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

[Sean Christopherson <seanjc@google.com>]

On Tue, Aug 04, 2026, Ackerley Tng wrote:
> "David Hildenbrand (Arm)" <david@kernel.org> writes:
> > 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.
> >
> 
> Thank you!
> 
> When we were discussing this earlier at guest_memfd biweekly, before
> deciding to refactor out a function like lru_cache_drain_for_folio(), we
> did say that the likelihood of actually draining in practice is low,
> especially on a machine with heavy load making allocations all the time.
> 
> I think the threads with Xiaoyao have resolved, I can put v10 out
> tomorrow. Would it be okay to go with the following from v8, and then
> clean up later when lru_cache_drain_for_folio() is available?

No.

> I'm hoping not to push this back by a full cycle to 7.4,
 
Sorry, but we've missed 7.3, irrespective of the lru_cache_drain_for_folio() fix.
Even if v10 is perfect, applying tomorrow means it will get ~3 business days in
linux-next before I send pull requests to Paolo.  That's just not enough soak
time for land a 40+ patch series, even if half of those patches are selftests.

> and also hold back other series dependent on this one.

Eh, I don't think there will be meaningful impact in practice.  If v10 is good
to go, I'll get it applied on 7.3-r1, and will also get an early pull request
over to Paolo (probably around 7.3-rc4).  I.e. folks can start posting against
the landed series shortly after rc1, and I'll have a set-in-stone base on which
to apply more stuff around rc4/rc5.

And if v10 has issues, then *not* rushing it into 7.3 will likely be the fastest
path forward.