[PATCH v3 2/4] mm/vmalloc: Add a helper to optimize vmalloc allocation gfps

Vishal Moola (Oracle)
2025-11-17T17:37:33Z

vm_area_alloc_pages() attempts to use different gfp flags as a way
to optimize allocations. This has been done inline which makes things
harder to read.

Add a helper function to make the code more readable.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
---
mm/vmalloc.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 5dc467c6cab4..0929f4f53ffe 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -3614,6 +3614,17 @@ void *vmap_pfn(unsigned long *pfns, unsigned int count, pgprot_t prot)
EXPORT_SYMBOL_GPL(vmap_pfn);
#endif /* CONFIG_VMAP_PFN */

+/*
+ * Helper for vmalloc to adjust the gfp flags for certain allocations.
+ */
+static inline gfp_t vmalloc_gfp_adjust(gfp_t flags, const bool large)
+{
+ flags |= __GFP_NOWARN;
+ if (large)
+ flags &= ~__GFP_NOFAIL;
+ return flags;
+}
+
static inline unsigned int
vm_area_alloc_pages(gfp_t gfp, int nid,
unsigned int order, unsigned int nr_pages, struct page **pages)
@@ -3852,9 +3863,9 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
* Please note, the __vmalloc_node_range_noprof() falls-back
* to order-0 pages if high-order attempt is unsuccessful.
*/
- area->nr_pages = vm_area_alloc_pages((page_order ?
- gfp_mask & ~__GFP_NOFAIL : gfp_mask) | __GFP_NOWARN,
- node, page_order, nr_small_pages, area->pages);
+ area->nr_pages = vm_area_alloc_pages(
+ vmalloc_gfp_adjust(gfp_mask, page_order), node,
+ page_order, nr_small_pages, area->pages);

atomic_long_add(area->nr_pages, &nr_vmalloc_pages);
/* All pages of vm should be charged to same memcg, so use first one. */
--
2.51.1