[PATCH net-next v3 1/5] xdp: reduce size of struct xdp_mem_info
From: Matteo Croce <hidden>
Date: 2021-04-09 22:38:26
Also in:
bpf, linux-mm, linux-rdma, lkml
Subsystem:
networking [general], the rest, xdp (express data path) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Alexei Starovoitov, Daniel Borkmann, David S. Miller, Jesper Dangaard Brouer, John Fastabend
From: Jesper Dangaard Brouer <redacted> It is possible to compress/reduce the size of struct xdp_mem_info. This change reduce struct xdp_mem_info from 8 bytes to 4 bytes. The member xdp_mem_info.id can be reduced to u16, as the mem_id_ht rhashtable in net/core/xdp.c is already limited by MEM_ID_MAX=0xFFFE which can safely fit in u16. The member xdp_mem_info.type could be reduced more than u16, as it stores the enum xdp_mem_type, but due to alignment it is only reduced to u16. Signed-off-by: Jesper Dangaard Brouer <redacted> --- include/net/xdp.h | 4 ++-- net/core/xdp.c | 8 ++++---- 2 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/include/net/xdp.h b/include/net/xdp.h
index a5bc214a49d9..c35864d59113 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h@@ -48,8 +48,8 @@ enum xdp_mem_type { #define XDP_XMIT_FLAGS_MASK XDP_XMIT_FLUSH struct xdp_mem_info { - u32 type; /* enum xdp_mem_type, but known size type */ - u32 id; + u16 type; /* enum xdp_mem_type, but known size type */ + u16 id; }; struct page_pool;
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 05354976c1fc..3dd47ed83778 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c@@ -35,11 +35,11 @@ static struct rhashtable *mem_id_ht; static u32 xdp_mem_id_hashfn(const void *data, u32 len, u32 seed) { - const u32 *k = data; - const u32 key = *k; + const u16 *k = data; + const u16 key = *k; BUILD_BUG_ON(sizeof_field(struct xdp_mem_allocator, mem.id) - != sizeof(u32)); + != sizeof(u16)); /* Use cyclic increasing ID as direct hash key */ return key;
@@ -49,7 +49,7 @@ static int xdp_mem_id_cmp(struct rhashtable_compare_arg *arg, const void *ptr) { const struct xdp_mem_allocator *xa = ptr; - u32 mem_id = *(u32 *)arg->key; + u16 mem_id = *(u16 *)arg->key; return xa->mem.id != mem_id; }
--
2.30.2