cd2a6e7d38
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 */
};
Cc: <stable@vger.kernel.org> # v4.13
Fixes:
|
||
|---|---|---|
| Documentation | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.