scx: Move p->scx.dsq_flags into p->scx.dsq_node

and give p->scx.dsq_node's type the name of scx_dsq_node. This will be used
to implement DSQ iterator.

This wastes 8 bytes on 64bit. Oh well.

include/linux/sched/ext.h

@@ -121,18 +121,20 @@ enum scx_kf_mask {
 	__SCX_KF_TERMINAL	= SCX_KF_ENQUEUE | SCX_KF_SELECT_CPU | SCX_KF_REST,
 };
 
+struct scx_dsq_node {
+	struct list_head	list;		/* dispatch order */
+	struct rb_node		priq;		/* p->scx.dsq_vtime order */
+	u32			flags;		/* SCX_TASK_DSQ_* flags */
+};
+
 /*
  * The following is embedded in task_struct and contains all fields necessary
  * for a task to be scheduled by SCX.
  */
 struct sched_ext_entity {
 	struct scx_dispatch_q	*dsq;
-	struct {
-		struct list_head	list;	/* dispatch order */
-		struct rb_node		priq;	/* p->scx.dsq_vtime order */
-	} dsq_node;
+	struct scx_dsq_node	dsq_node;	/* protected by dsq lock */
 	u32			flags;		/* protected by rq lock */
-	u32			dsq_flags;	/* protected by dsq lock */
 	u32			weight;
 	s32			sticky_cpu;
 	s32			holding_cpu;

kernel/sched/ext.c

@@ -1385,7 +1385,7 @@ static void dispatch_enqueue(struct scx_dispatch_q *dsq, struct task_struct *p,
 	bool is_local = dsq->id == SCX_DSQ_LOCAL;
 
 	WARN_ON_ONCE(p->scx.dsq || !list_empty(&p->scx.dsq_node.list));
-	WARN_ON_ONCE((p->scx.dsq_flags & SCX_TASK_DSQ_ON_PRIQ) ||
+	WARN_ON_ONCE((p->scx.dsq_node.flags & SCX_TASK_DSQ_ON_PRIQ) ||
 		     !RB_EMPTY_NODE(&p->scx.dsq_node.priq));
 
 	if (!is_local) {
@@ -1425,7 +1425,7 @@ static void dispatch_enqueue(struct scx_dispatch_q *dsq, struct task_struct *p,
 			scx_ops_error("DSQ ID 0x%016llx already had FIFO-enqueued tasks",
 				      dsq->id);
 
-		p->scx.dsq_flags |= SCX_TASK_DSQ_ON_PRIQ;
+		p->scx.dsq_node.flags |= SCX_TASK_DSQ_ON_PRIQ;
 		rb_add(&p->scx.dsq_node.priq, &dsq->priq, scx_dsq_priq_less);
 
 		/*
@@ -1492,10 +1492,10 @@ static void dispatch_enqueue(struct scx_dispatch_q *dsq, struct task_struct *p,
 static void task_unlink_from_dsq(struct task_struct *p,
 				 struct scx_dispatch_q *dsq)
 {
-	if (p->scx.dsq_flags & SCX_TASK_DSQ_ON_PRIQ) {
+	if (p->scx.dsq_node.flags & SCX_TASK_DSQ_ON_PRIQ) {
 		rb_erase(&p->scx.dsq_node.priq, &dsq->priq);
 		RB_CLEAR_NODE(&p->scx.dsq_node.priq);
-		p->scx.dsq_flags &= ~SCX_TASK_DSQ_ON_PRIQ;
+		p->scx.dsq_node.flags &= ~SCX_TASK_DSQ_ON_PRIQ;
 	}
 
 	list_del_init(&p->scx.dsq_node.list);
@@ -4318,7 +4318,7 @@ static void scx_dump_task(struct seq_buf *s, struct task_struct *p, char marker,
 	seq_buf_printf(s, "      scx_state/flags=%u/0x%x dsq_flags=0x%x ops_state/qseq=%lu/%lu\n",
 		       scx_get_task_state(p),
 		       p->scx.flags & ~SCX_TASK_STATE_MASK,
-		       p->scx.dsq_flags,
+		       p->scx.dsq_node.flags,
 		       ops_state & SCX_OPSS_STATE_MASK,
 		       ops_state >> SCX_OPSS_QSEQ_SHIFT);
 	seq_buf_printf(s, "      sticky/holding_cpu=%d/%d dsq_id=%s\n",