On 07.01.25 04:42, Alistair Popple wrote:
The rmap doesn't currently support adding a PUD mapping of a
folio. This patch adds support for entire PUD mappings of folios,
primarily to allow for more standard refcounting of device DAX
folios. Currently DAX is the only user of this and it doesn't require
support for partially mapped PUD-sized folios so we don't support for
that for now.
Signed-off-by: Alistair Popple <apopple@xxxxxxxxxx>
---
Changes for v5:
- Fixed accounting as suggested by David.
Changes for v4:
- New for v4, split out rmap changes as suggested by David.
---
include/linux/rmap.h | 15 ++++++++++-
mm/rmap.c | 65 ++++++++++++++++++++++++++++++++++++++++++---
2 files changed, 76 insertions(+), 4 deletions(-)
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 683a040..7043914 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -192,6 +192,7 @@ typedef int __bitwise rmap_t;
enum rmap_level {
RMAP_LEVEL_PTE = 0,
RMAP_LEVEL_PMD,
+ RMAP_LEVEL_PUD,
};
static inline void __folio_rmap_sanity_checks(const struct folio *folio,
@@ -228,6 +229,14 @@ static inline void __folio_rmap_sanity_checks(const struct folio *folio,
VM_WARN_ON_FOLIO(folio_nr_pages(folio) != HPAGE_PMD_NR, folio);
VM_WARN_ON_FOLIO(nr_pages != HPAGE_PMD_NR, folio);
break;
+ case RMAP_LEVEL_PUD:
+ /*
+ * Assume that we are creating * a single "entire" mapping of the
+ * folio.
Misplaced " *", can likely be fixed up when applying.
Apart from that LGTM
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
--
Cheers,
David / dhildenb
