From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 8 ++++++++
mm/memcontrol.c | 28 ++++++++++++++++++++++++++++
mm/migrate.c | 4 ++++
3 files changed, 40 insertions(+)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 70317e5..6f2d392 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,
@@ -510,6 +512,12 @@ static inline bool mem_cgroup_have_hugetlb_usage(struct cgroup *cgroup)
{
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 0b245fb..519d370 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3379,6 +3379,34 @@ 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 d7eb82d..2b931e5 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);
--
1.7.10
--
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