Re: [PATCH v2] mm/ksm: keep soft-dirty and uffd-wp when merging a page

[Lance Yang <lance.yang@linux.dev>]

Hi Samarth,

Could you send a v3 with just the soft-dirty fix, as David
suggested? Leave the uffd-wp/RWP bits to me (I'll take
a closer look).

On 2026/10/21 17:49, Lance Yang wrote:
> 
> 
> On 2026/10/21 16:55, Kiryl Shutsemau wrote:
>> On Wed, Oct 21, 2026 at 10:21:53AM +0200, David Hildenbrand (Arm) wrote:
>>>> +1. Did it ever actually work there :) Why not just skip them and
>>>> call it a day :D
>>>
>>> I think QEMU just always sets MADV_MERGABLE and later activates uffd. 
>>> So that
>>> needs some care to not disable them. So let's rather try to get it 
>>> fixed properly.
>>>
>>> Can you send out proper patches? Thanks!
> 
> Thanks David! Will take it over next week and get proper patches out :)
> 
>>
>> +1.
>>
>> Lance's direction is right. Unsharing is not an access: do_wp_page()
>> already skips the uffd-wp fault on FAULT_FLAG_UNSHARE, and RWP should do
>> the same.
> 
> Thanks Kiryl! Will take a close look at that :)
> 
> Cheers, Lance
>