diff mbox series

[bpf-next,v3,1/6] bpf: Avoid unnecessary extra percpu memory allocation

Message ID 20231216023010.3739758-1-yonghong.song@linux.dev (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series bpf: Reduce memory usage for bpf_global_percpu_ma | expand

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netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1122 this patch: 1122
netdev/cc_maintainers warning 7 maintainers not CCed: kpsingh@kernel.org haoluo@google.com martin.lau@linux.dev jolsa@kernel.org sdf@google.com song@kernel.org john.fastabend@gmail.com
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Commit Message

Yonghong Song Dec. 16, 2023, 2:30 a.m. UTC 
Currently, for percpu memory allocation, say if the user
requests allocation size to be 32 bytes, the actually
calculated size will be 40 bytes and it further rounds
to 64 bytes, and eventually 64 bytes are allocated,
wasting 32-byte memory.

Change bpf_mem_alloc() to calculate the cache index
based on the user-provided allocation size so unnecessary
extra memory can be avoided.

Suggested-by: Hou Tao <houtao1@huawei.com>
Acked-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
---
 kernel/bpf/memalloc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c
index 6a51cfe4c2d6..00e101c2a68b 100644
--- a/kernel/bpf/memalloc.c
+++ b/kernel/bpf/memalloc.c
@@ -871,7 +871,9 @@  void notrace *bpf_mem_alloc(struct bpf_mem_alloc *ma, size_t size)
 	if (!size)
 		return ZERO_SIZE_PTR;
 
-	idx = bpf_mem_cache_idx(size + LLIST_NODE_SZ);
+	if (!ma->percpu)
+		size += LLIST_NODE_SZ;
+	idx = bpf_mem_cache_idx(size);
 	if (idx < 0)
 		return NULL;