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Commit bb5b553c authored by Waiman Long's avatar Waiman Long Committed by Tejun Heo
Browse files

cpuset: Use descriptive text when reading/writing cpuset.sched.partition 



Currently, cpuset.sched.partition returns the values, 0, 1 or -1 on
read. A person who is not familiar with the partition code may not
understand what they mean.

In order to make cpuset.sched.partition more user-friendly, it will
now display the following descriptive text on read:

  "root" - A partition root (top cpuset of a partition)
  "member" - A non-root member of a partition
  "root invalid" - An invalid partition root

Note that there is at least one partition in the whole cgroup hierarchy.
The top cpuset is the root of that partition.  The rests are either a
root if it starts a new partition or a member of a partition.

The cpuset.sched.partition file will now also accept "root" and
"member" besides 1 and 0 as valid input values. The "root invalid"
value is internal only and cannot be written to the file.

Suggested-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarWaiman Long <longman@redhat.com>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 5776cecc

kernel/cgroup/cpuset.c

+51 −7
Original line number Diff line number Diff line
@@ -2278,9 +2278,6 @@ static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft, 
	case FILE_SCHED_RELAX_DOMAIN_LEVEL:

		retval = update_relax_domain_level(cs, val);

		break;

	case FILE_PARTITION_ROOT:

		retval = update_prstate(cs, val);

		break;

	default:

		retval = -EINVAL;

		break;
@@ -2431,8 +2428,6 @@ static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft) 
	switch (type) {

	case FILE_SCHED_RELAX_DOMAIN_LEVEL:

		return cs->relax_domain_level;

	case FILE_PARTITION_ROOT:

		return cs->partition_root_state;

	default:

		BUG();

	}
@@ -2441,6 +2436,55 @@ static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft) 
	return 0;

}



static int sched_partition_show(struct seq_file *seq, void *v)

{

	struct cpuset *cs = css_cs(seq_css(seq));



	switch (cs->partition_root_state) {

	case PRS_ENABLED:

		seq_puts(seq, "root\n");

		break;

	case PRS_DISABLED:

		seq_puts(seq, "member\n");

		break;

	case PRS_ERROR:

		seq_puts(seq, "root invalid\n");

		break;

	}

	return 0;

}



static ssize_t sched_partition_write(struct kernfs_open_file *of, char *buf,

				     size_t nbytes, loff_t off)

{

	struct cpuset *cs = css_cs(of_css(of));

	int val;

	int retval = -ENODEV;



	buf = strstrip(buf);



	/*

	 * Convert "root"/"1" to 1, and convert "member"/"0" to 0.

	 */

	if (!strcmp(buf, "root") || !strcmp(buf, "1"))

		val = PRS_ENABLED;

	else if (!strcmp(buf, "member") || !strcmp(buf, "0"))

		val = PRS_DISABLED;

	else

		return -EINVAL;



	css_get(&cs->css);

	mutex_lock(&cpuset_mutex);

	if (!is_cpuset_online(cs))

		goto out_unlock;



	retval = update_prstate(cs, val);

out_unlock:

	mutex_unlock(&cpuset_mutex);

	css_put(&cs->css);

	return retval ?: nbytes;

}



/*

 * for the common functions, 'private' gives the type of file

 */
@@ -2584,8 +2628,8 @@ static struct cftype dfl_files[] = { 


	{

		.name = "sched.partition",

		.read_s64 = cpuset_read_s64,

		.write_s64 = cpuset_write_s64,

		.seq_show = sched_partition_show,

		.write = sched_partition_write,

		.private = FILE_PARTITION_ROOT,

		.flags = CFTYPE_NOT_ON_ROOT,

	},