[PATCH v2 -next 07/11] cgroup/cpuset: move legacy hotplug update to cpuset-v1.c

Chen Ridong
2024-08-26T13:34:54Z

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: Chen Ridong <chenridong@huawei.com>
---
kernel/cgroup/cpuset-internal.h | 5 ++
kernel/cgroup/cpuset-v1.c | 91 +++++++++++++++++++++++++++++++
kernel/cgroup/cpuset.c | 96 +--------------------------------
3 files changed, 98 insertions(+), 94 deletions(-)

diff --git a/kernel/cgroup/cpuset-internal.h b/kernel/cgroup/cpuset-internal.h
index 9a60dd6681e4..7cd30ad809d5 100644
--- a/kernel/cgroup/cpuset-internal.h
+++ b/kernel/cgroup/cpuset-internal.h
@@ -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 */
diff --git a/kernel/cgroup/cpuset-v1.c b/kernel/cgroup/cpuset-v1.c
index 320abd4bf2c3..ce1d00746e92 100644
--- a/kernel/cgroup/cpuset-v1.c
+++ b/kernel/cgroup/cpuset-v1.c
@@ -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?
*
@@ -237,3 +245,86 @@ void update_tasks_flags(struct cpuset *cs)
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);
+ }
+}
+
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 2b2dc963299b..b93ef0b48eae 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -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
*/
@@ -1138,7 +1130,7 @@ 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;
@@ -2591,7 +2583,7 @@ 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;
@@ -3923,90 +3915,6 @@ 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,
--
2.34.1