Commit 23ca5237 authored by Chen Ridong's avatar Chen Ridong Committed by Tejun Heo
Browse files

cgroup/cpuset: move legacy hotplug update to cpuset-v1.c 



There are some differents about hotplug update between cpuset v1 and
cpuset v2. Move the legacy code to cpuset-v1.c.

'update_tasks_cpumask' and 'update_tasks_nodemask' are both used in cpuset
v1 and cpuset v2, declare them in cpuset-internal.h.

The change from original code is that use callback_lock helpers to get
callback_lock lock/unlock.

Signed-off-by: default avatarChen Ridong <chenridong@huawei.com>
Acked-by: default avatarWaiman Long <longman@redhat.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 530020f2

kernel/cgroup/cpuset-internal.h

+5 −0
Original line number Diff line number Diff line
@@ -241,6 +241,8 @@ static inline int is_spread_slab(const struct cpuset *cs) 
void rebuild_sched_domains_locked(void);

void callback_lock_irq(void);

void callback_unlock_irq(void);

void update_tasks_cpumask(struct cpuset *cs, struct cpumask *new_cpus);

void update_tasks_nodemask(struct cpuset *cs);



/*

 * cpuset-v1.c
@@ -253,5 +255,8 @@ s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft); 
void cpuset_update_task_spread_flags(struct cpuset *cs,

					struct task_struct *tsk);

void update_tasks_flags(struct cpuset *cs);

void hotplug_update_tasks_legacy(struct cpuset *cs,

			    struct cpumask *new_cpus, nodemask_t *new_mems,

			    bool cpus_updated, bool mems_updated);



#endif /* __CPUSET_INTERNAL_H */

kernel/cgroup/cpuset-v1.c

+91 −0
Original line number Diff line number Diff line
@@ -2,6 +2,14 @@ 


#include "cpuset-internal.h"



/*

 * Legacy hierarchy call to cgroup_transfer_tasks() is handled asynchrously

 */

struct cpuset_remove_tasks_struct {

	struct work_struct work;

	struct cpuset *cs;

};



/*

 * Frequency meter - How fast is some event occurring?

 *
@@ -236,3 +244,86 @@ void update_tasks_flags(struct cpuset *cs) 
		cpuset_update_task_spread_flags(cs, task);

	css_task_iter_end(&it);

}



/*

 * If CPU and/or memory hotplug handlers, below, unplug any CPUs

 * or memory nodes, we need to walk over the cpuset hierarchy,

 * removing that CPU or node from all cpusets.  If this removes the

 * last CPU or node from a cpuset, then move the tasks in the empty

 * cpuset to its next-highest non-empty parent.

 */

static void remove_tasks_in_empty_cpuset(struct cpuset *cs)

{

	struct cpuset *parent;



	/*

	 * Find its next-highest non-empty parent, (top cpuset

	 * has online cpus, so can't be empty).

	 */

	parent = parent_cs(cs);

	while (cpumask_empty(parent->cpus_allowed) ||

			nodes_empty(parent->mems_allowed))

		parent = parent_cs(parent);



	if (cgroup_transfer_tasks(parent->css.cgroup, cs->css.cgroup)) {

		pr_err("cpuset: failed to transfer tasks out of empty cpuset ");

		pr_cont_cgroup_name(cs->css.cgroup);

		pr_cont("\n");

	}

}



static void cpuset_migrate_tasks_workfn(struct work_struct *work)

{

	struct cpuset_remove_tasks_struct *s;



	s = container_of(work, struct cpuset_remove_tasks_struct, work);

	remove_tasks_in_empty_cpuset(s->cs);

	css_put(&s->cs->css);

	kfree(s);

}



void hotplug_update_tasks_legacy(struct cpuset *cs,

			    struct cpumask *new_cpus, nodemask_t *new_mems,

			    bool cpus_updated, bool mems_updated)

{

	bool is_empty;



	callback_lock_irq();

	cpumask_copy(cs->cpus_allowed, new_cpus);

	cpumask_copy(cs->effective_cpus, new_cpus);

	cs->mems_allowed = *new_mems;

	cs->effective_mems = *new_mems;

	callback_unlock_irq();



	/*

	 * Don't call update_tasks_cpumask() if the cpuset becomes empty,

	 * as the tasks will be migrated to an ancestor.

	 */

	if (cpus_updated && !cpumask_empty(cs->cpus_allowed))

		update_tasks_cpumask(cs, new_cpus);

	if (mems_updated && !nodes_empty(cs->mems_allowed))

		update_tasks_nodemask(cs);



	is_empty = cpumask_empty(cs->cpus_allowed) ||

		   nodes_empty(cs->mems_allowed);



	/*

	 * Move tasks to the nearest ancestor with execution resources,

	 * This is full cgroup operation which will also call back into

	 * cpuset. Execute it asynchronously using workqueue.

	 */

	if (is_empty && cs->css.cgroup->nr_populated_csets &&

	    css_tryget_online(&cs->css)) {

		struct cpuset_remove_tasks_struct *s;



		s = kzalloc(sizeof(*s), GFP_KERNEL);

		if (WARN_ON_ONCE(!s)) {

			css_put(&cs->css);

			return;

		}



		s->cs = cs;

		INIT_WORK(&s->work, cpuset_migrate_tasks_workfn);

		schedule_work(&s->work);

	}

}

kernel/cgroup/cpuset.c

+2 −94
Original line number Diff line number Diff line
@@ -65,14 +65,6 @@ static const char * const perr_strings[] = { 
	[PERR_ACCESS]    = "Enable partition not permitted",

};



/*

 * Legacy hierarchy call to cgroup_transfer_tasks() is handled asynchrously

 */

struct cpuset_remove_tasks_struct {

	struct work_struct work;

	struct cpuset *cs;

};



/*

 * Exclusive CPUs distributed out to sub-partitions of top_cpuset

 */
@@ -1144,7 +1136,7 @@ void rebuild_sched_domains(void) 
 * is used instead of effective_cpus to make sure all offline CPUs are also

 * included as hotplug code won't update cpumasks for tasks in top_cpuset.

 */

static void update_tasks_cpumask(struct cpuset *cs, struct cpumask *new_cpus)

void update_tasks_cpumask(struct cpuset *cs, struct cpumask *new_cpus)

{

	struct css_task_iter it;

	struct task_struct *task;
@@ -2597,7 +2589,7 @@ static void *cpuset_being_rebound; 
 * effective cpuset's.  As this function is called with cpuset_mutex held,

 * cpuset membership stays stable.

 */

static void update_tasks_nodemask(struct cpuset *cs)

void update_tasks_nodemask(struct cpuset *cs)

{

	static nodemask_t newmems;	/* protected by cpuset_mutex */

	struct css_task_iter it;
@@ -3936,90 +3928,6 @@ int __init cpuset_init(void) 
	return 0;

}



/*

 * If CPU and/or memory hotplug handlers, below, unplug any CPUs

 * or memory nodes, we need to walk over the cpuset hierarchy,

 * removing that CPU or node from all cpusets.  If this removes the

 * last CPU or node from a cpuset, then move the tasks in the empty

 * cpuset to its next-highest non-empty parent.

 */

static void remove_tasks_in_empty_cpuset(struct cpuset *cs)

{

	struct cpuset *parent;



	/*

	 * Find its next-highest non-empty parent, (top cpuset

	 * has online cpus, so can't be empty).

	 */

	parent = parent_cs(cs);

	while (cpumask_empty(parent->cpus_allowed) ||

			nodes_empty(parent->mems_allowed))

		parent = parent_cs(parent);



	if (cgroup_transfer_tasks(parent->css.cgroup, cs->css.cgroup)) {

		pr_err("cpuset: failed to transfer tasks out of empty cpuset ");

		pr_cont_cgroup_name(cs->css.cgroup);

		pr_cont("\n");

	}

}



static void cpuset_migrate_tasks_workfn(struct work_struct *work)

{

	struct cpuset_remove_tasks_struct *s;



	s = container_of(work, struct cpuset_remove_tasks_struct, work);

	remove_tasks_in_empty_cpuset(s->cs);

	css_put(&s->cs->css);

	kfree(s);

}



static void

hotplug_update_tasks_legacy(struct cpuset *cs,

			    struct cpumask *new_cpus, nodemask_t *new_mems,

			    bool cpus_updated, bool mems_updated)

{

	bool is_empty;



	spin_lock_irq(&callback_lock);

	cpumask_copy(cs->cpus_allowed, new_cpus);

	cpumask_copy(cs->effective_cpus, new_cpus);

	cs->mems_allowed = *new_mems;

	cs->effective_mems = *new_mems;

	spin_unlock_irq(&callback_lock);



	/*

	 * Don't call update_tasks_cpumask() if the cpuset becomes empty,

	 * as the tasks will be migrated to an ancestor.

	 */

	if (cpus_updated && !cpumask_empty(cs->cpus_allowed))

		update_tasks_cpumask(cs, new_cpus);

	if (mems_updated && !nodes_empty(cs->mems_allowed))

		update_tasks_nodemask(cs);



	is_empty = cpumask_empty(cs->cpus_allowed) ||

		   nodes_empty(cs->mems_allowed);



	/*

	 * Move tasks to the nearest ancestor with execution resources,

	 * This is full cgroup operation which will also call back into

	 * cpuset. Execute it asynchronously using workqueue.

	 */

	if (is_empty && cs->css.cgroup->nr_populated_csets &&

	    css_tryget_online(&cs->css)) {

		struct cpuset_remove_tasks_struct *s;



		s = kzalloc(sizeof(*s), GFP_KERNEL);

		if (WARN_ON_ONCE(!s)) {

			css_put(&cs->css);

			return;

		}



		s->cs = cs;

		INIT_WORK(&s->work, cpuset_migrate_tasks_workfn);

		schedule_work(&s->work);

	}

}



static void

hotplug_update_tasks(struct cpuset *cs,

		     struct cpumask *new_cpus, nodemask_t *new_mems,