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b=bMs9RZNCuFCGpxMnuN/GlcJjkXynXrV0LclIUQD6JvPK5QrSyTBQJTqUF7+TVW6FO 1K6z3hMAOA099qVd5GR6tSZjx8FS/X+8lBZ0/AKAYK7ucrziX4+PuEoE80THntxuv/ TWHocyxmoUw4hOODVAZGbvUGeKk/JYZgzhdD45h8/FyxUgYRW7m/BKkgL54bPfKj6u EfPE8kCQlMS8f7unbRmZMB3/eGv1hSRzv8p2/iyQRpRNe+A6xO/ZBBBYt2GyLBO/dI GaO558pnhFY4zgrgplFktxr/jxQNTn7H5CDgLwqFJuRiUyz6PEVLR6PTunViHie0Jm KQGFkf8cvD1DA== Date: Thu, 13 Aug 2026 09:28:19 +0100 From: "Lorenzo Stoakes (ARM)" To: Gregory Price Cc: SJ Park , 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() Message-ID: References: <20260807000938.79851-1-sj@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 1E3F740004 X-Stat-Signature: mwxkiszaajgxempj9grce5qxzyhod5ha X-Rspam-User: X-HE-Tag: 1786609723-728172 X-HE-Meta: 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 oeWW9709 FBqW+zXRE7zpa7NYLkFc+hRBZj/ikpgCOoZzSoLGepKGHeb5a5wY6X6Jct+WdbmqV0QUuEEozK/KtuFa3wXhOipcgyh4GnTVcARZOldUj82oD8zgWewjch8mpPjWPoG9t/+4lUVPlJHZrd6IPZo2x1hyoYNm2bEFk0xAtfSabY5aErk1TdTkEh58KBno7QohUlBehaLSLZxzFfL1XVdWRl3WJ/cDf/ROA54XQzE0ejaK93U2D/62mWt8jK560+mHSh3ZERLGDPNCscgpzPAWiTk+3urJ3xn0TBCnMK0mqdCuf9i6b3E0dxji+VOBLadBrk3ObiRFo+b+orWfcO7zMYgMMKVQK1PQlgeHuT2ga6895NgvARxU/HAXafUiNqKPevLDyFswUf0xC74z6D/zvZGcpWnWaEq6neZsoPnDIj4Hlf/RRlGD6ODFjKzM3iO81Q5DfUe6JAuL0kno= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Aug 12, 2026 at 10:26:08PM -0400, Gregory Price wrote: > On Thu, Aug 06, 2026 at 05:09:37PM -0700, SJ Park wrote: > > 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. > > > > Sorry I didn't mean to imply you pushed for one side or another, just > that the feedback you gave about not wanting dead code is reason enough > to drop it. > > I will probably just go ahead and drop it unless Lorenzo thinks the > patch is worth keeping. In my next private node iteration, it ends up > back in anyway - so we get a two for one without the intermediate patch. Yeah it's damon code so if SJ isn't happy let's drop it for now and we can revisit later! > > ~Gregory -- Cheers, Lorenzo