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thp: set recommended min free kbytes

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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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrea Arcangeli 2011-01-13 15:47:04 -08:00 committed by Linus Torvalds
parent cd7548ab36
commit f000565adb
1 changed files with 52 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

52
mm/huge_memory.c
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@ -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 = pageblock_nr_pages * 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 += pageblock_nr_pages * nr_zones *
MIGRATE_PCPTYPES * MIGRATE_PCPTYPES;
/* 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 kobject *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;
}