hv: clear NEED_RESCHEDULE flag in schedule

Now, need_reschedule will test_and_clear the bit NEED_RESCHEDULE in
schedule context, then call schedule. It is not a exact match with the
name.
This patch move the flag clearing into scheudle, and need_reschedule
just check and return.

Tracked-On: #1821
Signed-off-by: Shuo A Liu <shuo.a.liu@intel.com>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

Author: Shuo A Liu

hypervisor/common/hv_main.c

@@ -45,7 +45,7 @@ void vcpu_thread(struct sched_object *obj)
 			continue;
 		}
 
-		if (need_reschedule(vcpu->pcpu_id) != 0) {
+		if (need_reschedule(vcpu->pcpu_id)) {
 			/*
 			 * In extrem case, schedule() could return. Which
 			 * means the vcpu resume happens before schedule()
@@ -95,7 +95,7 @@ void default_idle(__unused struct sched_object *obj)
 	uint16_t pcpu_id = get_cpu_id();
 
 	while (1) {
-		if (need_reschedule(pcpu_id) != 0) {
+		if (need_reschedule(pcpu_id)) {
 			schedule();
 		} else if (need_offline(pcpu_id) != 0) {
 			cpu_dead();

hypervisor/common/schedule.c

@@ -81,9 +81,8 @@ void remove_from_cpu_runqueue(struct sched_object *obj, uint16_t pcpu_id)
 	spinlock_release(&ctx->runqueue_lock);
 }
 
-static struct sched_object *get_next_sched_obj(uint16_t pcpu_id)
+static struct sched_object *get_next_sched_obj(struct sched_context *ctx)
 {
-	struct sched_context *ctx = &per_cpu(sched_ctx, pcpu_id);
 	struct sched_object *obj = NULL;
 
 	spinlock_obtain(&ctx->runqueue_lock);
@@ -105,11 +104,11 @@ void make_reschedule_request(uint16_t pcpu_id)
 	}
 }
 
-int32_t need_reschedule(uint16_t pcpu_id)
+bool need_reschedule(uint16_t pcpu_id)
 {
 	struct sched_context *ctx = &per_cpu(sched_ctx, pcpu_id);
 
-	return bitmap_test_and_clear_lock(NEED_RESCHEDULE, &ctx->flags);
+	return bitmap_test(NEED_RESCHEDULE, &ctx->flags);
 }
 
 void make_pcpu_offline(uint16_t pcpu_id)
@@ -173,11 +172,13 @@ static void prepare_switch(struct sched_object *prev, struct sched_object *next)
 void schedule(void)
 {
 	uint16_t pcpu_id = get_cpu_id();
+	struct sched_context *ctx = &per_cpu(sched_ctx, pcpu_id);
 	struct sched_object *next = NULL;
-	struct sched_object *prev = per_cpu(sched_ctx, pcpu_id).curr_obj;
+	struct sched_object *prev = ctx->curr_obj;
 
 	get_schedule_lock(pcpu_id);
-	next = get_next_sched_obj(pcpu_id);
+	next = get_next_sched_obj(ctx);
+	bitmap_clear_lock(NEED_RESCHEDULE, &ctx->flags);
 
 	if (prev == next) {
 		release_schedule_lock(pcpu_id);

hypervisor/include/common/schedule.h

@@ -41,7 +41,7 @@ void add_to_cpu_runqueue(struct sched_object *obj, uint16_t pcpu_id);
 void remove_from_cpu_runqueue(struct sched_object *obj, uint16_t pcpu_id);
 
 void make_reschedule_request(uint16_t pcpu_id);
-int32_t need_reschedule(uint16_t pcpu_id);
+bool need_reschedule(uint16_t pcpu_id);
 void make_pcpu_offline(uint16_t pcpu_id);
 int32_t need_offline(uint16_t pcpu_id);