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charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 0E6E21C000F X-Stat-Signature: jxy67pkzr1hx111rqy1y9qas3xsuttqd X-HE-Tag: 1714139401-947571 X-HE-Meta: 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 cFk5jyTz /gRP1GrlCOTbnP3hn4CrUVjpCgMfFyLPZ4D+DxOohpZKifpVpFWaETUn/5w== X-Bogosity: Ham, tests=bogofilter, spamicity=0.007442, 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 Fri, Apr 26, 2024 at 2:42=E2=80=AFAM David Hildenbrand wrote: > > On 26.04.24 05:43, Pasha Tatashin wrote: > > Changelog > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > v2: Use mapcount instead of refcount > > Synchronized with IOMMU Observability changes. > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > > > This series frees empty page tables on unmaps. It intends to be a > > low overhead feature. > > > > The read-writer lock is used to synchronize page table, but most of > > time the lock is held is reader. It is held as a writer for short > > period of time when unmapping a page that is bigger than the current > > iova request. For all other cases this lock is read-only. > > > > page->mapcount is used in order to track number of entries at each page > > table. > > I'm wondering if this will conflict with page_type at some point? We're > already converting other page table users to ptdesc. CCing Willy. Hi David, This contradicts with the following comment in mm_types.h: * If your page will not be mapped to userspace, you can also use the four * bytes in the mapcount union, but you must call page_mapcount_reset() * before freeing it. Thank you, Pasha