On Wed, Jul 11, 2012 at 02:02:23PM +0530, Aneesh Kumar K.V wrote:

Wanpeng Li [off-list ref] writes:

quoted

From: Wanpeng Li <redacted>

hugepage_activelist is used to track currently used HugeTLB pages.
We can find the in-use HugeTLB pages to support HugeTLB cgroup
removal. Don't keep unused page in hugetlb_activelist too long.
Otherwise, on cgroup removal we should update the unused page's 
charge to parent count. To reduce this overhead, remove unused page 
from hugepage_activelist immediately.

Signed-off-by: Wanpeng Li <redacted>
---
 mm/hugetlb_cgroup.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
index b834e8d..d819d66 100644
--- a/mm/hugetlb_cgroup.c
+++ b/mm/hugetlb_cgroup.c

@@ -398,6 +398,7 @@ void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
 	spin_lock(&hugetlb_lock);
 	h_cg = hugetlb_cgroup_from_page(oldhpage);
 	set_hugetlb_cgroup(oldhpage, NULL);
+	list_del(&oldhpage->lru);

 	/* move the h_cg details to new cgroup */
 	set_hugetlb_cgroup(newhpage, h_cg);

put_page on the oldhpage will do that. If we do list_del here
free_huge_page() will have error list_move().

I don't know if move the page to other lists when migration in order 
to reduce overhead I mentioned make sense. :-)

Regards,
Wanpeng Li

-aneesh