Re: [PATCH 1/4] mm/damon: defensively skip zone device folios in damon_get_folio()

[SJ Park]

On Thu, 6 Aug 2026 12:05:00 -0500 Gregory Price <gourry@xxxxxxxxxx> wrote:

> On Thu, Aug 06, 2026 at 02:37:59PM +0100, Lorenzo Stoakes (ARM) wrote:
> > On Tue, Jul 28, 2026 at 03:47:11PM -0400, Gregory Price wrote:
> > > All DAMON physical- and virtual-address operations obtain their folios
> > > through damon_get_folio(). That helper already excludes ZONE_DEVICE
> > > memory implicitly via pfn_to_online_page() and folio_test_lru(), but
> > > this is inconsistent with other callers in mm/ which test explicitly.
> > >
> > > Add an explicit folio_is_zone_device() rejection in damon_get_folio()
> > > so the guarantee lives in one place and covers every caller uniformly,
> > > consistent with other mm walkers that reject zone device folios.
> > >
> > > Signed-off-by: Gregory Price (Meta) <gourry@xxxxxxxxxx>
> > 
> > Thanks, nice to make it explicit!
> > 
> > Acked-by: Lorenzo Stoakes (ARM) <ljs@xxxxxxxxxx>
> >
> 
> SJ Asked me to drop it,

I didn't asked you to drop this.  I asked your thought about revisioning this
for my concern.  And you replied [1] you can drop this.

I interprete it as a withdrawal, rather than being asked to be dropped.  My
dictionary is definitely not a good one, though.

Anyway, if your intention was not withdrawing, please feel free to push back
with the original change (explain me why my concern is wrong) or restart a
discussion for making DAMON code better in a way that can resolve both of our
concerns.

[1] https://lore.kernel.org/amoXZr2vB_q5q5Wu@gourry-fedora-PF4VCD3F


Thanks,
SJ

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