Re: [PATCH v9 14/41] mm: swap: Introduce lru_add_drain_progressive()

On 8/3/26 17:03, Sean Christopherson wrote:
> On Fri, Jul 31, 2026, David Hildenbrand (Arm) wrote:
>> I sent a fix for the GUP code that always makes us drain right now:
>>
>> https://lore.kernel.org/r/20260731-check_and_migrate_movable_folios-v1-1-e0002d7b791e@kernel.org
>>
>> Would the following (agains mm-unstable + fix) work for you?
>>
>>
>> I assume that you'd have to call it as
>>
>> 	lru_cache_drain_for_folio(folio, 0, NULL);
>>
>> But maybe there are indeed extra references that are not reflected in
>> folio_expected_ref_count() that you would have to consider? I doubt it, but please check if
>> there would be a problem.
>>
>> There is a small problem for merging:
>>
>> (1) The patch depends on the fix.
>>
>> (2) mm/swap.c was moved to mm/folio.c in the mm tree.
>>
>> We could write what I have below against Linus' tree and have the conflict be
>> resolved when merging. Topic branches are unfortunately not yet a thing in MM
>> land.
> 
> Are you expecting the aforementioned fix to land in 7.2, 7.3, or 7.4?  If it's

Andrew wants to give it some more time in -next, so I'm expecting it to land for 7.3.

> 7.2 or 7.3, then I would strongly prefer to base v10 on linux-next (where the fix
> will presumably land soonish), and target 7.4 for in-place conversion. Then v10> can be applied against an early 7.3-rcN and we don't need to juggle branches
> (assuming Andrew is ok taking the proposed patch through the KVM tree).

Agreed. We'd also have to get the actual preparation patch into 7.3. I can send it out
and coordinate with Andrew.

-- 
Cheers,

David