a parallel THP split

[Rik van Riel]

On 03/15/2014 06:47 AM, Aneesh Kumar K.V wrote:
> From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
> 
> We have generic code like the one in get_futex_key that assume that
> a local_irq_disable prevents a parallel THP split. Support that by
> adding a dummy smp call function after setting _PAGE_SPLITTING. Code
> paths like get_user_pages_fast still need to check for _PAGE_SPLITTING
> after disabling IRQ which indicate that a parallel THP splitting is
> ongoing. Now if they don't find _PAGE_SPLITTING set, then we can be
> sure that parallel split will now block in pmdp_splitting flush
> until we enables IRQ
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>

Acked-by: Rik van Riel <riel@xxxxxxxxxx>

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