[tip:sched/core] mm: Account for a THP NUMA hinting update as one PTE update

From: tip-bot for Mel Gorman
Date: Wed Oct 09 2013 - 13:42:58 EST


Commit-ID: afcae2655b0ab67e65f161b1bb214efcfa1db415
Gitweb: http://git.kernel.org/tip/afcae2655b0ab67e65f161b1bb214efcfa1db415
Author: Mel Gorman <mgorman@xxxxxxx>
AuthorDate: Mon, 7 Oct 2013 11:28:47 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 9 Oct 2013 12:39:46 +0200

mm: Account for a THP NUMA hinting update as one PTE update

A THP PMD update is accounted for as 512 pages updated in vmstat. This is
large difference when estimating the cost of automatic NUMA balancing and
can be misleading when comparing results that had collapsed versus split
THP. This patch addresses the accounting issue.

Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1381141781-10992-10-git-send-email-mgorman@xxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
mm/mprotect.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/mprotect.c b/mm/mprotect.c
index 94722a4..2bbb648 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -145,7 +145,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
split_huge_page_pmd(vma, addr, pmd);
else if (change_huge_pmd(vma, pmd, addr, newprot,
prot_numa)) {
- pages += HPAGE_PMD_NR;
+ pages++;
continue;
}
/* fall through */
--
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