Subject: [PATCH v2 2/8] mm: vmalloc: don't account for number of nodes for HUGE_VMAP allocations

From: Mike Rapoport <[email-masked]>
Date: Mon, 26 Aug 2024 09:55:26 +0300

From: "Mike Rapoport (Microsoft)" <[email-masked]>

vmalloc allocations with VM_ALLOW_HUGE_VMAP that do not explicitly
specify node ID will use huge pages only if size_per_node is larger than
a huge page.
Still the actual allocated memory is not distributed between nodes and
there is no advantage in such approach.
On the contrary, BPF allocates SZ_2M * num_possible_nodes() for each
new bpf_prog_pack, while it could do with a single huge page per pack.

Don't account for number of nodes for VM_ALLOW_HUGE_VMAP with
NUMA_NO_NODE and use huge pages whenever the requested allocation size
is larger than a huge page.

Signed-off-by: Mike Rapoport (Microsoft) <[email-masked]>
---
 mm/vmalloc.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index af2de36549d6..d0fbe6b2b73c 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -3769,8 +3769,6 @@ void *__vmalloc_node_range_noprof(unsigned long size, unsigned long align,
 	}
 
 	if (vmap_allow_huge && (vm_flags & VM_ALLOW_HUGE_VMAP)) {
-		unsigned long size_per_node;
-
 		/*
 		 * Try huge pages. Only try for PAGE_KERNEL allocations,
 		 * others like modules don't yet expect huge pages in
@@ -3778,13 +3776,10 @@ void *__vmalloc_node_range_noprof(unsigned long size, unsigned long align,
 		 * supporting them.
 		 */
 
-		size_per_node = size;
-		if (node == NUMA_NO_NODE)
-			size_per_node /= num_online_nodes();
-		if (arch_vmap_pmd_supported(prot) && size_per_node >= PMD_SIZE)
+		if (arch_vmap_pmd_supported(prot) && size >= PMD_SIZE)
 			shift = PMD_SHIFT;
 		else
-			shift = arch_vmap_pte_supported_shift(size_per_node);
+			shift = arch_vmap_pte_supported_shift(size);
 
 		align = max(real_align, 1UL << shift);
 		size = ALIGN(real_size, 1UL << shift);
-- 
2.43.0