Commit ae1c8023 authored by Li Zefan's avatar Li Zefan Committed by Tejun Heo
Browse files

cpuset: apply cs->effective_{cpus,mems} 



Now we can use cs->effective_{cpus,mems} as effective masks. It's
used whenever:

- we update tasks' cpus_allowed/mems_allowed,
- we want to retrieve tasks_cs(tsk)'s cpus_allowed/mems_allowed.

They actually replace effective_{cpu,node}mask_cpuset().

effective_mask == configured_mask & parent effective_mask except when
the reault is empty, in which case it inherits parent effective_mask.
The result equals the mask computed from effective_{cpu,node}mask_cpuset().

This won't affect the original legacy hierarchy, because in this case we
make sure the effective masks are always the same with user-configured
masks.

Signed-off-by: default avatarLi Zefan <lizefan@huawei.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 39bd0d15

kernel/cpuset.c

+14 −69
Original line number Diff line number Diff line
@@ -313,9 +313,9 @@ static struct file_system_type cpuset_fs_type = { 
 */

static void guarantee_online_cpus(struct cpuset *cs, struct cpumask *pmask)

{

	while (!cpumask_intersects(cs->cpus_allowed, cpu_online_mask))

	while (!cpumask_intersects(cs->effective_cpus, cpu_online_mask))

		cs = parent_cs(cs);

	cpumask_and(pmask, cs->cpus_allowed, cpu_online_mask);

	cpumask_and(pmask, cs->effective_cpus, cpu_online_mask);

}



/*
@@ -331,9 +331,9 @@ static void guarantee_online_cpus(struct cpuset *cs, struct cpumask *pmask) 
 */

static void guarantee_online_mems(struct cpuset *cs, nodemask_t *pmask)

{

	while (!nodes_intersects(cs->mems_allowed, node_states[N_MEMORY]))

	while (!nodes_intersects(cs->effective_mems, node_states[N_MEMORY]))

		cs = parent_cs(cs);

	nodes_and(*pmask, cs->mems_allowed, node_states[N_MEMORY]);

	nodes_and(*pmask, cs->effective_mems, node_states[N_MEMORY]);

}



/*
@@ -795,45 +795,6 @@ void rebuild_sched_domains(void) 
	mutex_unlock(&cpuset_mutex);

}



/*

 * effective_cpumask_cpuset - return nearest ancestor with non-empty cpus

 * @cs: the cpuset in interest

 *

 * A cpuset's effective cpumask is the cpumask of the nearest ancestor

 * with non-empty cpus. We use effective cpumask whenever:

 * - we update tasks' cpus_allowed. (they take on the ancestor's cpumask

 *   if the cpuset they reside in has no cpus)

 * - we want to retrieve task_cs(tsk)'s cpus_allowed.

 *

 * Called with cpuset_mutex held. cpuset_cpus_allowed_fallback() is an

 * exception. See comments there.

 */

static struct cpuset *effective_cpumask_cpuset(struct cpuset *cs)

{

	while (cpumask_empty(cs->cpus_allowed))

		cs = parent_cs(cs);

	return cs;

}



/*

 * effective_nodemask_cpuset - return nearest ancestor with non-empty mems

 * @cs: the cpuset in interest

 *

 * A cpuset's effective nodemask is the nodemask of the nearest ancestor

 * with non-empty memss. We use effective nodemask whenever:

 * - we update tasks' mems_allowed. (they take on the ancestor's nodemask

 *   if the cpuset they reside in has no mems)

 * - we want to retrieve task_cs(tsk)'s mems_allowed.

 *

 * Called with cpuset_mutex held.

 */

static struct cpuset *effective_nodemask_cpuset(struct cpuset *cs)

{

	while (nodes_empty(cs->mems_allowed))

		cs = parent_cs(cs);

	return cs;

}



/**

 * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset.

 * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed
@@ -844,13 +805,12 @@ static struct cpuset *effective_nodemask_cpuset(struct cpuset *cs) 
 */

static void update_tasks_cpumask(struct cpuset *cs)

{

	struct cpuset *cpus_cs = effective_cpumask_cpuset(cs);

	struct css_task_iter it;

	struct task_struct *task;



	css_task_iter_start(&cs->css, &it);

	while ((task = css_task_iter_next(&it)))

		set_cpus_allowed_ptr(task, cpus_cs->cpus_allowed);

		set_cpus_allowed_ptr(task, cs->effective_cpus);

	css_task_iter_end(&it);

}
@@ -988,15 +948,13 @@ static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from, 
							const nodemask_t *to)

{

	struct task_struct *tsk = current;

	struct cpuset *mems_cs;



	tsk->mems_allowed = *to;



	do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL);



	rcu_read_lock();

	mems_cs = effective_nodemask_cpuset(task_cs(tsk));

	guarantee_online_mems(mems_cs, &tsk->mems_allowed);

	guarantee_online_mems(task_cs(tsk), &tsk->mems_allowed);

	rcu_read_unlock();

}
@@ -1065,13 +1023,12 @@ static void *cpuset_being_rebound; 
static void update_tasks_nodemask(struct cpuset *cs)

{

	static nodemask_t newmems;	/* protected by cpuset_mutex */

	struct cpuset *mems_cs = effective_nodemask_cpuset(cs);

	struct css_task_iter it;

	struct task_struct *task;



	cpuset_being_rebound = cs;		/* causes mpol_dup() rebind */



	guarantee_online_mems(mems_cs, &newmems);

	guarantee_online_mems(cs, &newmems);



	/*

	 * The mpol_rebind_mm() call takes mmap_sem, which we couldn't
@@ -1497,8 +1454,6 @@ static void cpuset_attach(struct cgroup_subsys_state *css, 
	struct task_struct *leader = cgroup_taskset_first(tset);

	struct cpuset *cs = css_cs(css);

	struct cpuset *oldcs = cpuset_attach_old_cs;

	struct cpuset *cpus_cs = effective_cpumask_cpuset(cs);

	struct cpuset *mems_cs = effective_nodemask_cpuset(cs);



	mutex_lock(&cpuset_mutex);
@@ -1506,9 +1461,9 @@ static void cpuset_attach(struct cgroup_subsys_state *css, 
	if (cs == &top_cpuset)

		cpumask_copy(cpus_attach, cpu_possible_mask);

	else

		guarantee_online_cpus(cpus_cs, cpus_attach);

		guarantee_online_cpus(cs, cpus_attach);



	guarantee_online_mems(mems_cs, &cpuset_attach_nodemask_to);

	guarantee_online_mems(cs, &cpuset_attach_nodemask_to);



	cgroup_taskset_for_each(task, tset) {

		/*
@@ -1525,11 +1480,9 @@ static void cpuset_attach(struct cgroup_subsys_state *css, 
	 * Change mm, possibly for multiple threads in a threadgroup. This is

	 * expensive and may sleep.

	 */

	cpuset_attach_nodemask_to = cs->mems_allowed;

	cpuset_attach_nodemask_to = cs->effective_mems;

	mm = get_task_mm(leader);

	if (mm) {

		struct cpuset *mems_oldcs = effective_nodemask_cpuset(oldcs);



		mpol_rebind_mm(mm, &cpuset_attach_nodemask_to);



		/*
@@ -1540,7 +1493,7 @@ static void cpuset_attach(struct cgroup_subsys_state *css, 
		 * mm from.

		 */

		if (is_memory_migrate(cs)) {

			cpuset_migrate_mm(mm, &mems_oldcs->old_mems_allowed,

			cpuset_migrate_mm(mm, &oldcs->old_mems_allowed,

					  &cpuset_attach_nodemask_to);

		}

		mmput(mm);
@@ -2331,23 +2284,17 @@ void __init cpuset_init_smp(void) 


void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask)

{

	struct cpuset *cpus_cs;



	mutex_lock(&callback_mutex);

	rcu_read_lock();

	cpus_cs = effective_cpumask_cpuset(task_cs(tsk));

	guarantee_online_cpus(cpus_cs, pmask);

	guarantee_online_cpus(task_cs(tsk), pmask);

	rcu_read_unlock();

	mutex_unlock(&callback_mutex);

}



void cpuset_cpus_allowed_fallback(struct task_struct *tsk)

{

	struct cpuset *cpus_cs;



	rcu_read_lock();

	cpus_cs = effective_cpumask_cpuset(task_cs(tsk));

	do_set_cpus_allowed(tsk, cpus_cs->cpus_allowed);

	do_set_cpus_allowed(tsk, task_cs(tsk)->effective_cpus);

	rcu_read_unlock();



	/*
@@ -2386,13 +2333,11 @@ void cpuset_init_current_mems_allowed(void) 


nodemask_t cpuset_mems_allowed(struct task_struct *tsk)

{

	struct cpuset *mems_cs;

	nodemask_t mask;



	mutex_lock(&callback_mutex);

	rcu_read_lock();

	mems_cs = effective_nodemask_cpuset(task_cs(tsk));

	guarantee_online_mems(mems_cs, &mask);

	guarantee_online_mems(task_cs(tsk), &mask);

	rcu_read_unlock();

	mutex_unlock(&callback_mutex);

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