[PATCH v4 4/8] mm: Introduce pure page table freeing function

Lu Baolu
2025-09-05T05:53:31Z

From: Dave Hansen <dave.hansen@linux.intel.com>

The pages used for ptdescs are currently freed back to the allocator
in a single location. They will shortly be freed from a second
location.

Create a simple helper that just frees them back to the allocator.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
include/linux/mm.h | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index f3db3a5ebefe..668d519edc0f 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2884,6 +2884,13 @@ static inline struct ptdesc *pagetable_alloc_noprof(gfp_t gfp, unsigned int orde
}
#define pagetable_alloc(...) alloc_hooks(pagetable_alloc_noprof(__VA_ARGS__))

+static inline void __pagetable_free(struct ptdesc *pt)
+{
+ struct page *page = ptdesc_page(pt);
+
+ __free_pages(page, compound_order(page));
+}
+
/**
* pagetable_free - Free pagetables
* @pt: The page table descriptor
@@ -2893,12 +2900,10 @@ static inline struct ptdesc *pagetable_alloc_noprof(gfp_t gfp, unsigned int orde
*/
static inline void pagetable_free(struct ptdesc *pt)
{
- struct page *page = ptdesc_page(pt);
-
if (ptdesc_test_kernel(pt))
ptdesc_clear_kernel(pt);

- __free_pages(page, compound_order(page));
+ __pagetable_free(pt);
}

#if defined(CONFIG_SPLIT_PTE_PTLOCKS)
--
2.43.0