Re: [PATCH 4/9] memcg: manually inline __refill_stock

[Vlastimil Babka <vbabka@suse.cz>]

On 3/18/25 01:58, Roman Gushchin wrote:
> On Sat, Mar 15, 2025 at 10:49:25AM -0700, Shakeel Butt wrote:
>> There are no more multiple callers of __refill_stock(), so simply inline
>> it to refill_stock().
>> 
>> Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
>> Acked-by: Vlastimil Babka <vbabka@suse.cz>
>> ---
>>  mm/memcontrol.c | 32 ++++++++++++--------------------
>>  1 file changed, 12 insertions(+), 20 deletions(-)
>> 
>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
>> index b54e3a1d23bd..7054b0ebd207 100644
>> --- a/mm/memcontrol.c
>> +++ b/mm/memcontrol.c
>> @@ -1865,14 +1865,21 @@ static void drain_local_stock(struct work_struct *dummy)
>>  	obj_cgroup_put(old);
>>  }
>>  
>> -/*
>> - * Cache charges(val) to local per_cpu area.
>> - * This will be consumed by consume_stock() function, later.
>> - */
>> -static void __refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
>> +/* Should never be called with root_mem_cgroup. */
> 
> How about adding something like this?
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 768d6b15dbfa..5c26002f2168 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1881,6 +1881,8 @@ static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
>  {
>         unsigned long flags;
> 
> +       VM_WARN_ON_ONCE(mem_cgroup_is_root(memcg));

Already in patch 1 though? But I agree.

> +
>         local_lock_irqsave(&memcg_stock.stock_lock, flags);
>         __refill_stock(memcg, nr_pages);
>         local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
> 
> 
> Other than that,
> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>