Commit 11e5f407 authored by Waiman Long's avatar Waiman Long Committed by Tejun Heo
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cgroup/cpuset: Keep track of CPUs in isolated partitions 



Add a new internal isolated_cpus mask to keep track of the CPUs that are in
isolated partitions. Expose that new cpumask as a new root-only control file
".cpuset.cpus.isolated".

tj: Updated patch description to reflect dropping __DEBUG__ prefix.

Signed-off-by: default avatarWaiman Long <longman@redhat.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 14060dfc

kernel/cgroup/cpuset.c

+127 −63
Original line number Diff line number Diff line
@@ -204,6 +204,11 @@ struct cpuset { 
 */

static cpumask_var_t	subpartitions_cpus;



/*

 * Exclusive CPUs in isolated partitions

 */

static cpumask_var_t	isolated_cpus;



/* List of remote partition root children */

static struct list_head remote_children;
@@ -1317,6 +1322,7 @@ static void compute_effective_cpumask(struct cpumask *new_cpus, 
 */

enum partition_cmd {

	partcmd_enable,		/* Enable partition root	  */

	partcmd_enablei,	/* Enable isolated partition root */

	partcmd_disable,	/* Disable partition root	  */

	partcmd_update,		/* Update parent's effective_cpus */

	partcmd_invalidate,	/* Make partition invalid	  */
@@ -1418,6 +1424,74 @@ static void reset_partition_data(struct cpuset *cs) 
	}

}



/*

 * partition_xcpus_newstate - Exclusive CPUs state change

 * @old_prs: old partition_root_state

 * @new_prs: new partition_root_state

 * @xcpus: exclusive CPUs with state change

 */

static void partition_xcpus_newstate(int old_prs, int new_prs, struct cpumask *xcpus)

{

	WARN_ON_ONCE(old_prs == new_prs);

	if (new_prs == PRS_ISOLATED)

		cpumask_or(isolated_cpus, isolated_cpus, xcpus);

	else

		cpumask_andnot(isolated_cpus, isolated_cpus, xcpus);

}



/*

 * partition_xcpus_add - Add new exclusive CPUs to partition

 * @new_prs: new partition_root_state

 * @parent: parent cpuset

 * @xcpus: exclusive CPUs to be added

 *

 * Remote partition if parent == NULL

 */

static void partition_xcpus_add(int new_prs, struct cpuset *parent,

				struct cpumask *xcpus)

{

	WARN_ON_ONCE(new_prs < 0);

	lockdep_assert_held(&callback_lock);

	if (!parent)

		parent = &top_cpuset;



	if (parent == &top_cpuset)

		cpumask_or(subpartitions_cpus, subpartitions_cpus, xcpus);



	if (new_prs != parent->partition_root_state)

		partition_xcpus_newstate(parent->partition_root_state, new_prs,

					 xcpus);



	cpumask_andnot(parent->effective_cpus, parent->effective_cpus, xcpus);

}



/*

 * partition_xcpus_del - Remove exclusive CPUs from partition

 * @old_prs: old partition_root_state

 * @parent: parent cpuset

 * @xcpus: exclusive CPUs to be removed

 *

 * Remote partition if parent == NULL

 */

static void partition_xcpus_del(int old_prs, struct cpuset *parent,

				struct cpumask *xcpus)

{

	WARN_ON_ONCE(old_prs < 0);

	lockdep_assert_held(&callback_lock);

	if (!parent)

		parent = &top_cpuset;



	if (parent == &top_cpuset)

		cpumask_andnot(subpartitions_cpus, subpartitions_cpus, xcpus);



	if (old_prs != parent->partition_root_state)

		partition_xcpus_newstate(old_prs, parent->partition_root_state,

					 xcpus);



	cpumask_and(xcpus, xcpus, cpu_active_mask);

	cpumask_or(parent->effective_cpus, parent->effective_cpus, xcpus);

}



/*

 * compute_effective_exclusive_cpumask - compute effective exclusive CPUs

 * @cs: cpuset
@@ -1456,13 +1530,15 @@ static inline bool is_local_partition(struct cpuset *cs) 
/*

 * remote_partition_enable - Enable current cpuset as a remote partition root

 * @cs: the cpuset to update

 * @new_prs: new partition_root_state

 * @tmp: temparary masks

 * Return: 1 if successful, 0 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.

 */

static int remote_partition_enable(struct cpuset *cs, struct tmpmasks *tmp)

static int remote_partition_enable(struct cpuset *cs, int new_prs,

				   struct tmpmasks *tmp)

{

	/*

	 * The user must have sysadmin privilege.
@@ -1485,18 +1561,14 @@ static int remote_partition_enable(struct cpuset *cs, struct tmpmasks *tmp) 
		return 0;



	spin_lock_irq(&callback_lock);

	cpumask_andnot(top_cpuset.effective_cpus,

		       top_cpuset.effective_cpus, tmp->new_cpus);

	cpumask_or(subpartitions_cpus,

		   subpartitions_cpus, tmp->new_cpus);



	partition_xcpus_add(new_prs, NULL, tmp->new_cpus);

	list_add(&cs->remote_sibling, &remote_children);

	if (cs->use_parent_ecpus) {

		struct cpuset *parent = parent_cs(cs);



		cs->use_parent_ecpus = false;

		parent->child_ecpus_count--;

	}

	list_add(&cs->remote_sibling, &remote_children);

	spin_unlock_irq(&callback_lock);



	/*
@@ -1524,13 +1596,8 @@ static void remote_partition_disable(struct cpuset *cs, struct tmpmasks *tmp) 
	WARN_ON_ONCE(!cpumask_subset(tmp->new_cpus, subpartitions_cpus));



	spin_lock_irq(&callback_lock);

	cpumask_andnot(subpartitions_cpus,

		       subpartitions_cpus, tmp->new_cpus);

	cpumask_and(tmp->new_cpus,

		    tmp->new_cpus, cpu_active_mask);

	cpumask_or(top_cpuset.effective_cpus,

		   top_cpuset.effective_cpus, tmp->new_cpus);

	list_del_init(&cs->remote_sibling);

	partition_xcpus_del(cs->partition_root_state, NULL, tmp->new_cpus);

	cs->partition_root_state = -cs->partition_root_state;

	if (!cs->prs_err)

		cs->prs_err = PERR_INVCPUS;
@@ -1557,6 +1624,7 @@ static void remote_cpus_update(struct cpuset *cs, struct cpumask *newmask, 
			       struct tmpmasks *tmp)

{

	bool adding, deleting;

	int prs = cs->partition_root_state;



	if (WARN_ON_ONCE(!is_remote_partition(cs)))

		return;
@@ -1580,20 +1648,10 @@ static void remote_cpus_update(struct cpuset *cs, struct cpumask *newmask, 
		goto invalidate;



	spin_lock_irq(&callback_lock);

	if (adding) {

		cpumask_or(subpartitions_cpus,

			   subpartitions_cpus, tmp->addmask);

		cpumask_andnot(top_cpuset.effective_cpus,

			       top_cpuset.effective_cpus, tmp->addmask);

	}

	if (deleting) {

		cpumask_andnot(subpartitions_cpus,

			       subpartitions_cpus, tmp->delmask);

		cpumask_and(tmp->delmask,

			    tmp->delmask, cpu_active_mask);

		cpumask_or(top_cpuset.effective_cpus,

			   top_cpuset.effective_cpus, tmp->delmask);

	}

	if (adding)

		partition_xcpus_add(prs, NULL, tmp->addmask);

	if (deleting)

		partition_xcpus_del(prs, NULL, tmp->delmask);

	spin_unlock_irq(&callback_lock);



	/*
@@ -1676,11 +1734,11 @@ static bool prstate_housekeeping_conflict(int prstate, struct cpumask *new_cpus) 
 * @tmp:     Temporary addmask and delmask

 * Return:   0 or a partition root state error code

 *

 * For partcmd_enable, the cpuset is being transformed from a non-partition

 * root to a partition root. The effective_xcpus (cpus_allowed if effective_xcpus

 * not set) mask of the given cpuset will be taken away from parent's

 * effective_cpus. The function will return 0 if all the CPUs listed in

 * effective_xcpus can be granted or an error code will be returned.

 * For partcmd_enable*, the cpuset is being transformed from a non-partition

 * root to a partition root. The effective_xcpus (cpus_allowed if

 * effective_xcpus not set) mask of the given cpuset will be taken away from

 * parent's effective_cpus. The function will return 0 if all the CPUs listed

 * in effective_xcpus can be granted or an error code will be returned.

 *

 * For partcmd_disable, the cpuset is being transformed from a partition

 * root back to a non-partition root. Any CPUs in effective_xcpus will be
@@ -1695,7 +1753,7 @@ static bool prstate_housekeeping_conflict(int prstate, struct cpumask *new_cpus) 
 *

 * For partcmd_invalidate, the current partition will be made invalid.

 *

 * The partcmd_enable and partcmd_disable commands are used by

 * The partcmd_enable* and partcmd_disable commands are used by

 * update_prstate(). An error code may be returned and the caller will check

 * for error.

 *
@@ -1760,7 +1818,7 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd, 


	nocpu = tasks_nocpu_error(parent, cs, xcpus);



	if (cmd == partcmd_enable) {

	if ((cmd == partcmd_enable) || (cmd == partcmd_enablei)) {

		/*

		 * Enabling partition root is not allowed if its

		 * effective_xcpus is empty or doesn't overlap with
@@ -1783,6 +1841,7 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd, 
		cpumask_copy(tmp->delmask, xcpus);

		deleting = true;

		subparts_delta++;

		new_prs = (cmd == partcmd_enable) ? PRS_ROOT : PRS_ISOLATED;

	} else if (cmd == partcmd_disable) {

		/*

		 * May need to add cpus to parent's effective_cpus for
@@ -1792,6 +1851,7 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd, 
			  cpumask_and(tmp->addmask, xcpus, parent->effective_xcpus);

		if (adding)

			subparts_delta--;

		new_prs = PRS_MEMBER;

	} else if (newmask) {

		/*

		 * Empty cpumask is not allowed
@@ -1940,37 +2000,24 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd, 
	 * newly deleted ones will be added back to effective_cpus.

	 */

	spin_lock_irq(&callback_lock);

	if (adding) {

		if (parent == &top_cpuset)

			cpumask_andnot(subpartitions_cpus,

				       subpartitions_cpus, tmp->addmask);

	if (old_prs != new_prs) {

		cs->partition_root_state = new_prs;

		if (new_prs <= 0)

			cs->nr_subparts = 0;

	}

	/*

		 * Some of the CPUs in effective_xcpus might have been offlined.

	 * Adding to parent's effective_cpus means deletion CPUs from cs

	 * and vice versa.

	 */

		cpumask_or(parent->effective_cpus,

			   parent->effective_cpus, tmp->addmask);

		cpumask_and(parent->effective_cpus,

			    parent->effective_cpus, cpu_active_mask);

	}

	if (deleting) {

		if (parent == &top_cpuset)

			cpumask_or(subpartitions_cpus,

				   subpartitions_cpus, tmp->delmask);

		cpumask_andnot(parent->effective_cpus,

			       parent->effective_cpus, tmp->delmask);

	}

	if (adding)

		partition_xcpus_del(old_prs, parent, tmp->addmask);

	if (deleting)

		partition_xcpus_add(new_prs, parent, tmp->delmask);



	if (is_partition_valid(parent)) {

		parent->nr_subparts += subparts_delta;

		WARN_ON_ONCE(parent->nr_subparts < 0);

	}



	if (old_prs != new_prs) {

		cs->partition_root_state = new_prs;

		if (new_prs <= 0)

			cs->nr_subparts = 0;

	}



	spin_unlock_irq(&callback_lock);



	if ((old_prs != new_prs) && (cmd == partcmd_update))
@@ -2948,6 +2995,7 @@ static int update_prstate(struct cpuset *cs, int new_prs) 
	int err = PERR_NONE, old_prs = cs->partition_root_state;

	struct cpuset *parent = parent_cs(cs);

	struct tmpmasks tmpmask;

	bool new_xcpus_state = false;



	if (old_prs == new_prs)

		return 0;
@@ -2977,6 +3025,9 @@ 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 cannot be empty.

		 */
@@ -2985,19 +3036,18 @@ static int update_prstate(struct cpuset *cs, int new_prs) 
			goto out;

		}



		err = update_parent_effective_cpumask(cs, partcmd_enable,

						      NULL, &tmpmask);

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

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

			err = 0;

	} else if (old_prs && new_prs) {

		/*

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

		 */

		;

		new_xcpus_state = true;

	} else {

		/*

		 * Switching back to member is always allowed even if it
@@ -3029,6 +3079,8 @@ static int update_prstate(struct cpuset *cs, int new_prs) 
	WRITE_ONCE(cs->prs_err, err);

	if (!is_partition_valid(cs))

		reset_partition_data(cs);

	else if (new_xcpus_state)

		partition_xcpus_newstate(old_prs, new_prs, cs->effective_xcpus);

	spin_unlock_irq(&callback_lock);



	/* Force update if switching back to member */
@@ -3386,6 +3438,7 @@ typedef enum { 
	FILE_SUBPARTS_CPULIST,

	FILE_EXCLUSIVE_CPULIST,

	FILE_EFFECTIVE_XCPULIST,

	FILE_ISOLATED_CPULIST,

	FILE_CPU_EXCLUSIVE,

	FILE_MEM_EXCLUSIVE,

	FILE_MEM_HARDWALL,
@@ -3582,6 +3635,9 @@ static int cpuset_common_seq_show(struct seq_file *sf, void *v) 
	case FILE_SUBPARTS_CPULIST:

		seq_printf(sf, "%*pbl\n", cpumask_pr_args(subpartitions_cpus));

		break;

	case FILE_ISOLATED_CPULIST:

		seq_printf(sf, "%*pbl\n", cpumask_pr_args(isolated_cpus));

		break;

	default:

		ret = -EINVAL;

	}
@@ -3875,6 +3931,13 @@ static struct cftype dfl_files[] = { 
		.flags = CFTYPE_ONLY_ON_ROOT | CFTYPE_DEBUG,

	},



	{

		.name = "cpus.isolated",

		.seq_show = cpuset_common_seq_show,

		.private = FILE_ISOLATED_CPULIST,

		.flags = CFTYPE_ONLY_ON_ROOT | CFTYPE_DEBUG,

	},



	{ }	/* terminate */

};
@@ -4194,6 +4257,7 @@ int __init cpuset_init(void) 
	BUG_ON(!alloc_cpumask_var(&top_cpuset.effective_xcpus, GFP_KERNEL));

	BUG_ON(!alloc_cpumask_var(&top_cpuset.exclusive_cpus, GFP_KERNEL));

	BUG_ON(!zalloc_cpumask_var(&subpartitions_cpus, GFP_KERNEL));

	BUG_ON(!zalloc_cpumask_var(&isolated_cpus, GFP_KERNEL));



	cpumask_setall(top_cpuset.cpus_allowed);

	nodes_setall(top_cpuset.mems_allowed);