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    SubjectRe: [LKP] [mm] 3484b2de949: -46.2% aim7.jobs-per-min
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    On Fri, 2015-02-27 at 11:53 +0000, Mel Gorman wrote:
    > On Fri, Feb 27, 2015 at 03:21:36PM +0800, Huang Ying wrote:
    > > FYI, we noticed the below changes on
    > >
    > > git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
    > > commit 3484b2de9499df23c4604a513b36f96326ae81ad ("mm: rearrange zone fields into read-only, page alloc, statistics and page reclaim lines")
    > >
    > > The perf cpu-cycles for spinlock (zone->lock) increased a lot. I suspect there are some cache ping-pong or false sharing.
    > >
    >
    > Annoying because this is pretty much the opposite of what I found during
    > testing. What is the kernel config? Similar to the kernel config, can you
    > post "pahole -C zone vmlinux" for the kernel you built? I should get the same
    > result if I use the same kernel config but no harm in being sure. Thanks.

    The output of pahole -C zone vmlinux for the kernels are as below.

    Best Regards,
    Huang, Ying

    3484b2de94
    -------------------------------------------------------
    struct zone {
    long unsigned int watermark[3]; /* 0 24 */
    long int lowmem_reserve[4]; /* 24 32 */
    int node; /* 56 4 */
    unsigned int inactive_ratio; /* 60 4 */
    /* --- cacheline 1 boundary (64 bytes) --- */
    struct pglist_data * zone_pgdat; /* 64 8 */
    struct per_cpu_pageset * pageset; /* 72 8 */
    long unsigned int dirty_balance_reserve; /* 80 8 */
    long unsigned int min_unmapped_pages; /* 88 8 */
    long unsigned int min_slab_pages; /* 96 8 */
    long unsigned int zone_start_pfn; /* 104 8 */
    long unsigned int managed_pages; /* 112 8 */
    long unsigned int spanned_pages; /* 120 8 */
    /* --- cacheline 2 boundary (128 bytes) --- */
    long unsigned int present_pages; /* 128 8 */
    const char * name; /* 136 8 */
    int nr_migrate_reserve_block; /* 144 4 */
    seqlock_t span_seqlock; /* 148 8 */

    /* XXX 4 bytes hole, try to pack */

    wait_queue_head_t * wait_table; /* 160 8 */
    long unsigned int wait_table_hash_nr_entries; /* 168 8 */
    long unsigned int wait_table_bits; /* 176 8 */

    /* XXX 8 bytes hole, try to pack */

    /* --- cacheline 3 boundary (192 bytes) --- */
    struct zone_padding _pad1_; /* 192 0 */
    spinlock_t lock; /* 192 4 */

    /* XXX 4 bytes hole, try to pack */

    struct free_area free_area[11]; /* 200 968 */
    /* --- cacheline 18 boundary (1152 bytes) was 16 bytes ago --- */
    long unsigned int flags; /* 1168 8 */

    /* XXX 40 bytes hole, try to pack */

    /* --- cacheline 19 boundary (1216 bytes) --- */
    struct zone_padding _pad2_; /* 1216 0 */
    spinlock_t lru_lock; /* 1216 4 */

    /* XXX 4 bytes hole, try to pack */

    long unsigned int pages_scanned; /* 1224 8 */
    struct lruvec lruvec; /* 1232 120 */
    /* --- cacheline 21 boundary (1344 bytes) was 8 bytes ago --- */
    atomic_long_t inactive_age; /* 1352 8 */
    long unsigned int percpu_drift_mark; /* 1360 8 */
    long unsigned int compact_cached_free_pfn; /* 1368 8 */
    long unsigned int compact_cached_migrate_pfn[2]; /* 1376 16 */
    unsigned int compact_considered; /* 1392 4 */
    unsigned int compact_defer_shift; /* 1396 4 */
    int compact_order_failed; /* 1400 4 */
    bool compact_blockskip_flush; /* 1404 1 */

    /* XXX 3 bytes hole, try to pack */

    /* --- cacheline 22 boundary (1408 bytes) --- */
    struct zone_padding _pad3_; /* 1408 0 */
    atomic_long_t vm_stat[38]; /* 1408 304 */
    /* --- cacheline 26 boundary (1664 bytes) was 48 bytes ago --- */

    /* size: 1728, cachelines: 27, members: 37 */
    /* sum members: 1649, holes: 6, sum holes: 63 */
    /* padding: 16 */
    };

    24b7e5819a
    ---------------------------------------------------------------
    struct zone {
    long unsigned int watermark[3]; /* 0 24 */
    long unsigned int percpu_drift_mark; /* 24 8 */
    long unsigned int lowmem_reserve[4]; /* 32 32 */
    /* --- cacheline 1 boundary (64 bytes) --- */
    long unsigned int dirty_balance_reserve; /* 64 8 */
    int node; /* 72 4 */

    /* XXX 4 bytes hole, try to pack */

    long unsigned int min_unmapped_pages; /* 80 8 */
    long unsigned int min_slab_pages; /* 88 8 */
    struct per_cpu_pageset * pageset; /* 96 8 */
    spinlock_t lock; /* 104 4 */
    bool compact_blockskip_flush; /* 108 1 */

    /* XXX 3 bytes hole, try to pack */

    long unsigned int compact_cached_free_pfn; /* 112 8 */
    long unsigned int compact_cached_migrate_pfn[2]; /* 120 16 */
    /* --- cacheline 2 boundary (128 bytes) was 8 bytes ago --- */
    seqlock_t span_seqlock; /* 136 8 */
    struct free_area free_area[11]; /* 144 968 */
    /* --- cacheline 17 boundary (1088 bytes) was 24 bytes ago --- */
    unsigned int compact_considered; /* 1112 4 */
    unsigned int compact_defer_shift; /* 1116 4 */
    int compact_order_failed; /* 1120 4 */

    /* XXX 28 bytes hole, try to pack */

    /* --- cacheline 18 boundary (1152 bytes) --- */
    struct zone_padding _pad1_; /* 1152 0 */
    spinlock_t lru_lock; /* 1152 4 */

    /* XXX 4 bytes hole, try to pack */

    struct lruvec lruvec; /* 1160 120 */
    /* --- cacheline 20 boundary (1280 bytes) --- */
    atomic_long_t inactive_age; /* 1280 8 */
    long unsigned int pages_scanned; /* 1288 8 */
    long unsigned int flags; /* 1296 8 */
    atomic_long_t vm_stat[38]; /* 1304 304 */
    /* --- cacheline 25 boundary (1600 bytes) was 8 bytes ago --- */
    unsigned int inactive_ratio; /* 1608 4 */

    /* XXX 52 bytes hole, try to pack */

    /* --- cacheline 26 boundary (1664 bytes) --- */
    struct zone_padding _pad2_; /* 1664 0 */
    wait_queue_head_t * wait_table; /* 1664 8 */
    long unsigned int wait_table_hash_nr_entries; /* 1672 8 */
    long unsigned int wait_table_bits; /* 1680 8 */
    struct pglist_data * zone_pgdat; /* 1688 8 */
    long unsigned int zone_start_pfn; /* 1696 8 */
    long unsigned int spanned_pages; /* 1704 8 */
    long unsigned int present_pages; /* 1712 8 */
    long unsigned int managed_pages; /* 1720 8 */
    /* --- cacheline 27 boundary (1728 bytes) --- */
    int nr_migrate_reserve_block; /* 1728 4 */

    /* XXX 4 bytes hole, try to pack */

    const char * name; /* 1736 8 */

    /* size: 1792, cachelines: 28, members: 36 */
    /* sum members: 1649, holes: 6, sum holes: 95 */
    /* padding: 48 */
    };




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