[PATCH v2 2/4] mm: memcontrol: change val type to long in __mod_memcg_{lruvec_}state()

Qi Zheng
2026-03-25T14:14:19Z

From: Qi Zheng <zhengqi.arch@bytedance.com>

The __mod_memcg_state() and __mod_memcg_lruvec_state() functions are also
used to reparent non-hierarchical stats. In this scenario, the values
passed to them are accumulated statistics that might be extremely large
and exceed the upper limit of a 32-bit integer.

Change the val parameter type from int to long in these functions and
their corresponding tracepoints (memcg_rstat_stats) to prevent potential
overflow issues.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
include/trace/events/memcg.h | 10 +++++-----
mm/memcontrol.c | 8 ++++----
2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/include/trace/events/memcg.h b/include/trace/events/memcg.h
index dfe2f51019b4c..51b62c5931fc2 100644
--- a/include/trace/events/memcg.h
+++ b/include/trace/events/memcg.h
@@ -11,14 +11,14 @@

DECLARE_EVENT_CLASS(memcg_rstat_stats,

- TP_PROTO(struct mem_cgroup *memcg, int item, int val),
+ TP_PROTO(struct mem_cgroup *memcg, int item, long val),

TP_ARGS(memcg, item, val),

TP_STRUCT__entry(
__field(u64, id)
__field(int, item)
- __field(int, val)
+ __field(long, val)
),

TP_fast_assign(
@@ -27,20 +27,20 @@ DECLARE_EVENT_CLASS(memcg_rstat_stats,
__entry->val = val;
),

- TP_printk("memcg_id=%llu item=%d val=%d",
+ TP_printk("memcg_id=%llu item=%d val=%ld",
__entry->id, __entry->item, __entry->val)
);

DEFINE_EVENT(memcg_rstat_stats, mod_memcg_state,

- TP_PROTO(struct mem_cgroup *memcg, int item, int val),
+ TP_PROTO(struct mem_cgroup *memcg, int item, long val),

TP_ARGS(memcg, item, val)
);

DEFINE_EVENT(memcg_rstat_stats, mod_memcg_lruvec_state,

- TP_PROTO(struct mem_cgroup *memcg, int item, int val),
+ TP_PROTO(struct mem_cgroup *memcg, int item, long val),

TP_ARGS(memcg, item, val)
);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 7fb9cbc10dfbb..4a78550f6174e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -527,7 +527,7 @@ unsigned long lruvec_page_state_local(struct lruvec *lruvec,

#ifdef CONFIG_MEMCG_V1
static void __mod_memcg_lruvec_state(struct mem_cgroup_per_node *pn,
- enum node_stat_item idx, int val);
+ enum node_stat_item idx, long val);

void reparent_memcg_lruvec_state_local(struct mem_cgroup *memcg,
struct mem_cgroup *parent, int idx)
@@ -784,7 +784,7 @@ static int memcg_page_state_unit(int item);
* Normalize the value passed into memcg_rstat_updated() to be in pages. Round
* up non-zero sub-page updates to 1 page as zero page updates are ignored.
*/
-static int memcg_state_val_in_pages(int idx, int val)
+static long memcg_state_val_in_pages(int idx, long val)
{
int unit = memcg_page_state_unit(idx);

@@ -831,7 +831,7 @@ static inline void get_non_dying_memcg_end(void)
#endif

static void __mod_memcg_state(struct mem_cgroup *memcg,
- enum memcg_stat_item idx, int val)
+ enum memcg_stat_item idx, long val)
{
int i = memcg_stats_index(idx);
int cpu;
@@ -896,7 +896,7 @@ void reparent_memcg_state_local(struct mem_cgroup *memcg,
#endif

static void __mod_memcg_lruvec_state(struct mem_cgroup_per_node *pn,
- enum node_stat_item idx, int val)
+ enum node_stat_item idx, long val)
{
struct mem_cgroup *memcg = pn->memcg;
int i = memcg_stats_index(idx);
--
2.20.1