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From: Mike Rapoport <rppt@kernel.org>
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Subject: [RFC PATCH 2/7] mm: vmalloc: don't account for number of nodes for HUGE_VMAP allocations
Date: Thu, 11 Apr 2024 19:05:21 +0300
Message-ID: <20240411160526.2093408-3-rppt@kernel.org>
In-Reply-To: <20240411160526.2093408-1-rppt@kernel.org>
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From: "Mike Rapoport (IBM)" <rppt@kernel.org>

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

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 PMD_SIZE.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 mm/vmalloc.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 22aa63f4ef63..5fc8b514e457 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -3737,8 +3737,6 @@ void *__vmalloc_node_range(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
@@ -3746,13 +3744,10 @@ void *__vmalloc_node_range(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