This is a note to let you know that I've just added the patch titled
IB/core: Fix ib_wc structure size to remain in 64 bytes boundary
to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: ib-core-fix-ib_wc-structure-size-to-remain-in-64-bytes-boundary.patch and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From cd2a6e7d384b043d5d029e39663061cebc949385 Mon Sep 17 00:00:00 2001
From: Bodong Wang bodong@mellanox.com Date: Fri, 12 Jan 2018 07:58:41 +0200 Subject: IB/core: Fix ib_wc structure size to remain in 64 bytes boundary
From: Bodong Wang bodong@mellanox.com
commit cd2a6e7d384b043d5d029e39663061cebc949385 upstream.
The change of slid from u16 to u32 results in sizeof(struct ib_wc) cross 64B boundary, which causes more cache misses. This patch rearranges the fields and remain the size to 64B.
Pahole output before this change:
struct ib_wc { union { u64 wr_id; /* 8 */ struct ib_cqe * wr_cqe; /* 8 */ }; /* 0 8 */ enum ib_wc_status status; /* 8 4 */ enum ib_wc_opcode opcode; /* 12 4 */ u32 vendor_err; /* 16 4 */ u32 byte_len; /* 20 4 */ struct ib_qp * qp; /* 24 8 */ union { __be32 imm_data; /* 4 */ u32 invalidate_rkey; /* 4 */ } ex; /* 32 4 */ u32 src_qp; /* 36 4 */ int wc_flags; /* 40 4 */ u16 pkey_index; /* 44 2 */
/* XXX 2 bytes hole, try to pack */
u32 slid; /* 48 4 */ u8 sl; /* 52 1 */ u8 dlid_path_bits; /* 53 1 */ u8 port_num; /* 54 1 */ u8 smac[6]; /* 55 6 */
/* XXX 1 byte hole, try to pack */
u16 vlan_id; /* 62 2 */ /* --- cacheline 1 boundary (64 bytes) --- */ u8 network_hdr_type; /* 64 1 */
/* size: 72, cachelines: 2, members: 17 */ /* sum members: 62, holes: 2, sum holes: 3 */ /* padding: 7 */ /* last cacheline: 8 bytes */ };
Pahole output after this change:
struct ib_wc { union { u64 wr_id; /* 8 */ struct ib_cqe * wr_cqe; /* 8 */ }; /* 0 8 */ enum ib_wc_status status; /* 8 4 */ enum ib_wc_opcode opcode; /* 12 4 */ u32 vendor_err; /* 16 4 */ u32 byte_len; /* 20 4 */ struct ib_qp * qp; /* 24 8 */ union { __be32 imm_data; /* 4 */ u32 invalidate_rkey; /* 4 */ } ex; /* 32 4 */ u32 src_qp; /* 36 4 */ u32 slid; /* 40 4 */ int wc_flags; /* 44 4 */ u16 pkey_index; /* 48 2 */ u8 sl; /* 50 1 */ u8 dlid_path_bits; /* 51 1 */ u8 port_num; /* 52 1 */ u8 smac[6]; /* 53 6 */
/* XXX 1 byte hole, try to pack */
u16 vlan_id; /* 60 2 */ u8 network_hdr_type; /* 62 1 */
/* size: 64, cachelines: 1, members: 17 */ /* sum members: 62, holes: 1, sum holes: 1 */ /* padding: 1 */ };
Fixes: 7db20ecd1d97 ("IB/core: Change wc.slid from 16 to 32 bits") Signed-off-by: Bodong Wang bodong@mellanox.com Reviewed-by: Parav Pandit parav@mellanox.com Signed-off-by: Leon Romanovsky leon@kernel.org Signed-off-by: Jason Gunthorpe jgg@mellanox.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- include/rdma/ib_verbs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/include/rdma/ib_verbs.h +++ b/include/rdma/ib_verbs.h @@ -971,9 +971,9 @@ struct ib_wc { u32 invalidate_rkey; } ex; u32 src_qp; + u32 slid; int wc_flags; u16 pkey_index; - u32 slid; u8 sl; u8 dlid_path_bits; u8 port_num; /* valid only for DR SMPs on switches */
Patches currently in stable-queue which might be from bodong@mellanox.com are
queue-4.14/ib-core-fix-ib_wc-structure-size-to-remain-in-64-bytes-boundary.patch