Merge pull request #3769 from jesven/fix_yield

解决yield操作不能及时释放cpu的问题

Author: BernardXiong

src/clock.c

@@ -91,8 +91,7 @@ void rt_tick_increase(void)
 
         thread->stat |= RT_THREAD_STAT_YIELD;
 
-        /* yield */
-        rt_thread_yield();
+        rt_schedule();
     }
 
     /* check timer */

src/scheduler.c

@@ -346,9 +346,9 @@ void rt_schedule(void)
                 }
                 else
                 {
-                    current_thread->stat &= ~RT_THREAD_STAT_YIELD_MASK;
                     rt_schedule_insert_thread(current_thread);
                 }
+                current_thread->stat &= ~RT_THREAD_STAT_YIELD_MASK;
             }
             to_thread->oncpu = cpu_id;
             if (to_thread != current_thread)
@@ -444,9 +444,9 @@ void rt_schedule(void)
                 }
                 else
                 {
-                    rt_current_thread->stat &= ~RT_THREAD_STAT_YIELD_MASK;
                     need_insert_from_thread = 1;
                 }
+                rt_current_thread->stat &= ~RT_THREAD_STAT_YIELD_MASK;
             }
 
             if (to_thread != rt_current_thread)
@@ -595,9 +595,9 @@ void rt_scheduler_do_irq_switch(void *context)
                 }
                 else
                 {
-                    current_thread->stat &= ~RT_THREAD_STAT_YIELD_MASK;
                     rt_schedule_insert_thread(current_thread);
                 }
+                current_thread->stat &= ~RT_THREAD_STAT_YIELD_MASK;
             }
             to_thread->oncpu = cpu_id;
             if (to_thread != current_thread)

src/thread.c

@@ -478,7 +478,15 @@ RTM_EXPORT(rt_thread_delete);
  */
 rt_err_t rt_thread_yield(void)
 {
+    struct rt_thread *thread;
+    rt_base_t lock;
+
+    thread = rt_thread_self();
+    lock = rt_hw_interrupt_disable();
+    thread->remaining_tick = thread->init_tick;
+    thread->stat |= RT_THREAD_STAT_YIELD;
     rt_schedule();
+    rt_hw_interrupt_enable(lock);
 
     return RT_EOK;
 }