Re: [v2 PATCH 2/2] powerpc/64s/radix: don't need to broadcast IPI for radix pmd collapse flush

[Peter Xu]

On Wed, Sep 07, 2022 at 11:01:44AM -0700, Yang Shi wrote:
> The IPI broadcast is used to serialize against fast-GUP, but fast-GUP
> will move to use RCU instead of disabling local interrupts in fast-GUP.
> Using an IPI is the old-styled way of serializing against fast-GUP
> although it still works as expected now.
> 
> And fast-GUP now fixed the potential race with THP collapse by checking
> whether PMD is changed or not.  So IPI broadcast in radix pmd collapse
> flush is not necessary anymore.  But it is still needed for hash TLB.
> 
> Suggested-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
> Signed-off-by: Yang Shi <shy828301@xxxxxxxxx>

Acked-by: Peter Xu <peterx@xxxxxxxxxx>

-- 
Peter Xu