From: Guopeng Zhang <[email protected]>
effective_xcpus includes CPUs granted to valid child partitions. Passing
the whole mask to isolated_cpus_update() during a root-to-isolated or
isolated-to-root change applies the parent's new state to child-owned
CPUs as well.
Build a mask of CPUs owned by the partition by subtracting the
effective_xcpus of valid children. Use this mask when updating
isolated_cpus for a partition type change.
Fixes: 11e5f407b64a ("cgroup/cpuset: Keep track of CPUs in isolated partitions")
Signed-off-by: Guopeng Zhang <[email protected]>
---
kernel/cgroup/cpuset.c | 30 ++++++++++++++++++++++++++++--
1 file changed, 28 insertions(+), 2 deletions(-)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 2538faac9aba..468272baadb2 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -2155,6 +2155,30 @@ static void compute_partition_effective_cpumask(struct
cpuset *cs,
rcu_read_unlock();
}
+/*
+ * Compute CPUs owned directly by a partition.
+ *
+ * effective_xcpus includes CPUs granted to valid child partitions. Exclude
+ * those CPUs when changing only this partition's type.
+ */
+static void compute_partition_owned_cpumask(struct cpuset *cs,
+ struct cpumask *owned_cpus)
+{
+ struct cgroup_subsys_state *css;
+ struct cpuset *child;
+
+ lockdep_assert_held(&cpuset_mutex);
+ cpumask_copy(owned_cpus, cs->effective_xcpus);
+
+ rcu_read_lock();
+ cpuset_for_each_child(child, css, cs) {
+ if (is_partition_valid(child))
+ cpumask_andnot(owned_cpus, owned_cpus,
+ child->effective_xcpus);
+ }
+ rcu_read_unlock();
+}
+
/*
* update_cpumasks_hier - Update effective cpumasks and tasks in the subtree
* @cs: the cpuset to consider
@@ -2990,8 +3014,10 @@ static int update_prstate(struct cpuset *cs, int new_prs)
} else if (old_prs && new_prs) {
/*
* A change in load balance state only, no change in cpumasks.
- * Need to update isolated_cpus.
+ * Need to update isolated_cpus for CPUs owned by this
partition,
+ * excluding CPUs distributed to valid child partitions.
*/
+ compute_partition_owned_cpumask(cs, tmpmask.new_cpus);
if (((new_prs == PRS_ISOLATED) &&
!isolated_cpus_can_update(cs->effective_xcpus, NULL)) ||
prstate_housekeeping_conflict(new_prs, cs->effective_xcpus))
@@ -3030,7 +3056,7 @@ static int update_prstate(struct cpuset *cs, int new_prs)
if (!is_partition_valid(cs))
reset_partition_data(cs);
else if (isolcpus_updated)
- isolated_cpus_update(old_prs, new_prs, cs->effective_xcpus);
+ isolated_cpus_update(old_prs, new_prs, tmpmask.new_cpus);
spin_unlock_irq(&callback_lock);
/* Force update if switching back to member & update effective_xcpus */
--
2.43.0
