Re: [PATCH] mm/gup: Drain batched mlock folio processing before attempting migration

[Will Deacon]

On Fri, Aug 29, 2025 at 12:57:43PM +0100, Will Deacon wrote:
> On Thu, Aug 28, 2025 at 01:47:14AM -0700, Hugh Dickins wrote:
> > Patch is against 6.17-rc3; but if you'd prefer the patch against 6.12
> > (or an intervening release), I already did the backport so please just
> > ask.
> 
> We've got 6.15 working well at the moment, so I'll backport your diff
> to that.

Notwithstanding my question about the synchronisation, I cherry-picked
86ebd50224c0 ("mm: add folio_expected_ref_count() for reference count
calculation") to my 6.15-based Android tree and applied your diff on top.

With that, I've not managed to reproduce the original failure and
haven't observed any migration failures on the GUP path.

Cheers,

Will