[PATCH v7 2/8] mm: vmalloc: don't account for number of nodes for HUGE_VMAP allocations

Mike Rapoport
2024-10-23T16:28:09Z

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

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) <rppt@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Tested-by: kdevops <kdevops@lists.linux.dev>
---
mm/vmalloc.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 634162271c00..86b2344d7461 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -3763,8 +3763,6 @@ 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
@@ -3772,13 +3770,10 @@ 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