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Commit 7e88291b authored by Li Zefan's avatar Li Zefan Committed by Tejun Heo
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cpuset: make cs->{cpus, mems}_allowed as user-configured masks 



Now we've used effective cpumasks to enforce hierarchical manner,
we can use cs->{cpus,mems}_allowed as configured masks.

Configured masks can be changed by writing cpuset.cpus and cpuset.mems
only. The new behaviors are:

- They won't be changed by hotplug anymore.
- They won't be limited by its parent's masks.

This ia a behavior change, but won't take effect unless mount with
sane_behavior.

v2:
- Add comments to explain the differences between configured masks and
effective masks.

Signed-off-by: default avatarLi Zefan <lizefan@huawei.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent ae1c8023

kernel/cpuset.c

+29 −6
Original line number Diff line number Diff line
@@ -77,6 +77,26 @@ struct cpuset { 


	unsigned long flags;		/* "unsigned long" so bitops work */



	/*

	 * On default hierarchy:

	 *

	 * The user-configured masks can only be changed by writing to

	 * cpuset.cpus and cpuset.mems, and won't be limited by the

	 * parent masks.

	 *

	 * The effective masks is the real masks that apply to the tasks

	 * in the cpuset. They may be changed if the configured masks are

	 * changed or hotplug happens.

	 *

	 * effective_mask == configured_mask & parent's effective_mask,

	 * and if it ends up empty, it will inherit the parent's mask.

	 *

	 *

	 * On legacy hierachy:

	 *

	 * The user-configured masks are always the same with effective masks.

	 */



	/* user-configured CPUs and Memory Nodes allow to tasks */

	cpumask_var_t cpus_allowed;

	nodemask_t mems_allowed;
@@ -450,9 +470,9 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial) 


	par = parent_cs(cur);



	/* We must be a subset of our parent cpuset */

	/* On legacy hiearchy, we must be a subset of our parent cpuset. */

	ret = -EACCES;

	if (!is_cpuset_subset(trial, par))

	if (!cgroup_on_dfl(cur->css.cgroup) && !is_cpuset_subset(trial, par))

		goto out;



	/*
@@ -2167,6 +2187,7 @@ static void cpuset_hotplug_workfn(struct work_struct *work) 
	static cpumask_t new_cpus;

	static nodemask_t new_mems;

	bool cpus_updated, mems_updated;

	bool on_dfl = cgroup_on_dfl(top_cpuset.css.cgroup);



	mutex_lock(&cpuset_mutex);
@@ -2174,12 +2195,13 @@ static void cpuset_hotplug_workfn(struct work_struct *work) 
	cpumask_copy(&new_cpus, cpu_active_mask);

	new_mems = node_states[N_MEMORY];



	cpus_updated = !cpumask_equal(top_cpuset.cpus_allowed, &new_cpus);

	mems_updated = !nodes_equal(top_cpuset.mems_allowed, new_mems);

	cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus);

	mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems);



	/* synchronize cpus_allowed to cpu_active_mask */

	if (cpus_updated) {

		mutex_lock(&callback_mutex);

		if (!on_dfl)

			cpumask_copy(top_cpuset.cpus_allowed, &new_cpus);

		cpumask_copy(top_cpuset.effective_cpus, &new_cpus);

		mutex_unlock(&callback_mutex);
@@ -2189,6 +2211,7 @@ static void cpuset_hotplug_workfn(struct work_struct *work) 
	/* synchronize mems_allowed to N_MEMORY */

	if (mems_updated) {

		mutex_lock(&callback_mutex);

		if (!on_dfl)

			top_cpuset.mems_allowed = new_mems;

		top_cpuset.effective_mems = new_mems;

		mutex_unlock(&callback_mutex);