Re: [PATCH] memcg: reduce size of per-cpu-stat to be appropriate size.

[Balbir Singh <balbir@linux.vnet.ibm.com>]

KAMEZAWA Hiroyuki wrote:
> How about this one ?
> tested on x86-64 + mmotm-Nov10, works well. 
> (test on other arch is welcome.)
> 
> -Kame
> ==
> As  Jan Blunck <jblunck@suse.de> pointed out, allocating
> per-cpu stat for memcg to the size of NR_CPUS is not good.
> 
> This patch changes mem_cgroup's cpustat allocation not based
> on NR_CPUS but based on nr_cpu_ids.
> 
> From: Jan Blunck <jblunck@suse.de>
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> 
> ---
>  mm/memcontrol.c |   34 ++++++++++++++++++----------------
>  1 file changed, 18 insertions(+), 16 deletions(-)
> 
> Index: mmotm-2.6.28-Nov10/mm/memcontrol.c
> ===================================================================
> --- mmotm-2.6.28-Nov10.orig/mm/memcontrol.c
> +++ mmotm-2.6.28-Nov10/mm/memcontrol.c
> @@ -60,7 +60,7 @@ struct mem_cgroup_stat_cpu {
>  } ____cacheline_aligned_in_smp;
> 
>  struct mem_cgroup_stat {
> -	struct mem_cgroup_stat_cpu cpustat[NR_CPUS];
> +	struct mem_cgroup_stat_cpu cpustat[0];
>  };
> 
>  /*
> @@ -129,11 +129,10 @@ struct mem_cgroup {
> 
>  	int	prev_priority;	/* for recording reclaim priority */
>  	/*
> -	 * statistics.
> +	 * statistics. This must be placed at the end of memcg.
>  	 */
>  	struct mem_cgroup_stat stat;
>  };
> -static struct mem_cgroup init_mem_cgroup;
> 
>  enum charge_type {
>  	MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
> @@ -1292,42 +1291,45 @@ static void free_mem_cgroup_per_zone_inf
>  	kfree(mem->info.nodeinfo[node]);
>  }
> 
> +static int mem_cgroup_size(void)

inline this function?

Other than that, I think the cont->parent check for freeing has already been
spotted and pointed out


-- 
	Balbir