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b=BtbvyL6ZMna8HAKgywO+rmaE4EQ85ji20cRsyI/3rtd1ai4+PCGAzcDE93xIF5Q01 B5BPh1oT4iTNs4IeHq+V7rWpXGIUqY9UjANEHMscGd2ARRJs1f4bClCc2IVrjqyexY XUXyEamjhpdN2aKu6SGIKd3aPS6x7dmhedDRHgcR6tOCY0ra90pVNPjCvTQqxHeMir gEt5KBBtiAUiewgz9RD3+3mEMLIayqTrYkKPPkkL1BF38WsWPh6O16xDd7F4uYAqJN AYVP6E380raZ6o6msbOO9O48SiLrGXWXY+fzM+hCHndtqKax52BIy8rtMAca2XtbwA MfiLBnnWXt7UA== From: SJ Park To: Gregory Price Cc: SJ Park , "Lorenzo Stoakes (ARM)" , linux-mm@kvack.org, damon@lists.linux.dev, linux-kernel@vger.kernel.org, kernel-team@meta.com, akpm@linux-foundation.org, david@kernel.org, ziy@nvidia.com, baolin.wang@linux.alibaba.com, liam@infradead.org, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, usama.arif@linux.dev, vbabka@kernel.org, jannh@google.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, ying.huang@linux.alibaba.com, apopple@nvidia.com Subject: Re: [PATCH 1/4] mm/damon: defensively skip zone device folios in damon_get_folio() Date: Thu, 6 Aug 2026 17:09:37 -0700 Message-ID: <20260807000938.79851-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 7A7501C000E X-Rspamd-Server: rspam10 X-Rspam-User: X-Stat-Signature: a4qfpasufzytus996dncuq3tho83qxs6 X-HE-Tag: 1786061382-284452 X-HE-Meta: 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 2LPufhvO it4/KrWHVhSd6prmzFyUhXjXxkpLtn3Iyd6Kwoh73mHfany7qX6o1CC/xN/F+yVLZxaxVSBi0Hxx2VvqVyMHqjttsmAlwtbe6MWAv355PEBn9XHfebYqNS9PkV9xNKarKo+3714oPqnKtNF1r+G7toE03LSyAgLTedUgnnBLakjrCQ8OiGzkKhX0mJv1Imb42voRoxpaLnffizj4Z87o8/YIks/4Mq71SMvS7e1u364JzOhEJHQw0PMW2Arzd4+2BVKEvfof4nx3PICc5KxNPOlSDNq2YUn7CwiWE7zQFcKHi71mu5I9VTpcrvJZcr+YCEmd7thRyGrxIDkTvwCaa0ojgOftfdg9Lvqw3VcrSMtMZLTcP8CvWT+64DcYD7aJ3ex9uSxrXuF2rWDCxDLXhbujeM+oTIJGnNpeO Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, 6 Aug 2026 12:05:00 -0500 Gregory Price 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) > > > > Thanks, nice to make it explicit! > > > > Acked-by: Lorenzo Stoakes (ARM) > > > > 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 [...]