diff mbox series

[v7,04/12] mm: vmscan: remove memcg_shrinker_map_size

Message ID 20210209174646.1310591-5-shy828301@gmail.com (mailing list archive)
State New
Headers show
Series [v7,01/12] mm: vmscan: use nid from shrink_control for tracepoint | expand

Commit Message

Yang Shi Feb. 9, 2021, 5:46 p.m. UTC
Both memcg_shrinker_map_size and shrinker_nr_max is maintained, but actually the
map size can be calculated via shrinker_nr_max, so it seems unnecessary to keep both.
Remove memcg_shrinker_map_size since shrinker_nr_max is also used by iterating the
bit map.

Acked-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Yang Shi <shy828301@gmail.com>
---
 mm/vmscan.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

Comments

Roman Gushchin Feb. 9, 2021, 8:43 p.m. UTC | #1
On Tue, Feb 09, 2021 at 09:46:38AM -0800, Yang Shi wrote:
> Both memcg_shrinker_map_size and shrinker_nr_max is maintained, but actually the
> map size can be calculated via shrinker_nr_max, so it seems unnecessary to keep both.
> Remove memcg_shrinker_map_size since shrinker_nr_max is also used by iterating the
> bit map.
> 
> Acked-by: Kirill Tkhai <ktkhai@virtuozzo.com>
> Signed-off-by: Yang Shi <shy828301@gmail.com>
> ---
>  mm/vmscan.c | 18 +++++++++---------
>  1 file changed, 9 insertions(+), 9 deletions(-)
> 
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index e4ddaaaeffe2..641077b09e5d 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -185,8 +185,10 @@ static LIST_HEAD(shrinker_list);
>  static DECLARE_RWSEM(shrinker_rwsem);
>  
>  #ifdef CONFIG_MEMCG
> +static int shrinker_nr_max;
>  
> -static int memcg_shrinker_map_size;
> +#define NR_MAX_TO_SHR_MAP_SIZE(nr_max) \
> +	(DIV_ROUND_UP(nr_max, BITS_PER_LONG) * sizeof(unsigned long))

How about something like this?

static inline int shrinker_map_size(int nr_items)
{
	return DIV_ROUND_UP(nr_items, BITS_PER_LONG) * sizeof(unsigned long);
}

I think it look less cryptic.

The rest of the patch looks good to me.

Thanks!
Yang Shi Feb. 9, 2021, 11:31 p.m. UTC | #2
On Tue, Feb 9, 2021 at 12:43 PM Roman Gushchin <guro@fb.com> wrote:
>
> On Tue, Feb 09, 2021 at 09:46:38AM -0800, Yang Shi wrote:
> > Both memcg_shrinker_map_size and shrinker_nr_max is maintained, but actually the
> > map size can be calculated via shrinker_nr_max, so it seems unnecessary to keep both.
> > Remove memcg_shrinker_map_size since shrinker_nr_max is also used by iterating the
> > bit map.
> >
> > Acked-by: Kirill Tkhai <ktkhai@virtuozzo.com>
> > Signed-off-by: Yang Shi <shy828301@gmail.com>
> > ---
> >  mm/vmscan.c | 18 +++++++++---------
> >  1 file changed, 9 insertions(+), 9 deletions(-)
> >
> > diff --git a/mm/vmscan.c b/mm/vmscan.c
> > index e4ddaaaeffe2..641077b09e5d 100644
> > --- a/mm/vmscan.c
> > +++ b/mm/vmscan.c
> > @@ -185,8 +185,10 @@ static LIST_HEAD(shrinker_list);
> >  static DECLARE_RWSEM(shrinker_rwsem);
> >
> >  #ifdef CONFIG_MEMCG
> > +static int shrinker_nr_max;
> >
> > -static int memcg_shrinker_map_size;
> > +#define NR_MAX_TO_SHR_MAP_SIZE(nr_max) \
> > +     (DIV_ROUND_UP(nr_max, BITS_PER_LONG) * sizeof(unsigned long))
>
> How about something like this?
>
> static inline int shrinker_map_size(int nr_items)
> {
>         return DIV_ROUND_UP(nr_items, BITS_PER_LONG) * sizeof(unsigned long);
> }
>
> I think it look less cryptic.

OK, I don't have a strong opinion for either one (inline function or
macro). If no one objects this I could do it in the new version.

>
> The rest of the patch looks good to me.
>
> Thanks!
Vlastimil Babka Feb. 10, 2021, 6:14 p.m. UTC | #3
On 2/9/21 9:43 PM, Roman Gushchin wrote:
> On Tue, Feb 09, 2021 at 09:46:38AM -0800, Yang Shi wrote:
>> Both memcg_shrinker_map_size and shrinker_nr_max is maintained, but actually the
>> map size can be calculated via shrinker_nr_max, so it seems unnecessary to keep both.
>> Remove memcg_shrinker_map_size since shrinker_nr_max is also used by iterating the
>> bit map.
>> 
>> Acked-by: Kirill Tkhai <ktkhai@virtuozzo.com>
>> Signed-off-by: Yang Shi <shy828301@gmail.com>

Acked-by: Vlastimil Babka <vbabka@suse.cz>

>> ---
>>  mm/vmscan.c | 18 +++++++++---------
>>  1 file changed, 9 insertions(+), 9 deletions(-)
>> 
>> diff --git a/mm/vmscan.c b/mm/vmscan.c
>> index e4ddaaaeffe2..641077b09e5d 100644
>> --- a/mm/vmscan.c
>> +++ b/mm/vmscan.c
>> @@ -185,8 +185,10 @@ static LIST_HEAD(shrinker_list);
>>  static DECLARE_RWSEM(shrinker_rwsem);
>>  
>>  #ifdef CONFIG_MEMCG
>> +static int shrinker_nr_max;
>>  
>> -static int memcg_shrinker_map_size;
>> +#define NR_MAX_TO_SHR_MAP_SIZE(nr_max) \
>> +	(DIV_ROUND_UP(nr_max, BITS_PER_LONG) * sizeof(unsigned long))
> 
> How about something like this?
> 
> static inline int shrinker_map_size(int nr_items)
> {
> 	return DIV_ROUND_UP(nr_items, BITS_PER_LONG) * sizeof(unsigned long);
> }
> 
> I think it look less cryptic.

Yeah that looks nicer so I'm fine with that potential change.

> The rest of the patch looks good to me.
> 
> Thanks!
>
diff mbox series

Patch

diff --git a/mm/vmscan.c b/mm/vmscan.c
index e4ddaaaeffe2..641077b09e5d 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -185,8 +185,10 @@  static LIST_HEAD(shrinker_list);
 static DECLARE_RWSEM(shrinker_rwsem);
 
 #ifdef CONFIG_MEMCG
+static int shrinker_nr_max;
 
-static int memcg_shrinker_map_size;
+#define NR_MAX_TO_SHR_MAP_SIZE(nr_max) \
+	(DIV_ROUND_UP(nr_max, BITS_PER_LONG) * sizeof(unsigned long))
 
 static void free_shrinker_map_rcu(struct rcu_head *head)
 {
@@ -247,7 +249,7 @@  int alloc_shrinker_maps(struct mem_cgroup *memcg)
 		return 0;
 
 	down_write(&shrinker_rwsem);
-	size = memcg_shrinker_map_size;
+	size = NR_MAX_TO_SHR_MAP_SIZE(shrinker_nr_max);
 	for_each_node(nid) {
 		map = kvzalloc_node(sizeof(*map) + size, GFP_KERNEL, nid);
 		if (!map) {
@@ -265,12 +267,13 @@  int alloc_shrinker_maps(struct mem_cgroup *memcg)
 static int expand_shrinker_maps(int new_id)
 {
 	int size, old_size, ret = 0;
+	int new_nr_max = new_id + 1;
 	struct mem_cgroup *memcg;
 
-	size = DIV_ROUND_UP(new_id + 1, BITS_PER_LONG) * sizeof(unsigned long);
-	old_size = memcg_shrinker_map_size;
+	size = NR_MAX_TO_SHR_MAP_SIZE(new_nr_max);
+	old_size = NR_MAX_TO_SHR_MAP_SIZE(shrinker_nr_max);
 	if (size <= old_size)
-		return 0;
+		goto out;
 
 	if (!root_mem_cgroup)
 		goto out;
@@ -287,7 +290,7 @@  static int expand_shrinker_maps(int new_id)
 	} while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
 out:
 	if (!ret)
-		memcg_shrinker_map_size = size;
+		shrinker_nr_max = new_nr_max;
 
 	return ret;
 }
@@ -320,7 +323,6 @@  void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id)
 #define SHRINKER_REGISTERING ((struct shrinker *)~0UL)
 
 static DEFINE_IDR(shrinker_idr);
-static int shrinker_nr_max;
 
 static int prealloc_memcg_shrinker(struct shrinker *shrinker)
 {
@@ -337,8 +339,6 @@  static int prealloc_memcg_shrinker(struct shrinker *shrinker)
 			idr_remove(&shrinker_idr, id);
 			goto unlock;
 		}
-
-		shrinker_nr_max = id + 1;
 	}
 	shrinker->id = id;
 	ret = 0;