[RFC PATCH v2 05/11] mm: shmem: run khugepaged for all shmem mTHP orders

[Baolin Wang]

When only non-PMD-sized mTHP is enabled (such as only 64K mTHP enabled),
we should also allow kicking khugepaged to attempt scanning and collapsing
64K shmem mTHP. Modify shmem_hpage_pmd_enabled() to support shmem mTHP
collapse, and while we are at it, rename it to make the function name
more clear.

Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
---
 include/linux/shmem_fs.h |  4 ++--
 mm/khugepaged.c          |  2 +-
 mm/shmem.c               | 10 +++++-----
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index acb8dd961b45..1ec358b40c9b 100644
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -131,7 +131,7 @@ int shmem_unuse(unsigned int type);
 unsigned long shmem_allowable_huge_orders(struct inode *inode,
 				struct vm_area_struct *vma, pgoff_t index,
 				loff_t write_end, bool shmem_huge_force);
-bool shmem_hpage_pmd_enabled(void);
+bool shmem_hpage_enabled(void);
 #else
 static inline unsigned long shmem_allowable_huge_orders(struct inode *inode,
 				struct vm_area_struct *vma, pgoff_t index,
@@ -140,7 +140,7 @@ static inline unsigned long shmem_allowable_huge_orders(struct inode *inode,
 	return 0;
 }
 
-static inline bool shmem_hpage_pmd_enabled(void)
+static inline bool shmem_hpage_enabled(void)
 {
 	return false;
 }
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 818d51915748..75b18ec4a6c3 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -532,7 +532,7 @@ static bool hugepage_enabled(void)
 		return true;
 	if (anon_hpage_enabled())
 		return true;
-	if (shmem_hpage_pmd_enabled())
+	if (shmem_hpage_enabled())
 		return true;
 	return false;
 }
diff --git a/mm/shmem.c b/mm/shmem.c
index 56c23a7b15c7..a8d30a123b1f 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1792,17 +1792,17 @@ static struct folio *shmem_swapin_cluster(swp_entry_t swap, gfp_t gfp,
 }
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-bool shmem_hpage_pmd_enabled(void)
+bool shmem_hpage_enabled(void)
 {
 	if (shmem_huge == SHMEM_HUGE_DENY)
 		return false;
-	if (test_bit(HPAGE_PMD_ORDER, &huge_shmem_orders_always))
+	if (READ_ONCE(huge_shmem_orders_always))
 		return true;
-	if (test_bit(HPAGE_PMD_ORDER, &huge_shmem_orders_madvise))
+	if (READ_ONCE(huge_shmem_orders_madvise))
 		return true;
-	if (test_bit(HPAGE_PMD_ORDER, &huge_shmem_orders_within_size))
+	if (READ_ONCE(huge_shmem_orders_within_size))
 		return true;
-	if (test_bit(HPAGE_PMD_ORDER, &huge_shmem_orders_inherit) &&
+	if (READ_ONCE(huge_shmem_orders_inherit) &&
 	    shmem_huge != SHMEM_HUGE_NEVER)
 		return true;
 
-- 
2.47.3