From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Thu, 3 May 2012 05:43:42 +0000 (+1000)
Subject: hugetlb: migrate memcg info from oldpage to new page during migration
X-Git-Tag: next-20120503~2^2~212
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=0a8b7efedc94c43d417c276ed74a55e7882512dd;p=karo-tx-linux.git

hugetlb: migrate memcg info from oldpage to new page during migration

With HugeTLB pages, memcg is uncharged in compound page destructor.  Since
we are holding a hugepage reference, we can be sure that old page won't
get uncharged till the last put_page().  On successful migrate, we can
move the memcg information to new page's page_cgroup and mark the old
page's page_cgroup unused.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 6a293b85f9b3..4eb13b349e67 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -464,6 +464,8 @@ extern int mem_cgroup_move_hugetlb_parent(int idx, struct cgroup *cgroup,
 					  struct page *page);
 extern bool mem_cgroup_have_hugetlb_usage(struct cgroup *cgroup);
 
+extern void  mem_cgroup_hugetlb_migrate(struct page *oldhpage,
+					struct page *newhpage);
 #else
 static inline int
 mem_cgroup_hugetlb_charge_page(int idx, unsigned long nr_pages,
@@ -499,6 +501,12 @@ static inline int mem_cgroup_hugetlb_file_init(int idx)
 	return 0;
 }
 
+static inline  void  mem_cgroup_hugetlb_migrate(struct page *oldhpage,
+						struct page *newhpage)
+{
+	return;
+}
+
 #endif  /* CONFIG_MEM_RES_CTLR_HUGETLB */
 #endif /* _LINUX_MEMCONTROL_H */
 
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6f7947778308..49d59e670e69 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3384,6 +3384,34 @@ err_out:
 out:
 	return ret;
 }
+
+void  mem_cgroup_hugetlb_migrate(struct page *oldhpage, struct page *newhpage)
+{
+	struct mem_cgroup *memcg;
+	struct page_cgroup *pc;
+
+	VM_BUG_ON(!PageHuge(oldhpage));
+
+	if (mem_cgroup_disabled())
+		return;
+
+	pc = lookup_page_cgroup(oldhpage);
+	lock_page_cgroup(pc);
+	memcg = pc->mem_cgroup;
+	pc->mem_cgroup = root_mem_cgroup;
+	ClearPageCgroupUsed(pc);
+	cgroup_exclude_rmdir(&memcg->css);
+	unlock_page_cgroup(pc);
+
+	/* move the mem_cg details to new cgroup */
+	pc = lookup_page_cgroup(newhpage);
+	lock_page_cgroup(pc);
+	pc->mem_cgroup = memcg;
+	SetPageCgroupUsed(pc);
+	unlock_page_cgroup(pc);
+	cgroup_release_and_wakeup_rmdir(&memcg->css);
+	return;
+}
 #endif /* CONFIG_MEM_RES_CTLR_HUGETLB */
 
 /*
diff --git a/mm/migrate.c b/mm/migrate.c
index 69065ab09d08..8bf5e1d5a0a3 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -928,6 +928,10 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
 
 	if (anon_vma)
 		put_anon_vma(anon_vma);
+
+	if (!rc)
+		mem_cgroup_hugetlb_migrate(hpage, new_hpage);
+
 	unlock_page(hpage);
 out:
 	put_page(new_hpage);