Commit e55f45b4 authored by Chen Ridong's avatar Chen Ridong Committed by Tejun Heo
Browse files

cgroup/cpuset: Correct invalid remote parition prs 



When enable a remote partition, I found that:

cd /sys/fs/cgroup/
mkdir test
mkdir test/test1
echo +cpuset > cgroup.subtree_control
echo +cpuset >  test/cgroup.subtree_control
echo 3 > test/test1/cpuset.cpus
echo root > test/test1/cpuset.cpus.partition
cat test/test1/cpuset.cpus.partition
root invalid (Parent is not a partition root)

The parent of a remote partition could not be a root. This is due to the
emtpy effective_xcpus. It would be better to prompt the message "invalid
cpu list in cpuset.cpus.exclusive".

Signed-off-by: default avatarChen Ridong <chenridong@huawei.com>
Reviewed-by: default avatarWaiman Long <longman@redhat.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent d1a92d2d

kernel/cgroup/cpuset.c

+16 −12
Original line number Diff line number Diff line
@@ -80,6 +80,7 @@ enum prs_errcode { 
	PERR_HOTPLUG,

	PERR_CPUSEMPTY,

	PERR_HKEEPING,

	PERR_ACCESS,

};



static const char * const perr_strings[] = {
@@ -91,6 +92,7 @@ static const char * const perr_strings[] = { 
	[PERR_HOTPLUG]   = "No cpu available due to hotplug",

	[PERR_CPUSEMPTY] = "cpuset.cpus and cpuset.cpus.exclusive are empty",

	[PERR_HKEEPING]  = "partition config conflicts with housekeeping setup",

	[PERR_ACCESS]    = "Enable partition not permitted",

};



struct cpuset {
@@ -1655,7 +1657,7 @@ static inline bool is_local_partition(struct cpuset *cs) 
 * @cs: the cpuset to update

 * @new_prs: new partition_root_state

 * @tmp: temparary masks

 * Return: 1 if successful, 0 if error

 * Return: 0 if successful, errcode if error

 *

 * Enable the current cpuset to become a remote partition root taking CPUs

 * directly from the top cpuset. cpuset_mutex must be held by the caller.
@@ -1669,7 +1671,7 @@ static int remote_partition_enable(struct cpuset *cs, int new_prs, 
	 * The user must have sysadmin privilege.

	 */

	if (!capable(CAP_SYS_ADMIN))

		return 0;

		return PERR_ACCESS;



	/*

	 * The requested exclusive_cpus must not be allocated to other
@@ -1683,7 +1685,7 @@ static int remote_partition_enable(struct cpuset *cs, int new_prs, 
	if (cpumask_empty(tmp->new_cpus) ||

	    cpumask_intersects(tmp->new_cpus, subpartitions_cpus) ||

	    cpumask_subset(top_cpuset.effective_cpus, tmp->new_cpus))

		return 0;

		return PERR_INVCPUS;



	spin_lock_irq(&callback_lock);

	isolcpus_updated = partition_xcpus_add(new_prs, NULL, tmp->new_cpus);
@@ -1698,7 +1700,7 @@ static int remote_partition_enable(struct cpuset *cs, int new_prs, 
	 */

	update_tasks_cpumask(&top_cpuset, tmp->new_cpus);

	update_sibling_cpumasks(&top_cpuset, NULL, tmp);

	return 1;

	return 0;

}



/*
@@ -3151,9 +3153,6 @@ static int update_prstate(struct cpuset *cs, int new_prs) 
		goto out;



	if (!old_prs) {

		enum partition_cmd cmd = (new_prs == PRS_ROOT)

				       ? partcmd_enable : partcmd_enablei;



		/*

		 * cpus_allowed and exclusive_cpus cannot be both empty.

		 */
@@ -3162,13 +3161,18 @@ static int update_prstate(struct cpuset *cs, int new_prs) 
			goto out;

		}



		err = update_parent_effective_cpumask(cs, cmd, NULL, &tmpmask);

		/*

		 * If an attempt to become local partition root fails,

		 * try to become a remote partition root instead.

		 * If parent is valid partition, enable local partiion.

		 * Otherwise, enable a remote partition.

		 */

		if (err && remote_partition_enable(cs, new_prs, &tmpmask))

			err = 0;

		if (is_partition_valid(parent)) {

			enum partition_cmd cmd = (new_prs == PRS_ROOT)

					       ? partcmd_enable : partcmd_enablei;



			err = update_parent_effective_cpumask(cs, cmd, NULL, &tmpmask);

		} else {

			err = remote_partition_enable(cs, new_prs, &tmpmask);

		}

	} else if (old_prs && new_prs) {

		/*

		 * A change in load balance state only, no change in cpumasks.