On Wed, Oct 16, 2024 at 03:24:18PM +0300, Mike Rapoport wrote:
From: "Mike Rapoport (Microsoft)" <rppt@xxxxxxxxxx>
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@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
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);
Looking at this place, i see that an overwriting a "size" approach seems as
something that is a bit hard to follow. Below we have following code:
<snip>
...
again:
area = __get_vm_area_node(real_size, align, shift, VM_ALLOC |
VM_UNINITIALIZED | vm_flags, start, end, node,
gfp_mask, caller);
...
<snip>
where we pass a "real_size", whereas there is only one place in the
__vmalloc_node_range_noprof() function where a "size" is used. It is
in the end of function:
<snip>
...
size = PAGE_ALIGN(size);
if (!(vm_flags & VM_DEFER_KMEMLEAK))
kmemleak_vmalloc(area, size, gfp_mask);
return area->addr;
<snip>
As fro this patch:
Reviewed-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
--
Uladzislau Rezki
