[PATCH v2 2/2] mm/memcg: set memcg when split page
As described in the split_page function comment, for the non-compound high order page, the sub-pages must be freed individually. If the memcg of the fisrt page is valid, the tail pages cannot be uncharged when be freed. For example, when alloc_pages_exact is used to allocate 1MB continuous physical memory, 2MB is charged(kmemcg is enabled and __GFP_ACCOUNT is set). When make_alloc_exact free the unused 1MB and free_pages_exact free the applied 1MB, actually, only 4KB(one page) is uncharged. Therefore, the memcg of the tail page needs to be set when split page. Signed-off-by: Zhou Guanghui --- mm/page_alloc.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 3e4b29ee2b1e..3ed783e25c3c 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3310,6 +3310,7 @@ void split_page(struct page *page, unsigned int order) for (i = 1; i < (1 << order); i++) set_page_refcounted(page + i); split_page_owner(page, 1 << order); + split_page_memcg(page, 1 << order); } EXPORT_SYMBOL_GPL(split_page); -- 2.25.0
[PATCH v2 1/2] mm/memcg: rename mem_cgroup_split_huge_fixup to split_page_memcg
Rename mem_cgroup_split_huge_fixup to split_page_memcg and explicitly
pass in page number argument.
In this way, the interface name is more common and can be used by
potential users. In addition, the complete info(memcg and flag) of
the memcg needs to be set to the tail pages.
Signed-off-by: Zhou Guanghui
---
include/linux/memcontrol.h | 6 ++
mm/huge_memory.c | 2 +-
mm/memcontrol.c| 15 ++-
3 files changed, 9 insertions(+), 14 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index e6dc793d587d..0c04d39a7967 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1061,9 +1061,7 @@ static inline void memcg_memory_event_mm(struct mm_struct
*mm,
rcu_read_unlock();
}
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-void mem_cgroup_split_huge_fixup(struct page *head);
-#endif
+void split_page_memcg(struct page *head, unsigned int nr);
#else /* CONFIG_MEMCG */
@@ -1400,7 +1398,7 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t
*pgdat, int order,
return 0;
}
-static inline void mem_cgroup_split_huge_fixup(struct page *head)
+static inline void split_page_memcg(struct page *head, unsigned int nr)
{
}
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 395c75111d33..e7f29308ebc8 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2471,7 +2471,7 @@ static void __split_huge_page(struct page *page, struct
list_head *list,
int i;
/* complete memcg works before add pages to LRU */
- mem_cgroup_split_huge_fixup(head);
+ split_page_memcg(head, nr);
if (PageAnon(head) && PageSwapCache(head)) {
swp_entry_t entry = { .val = page_private(head) };
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 845eec01ef9d..e064ac0d850a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3287,24 +3287,21 @@ void obj_cgroup_uncharge(struct obj_cgroup *objcg,
size_t size)
#endif /* CONFIG_MEMCG_KMEM */
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
/*
- * Because page_memcg(head) is not set on compound tails, set it now.
+ * Because page_memcg(head) is not set on tails, set it now.
*/
-void mem_cgroup_split_huge_fixup(struct page *head)
+void split_page_memcg(struct page *head, unsigned int nr)
{
struct mem_cgroup *memcg = page_memcg(head);
int i;
- if (mem_cgroup_disabled())
+ if (mem_cgroup_disabled() || !memcg)
return;
- for (i = 1; i < HPAGE_PMD_NR; i++) {
- css_get(>css);
- head[i].memcg_data = (unsigned long)memcg;
- }
+ for (i = 1; i < nr; i++)
+ head[i].memcg_data = head->memcg_data;
+ css_get_many(>css, nr - 1);
}
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#ifdef CONFIG_MEMCG_SWAP
/**
--
2.25.0
[PATCH v2 0/2] set memcg when split page
v2: 1. rename mem_cgroup_split_huge_fixup 2. use split_page_memcg when split page *** BLURB HERE *** Zhou Guanghui (2): mm/memcg: rename mem_cgroup_split_huge_fixup to split_page_memcg mm/memcg: set memcg when split pages include/linux/memcontrol.h | 6 ++ mm/huge_memory.c | 2 +- mm/memcontrol.c| 15 ++- mm/page_alloc.c| 1 + 4 files changed, 10 insertions(+), 14 deletions(-) -- 2.25.0
[PATCH] mm/memcg: set memcg when split pages
When split page, the memory cgroup info recorded in first page is
not copied to tail pages. In this case, when the tail pages are
freed, the uncharge operation is not performed. As a result, the
usage of this memcg keeps increasing, and the OOM may occur.
So, the copying of first page's memory cgroup info to tail pages
is needed when split page.
Signed-off-by: Zhou Guanghui
---
include/linux/memcontrol.h | 10 ++
mm/page_alloc.c| 4 +++-
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index e6dc793d587d..c7e2b4421dc1 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -867,6 +867,12 @@ void mem_cgroup_print_oom_group(struct mem_cgroup *memcg);
extern bool cgroup_memory_noswap;
#endif
+static inline void copy_page_memcg(struct page *dst, struct page *src)
+{
+ if (src->memcg_data)
+ dst->memcg_data = src->memcg_data;
+}
+
struct mem_cgroup *lock_page_memcg(struct page *page);
void __unlock_page_memcg(struct mem_cgroup *memcg);
void unlock_page_memcg(struct page *page);
@@ -1291,6 +1297,10 @@ mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg)
{
}
+static inline void copy_page_memcg(struct page *dst, struct page *src)
+{
+}
+
static inline struct mem_cgroup *lock_page_memcg(struct page *page)
{
return NULL;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3e4b29ee2b1e..ee0a63dc1c9b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3307,8 +3307,10 @@ void split_page(struct page *page, unsigned int order)
VM_BUG_ON_PAGE(PageCompound(page), page);
VM_BUG_ON_PAGE(!page_count(page), page);
- for (i = 1; i < (1 << order); i++)
+ for (i = 1; i < (1 << order); i++) {
set_page_refcounted(page + i);
+ copy_page_memcg(page + i, page);
+ }
split_page_owner(page, 1 << order);
}
EXPORT_SYMBOL_GPL(split_page);
--
2.25.0
