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Bodong Wang cd2a6e7d38 IB/core: Fix ib_wc structure size to remain in 64 bytes boundary
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: 7db20ecd1d ("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>
2018-01-15 15:33:21 -07:00
arch Merge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm 2017-12-03 10:51:08 -05:00
block Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-12-01 08:05:45 -05:00
certs
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2017-11-28 16:22:10 -08:00
Documentation hwmon fixes for v4.15-rc2 2017-12-03 10:46:16 -05:00
drivers IB/mlx4: Fix incorrectly releasing steerable UD QPs when have only ETH ports 2018-01-15 15:33:21 -07:00
firmware
fs NFS client fixes for Linux 4.15-rc2 2017-12-01 20:04:20 -05:00
include IB/core: Fix ib_wc structure size to remain in 64 bytes boundary 2018-01-15 15:33:21 -07:00
init
ipc Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
kernel Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-12-01 08:05:45 -05:00
lib RISC-V Cleanups and ABI Fixes for 4.15-rc2 2017-12-01 19:39:12 -05:00
mm Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-12-01 08:05:45 -05:00
net NFS client fixes for Linux 4.15-rc2 2017-12-01 20:04:20 -05:00
samples
scripts Merge branch 'akpm' (patches from Andrew) 2017-11-29 19:12:44 -08:00
security bug fixes: 2017-11-30 18:56:41 -05:00
sound Revert "ALSA: usb-audio: Fix potential zero-division at parsing FU" 2017-11-28 09:34:36 -08:00
tools Power management fixes for v4.15-rc2 2017-11-30 18:45:55 -05:00
usr
virt * x86 bugfixes: APIC, nested virtualization, IOAPIC 2017-11-30 08:15:19 -08:00
.cocciconfig
.get_maintainer.ignore
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MAINTAINERS rdma: Update maintainer contact for Intel RDMA drivers 2017-12-22 13:33:30 -07:00
Makefile Linux 4.15-rc2 2017-12-03 11:01:47 -05:00
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
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There are various text files in the Documentation/ subdirectory,
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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
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the problems which may result by upgrading your kernel.