Re: [patch 3/6] mm: memcg: print statistics directly to seq_file

[Michal Hocko]

On Mon 14-05-12 20:00:48, Johannes Weiner wrote:
> Being able to use seq_printf() allows being smarter about statistics
> name strings, which are currently listed twice, with the only
> difference being a "total_" prefix on the hierarchical version.
> 
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>

Nice
Acked-by: Michal Hocko <mhocko@xxxxxxx>

> ---
>  mm/memcontrol.c |   56 +++++++++++++++++++++++++++----------------------------
>  1 file changed, 28 insertions(+), 28 deletions(-)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index f0d248b..9e8551c 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -4274,24 +4274,21 @@ struct mcs_total_stat {
>  	s64 stat[NR_MCS_STAT];
>  };
>  
> -static struct {
> -	char *local_name;
> -	char *total_name;
> -} memcg_stat_strings[NR_MCS_STAT] = {
> -	{"cache", "total_cache"},
> -	{"rss", "total_rss"},
> -	{"mapped_file", "total_mapped_file"},
> -	{"mlock", "total_mlock"},
> -	{"pgpgin", "total_pgpgin"},
> -	{"pgpgout", "total_pgpgout"},
> -	{"swap", "total_swap"},
> -	{"pgfault", "total_pgfault"},
> -	{"pgmajfault", "total_pgmajfault"},
> -	{"inactive_anon", "total_inactive_anon"},
> -	{"active_anon", "total_active_anon"},
> -	{"inactive_file", "total_inactive_file"},
> -	{"active_file", "total_active_file"},
> -	{"unevictable", "total_unevictable"}
> +static const char *memcg_stat_strings[NR_MCS_STAT] = {
> +	"cache",
> +	"rss",
> +	"mapped_file",
> +	"mlock",
> +	"pgpgin",
> +	"pgpgout",
> +	"swap",
> +	"pgfault",
> +	"pgmajfault",
> +	"inactive_anon",
> +	"active_anon",
> +	"inactive_file",
> +	"active_file",
> +	"unevictable",
>  };
>  
>  
> @@ -4392,7 +4389,7 @@ static int mem_control_numa_stat_show(struct cgroup *cont, struct cftype *cft,
>  #endif /* CONFIG_NUMA */
>  
>  static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
> -				 struct cgroup_map_cb *cb)
> +				 struct seq_file *m)
>  {
>  	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
>  	struct mcs_total_stat mystat;
> @@ -4405,16 +4402,18 @@ static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
>  	for (i = 0; i < NR_MCS_STAT; i++) {
>  		if (i == MCS_SWAP && !do_swap_account)
>  			continue;
> -		cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
> +		seq_printf(m, "%s %llu\n", memcg_stat_strings[i],
> +			   (unsigned long long)mystat.stat[i]);
>  	}
>  
>  	/* Hierarchical information */
>  	{
>  		unsigned long long limit, memsw_limit;
>  		memcg_get_hierarchical_limit(memcg, &limit, &memsw_limit);
> -		cb->fill(cb, "hierarchical_memory_limit", limit);
> +		seq_printf(m, "hierarchical_memory_limit %llu\n", limit);
>  		if (do_swap_account)
> -			cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
> +			seq_printf(m, "hierarchical_memsw_limit %llu\n",
> +				   memsw_limit);
>  	}
>  
>  	memset(&mystat, 0, sizeof(mystat));
> @@ -4422,7 +4421,8 @@ static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
>  	for (i = 0; i < NR_MCS_STAT; i++) {
>  		if (i == MCS_SWAP && !do_swap_account)
>  			continue;
> -		cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
> +		seq_printf(m, "total_%s %llu\n", memcg_stat_strings[i],
> +			   (unsigned long long)mystat.stat[i]);
>  	}
>  
>  #ifdef CONFIG_DEBUG_VM
> @@ -4443,10 +4443,10 @@ static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
>  				recent_scanned[0] += rstat->recent_scanned[0];
>  				recent_scanned[1] += rstat->recent_scanned[1];
>  			}
> -		cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
> -		cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
> -		cb->fill(cb, "recent_scanned_anon", recent_scanned[0]);
> -		cb->fill(cb, "recent_scanned_file", recent_scanned[1]);
> +		seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]);
> +		seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]);
> +		seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]);
> +		seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]);
>  	}
>  #endif
>  
> @@ -4880,7 +4880,7 @@ static struct cftype mem_cgroup_files[] = {
>  	},
>  	{
>  		.name = "stat",
> -		.read_map = mem_control_stat_show,
> +		.read_seq_string = mem_control_stat_show,
>  	},
>  	{
>  		.name = "force_empty",
> -- 
> 1.7.10.1
> 

-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic
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