Re: [PATCH mm-unstable v1 2/3] mm/migrate.c: Prevent folio splitting from interacting with KSM

[David Hildenbrand (Arm)]

On 7/29/26 18:54, Nico Pache wrote:
> On Tue, Jul 21, 2026 at 8:02 AM David Hildenbrand (Arm)
> <david@xxxxxxxxxx> wrote:
>>
>> On 7/20/26 17:28, Nico Pache wrote:
>>> On Wed, Jul 15, 2026 at 3:30 AM David Hildenbrand (Arm)
>>> <david@xxxxxxxxxx> wrote:
>>>
>>> this series (v1) would be "dont scan VM_MERGEABLE entries when KSM is running"
>>>
>>> It stops all VM_MEREABLE entries from being candidates, while the V2 I
>>> would like to propose goes back to my RFC's alternative solution
>>> a ) "skip zeropage remapping if the split comes from KSM"
>>>
>>> I think (a) is better than V1 as it doesnt indiscriminately target all
>>> VM_MERGEABLE mapping but rather those that are triggering the issue
>>> (the split).
>>
>> Not sure. There could be anything else in the system triggering the split before
>> KSM comes around.
>>
>> So v1 just cleanly separates them, independent who triggers the split.
> 
> Yes but now all VM_MERGEABLEs lose the underutilized shrinker
> independent from weather KSM was the one who triggered it. 

Because KSM takes care of it?

What am I missing?

-- 
Cheers,

David