Re: [PATCH 2/3] Introduce the res_counter_populate() function

[Balbir Singh <balbir-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>]

Pavel Emelyanov wrote:
> 
> diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h
> index 61363ce..8ee8316 100644
> --- a/include/linux/res_counter.h
> +++ b/include/linux/res_counter.h
> @@ -58,6 +58,9 @@ ssize_t res_counter_write(struct res_cou
>  		const char __user *buf, size_t nbytes, loff_t *pos,
>  		int (*write_strategy)(char *buf, unsigned long long *val));
> 
> +int res_counter_populate(struct cgroup_subsys *ss, struct cgroup *cont,
> +		struct cftype files[], cft_read read_fn, cft_write write_fn);
> +
>  /*
>   * the field descriptors. one for each member of res_counter
>   */
> @@ -66,6 +69,8 @@ enum {
>  	RES_USAGE,
>  	RES_LIMIT,
>  	RES_FAILCNT,
> +
> +	RES_CFT_MAX,
>  };
> 

This is good

>  /*
> diff --git a/kernel/res_counter.c b/kernel/res_counter.c
> index d7f43cd..018eb2b 100644
> --- a/kernel/res_counter.c
> +++ b/kernel/res_counter.c
> @@ -10,9 +10,34 @@
>  #include <linux/types.h>
>  #include <linux/parser.h>
>  #include <linux/fs.h>
> +#include <linux/cgroup.h>
>  #include <linux/res_counter.h>
>  #include <linux/uaccess.h>
> 
> +int res_counter_populate(struct cgroup_subsys *ss, struct cgroup *cont,
> +		struct cftype files[], cft_read read_fn, cft_write write_fn)
> +{
> +	/*
> +	 * to be on the safe side
> +	 */
> +	memset(files, 0, RES_CFT_MAX * sizeof(struct cftype));
> +
> +	strcpy(files[RES_USAGE].name, "usage_in_bytes");

This needs to be controller pluggable

> +	files[RES_USAGE].private = RES_USAGE;
> +	files[RES_USAGE].read = read_fn;
> +
> +	strcpy(files[RES_LIMIT].name, "limit_in_bytes");

This needs to be controller pluggable

> +	files[RES_LIMIT].private = RES_LIMIT;
> +	files[RES_LIMIT].read = read_fn;
> +	files[RES_LIMIT].write = write_fn;
> +
> +	strcpy(files[RES_FAILCNT].name, "failcnt");
> +	files[RES_FAILCNT].private = RES_FAILCNT;
> +	files[RES_FAILCNT].read = read_fn;
> +
> +	return cgroup_add_files(cont, ss, files, RES_CFT_MAX);
> +}
> +

I've been thinking of writing a tool, that will generate all
the code necessary to write a controller under cgroups.
Another TODO (low priority).

>  void res_counter_init(struct res_counter *counter)
>  {
>  	spin_lock_init(&counter->lock);
> 
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-- 
	Warm Regards,
	Balbir Singh
	Linux Technology Center
	IBM, ISTL