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Mercier" , Isaac Manjarres Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: x9ayq16jiowg5c7rrcwd7djw64ujfsus X-Rspam-User: X-Rspamd-Queue-Id: CE0D140005 X-Rspamd-Server: rspam02 X-HE-Tag: 1754517292-339873 X-HE-Meta: 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 5lj9+KHO DjLcVEx5+bOSYrIB+ReV88XBHIbJ/hihDkvg/jYJRwceock5z2DmR7aUR4uenTNtEVQ++M3Huiq1dFNHYnxyjusCS8CvJ6x2jVGjBjv2LqN785mJGsa38oXE3kYgBhi4osyLEb0Fl21VofMQW0S0SHyV2MzNlVkTJaPFU58GTBXFj7DIM2xaOn9q7UE4ymm51vBxCrkxc+6mnQIFh/bfVU542eZN9FG8vRrpBFu1RUObvfNpkjg5NA621WRHthg9/QBjzpVkTm9ozU91je/QvzOUUGdIY6NQ9Zop7hXvypDi8gaGqiJoy7vjP5MJEKgoUl5JcElADSIqPggafWdKMwP/KFlLeolmIE9hEWDdV59drISW1Z+6oKJ9VTlVx+1aFWp7NvlGC/W7LzEc= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Aug 5, 2025 at 2:09=E2=80=AFPM Vlastimil Babka wro= te: > > On 8/5/25 19:12, Juan Yescas wrote: > > On Tue, Aug 5, 2025 at 2:52=E2=80=AFAM Vlastimil Babka = wrote: > >> > >> > > >> > Thanks David for the quick overview. > >> > > >> >> I still have no clue what this patch here tried to solve: it doesn'= t > >> >> make any sense. > >> >> > >> > > >> > The story started with this out of tree patch that is part of Androi= d. > >> > > >> > https://lore.kernel.org/lkml/cover.1604282969.git.cgoldswo@codeauror= a.org/T/#u > >> > > >> > This patch introduced the __GFP_CMA flag that allocates pages from > >> > MIGRATE_MOVABLE > >> > or MIGRATE_CMA. > >> > >> What kinds of allocations would then use __GFP_CMA? > > > > The __GFP_CMA allocations are used to allocate userspace anonymous memo= ry. This > > was done initially in the alloc_zeroed_user_highpage_movable() > > function, now it is done > > in vma_alloc_zeroed_movable_folio(). > > So that means you perceive the risk of anonymous memory being temporarily > pinned and thwarting a alloc_contig_pages() device CMA allocation lower t= han > for file pages? The pinning can be a gup(), or a compaction migrating the > page, etc... > I think that was the assumption when the patches were sent :( >