hv: sched: remove runqueue from current schedule logic

Currently we are using a 1:1 mapping logic for pcpu:vcpu. So don't need
a runqueue for it. Removing it as preparation work to abstract scheduler
framework.

Tracked-On: #3813
Signed-off-by: Jason Chen CJ <jason.cj.chen@intel.com>
Signed-off-by: Yu Wang <yu1.wang@intel.com>
Signed-off-by: Shuo A Liu <shuo.a.liu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

Author: Shuo A Liu

hypervisor/arch/x86/guest/vcpu.c

@@ -667,7 +667,7 @@ void pause_vcpu(struct acrn_vcpu *vcpu, enum vcpu_state new_state)
 	vcpu->state = new_state;
 
 	if (vcpu->running) {
-		remove_from_cpu_runqueue(&vcpu->thread_obj);
+		remove_thread_obj(&vcpu->thread_obj, vcpu->pcpu_id);
 
 		if (is_lapic_pt_enabled(vcpu)) {
 			make_reschedule_request(vcpu->pcpu_id, DEL_MODE_INIT);
@@ -683,7 +683,7 @@ void pause_vcpu(struct acrn_vcpu *vcpu, enum vcpu_state new_state)
 			}
 		}
 	} else {
-		remove_from_cpu_runqueue(&vcpu->thread_obj);
+		remove_thread_obj(&vcpu->thread_obj, vcpu->pcpu_id);
 		release_schedule_lock(vcpu->pcpu_id);
 	}
 }
@@ -696,7 +696,7 @@ void resume_vcpu(struct acrn_vcpu *vcpu)
 	vcpu->state = vcpu->prev_state;
 
 	if (vcpu->state == VCPU_RUNNING) {
-		add_to_cpu_runqueue(&vcpu->thread_obj, vcpu->pcpu_id);
+		insert_thread_obj(&vcpu->thread_obj, vcpu->pcpu_id);
 		make_reschedule_request(vcpu->pcpu_id, DEL_MODE_IPI);
 	}
 	release_schedule_lock(vcpu->pcpu_id);
@@ -733,7 +733,7 @@ void schedule_vcpu(struct acrn_vcpu *vcpu)
 	pr_dbg("vcpu%hu scheduled", vcpu->vcpu_id);
 
 	get_schedule_lock(vcpu->pcpu_id);
-	add_to_cpu_runqueue(&vcpu->thread_obj, vcpu->pcpu_id);
+	insert_thread_obj(&vcpu->thread_obj, vcpu->pcpu_id);
 	make_reschedule_request(vcpu->pcpu_id, DEL_MODE_IPI);
 	release_schedule_lock(vcpu->pcpu_id);
 }
@@ -747,7 +747,6 @@ int32_t prepare_vcpu(struct acrn_vm *vm, uint16_t pcpu_id)
 
 	ret = create_vcpu(pcpu_id, vm, &vcpu);
 	if (ret == 0) {
-		INIT_LIST_HEAD(&vcpu->thread_obj.run_list);
 		snprintf(thread_name, 16U, "vm%hu:vcpu%hu", vm->vm_id, vcpu->vcpu_id);
 		(void)strncpy_s(vcpu->thread_obj.name, 16U, thread_name, 16U);
 		vcpu->thread_obj.thread_entry = vcpu_thread;

hypervisor/common/schedule.c

@@ -23,7 +23,6 @@ void init_scheduler(void)
 		ctl = &per_cpu(sched_ctl, i);
 
 		spinlock_init(&ctl->scheduler_lock);
-		INIT_LIST_HEAD(&ctl->runqueue);
 		ctl->flags = 0UL;
 		ctl->curr_obj = NULL;
 	}
@@ -41,31 +40,23 @@ void release_schedule_lock(uint16_t pcpu_id)
 	spinlock_release(&ctl->scheduler_lock);
 }
 
-void add_to_cpu_runqueue(struct thread_object *obj, uint16_t pcpu_id)
+void insert_thread_obj(struct thread_object *obj, uint16_t pcpu_id)
 {
 	struct sched_control *ctl = &per_cpu(sched_ctl, pcpu_id);
 
-	if (list_empty(&obj->run_list)) {
-		list_add_tail(&obj->run_list, &ctl->runqueue);
-	}
+	ctl->thread_obj = obj;
 }
 
-void remove_from_cpu_runqueue(struct thread_object *obj)
+void remove_thread_obj(__unused struct thread_object *obj, uint16_t pcpu_id)
 {
-	list_del_init(&obj->run_list);
+	struct sched_control *ctl = &per_cpu(sched_ctl, pcpu_id);
+
+	ctl->thread_obj = NULL;
 }
 
-static struct thread_object *get_next_sched_obj(struct sched_control *ctl)
+static struct thread_object *get_next_sched_obj(const struct sched_control *ctl)
 {
-	struct thread_object *obj = NULL;
-
-	if (!list_empty(&ctl->runqueue)) {
-		obj = get_first_item(&ctl->runqueue, struct thread_object, run_list);
-	} else {
-		obj = &get_cpu_var(idle);
-	}
-
-	return obj;
+	return ctl->thread_obj == NULL ? &get_cpu_var(idle) : ctl->thread_obj;
 }
 
 /**

hypervisor/include/common/schedule.h

@@ -18,27 +18,27 @@ typedef void (*thread_entry_t)(struct thread_object *obj);
 typedef void (*switch_t)(struct thread_object *obj);
 struct thread_object {
 	char name[16];
-	struct list_head run_list;
 	uint64_t host_sp;
 	thread_entry_t thread_entry;
 	switch_t switch_out;
 	switch_t switch_in;
 };
 
 struct sched_control {
-	struct list_head runqueue;
 	uint64_t flags;
 	struct thread_object *curr_obj;
 	spinlock_t scheduler_lock;	/* to protect sched_control and thread_object */
+
+	struct thread_object *thread_obj;
 };
 
 void init_scheduler(void);
 void switch_to_idle(thread_entry_t idle_thread);
 void get_schedule_lock(uint16_t pcpu_id);
 void release_schedule_lock(uint16_t pcpu_id);
 
-void add_to_cpu_runqueue(struct thread_object *obj, uint16_t pcpu_id);
-void remove_from_cpu_runqueue(struct thread_object *obj);
+void insert_thread_obj(struct thread_object *obj, uint16_t pcpu_id);
+void remove_thread_obj(struct thread_object *obj, uint16_t pcpu_id);
 
 void make_reschedule_request(uint16_t pcpu_id, uint16_t delmode);
 bool need_reschedule(uint16_t pcpu_id);