Commit be04e96b authored by Waiman Long's avatar Waiman Long Committed by Tejun Heo
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cgroup/cpuset: Globally track isolated_cpus update 



The current cpuset code passes a local isolcpus_updated flag around in a
number of functions to determine if external isolation related cpumasks
like wq_unbound_cpumask should be updated. It is a bit cumbersome and
makes the code more complex. Simplify the code by using a global boolean
flag "isolated_cpus_updating" to track this. This flag will be set in
isolated_cpus_update() and cleared in update_isolation_cpumasks().

No functional change is expected.

Signed-off-by: default avatarWaiman Long <longman@redhat.com>
Reviewed-by: default avatarChen Ridong <chenridong@huawei.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent b1034a69

kernel/cgroup/cpuset.c

+35 −38
Original line number Diff line number Diff line
@@ -81,6 +81,13 @@ static cpumask_var_t subpartitions_cpus; 
 */

static cpumask_var_t	isolated_cpus;



/*

 * isolated_cpus updating flag (protected by cpuset_mutex)

 * Set if isolated_cpus is going to be updated in the current

 * cpuset_mutex crtical section.

 */

static bool isolated_cpus_updating;



/*

 * Housekeeping (HK_TYPE_DOMAIN) CPUs at boot

 */
@@ -1327,6 +1334,8 @@ static void isolated_cpus_update(int old_prs, int new_prs, struct cpumask *xcpus 
		cpumask_or(isolated_cpus, isolated_cpus, xcpus);

	else

		cpumask_andnot(isolated_cpus, isolated_cpus, xcpus);



	isolated_cpus_updating = true;

}



/*
@@ -1334,15 +1343,12 @@ static void isolated_cpus_update(int old_prs, int new_prs, struct cpumask *xcpus 
 * @new_prs: new partition_root_state

 * @parent: parent cpuset

 * @xcpus: exclusive CPUs to be added

 * Return: true if isolated_cpus modified, false otherwise

 *

 * Remote partition if parent == NULL

 */

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

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

				struct cpumask *xcpus)

{

	bool isolcpus_updated;



	WARN_ON_ONCE(new_prs < 0);

	lockdep_assert_held(&callback_lock);

	if (!parent)
@@ -1352,13 +1358,11 @@ static bool partition_xcpus_add(int new_prs, struct cpuset *parent, 
	if (parent == &top_cpuset)

		cpumask_or(subpartitions_cpus, subpartitions_cpus, xcpus);



	isolcpus_updated = (new_prs != parent->partition_root_state);

	if (isolcpus_updated)

	if (new_prs != parent->partition_root_state)

		isolated_cpus_update(parent->partition_root_state, new_prs,

				     xcpus);



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

	return isolcpus_updated;

}



/*
@@ -1366,15 +1370,12 @@ static bool partition_xcpus_add(int new_prs, struct cpuset *parent, 
 * @old_prs: old partition_root_state

 * @parent: parent cpuset

 * @xcpus: exclusive CPUs to be removed

 * Return: true if isolated_cpus modified, false otherwise

 *

 * Remote partition if parent == NULL

 */

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

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

				struct cpumask *xcpus)

{

	bool isolcpus_updated;



	WARN_ON_ONCE(old_prs < 0);

	lockdep_assert_held(&callback_lock);

	if (!parent)
@@ -1383,14 +1384,12 @@ static bool partition_xcpus_del(int old_prs, struct cpuset *parent, 
	if (parent == &top_cpuset)

		cpumask_andnot(subpartitions_cpus, subpartitions_cpus, xcpus);



	isolcpus_updated = (old_prs != parent->partition_root_state);

	if (isolcpus_updated)

	if (old_prs != parent->partition_root_state)

		isolated_cpus_update(old_prs, parent->partition_root_state,

				     xcpus);



	cpumask_and(xcpus, xcpus, cpu_active_mask);

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

	return isolcpus_updated;

}



/*
@@ -1452,17 +1451,24 @@ static bool prstate_housekeeping_conflict(int prstate, struct cpumask *new_cpus) 
	return false;

}



static void update_isolation_cpumasks(bool isolcpus_updated)

/*

 * update_isolation_cpumasks - Update external isolation related CPU masks

 *

 * The following external CPU masks will be updated if necessary:

 * - workqueue unbound cpumask

 */

static void update_isolation_cpumasks(void)

{

	int ret;



	lockdep_assert_cpus_held();



	if (!isolcpus_updated)

	if (!isolated_cpus_updating)

		return;



	lockdep_assert_cpus_held();



	ret = workqueue_unbound_exclude_cpumask(isolated_cpus);

	WARN_ON_ONCE(ret < 0);

	isolated_cpus_updating = false;

}



/**
@@ -1587,8 +1593,6 @@ static inline bool is_local_partition(struct cpuset *cs) 
static int remote_partition_enable(struct cpuset *cs, int new_prs,

				   struct tmpmasks *tmp)

{

	bool isolcpus_updated;



	/*

	 * The user must have sysadmin privilege.

	 */
@@ -1616,11 +1620,11 @@ static int remote_partition_enable(struct cpuset *cs, int new_prs, 
		return PERR_HKEEPING;



	spin_lock_irq(&callback_lock);

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

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

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

	cpumask_copy(cs->effective_xcpus, tmp->new_cpus);

	spin_unlock_irq(&callback_lock);

	update_isolation_cpumasks(isolcpus_updated);

	update_isolation_cpumasks();

	cpuset_force_rebuild();

	cs->prs_err = 0;
@@ -1643,15 +1647,12 @@ static int remote_partition_enable(struct cpuset *cs, int new_prs, 
 */

static void remote_partition_disable(struct cpuset *cs, struct tmpmasks *tmp)

{

	bool isolcpus_updated;



	WARN_ON_ONCE(!is_remote_partition(cs));

	WARN_ON_ONCE(!cpumask_subset(cs->effective_xcpus, subpartitions_cpus));



	spin_lock_irq(&callback_lock);

	list_del_init(&cs->remote_sibling);

	isolcpus_updated = partition_xcpus_del(cs->partition_root_state,

					       NULL, cs->effective_xcpus);

	partition_xcpus_del(cs->partition_root_state, NULL, cs->effective_xcpus);

	if (cs->prs_err)

		cs->partition_root_state = -cs->partition_root_state;

	else
@@ -1661,7 +1662,7 @@ static void remote_partition_disable(struct cpuset *cs, struct tmpmasks *tmp) 
	compute_excpus(cs, cs->effective_xcpus);

	reset_partition_data(cs);

	spin_unlock_irq(&callback_lock);

	update_isolation_cpumasks(isolcpus_updated);

	update_isolation_cpumasks();

	cpuset_force_rebuild();



	/*
@@ -1686,7 +1687,6 @@ static void remote_cpus_update(struct cpuset *cs, struct cpumask *xcpus, 
{

	bool adding, deleting;

	int prs = cs->partition_root_state;

	int isolcpus_updated = 0;



	if (WARN_ON_ONCE(!is_remote_partition(cs)))

		return;
@@ -1722,9 +1722,9 @@ static void remote_cpus_update(struct cpuset *cs, struct cpumask *xcpus, 


	spin_lock_irq(&callback_lock);

	if (adding)

		isolcpus_updated += partition_xcpus_add(prs, NULL, tmp->addmask);

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

	if (deleting)

		isolcpus_updated += partition_xcpus_del(prs, NULL, tmp->delmask);

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

	/*

	 * Need to update effective_xcpus and exclusive_cpus now as

	 * update_sibling_cpumasks() below may iterate back to the same cs.
@@ -1733,7 +1733,7 @@ static void remote_cpus_update(struct cpuset *cs, struct cpumask *xcpus, 
	if (xcpus)

		cpumask_copy(cs->exclusive_cpus, xcpus);

	spin_unlock_irq(&callback_lock);

	update_isolation_cpumasks(isolcpus_updated);

	update_isolation_cpumasks();

	if (adding || deleting)

		cpuset_force_rebuild();
@@ -1794,7 +1794,6 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd, 
	int deleting;	/* Deleting cpus from parent's effective_cpus	*/

	int old_prs, new_prs;

	int part_error = PERR_NONE;	/* Partition error? */

	int isolcpus_updated = 0;

	struct cpumask *xcpus = user_xcpus(cs);

	int parent_prs = parent->partition_root_state;

	bool nocpu;
@@ -2073,14 +2072,12 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd, 
	 * and vice versa.

	 */

	if (adding)

		isolcpus_updated += partition_xcpus_del(old_prs, parent,

							tmp->addmask);

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

	if (deleting)

		isolcpus_updated += partition_xcpus_add(new_prs, parent,

							tmp->delmask);

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



	spin_unlock_irq(&callback_lock);

	update_isolation_cpumasks(isolcpus_updated);

	update_isolation_cpumasks();



	if ((old_prs != new_prs) && (cmd == partcmd_update))

		update_partition_exclusive_flag(cs, new_prs);
@@ -3103,7 +3100,7 @@ static int update_prstate(struct cpuset *cs, int new_prs) 
	else if (isolcpus_updated)

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

	spin_unlock_irq(&callback_lock);

	update_isolation_cpumasks(isolcpus_updated);

	update_isolation_cpumasks();



	/* Force update if switching back to member & update effective_xcpus */

	update_cpumasks_hier(cs, &tmpmask, !new_prs);