[PATCH -v2 next 0/4] Some cleanup for memcg

[PATCH -v2 next 0/4] Some cleanup for memcg

[Chen Ridong]

From: Chen Ridong <chenridong@huawei.com>

Some cleanup for memcg.

---
v1->v2:
 - drop the patch 'simplify the mem_cgroup_update_lru_size function'.
 - for patch 3, rename '__refill_obj_stock' to replace_stock_objcg, and
   keep the 'objcg equal' check in the calling functions.

Chen Ridong (4):
  memcg: use OFP_PEAK_UNSET instead of -1
  memcg: call the free function when allocation of pn fails
  memcg: factor out the replace_stock_objcg function
  memcg: factor out stat(event)/stat_local(event_local) reading
    functions

 mm/memcontrol.c | 127 ++++++++++++++++++++++--------------------------
 1 file changed, 59 insertions(+), 68 deletions(-)

-- 
2.34.1

[PATCH -v2 next 1/4] memcg: use OFP_PEAK_UNSET instead of -1

[Chen Ridong]

From: Chen Ridong <chenridong@huawei.com>

The 'OFP_PEAK_UNSET' has been defined, use it instead of '-1'.

Signed-off-by: Chen Ridong <chenridong@huawei.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Acked-by: David Finkel <davidf@vimeo.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
---
 mm/memcontrol.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 46f8b372d212..05a32c860554 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4004,7 +4004,7 @@ static ssize_t peak_write(struct kernfs_open_file *of, char *buf, size_t nbytes,
 			WRITE_ONCE(peer_ctx->value, usage);
 
 	/* initial write, register watcher */
-	if (ofp->value == -1)
+	if (ofp->value == OFP_PEAK_UNSET)
 		list_add(&ofp->list, watchers);
 
 	WRITE_ONCE(ofp->value, usage);
-- 
2.34.1

Re: [PATCH -v2 next 1/4] memcg: use OFP_PEAK_UNSET instead of -1

[Roman Gushchin]

On Tue, Jan 14, 2025 at 12:25:16PM +0000, Chen Ridong wrote:
> From: Chen Ridong <chenridong@huawei.com>
> 
> The 'OFP_PEAK_UNSET' has been defined, use it instead of '-1'.
> 
> Signed-off-by: Chen Ridong <chenridong@huawei.com>
> Reviewed-by: Michal Koutný <mkoutny@suse.com>
> Acked-by: David Finkel <davidf@vimeo.com>
> Acked-by: Shakeel Butt <shakeel.butt@linux.dev>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

[PATCH -v2 next 2/4] memcg: call the free function when allocation of pn fails

[Chen Ridong]

From: Chen Ridong <chenridong@huawei.com>

The 'free_mem_cgroup_per_node_info' function is used to free
the 'mem_cgroup_per_node' struct. Using 'pn' as the input for the
free_mem_cgroup_per_node_info function will be much clearer.
Call 'free_mem_cgroup_per_node_info' when 'alloc_mem_cgroup_per_node_info'
fails, to free 'pn' as a whole, which makes the code more cohesive.

Signed-off-by: Chen Ridong <chenridong@huawei.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
---
 mm/memcontrol.c | 27 ++++++++++++---------------
 1 file changed, 12 insertions(+), 15 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 05a32c860554..98f84a9fa228 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3424,6 +3424,16 @@ struct mem_cgroup *mem_cgroup_get_from_ino(unsigned long ino)
 }
 #endif
 
+static void free_mem_cgroup_per_node_info(struct mem_cgroup_per_node *pn)
+{
+	if (!pn)
+		return;
+
+	free_percpu(pn->lruvec_stats_percpu);
+	kfree(pn->lruvec_stats);
+	kfree(pn);
+}
+
 static bool alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
 {
 	struct mem_cgroup_per_node *pn;
@@ -3448,23 +3458,10 @@ static bool alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
 	memcg->nodeinfo[node] = pn;
 	return true;
 fail:
-	kfree(pn->lruvec_stats);
-	kfree(pn);
+	free_mem_cgroup_per_node_info(pn);
 	return false;
 }
 
-static void free_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
-{
-	struct mem_cgroup_per_node *pn = memcg->nodeinfo[node];
-
-	if (!pn)
-		return;
-
-	free_percpu(pn->lruvec_stats_percpu);
-	kfree(pn->lruvec_stats);
-	kfree(pn);
-}
-
 static void __mem_cgroup_free(struct mem_cgroup *memcg)
 {
 	int node;
@@ -3472,7 +3469,7 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg)
 	obj_cgroup_put(memcg->orig_objcg);
 
 	for_each_node(node)
-		free_mem_cgroup_per_node_info(memcg, node);
+		free_mem_cgroup_per_node_info(memcg->nodeinfo[node]);
 	memcg1_free_events(memcg);
 	kfree(memcg->vmstats);
 	free_percpu(memcg->vmstats_percpu);
-- 
2.34.1

Re: [PATCH -v2 next 2/4] memcg: call the free function when allocation of pn fails

[Roman Gushchin]

On Tue, Jan 14, 2025 at 12:25:17PM +0000, Chen Ridong wrote:
> From: Chen Ridong <chenridong@huawei.com>
> 
> The 'free_mem_cgroup_per_node_info' function is used to free
> the 'mem_cgroup_per_node' struct. Using 'pn' as the input for the
> free_mem_cgroup_per_node_info function will be much clearer.
> Call 'free_mem_cgroup_per_node_info' when 'alloc_mem_cgroup_per_node_info'
> fails, to free 'pn' as a whole, which makes the code more cohesive.
> 
> Signed-off-by: Chen Ridong <chenridong@huawei.com>
> Reviewed-by: Michal Koutný <mkoutny@suse.com>
> Acked-by: Shakeel Butt <shakeel.butt@linux.dev>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

[PATCH -v2 next 3/4] memcg: factor out the replace_stock_objcg function

[Chen Ridong]

From: Chen Ridong <chenridong@huawei.com>

Factor out the 'replace_stock_objcg' function to make the code more
cohesive.

Signed-off-by: Chen Ridong <chenridong@huawei.com>
---
 mm/memcontrol.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 98f84a9fa228..b10e0a8f3375 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2691,6 +2691,20 @@ void __memcg_kmem_uncharge_page(struct page *page, int order)
 	obj_cgroup_put(objcg);
 }
 
+/* Replace the stock objcg with objcg, return the old objcg */
+static struct obj_cgroup *replace_stock_objcg(struct memcg_stock_pcp *stock,
+					     struct obj_cgroup *objcg)
+{
+	struct obj_cgroup *old = NULL;
+
+	old = drain_obj_stock(stock);
+	obj_cgroup_get(objcg);
+	stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
+			? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0;
+	WRITE_ONCE(stock->cached_objcg, objcg);
+	return old;
+}
+
 static void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
 		     enum node_stat_item idx, int nr)
 {
@@ -2708,11 +2722,7 @@ static void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
 	 * changes.
 	 */
 	if (READ_ONCE(stock->cached_objcg) != objcg) {
-		old = drain_obj_stock(stock);
-		obj_cgroup_get(objcg);
-		stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
-				? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0;
-		WRITE_ONCE(stock->cached_objcg, objcg);
+		old = replace_stock_objcg(stock, objcg);
 		stock->cached_pgdat = pgdat;
 	} else if (stock->cached_pgdat != pgdat) {
 		/* Flush the existing cached vmstat data */
@@ -2866,11 +2876,7 @@ static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes,
 
 	stock = this_cpu_ptr(&memcg_stock);
 	if (READ_ONCE(stock->cached_objcg) != objcg) { /* reset if necessary */
-		old = drain_obj_stock(stock);
-		obj_cgroup_get(objcg);
-		WRITE_ONCE(stock->cached_objcg, objcg);
-		stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
-				? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0;
+		old = replace_stock_objcg(stock, objcg);
 		allow_uncharge = true;	/* Allow uncharge when objcg changes */
 	}
 	stock->nr_bytes += nr_bytes;
-- 
2.34.1

Re: [PATCH -v2 next 3/4] memcg: factor out the replace_stock_objcg function

[Roman Gushchin]

On Tue, Jan 14, 2025 at 12:25:18PM +0000, Chen Ridong wrote:
> From: Chen Ridong <chenridong@huawei.com>
> 
> Factor out the 'replace_stock_objcg' function to make the code more
> cohesive.
> 
> Signed-off-by: Chen Ridong <chenridong@huawei.com>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

Re: [PATCH -v2 next 3/4] memcg: factor out the replace_stock_objcg function

[Shakeel Butt]

On Tue, Jan 14, 2025 at 12:25:18PM +0000, Chen Ridong wrote:
> From: Chen Ridong <chenridong@huawei.com>
> 
> Factor out the 'replace_stock_objcg' function to make the code more
> cohesive.
> 
> Signed-off-by: Chen Ridong <chenridong@huawei.com>

Acked-by: Shakeel Butt <shakeel.butt@linux.dev>

[PATCH -v2 next 4/4] memcg: factor out stat(event)/stat_local(event_local) reading functions

[Chen Ridong]

From: Chen Ridong <chenridong@huawei.com>

The only difference between 'lruvec_page_state' and
'lruvec_page_state_local' is that they read 'state' and 'state_local',
respectively. Factor out an inner functions to make the code more concise.
Do the same for reading 'memcg_page_stat' and 'memcg_events'.

Signed-off-by: Chen Ridong <chenridong@huawei.com>
---
 mm/memcontrol.c | 72 +++++++++++++++++++++----------------------------
 1 file changed, 30 insertions(+), 42 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index b10e0a8f3375..14541610cad0 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -375,7 +375,8 @@ struct lruvec_stats {
 	long state_pending[NR_MEMCG_NODE_STAT_ITEMS];
 };
 
-unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
+static unsigned long __lruvec_page_state(struct lruvec *lruvec,
+		enum node_stat_item idx, bool local)
 {
 	struct mem_cgroup_per_node *pn;
 	long x;
@@ -389,7 +390,8 @@ unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
 		return 0;
 
 	pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
-	x = READ_ONCE(pn->lruvec_stats->state[i]);
+	x = local ? READ_ONCE(pn->lruvec_stats->state_local[i]) :
+		    READ_ONCE(pn->lruvec_stats->state[i]);
 #ifdef CONFIG_SMP
 	if (x < 0)
 		x = 0;
@@ -397,27 +399,16 @@ unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
 	return x;
 }
 
+
+unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
+{
+	return __lruvec_page_state(lruvec, idx, false);
+}
+
 unsigned long lruvec_page_state_local(struct lruvec *lruvec,
 				      enum node_stat_item idx)
 {
-	struct mem_cgroup_per_node *pn;
-	long x;
-	int i;
-
-	if (mem_cgroup_disabled())
-		return node_page_state(lruvec_pgdat(lruvec), idx);
-
-	i = memcg_stats_index(idx);
-	if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, idx))
-		return 0;
-
-	pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
-	x = READ_ONCE(pn->lruvec_stats->state_local[i]);
-#ifdef CONFIG_SMP
-	if (x < 0)
-		x = 0;
-#endif
-	return x;
+	return __lruvec_page_state(lruvec, idx, true);
 }
 
 /* Subset of vm_event_item to report for memcg event stats */
@@ -651,7 +642,7 @@ static void flush_memcg_stats_dwork(struct work_struct *w)
 	queue_delayed_work(system_unbound_wq, &stats_flush_dwork, FLUSH_TIME);
 }
 
-unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
+static unsigned long __memcg_page_state(struct mem_cgroup *memcg, int idx, bool local)
 {
 	long x;
 	int i = memcg_stats_index(idx);
@@ -659,7 +650,9 @@ unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
 	if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, idx))
 		return 0;
 
-	x = READ_ONCE(memcg->vmstats->state[i]);
+	x = local ? READ_ONCE(memcg->vmstats->state_local[i]) :
+		    READ_ONCE(memcg->vmstats->state[i]);
+
 #ifdef CONFIG_SMP
 	if (x < 0)
 		x = 0;
@@ -667,6 +660,11 @@ unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
 	return x;
 }
 
+unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
+{
+	return __memcg_page_state(memcg, idx, false);
+}
+
 static int memcg_page_state_unit(int item);
 
 /*
@@ -709,18 +707,7 @@ void __mod_memcg_state(struct mem_cgroup *memcg, enum memcg_stat_item idx,
 /* idx can be of type enum memcg_stat_item or node_stat_item. */
 unsigned long memcg_page_state_local(struct mem_cgroup *memcg, int idx)
 {
-	long x;
-	int i = memcg_stats_index(idx);
-
-	if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, idx))
-		return 0;
-
-	x = READ_ONCE(memcg->vmstats->state_local[i]);
-#ifdef CONFIG_SMP
-	if (x < 0)
-		x = 0;
-#endif
-	return x;
+	return __memcg_page_state(memcg, idx, true);
 }
 
 static void __mod_memcg_lruvec_state(struct lruvec *lruvec,
@@ -859,24 +846,25 @@ void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx,
 	memcg_stats_unlock();
 }
 
-unsigned long memcg_events(struct mem_cgroup *memcg, int event)
+static unsigned long __memcg_events(struct mem_cgroup *memcg, int event, bool local)
 {
 	int i = memcg_events_index(event);
 
 	if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, event))
 		return 0;
 
-	return READ_ONCE(memcg->vmstats->events[i]);
+	return local ? READ_ONCE(memcg->vmstats->events_local[i]) :
+		    READ_ONCE(memcg->vmstats->events[i]);
 }
 
-unsigned long memcg_events_local(struct mem_cgroup *memcg, int event)
+unsigned long memcg_events(struct mem_cgroup *memcg, int event)
 {
-	int i = memcg_events_index(event);
-
-	if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, event))
-		return 0;
+	return __memcg_events(memcg, event, false);
+}
 
-	return READ_ONCE(memcg->vmstats->events_local[i]);
+unsigned long memcg_events_local(struct mem_cgroup *memcg, int event)
+{
+	return __memcg_events(memcg, event, true);
 }
 
 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
-- 
2.34.1

Re: [PATCH -v2 next 4/4] memcg: factor out stat(event)/stat_local(event_local) reading functions

[Roman Gushchin]

On Tue, Jan 14, 2025 at 12:25:19PM +0000, Chen Ridong wrote:
> From: Chen Ridong <chenridong@huawei.com>
> 
> The only difference between 'lruvec_page_state' and
> 'lruvec_page_state_local' is that they read 'state' and 'state_local',
> respectively. Factor out an inner functions to make the code more concise.
> Do the same for reading 'memcg_page_stat' and 'memcg_events'.
> 
> Signed-off-by: Chen Ridong <chenridong@huawei.com>
> ---
>  mm/memcontrol.c | 72 +++++++++++++++++++++----------------------------
>  1 file changed, 30 insertions(+), 42 deletions(-)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index b10e0a8f3375..14541610cad0 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -375,7 +375,8 @@ struct lruvec_stats {
>  	long state_pending[NR_MEMCG_NODE_STAT_ITEMS];
>  };
>  
> -unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
> +static unsigned long __lruvec_page_state(struct lruvec *lruvec,
> +		enum node_stat_item idx, bool local)
>  {
>  	struct mem_cgroup_per_node *pn;
>  	long x;
> @@ -389,7 +390,8 @@ unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
>  		return 0;
>  
>  	pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
> -	x = READ_ONCE(pn->lruvec_stats->state[i]);
> +	x = local ? READ_ONCE(pn->lruvec_stats->state_local[i]) :
> +		    READ_ONCE(pn->lruvec_stats->state[i]);
>  #ifdef CONFIG_SMP
>  	if (x < 0)
>  		x = 0;
> @@ -397,27 +399,16 @@ unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
>  	return x;
>  }
>  
> +
> +unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
> +{
> +	return __lruvec_page_state(lruvec, idx, false);
> +}

I'd move these wrapper function definitions to memcontrol.h and make them
static inline.

Other than that, lgtm.

Thank you!

Re: [PATCH -v2 next 4/4] memcg: factor out stat(event)/stat_local(event_local) reading functions

[Shakeel Butt]

On Tue, Jan 14, 2025 at 06:45:20PM +0000, Roman Gushchin wrote:
> On Tue, Jan 14, 2025 at 12:25:19PM +0000, Chen Ridong wrote:
> > From: Chen Ridong <chenridong@huawei.com>
> > 
> > The only difference between 'lruvec_page_state' and
> > 'lruvec_page_state_local' is that they read 'state' and 'state_local',
> > respectively. Factor out an inner functions to make the code more concise.
> > Do the same for reading 'memcg_page_stat' and 'memcg_events'.
> > 
> > Signed-off-by: Chen Ridong <chenridong@huawei.com>
> > ---
> >  mm/memcontrol.c | 72 +++++++++++++++++++++----------------------------
> >  1 file changed, 30 insertions(+), 42 deletions(-)
> > 
> > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> > index b10e0a8f3375..14541610cad0 100644
> > --- a/mm/memcontrol.c
> > +++ b/mm/memcontrol.c
> > @@ -375,7 +375,8 @@ struct lruvec_stats {
> >  	long state_pending[NR_MEMCG_NODE_STAT_ITEMS];
> >  };
> >  
> > -unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
> > +static unsigned long __lruvec_page_state(struct lruvec *lruvec,
> > +		enum node_stat_item idx, bool local)
> >  {
> >  	struct mem_cgroup_per_node *pn;
> >  	long x;
> > @@ -389,7 +390,8 @@ unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
> >  		return 0;
> >  
> >  	pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
> > -	x = READ_ONCE(pn->lruvec_stats->state[i]);
> > +	x = local ? READ_ONCE(pn->lruvec_stats->state_local[i]) :
> > +		    READ_ONCE(pn->lruvec_stats->state[i]);
> >  #ifdef CONFIG_SMP
> >  	if (x < 0)
> >  		x = 0;
> > @@ -397,27 +399,16 @@ unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
> >  	return x;
> >  }
> >  
> > +
> > +unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
> > +{
> > +	return __lruvec_page_state(lruvec, idx, false);
> > +}
> 
> I'd move these wrapper function definitions to memcontrol.h and make them
> static inline.

+1

> 
> Other than that, lgtm.
> 
> Thank you!

Re: [PATCH -v2 next 4/4] memcg: factor out stat(event)/stat_local(event_local) reading functions

[Chen Ridong]

On 2025/1/16 8:57, Shakeel Butt wrote:
> On Tue, Jan 14, 2025 at 06:45:20PM +0000, Roman Gushchin wrote:
>> On Tue, Jan 14, 2025 at 12:25:19PM +0000, Chen Ridong wrote:
>>> From: Chen Ridong <chenridong@huawei.com>
>>>
>>> The only difference between 'lruvec_page_state' and
>>> 'lruvec_page_state_local' is that they read 'state' and 'state_local',
>>> respectively. Factor out an inner functions to make the code more concise.
>>> Do the same for reading 'memcg_page_stat' and 'memcg_events'.
>>>
>>> Signed-off-by: Chen Ridong <chenridong@huawei.com>
>>> ---
>>>  mm/memcontrol.c | 72 +++++++++++++++++++++----------------------------
>>>  1 file changed, 30 insertions(+), 42 deletions(-)
>>>
>>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
>>> index b10e0a8f3375..14541610cad0 100644
>>> --- a/mm/memcontrol.c
>>> +++ b/mm/memcontrol.c
>>> @@ -375,7 +375,8 @@ struct lruvec_stats {
>>>  	long state_pending[NR_MEMCG_NODE_STAT_ITEMS];
>>>  };
>>>  
>>> -unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
>>> +static unsigned long __lruvec_page_state(struct lruvec *lruvec,
>>> +		enum node_stat_item idx, bool local)
>>>  {
>>>  	struct mem_cgroup_per_node *pn;
>>>  	long x;
>>> @@ -389,7 +390,8 @@ unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
>>>  		return 0;
>>>  
>>>  	pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
>>> -	x = READ_ONCE(pn->lruvec_stats->state[i]);
>>> +	x = local ? READ_ONCE(pn->lruvec_stats->state_local[i]) :
>>> +		    READ_ONCE(pn->lruvec_stats->state[i]);
>>>  #ifdef CONFIG_SMP
>>>  	if (x < 0)
>>>  		x = 0;
>>> @@ -397,27 +399,16 @@ unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
>>>  	return x;
>>>  }
>>>  
>>> +
>>> +unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
>>> +{
>>> +	return __lruvec_page_state(lruvec, idx, false);
>>> +}
>>
>> I'd move these wrapper function definitions to memcontrol.h and make them
>> static inline.
> 
> +1
> 

Thank you.

Will update.

Best regards,
Ridong
>>
>> Other than that, lgtm.
>>
>> Thank you!