Re: [PATCH] mm, memcg: add workingset_restore in memory.stat

[Michal Hocko <mhocko@kernel.org>]

On Sat 02-05-20 10:18:49, Yafang Shao wrote:
> There's a new workingset counter introduced in commit 1899ad18c607 ("mm:
> workingset: tell cache transitions from workingset thrashing"). With the
> help of this counter we can know the workingset is transitioning or
> thrashing. To leverage the benifit of this counter to memcg, we should
> introduce it into memory.stat. Then we could know the workingset of the
> workload inside a memcg better.
> 
> Bellow is the verification of this new counter in memory.stat.
> Read a file into the memory and then read it again to make these pages be
> active. The size of this file is 1G. (memory.max is greater than file size)
> The counters in memory.stat will be,
> 	inactive_file 0
> 	active_file 1073639424
> 
> 	workingset_refault 0
> 	workingset_activate 0
> 	workingset_restore 0
> 	workingset_nodereclaim 0
> Trigger the memcg reclaim by setting a lower value to memory.high, and
> then some pages will be demoted into inactive list, and then some pages
> in the inactive list will be evicted into the storage.
> 	inactive_file 498094080
> 	active_file 310063104
> 
> 	workingset_refault 0
> 	workingset_activate 0
> 	workingset_restore 0
> 	workingset_nodereclaim 0
> Then recover the memory.high and read the file into memory again. As a
> result of it, the transitioning will occur. Bellow is the result of this
> transitioning,
> 	inactive_file 498094080
> 	active_file 575397888
> 
> 	workingset_refault 64746
> 	workingset_activate 64746
> 	workingset_restore 64746
> 	workingset_nodereclaim 0

Could you update Documentation/admin-guide/cgroup-v2.rst as well please?

> Signed-off-by: Yafang Shao <laoar.shao@gmail.com>

Acked-by: Michal Hocko <mhocko@suse.com>

> ---
>  mm/memcontrol.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 5beea03dd58a..0395e479995b 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1451,6 +1451,8 @@ static char *memory_stat_format(struct mem_cgroup *memcg)
>  		       memcg_page_state(memcg, WORKINGSET_REFAULT));
>  	seq_buf_printf(&s, "workingset_activate %lu\n",
>  		       memcg_page_state(memcg, WORKINGSET_ACTIVATE));
> +	seq_buf_printf(&s, "workingset_restore %lu\n",
> +		       memcg_page_state(memcg, WORKINGSET_RESTORE));
>  	seq_buf_printf(&s, "workingset_nodereclaim %lu\n",
>  		       memcg_page_state(memcg, WORKINGSET_NODERECLAIM));
>  
> -- 
> 2.18.2

-- 
Michal Hocko
SUSE Labs