[PATCH v5 7/9] mm/mremap: Move TLB flush outside page table lock

[Aneesh Kumar K.V]

On 5/21/21 9:33 PM, Linus Torvalds wrote:
> On Fri, May 21, 2021 at 3:04 AM Aneesh Kumar K.V
> <aneesh.kumar at linux.ibm.com> wrote:
>>
>> We could do MOVE_PMD with something like below? A equivalent MOVE_PUD
>> will be costlier which makes me wonder whether we should even support that?
> 
> Well, without USE_SPLIT_PTE_PTLOCKS the pud case would be trivial too.
> But everybody uses split pte locks in practice.
> 

Ok I can get a patch series enabling MOVE_PUD only with 
SPLIT_PTE_PTLOCKS disabled.

> I get the feeling that the rmap code might have to use
> pud_lock/pmd_lock. I wonder how painful that would be.
> 

and work long term on that? The lock/unlocking can get complicated 
because the page_vma_walk now need to return all the held locks.


-aneesh