sched_ext: Wrap global DSQs in per-node structure

Global DSQs are currently stored as an array of scx_dispatch_q pointers,
one per NUMA node. To allow adding more per-node data structures, wrap the
global DSQ in scx_sched_pnode and replace global_dsqs with pnode array.

NUMA-aware allocation is maintained. No functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Andrea Righi <arighi@nvidia.com>

2 files changed, 21 insertions, 17 deletions

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index fa8968164fd2..28db05944390 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -344,7 +344,7 @@ static bool scx_is_descendant(struct scx_sched *sch, struct scx_sched *ancestor)
 static struct scx_dispatch_q *find_global_dsq(struct scx_sched *sch,
 					      struct task_struct *p)
 {
-	return sch->global_dsqs[cpu_to_node(task_cpu(p))];
+	return &sch->pnode[cpu_to_node(task_cpu(p))]->global_dsq;
 }
 
 static struct scx_dispatch_q *find_user_dsq(struct scx_sched *sch, u64 dsq_id)
@@ -2228,7 +2228,7 @@ static bool consume_global_dsq(struct scx_sched *sch, struct rq *rq)
 {
 	int node = cpu_to_node(cpu_of(rq));
 
-	return consume_dispatch_q(sch, rq, sch->global_dsqs[node]);
+	return consume_dispatch_q(sch, rq, &sch->pnode[node]->global_dsq);
 }
 
 /**
@@ -4147,8 +4147,8 @@ static void scx_sched_free_rcu_work(struct work_struct *work)
 	free_percpu(sch->pcpu);
 
 	for_each_node_state(node, N_POSSIBLE)
-		kfree(sch->global_dsqs[node]);
-	kfree(sch->global_dsqs);
+		kfree(sch->pnode[node]);
+	kfree(sch->pnode);
 
 	rhashtable_walk_enter(&sch->dsq_hash, &rht_iter);
 	do {
@@ -5706,23 +5706,23 @@ static struct scx_sched *scx_alloc_and_add_sched(struct sched_ext_ops *ops,
 	if (ret < 0)
 		goto err_free_ei;
 
-	sch->global_dsqs = kzalloc_objs(sch->global_dsqs[0], nr_node_ids);
-	if (!sch->global_dsqs) {
+	sch->pnode = kzalloc_objs(sch->pnode[0], nr_node_ids);
+	if (!sch->pnode) {
 		ret = -ENOMEM;
 		goto err_free_hash;
 	}
 
 	for_each_node_state(node, N_POSSIBLE) {
-		struct scx_dispatch_q *dsq;
+		struct scx_sched_pnode *pnode;
 
-		dsq = kzalloc_node(sizeof(*dsq), GFP_KERNEL, node);
-		if (!dsq) {
+		pnode = kzalloc_node(sizeof(*pnode), GFP_KERNEL, node);
+		if (!pnode) {
 			ret = -ENOMEM;
-			goto err_free_gdsqs;
+			goto err_free_pnode;
 		}
 
-		init_dsq(dsq, SCX_DSQ_GLOBAL, sch);
-		sch->global_dsqs[node] = dsq;
+		init_dsq(&pnode->global_dsq, SCX_DSQ_GLOBAL, sch);
+		sch->pnode[node] = pnode;
 	}
 
 	sch->dsp_max_batch = ops->dispatch_max_batch ?: SCX_DSP_DFL_MAX_BATCH;
@@ -5731,7 +5731,7 @@ static struct scx_sched *scx_alloc_and_add_sched(struct sched_ext_ops *ops,
 				   __alignof__(struct scx_sched_pcpu));
 	if (!sch->pcpu) {
 		ret = -ENOMEM;
-		goto err_free_gdsqs;
+		goto err_free_pnode;
 	}
 
 	for_each_possible_cpu(cpu)
@@ -5818,10 +5818,10 @@ err_stop_helper:
 	kthread_destroy_worker(sch->helper);
 err_free_pcpu:
 	free_percpu(sch->pcpu);
-err_free_gdsqs:
+err_free_pnode:
 	for_each_node_state(node, N_POSSIBLE)
-		kfree(sch->global_dsqs[node]);
-	kfree(sch->global_dsqs);
+		kfree(sch->pnode[node]);
+	kfree(sch->pnode);
 err_free_hash:
 	rhashtable_free_and_destroy(&sch->dsq_hash, NULL, NULL);
 err_free_ei:
diff --git a/kernel/sched/ext_internal.h b/kernel/sched/ext_internal.h
index 4cb97093b872..9e5ebd00ea0c 100644
--- a/kernel/sched/ext_internal.h
+++ b/kernel/sched/ext_internal.h
@@ -975,6 +975,10 @@ struct scx_sched_pcpu {
 	struct scx_dsp_ctx	dsp_ctx;
 };
 
+struct scx_sched_pnode {
+	struct scx_dispatch_q	global_dsq;
+};
+
 struct scx_sched {
 	struct sched_ext_ops	ops;
 	DECLARE_BITMAP(has_op, SCX_OPI_END);
@@ -988,7 +992,7 @@ struct scx_sched {
 	 * per-node split isn't sufficient, it can be further split.
 	 */
 	struct rhashtable	dsq_hash;
-	struct scx_dispatch_q	**global_dsqs;
+	struct scx_sched_pnode	**pnode;
 	struct scx_sched_pcpu __percpu *pcpu;
 
 	u64			slice_dfl;