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    Subject[PATCH 51 of 66] set recommended min free kbytes
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    From: Andrea Arcangeli <aarcange@redhat.com>

    If transparent hugepage is enabled initialize min_free_kbytes to an optimal
    value by default. This moves the hugeadm algorithm in kernel.

    Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
    ---

    diff --git a/mm/huge_memory.c b/mm/huge_memory.c
    --- a/mm/huge_memory.c
    +++ b/mm/huge_memory.c
    @@ -85,6 +85,47 @@ struct khugepaged_scan {
    .mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head),
    };

    +
    +static int set_recommended_min_free_kbytes(void)
    +{
    + struct zone *zone;
    + int nr_zones = 0;
    + unsigned long recommended_min;
    + extern int min_free_kbytes;
    +
    + if (!test_bit(TRANSPARENT_HUGEPAGE_FLAG,
    + &transparent_hugepage_flags) &&
    + !test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
    + &transparent_hugepage_flags))
    + return 0;
    +
    + for_each_populated_zone(zone)
    + nr_zones++;
    +
    + /* Make sure at least 2 hugepages are free for MIGRATE_RESERVE */
    + recommended_min = HPAGE_PMD_NR * nr_zones * 2;
    +
    + /*
    + * Make sure that on average at least two pageblocks are almost free
    + * of another type, one for a migratetype to fall back to and a
    + * second to avoid subsequent fallbacks of other types There are 3
    + * MIGRATE_TYPES we care about.
    + */
    + recommended_min += HPAGE_PMD_NR * nr_zones * 3 * 3;
    +
    + /* don't ever allow to reserve more than 5% of the lowmem */
    + recommended_min = min(recommended_min,
    + (unsigned long) nr_free_buffer_pages() / 20);
    + recommended_min <<= (PAGE_SHIFT-10);
    +
    + if (recommended_min > min_free_kbytes) {
    + min_free_kbytes = recommended_min;
    + setup_per_zone_wmarks();
    + }
    + return 0;
    +}
    +late_initcall(set_recommended_min_free_kbytes);
    +
    static int start_khugepaged(void)
    {
    int err = 0;
    @@ -108,6 +149,8 @@ static int start_khugepaged(void)
    mutex_unlock(&khugepaged_mutex);
    if (wakeup)
    wake_up_interruptible(&khugepaged_wait);
    +
    + set_recommended_min_free_kbytes();
    } else
    /* wakeup to exit */
    wake_up_interruptible(&khugepaged_wait);
    @@ -177,6 +220,13 @@ static ssize_t enabled_store(struct kobj
    ret = err;
    }

    + if (ret > 0 &&
    + (test_bit(TRANSPARENT_HUGEPAGE_FLAG,
    + &transparent_hugepage_flags) ||
    + test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
    + &transparent_hugepage_flags)))
    + set_recommended_min_free_kbytes();
    +
    return ret;
    }
    static struct kobj_attribute enabled_attr =
    @@ -464,6 +514,8 @@ static int __init hugepage_init(void)

    start_khugepaged();

    + set_recommended_min_free_kbytes();
    +
    out:
    return err;
    }

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      Last update: 2010-11-03 16:53    [W:0.025 / U:91.700 seconds]
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