On Tue, Jul 15, 2014 at 02:43:58PM -0400, Naoya Horiguchi wrote:

On Tue, Jul 15, 2014 at 01:34:39PM -0400, Johannes Weiner wrote:

quoted

On Tue, Jul 15, 2014 at 06:07:35PM +0200, Michal Hocko wrote:

quoted

On Tue 15-07-14 11:55:37, Naoya Horiguchi wrote:

quoted

On Wed, Jun 18, 2014 at 04:40:45PM -0400, Johannes Weiner wrote:
...

quoted

diff --git a/mm/swap.c b/mm/swap.c
index a98f48626359..3074210f245d 100644
--- a/mm/swap.c
+++ b/mm/swap.c

@@ -62,6 +62,7 @@ static void __page_cache_release(struct page *page)
 		del_page_from_lru_list(page, lruvec, page_off_lru(page));
 		spin_unlock_irqrestore(&zone->lru_lock, flags);
 	}
+	mem_cgroup_uncharge(page);
 }
 
 static void __put_single_page(struct page *page)

This seems to cause a list breakage in hstate->hugepage_activelist
when freeing a hugetlbfs page.

This looks like a fall out from
http://marc.info/?l=linux-mm&m=140475936311294&w=2

I didn't get to review this one but the easiest fix seems to be check
HugePage and do not call uncharge.

Yes, that makes sense.  I'm also moving the uncharge call into
__put_single_page() and __put_compound_page() so that PageHuge(), a
function call, only needs to be checked for compound pages.

quoted

quoted

For hugetlbfs, we uncharge in free_huge_page() which is called after
__page_cache_release(), so I think that we don't have to uncharge here.

In my testing, moving mem_cgroup_uncharge() inside if (PageLRU) block
fixed the problem, so if that works for you, could you fold the change
into your patch?

Memcg pages that *do* need uncharging might not necessarily be on the
LRU list.

OK.

quoted

Does the following work for you?

Unfortunately, with this change I saw the following bug message when
stressing with hugepage migration.
move_to_new_page() is called by unmap_and_move_huge_page() too, so
we need some hugetlb related code around mem_cgroup_migrate().

Can we just move hugetlb_cgroup_migrate() into move_to_new_page()?  It
doesn't seem to be dependent of any page-specific state.

diff --git a/mm/migrate.c b/mm/migrate.c
index 7f5a42403fae..219da52d2f43 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c

@@ -781,7 +781,10 @@ static int move_to_new_page(struct page *newpage, struct page *page,
 		if (!PageAnon(newpage))
 			newpage->mapping = NULL;
 	} else {
-		mem_cgroup_migrate(page, newpage, false);
+		if (PageHuge(page))
+			hugetlb_cgroup_migrate(hpage, new_hpage);
+		else
+			mem_cgroup_migrate(page, newpage, false);
 		if (remap_swapcache)
 			remove_migration_ptes(page, newpage);
 		if (!PageAnon(page))

@@ -1064,9 +1067,6 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
 	if (anon_vma)
 		put_anon_vma(anon_vma);
 
-	if (rc == MIGRATEPAGE_SUCCESS)
-		hugetlb_cgroup_migrate(hpage, new_hpage);
-
 	unlock_page(hpage);
 out:
 	if (rc != -EAGAIN)