[Devel] Re: [PATCH v2 03/13] memcg: Uncharge all kmem when deleting a cgroup.

[KAMEZAWA Hiroyuki]

On Fri,  9 Mar 2012 12:39:06 -0800
Suleiman Souhlal <ssouhlal at FreeBSD.org> wrote:

> Signed-off-by: Suleiman Souhlal <suleiman at google.com>
> ---
>  mm/memcontrol.c |   31 ++++++++++++++++++++++++++++++-
>  1 files changed, 30 insertions(+), 1 deletions(-)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index e6fd558..6fbb438 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -382,6 +382,7 @@ static void mem_cgroup_get(struct mem_cgroup *memcg);
>  static void mem_cgroup_put(struct mem_cgroup *memcg);
>  static void memcg_kmem_init(struct mem_cgroup *memcg,
>      struct mem_cgroup *parent);
> +static void memcg_kmem_move(struct mem_cgroup *memcg);
>  
>  static inline bool
>  mem_cgroup_test_flag(const struct mem_cgroup *memcg, enum memcg_flags flag)
> @@ -3700,6 +3701,7 @@ static int mem_cgroup_force_empty(struct mem_cgroup *memcg, bool free_all)
>  	int ret;
>  	int node, zid, shrink;
>  	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
> +	unsigned long usage;
>  	struct cgroup *cgrp = memcg->css.cgroup;
>  
>  	css_get(&memcg->css);
> @@ -3719,6 +3721,8 @@ move_account:
>  		/* This is for making all *used* pages to be on LRU. */
>  		lru_add_drain_all();
>  		drain_all_stock_sync(memcg);
> +		if (!free_all)
> +			memcg_kmem_move(memcg);
>  		ret = 0;
>  		mem_cgroup_start_move(memcg);
>  		for_each_node_state(node, N_HIGH_MEMORY) {
> @@ -3740,8 +3744,14 @@ move_account:
>  		if (ret == -ENOMEM)
>  			goto try_to_free;
>  		cond_resched();
> +		usage = memcg->res.usage;
> +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
> +		if (free_all && !mem_cgroup_test_flag(memcg,
> +		    MEMCG_INDEPENDENT_KMEM_LIMIT))
> +			usage -= memcg->kmem.usage;
> +#endif
>  	/* "ret" should also be checked to ensure all lists are empty. */
> -	} while (memcg->res.usage > 0 || ret);
> +	} while (usage > 0 || ret);
>  out:
>  	css_put(&memcg->css);
>  	return ret;
> @@ -5689,9 +5699,28 @@ memcg_kmem_init(struct mem_cgroup *memcg, struct mem_cgroup *parent)
>  		parent_res = &parent->kmem;
>  	res_counter_init(&memcg->kmem, parent_res);
>  }
> +
> +static void
> +memcg_kmem_move(struct mem_cgroup *memcg)

the function name says 'move' but the code seems just do 'forget'
or 'leak'...


> +{
> +	unsigned long flags;
> +	long kmem;
> +
> +	spin_lock_irqsave(&memcg->kmem.lock, flags);
> +	kmem = memcg->kmem.usage;
> +	res_counter_uncharge_locked(&memcg->kmem, kmem);
> +	spin_unlock_irqrestore(&memcg->kmem.lock, flags);
> +	if (!mem_cgroup_test_flag(memcg, MEMCG_INDEPENDENT_KMEM_LIMIT))
> +		res_counter_uncharge(&memcg->res, kmem);
> +}

please update memcg->memsw, too.

Thanks,
-Kame



>  #else /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
>  static void
>  memcg_kmem_init(struct mem_cgroup *memcg, struct mem_cgroup *parent)
>  {
>  }
> +
> +static void
> +memcg_kmem_move(struct mem_cgroup *memcg)
> +{
> +}
>  #endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
> -- 
> 1.7.7.3
>