[PATCH 04/19] mm: Allow THP orders for PFNMAPs

Peter Xu
2024-08-09T16:09:26Z

This enables PFNMAPs to be mapped at either pmd/pud layers. Generalize the
dax case into vma_is_special_huge() so as to cover both. Meanwhile, rename
the macro to THP_ORDERS_ALL_SPECIAL.

Cc: Matthew Wilcox <willy@infradead.org>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
include/linux/huge_mm.h | 6 +++---
mm/huge_memory.c | 4 ++--
2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 2121060232ce..984cbc960d8b 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -76,9 +76,9 @@ extern struct kobj_attribute thpsize_shmem_enabled_attr;
/*
* Mask of all large folio orders supported for file THP. Folios in a DAX
* file is never split and the MAX_PAGECACHE_ORDER limit does not apply to
- * it.
+ * it. Same to PFNMAPs where there's neither page* nor pagecache.
*/
-#define THP_ORDERS_ALL_FILE_DAX \
+#define THP_ORDERS_ALL_SPECIAL \
(BIT(PMD_ORDER) | BIT(PUD_ORDER))
#define THP_ORDERS_ALL_FILE_DEFAULT \
((BIT(MAX_PAGECACHE_ORDER + 1) - 1) & ~BIT(0))
@@ -87,7 +87,7 @@ extern struct kobj_attribute thpsize_shmem_enabled_attr;
* Mask of all large folio orders supported for THP.
*/
#define THP_ORDERS_ALL \
- (THP_ORDERS_ALL_ANON | THP_ORDERS_ALL_FILE_DAX | THP_ORDERS_ALL_FILE_DEFAULT)
+ (THP_ORDERS_ALL_ANON | THP_ORDERS_ALL_SPECIAL | THP_ORDERS_ALL_FILE_DEFAULT)

#define TVA_SMAPS (1 << 0) /* Will be used for procfs */
#define TVA_IN_PF (1 << 1) /* Page fault handler */
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index e95b3a468aee..6568586b21ab 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -95,8 +95,8 @@ unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma,
/* Check the intersection of requested and supported orders. */
if (vma_is_anonymous(vma))
supported_orders = THP_ORDERS_ALL_ANON;
- else if (vma_is_dax(vma))
- supported_orders = THP_ORDERS_ALL_FILE_DAX;
+ else if (vma_is_special_huge(vma))
+ supported_orders = THP_ORDERS_ALL_SPECIAL;
else
supported_orders = THP_ORDERS_ALL_FILE_DEFAULT;

--
2.45.0