[Devel] [PATCH rh7 v2] mm/memcg: fix cache growth above cache.limit_in_bytes

[Denis V. Lunev]

On 7/30/20 4:58 PM, Andrey Ryabinin wrote:
> Exceeding cache above cache.limit_in_bytes schedules high_work_func()
> which tries to reclaim 32 pages. If cache generated fast enough or it allows
> cgroup to steadily grow above cache.limit_in_bytes because we don't reclaim
> enough. Try to reclaim exceeded amount of cache instead.
>
> https://jira.sw.ru/browse/PSBM-106384
> Signed-off-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
> ---
>
> Changes since v1: add bug link to changelog
>
>  mm/memcontrol.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 3cf200f506c3..e5adb0e81cbb 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -3080,12 +3080,16 @@ static void reclaim_high(struct mem_cgroup *memcg,
>  {
>  
>  	do {
> +		unsigned long cache_overused;
> +
>  		if (page_counter_read(&memcg->memory) > memcg->high)
>  			try_to_free_mem_cgroup_pages(memcg, nr_pages, gfp_mask, 0);
>  
> -		if (page_counter_read(&memcg->cache) > memcg->cache.limit)
> -			try_to_free_mem_cgroup_pages(memcg, nr_pages, gfp_mask,
> -						MEM_CGROUP_RECLAIM_NOSWAP);
> +		cache_overused = page_counter_read(&memcg->cache) -
> +			memcg->cache.limit;
> +		if (cache_overused)
> +			try_to_free_mem_cgroup_pages(memcg, cache_overused,
> +					gfp_mask, MEM_CGROUP_RECLAIM_NOSWAP);
>  
>  	} while ((memcg = parent_mem_cgroup(memcg)));
>  }
can we run some testing and after that create custom RK to make check with
HostEurope on Monday?