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);
--
2.20.1On Wed, Mar 25, 2026 at 10:13:23PM +0800, Qi Zheng wrote:
> 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>
LGTM, so:
Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
> ---
> 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
>
On Thu, 26 Mar 2026 09:19:29 +0000
"Lorenzo Stoakes (Oracle)" <ljs@kernel.org> wrote:
> On Wed, Mar 25, 2026 at 10:13:23PM +0800, Qi Zheng wrote:
> > 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.
Won't that are be true on 32bit systems?
Which means the underlying values need to be u64 not long.
David
> >
> > Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
>
> LGTM, so:
>
> Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
>
> > ---
> > 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
> >
>
On 3/26/26 10:37 PM, David Laight wrote:
> On Thu, 26 Mar 2026 09:19:29 +0000
> "Lorenzo Stoakes (Oracle)" <ljs@kernel.org> wrote:
>
>> On Wed, Mar 25, 2026 at 10:13:23PM +0800, Qi Zheng wrote:
>>> 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.
>
> Won't that are be true on 32bit systems?
> Which means the underlying values need to be u64 not long.
On a 32-bit system, such a large number of values should not accumulate.
Furthermore, changing it to u64/s64 would mean modifying
memcg_vmstats_percpu->state and lruvec_stats_percpu->state,
which involves significant changes, so I think it might be unnecessary.
Thanks,
Qi
>
> David
>
>>>
>>> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
>>
>> LGTM, so:
>>
>> Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
>>
>>> ---
>>> 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
>>>
>>
>
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