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From: Waiman Long <longman@redhat.com>
To: "Ridong Chen" <ridong.chen@linux.dev>,
	"Tejun Heo" <tj@kernel.org>,
	"Johannes Weiner" <hannes@cmpxchg.org>,
	"Michal Koutný" <mkoutny@suse.com>,
	"Shuah Khan" <shuah@kernel.org>
Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-kselftest@vger.kernel.org,
	Guopeng Zhang <guopeng.zhang@linux.dev>,
	Waiman Long <longman@redhat.com>
Subject: [PATCH-next v2 09/10] cgroup/cpuset: Relocate compute_*effective_cpumask() and compute_effective_nodemask()
Date: Fri, 23 Oct 2026 16:00:35 -0400	[thread overview]
Message-ID: <20261023200036.60560-10-longman@redhat.com> (raw)
In-Reply-To: <20261023200036.60560-1-longman@redhat.com>

Relocate compute_partition_effective_cpumask(),
compute_effective_cpumask(), and compute_effective_nodemask() together so
that compute_effective_cpumask() and compute_partition_effective_cpumask()
can be further integrated together. There is no functional change.

Signed-off-by: Waiman Long <longman@redhat.com>
---
 kernel/cgroup/cpuset.c | 212 ++++++++++++++++++++---------------------
 1 file changed, 106 insertions(+), 106 deletions(-)

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 03c666f658e4..f9ba711e1e1a 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -1135,43 +1135,6 @@ void cpuset_update_tasks_cpumask(struct cpuset *cs, struct cpumask *new_cpus)
 	css_task_iter_end(&it);
 }
 
-/**
- * compute_effective_cpumask - Compute the effective cpumask of the cpuset
- * @new_cpus: the temp variable for the new effective_cpus mask
- * @cs: the cpuset the need to recompute the new effective_cpus mask
- * @parent: the parent cpuset
- *
- * For v2, the parent's effective_cpus is inherited if cpumask is empty.
- * The result is valid only if the given cpuset isn't a partition root.
- */
-static void compute_effective_cpumask(struct cpumask *new_cpus,
-				      struct cpuset *cs, struct cpuset *parent)
-{
-	bool has_cpus;
-
-	has_cpus = cpumask_and(new_cpus, cs->cpus_allowed, parent->effective_cpus);
-	if (!has_cpus && is_in_v2_mode())
-		cpumask_copy(new_cpus, parent->effective_cpus);
-}
-
-/**
- * compute_effective_nodemask - Compute the effective nodemask of the cpuset
- * @new_mems: the temp variable for the new effective_mems mask
- * @cs: the cpuset the need to recompute the new effective_mems mask
- * @parent: the parent cpuset
- *
- * For v2, the parent's effective_mems is inherited if nodemask is empty.
- */
-static void compute_effective_nodemask(nodemask_t *new_mems,
-				       struct cpuset *cs, struct cpuset *parent)
-{
-	bool has_mems;
-
-	has_mems = nodes_and(*new_mems, cs->mems_allowed, parent->effective_mems);
-	if (!has_mems && is_in_v2_mode())
-		nodes_copy(*new_mems, parent->effective_mems);
-}
-
 /*
  * Commands for update_parent_effective_cpumask
  */
@@ -1583,6 +1546,112 @@ static inline bool is_local_partition(struct cpuset *cs)
 	return is_partition_valid(cs) && !is_remote_partition(cs);
 }
 
+/**
+ * compute_partition_effective_cpumask - compute effective_cpus for partition
+ * @cs: partition root cpuset
+ * @new_ecpus: previously computed effective_cpus to be updated
+ *
+ * Compute the effective_cpus of a partition root by scanning effective_xcpus
+ * of child partition roots and excluding their effective_xcpus.
+ *
+ * This has the side effect of invalidating valid child partition roots,
+ * if necessary. Since it is called from either cpuset_hotplug_update_tasks()
+ * or update_cpumasks_hier() where parent and children are modified
+ * successively, we don't need to call update_parent_effective_cpumask()
+ * and the child's effective_cpus will be updated in later iterations.
+ */
+static void compute_partition_effective_cpumask(struct cpuset *cs,
+						struct cpumask *new_ecpus)
+{
+	struct cgroup_subsys_state *css;
+	struct cpuset *child;
+	bool populated = partition_is_populated(cs, NULL);
+
+	WARN_ON_ONCE(!is_partition_valid(cs));
+
+	/*
+	 * Check child partition roots to see if they should be invalidated
+	 * when all the effective_cpus will be used up and cs is populated.
+	 * It is better to sacrifice a child partition root than invalidating
+	 * the whole subtree.
+	 *
+	 * Return early if the effective_cpus is already empty.
+	 */
+	compute_excpus(cs, new_ecpus);
+	if (!cpumask_and(new_ecpus, new_ecpus, cpu_active_mask))
+		return;
+
+	rcu_read_lock();
+	cpuset_for_each_child(child, css, cs) {
+		if (!is_partition_valid(child))
+			continue;
+
+		/*
+		 * There shouldn't be a remote partition underneath another
+		 * partition root.
+		 */
+		WARN_ON_ONCE(is_remote_partition(child));
+		if (populated && cpumask_subset(new_ecpus, child->effective_xcpus)) {
+			int old_prs = child->partition_root_state;
+			int parent_prs = cs->partition_root_state;
+
+			/*
+			 * Invalidate child partition and update isolated_cpus
+			 * if necessary.
+			 */
+			spin_lock_irq(&callback_lock);
+			WRITE_ONCE(child->prs_err, PERR_NOCPUS);
+			if ((old_prs == PRS_ISOLATED) && (parent_prs == PRS_ROOT))
+				isolated_cpus_update(old_prs, parent_prs,
+						     child->effective_xcpus);
+			child->partition_root_state = -old_prs;
+			spin_unlock_irq(&callback_lock);
+			notify_partition_change(child, old_prs);
+			continue;
+		}
+		cpumask_andnot(new_ecpus, new_ecpus,
+			       child->effective_xcpus);
+	}
+	rcu_read_unlock();
+}
+
+/**
+ * compute_effective_cpumask - Compute the effective cpumask of the cpuset
+ * @new_cpus: the temp variable for the new effective_cpus mask
+ * @cs: the cpuset the need to recompute the new effective_cpus mask
+ * @parent: the parent cpuset
+ *
+ * For v2, the parent's effective_cpus is inherited if cpumask is empty.
+ * The result is valid only if the given cpuset isn't a partition root.
+ */
+static void compute_effective_cpumask(struct cpumask *new_cpus,
+				      struct cpuset *cs, struct cpuset *parent)
+{
+	bool has_cpus;
+
+	has_cpus = cpumask_and(new_cpus, cs->cpus_allowed, parent->effective_cpus);
+	if (!has_cpus && is_in_v2_mode())
+		cpumask_copy(new_cpus, parent->effective_cpus);
+}
+
+/**
+ * compute_effective_nodemask - Compute the effective nodemask of the cpuset
+ * @new_mems: the temp variable for the new effective_mems mask
+ * @cs: the cpuset the need to recompute the new effective_mems mask
+ * @parent: the parent cpuset
+ *
+ * For v2, the parent's effective_mems is inherited if nodemask is empty.
+ */
+static void compute_effective_nodemask(nodemask_t *new_mems,
+				       struct cpuset *cs, struct cpuset *parent)
+{
+	bool has_mems;
+
+	has_mems = nodes_and(*new_mems, cs->mems_allowed, parent->effective_mems);
+	if (!has_mems && is_in_v2_mode())
+		nodes_copy(*new_mems, parent->effective_mems);
+}
+
 /*
  * remote_partition_enable - Enable current cpuset as a remote partition root
  * @cs: the cpuset to update
@@ -2084,75 +2153,6 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd,
 	return 0;
 }
 
-/**
- * compute_partition_effective_cpumask - compute effective_cpus for partition
- * @cs: partition root cpuset
- * @new_ecpus: previously computed effective_cpus to be updated
- *
- * Compute the effective_cpus of a partition root by scanning effective_xcpus
- * of child partition roots and excluding their effective_xcpus.
- *
- * This has the side effect of invalidating valid child partition roots,
- * if necessary. Since it is called from either cpuset_hotplug_update_tasks()
- * or update_cpumasks_hier() where parent and children are modified
- * successively, we don't need to call update_parent_effective_cpumask()
- * and the child's effective_cpus will be updated in later iterations.
- */
-static void compute_partition_effective_cpumask(struct cpuset *cs,
-						struct cpumask *new_ecpus)
-{
-	struct cgroup_subsys_state *css;
-	struct cpuset *child;
-	bool populated = partition_is_populated(cs, NULL);
-
-	WARN_ON_ONCE(!is_partition_valid(cs));
-
-	/*
-	 * Check child partition roots to see if they should be invalidated
-	 * when all the effective_cpus will be used up and cs is populated.
-	 * It is better to sacrifice a child partition root than invalidating
-	 * the whole subtree.
-	 *
-	 * Return early if the effective_cpus is already empty.
-	 */
-	compute_excpus(cs, new_ecpus);
-	if (!cpumask_and(new_ecpus, new_ecpus, cpu_active_mask))
-		return;
-
-	rcu_read_lock();
-	cpuset_for_each_child(child, css, cs) {
-		if (!is_partition_valid(child))
-			continue;
-
-		/*
-		 * There shouldn't be a remote partition underneath another
-		 * partition root.
-		 */
-		WARN_ON_ONCE(is_remote_partition(child));
-		if (populated && cpumask_subset(new_ecpus, child->effective_xcpus)) {
-			int old_prs = child->partition_root_state;
-			int parent_prs = cs->partition_root_state;
-
-			/*
-			 * Invalidate child partition and update isolated_cpus
-			 * if necessary.
-			 */
-			spin_lock_irq(&callback_lock);
-			WRITE_ONCE(child->prs_err, PERR_NOCPUS);
-			if ((old_prs == PRS_ISOLATED) && (parent_prs == PRS_ROOT))
-				isolated_cpus_update(old_prs, parent_prs,
-						     child->effective_xcpus);
-			child->partition_root_state = -old_prs;
-			spin_unlock_irq(&callback_lock);
-			notify_partition_change(child, old_prs);
-			continue;
-		}
-		cpumask_andnot(new_ecpus, new_ecpus,
-			       child->effective_xcpus);
-	}
-	rcu_read_unlock();
-}
-
 /*
  * furthest isolated_ancestor - Return furthest isolated partition root ancestor available
  * @cs: the current cpuset
-- 
2.56.0


  parent reply	other threads:[~2026-10-23 20:01 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-23 20:00 [PATCH-next v2 00/10] cgroup/cpuset: Miscellaneous bug fixes & cleanup Waiman Long
2026-10-23 20:00 ` [PATCH-next v2 01/10] cgroup/cpuset: Find furthest isolated ancestor for invalidated isolated partition Waiman Long
2026-10-23 20:00 ` [PATCH-next v2 02/10] cgroup/cpuset: Properly compute effective xcpus in update_parent_effective_cpumask() Waiman Long
2026-10-23 20:00 ` [PATCH-next v2 03/10] cgroup/cpuset: Fix incorrect effective_cpus bug in update_cpumasks_hier() Waiman Long
2026-10-23 20:00 ` [PATCH-next v2 04/10] cgroup/cpuset: Minor fixes to prstate_housekeeping_conflict() Waiman Long
2026-10-23 20:00 ` [PATCH-next v2 05/10] selftests/cgroup: Check for a single range nohz_full CPUs before running test matrix Waiman Long
2026-10-23 20:00 ` [PATCH-next v2 06/10] cgroup/cpuset: Prevent recursive call of remote_cpus_update() via update_cpumasks_hier() Waiman Long
2026-10-23 20:00 ` [PATCH-next v2 07/10] cgroup/cpuset: Make sure compute_partition_effective_cpumask() is only called for valid partition Waiman Long
2026-10-23 20:00 ` [PATCH-next v2 08/10] cgroup/cpuset: Update isolated_cpus if necessary in compute_partition_effective_cpumask() Waiman Long
2026-10-23 20:00 ` Waiman Long [this message]
2026-10-23 20:00 ` [PATCH-next v2 10/10] cgroup/cpuset: Integrate compute_partition_effective_cpumask() into compute_effective_cpumask() Waiman Long

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