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Subject: Re: [PATCH] mm: Add missed mem_cgroup_iter_break() into
 shrink_node_memcgs()
To:     Kirill Tkhai <ktkhai@virtuozzo.com>, akpm@linux-foundation.org,
        guro@fb.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org
References: <158142103093.888182.8911729633457501747.stgit@localhost.localdomain>
From:   Vasily Averin <vvs@virtuozzo.com>
Message-ID: <792e25d0-413f-28e0-1fd0-560523b63a45@virtuozzo.com>
Date:   Tue, 11 Feb 2020 14:46:23 +0300
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On 2/11/20 2:38 PM, Kirill Tkhai wrote:
> Leaving mem_cgroup_iter() loop requires mem_cgroup_iter_break().
> 
> Fixes: bf8d5d52ffe8 "memcg: introduce memory.min"
> Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
> ---
>  mm/vmscan.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index b1863de475fb..f6efe2348ba3 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -2653,8 +2653,9 @@ static void shrink_node_memcgs(pg_data_t *pgdat, struct scan_control *sc)
>  				continue;
>  			}
>  			memcg_memory_event(memcg, MEMCG_LOW);
> -			break;

It is not cycle break, it is switch/case break.

> +			/* fallthrough */
>  		case MEMCG_PROT_NONE:
> +			mem_cgroup_iter_break(target_memcg, memcg);
>  			/*
>  			 * All protection thresholds breached. We may
>  			 * still choose to vary the scan pressure
> 
>