psi: Optimize task switch inside shared cgroups

[linux-2.6-microblaze.git] / kernel / sched / stats.h

diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
index 9e4e67a..dc218e9 100644 (file)
--- a/kernel/sched/stats.h
+++ b/kernel/sched/stats.h
@@ -84,28 +84,24 @@ static inline void psi_enqueue(struct task_struct *p, bool wakeup)
 
 static inline void psi_dequeue(struct task_struct *p, bool sleep)
 {
-       int clear = TSK_RUNNING, set = 0;
+       int clear = TSK_RUNNING;
 
        if (static_branch_likely(&psi_disabled))
                return;
 
-       if (!sleep) {
-               if (p->in_memstall)
-                       clear |= TSK_MEMSTALL;
-       } else {
-               /*
-                * When a task sleeps, schedule() dequeues it before
-                * switching to the next one. Merge the clearing of
-                * TSK_RUNNING and TSK_ONCPU to save an unnecessary
-                * psi_task_change() call in psi_sched_switch().
-                */
-               clear |= TSK_ONCPU;
+       /*
+        * A voluntary sleep is a dequeue followed by a task switch. To
+        * avoid walking all ancestors twice, psi_task_switch() handles
+        * TSK_RUNNING and TSK_IOWAIT for us when it moves TSK_ONCPU.
+        * Do nothing here.
+        */
+       if (sleep)
+               return;
 
-               if (p->in_iowait)
-                       set |= TSK_IOWAIT;
-       }
+       if (p->in_memstall)
+               clear |= TSK_MEMSTALL;
 
-       psi_task_change(p, clear, set);
+       psi_task_change(p, clear, 0);
 }
 
 static inline void psi_ttwu_dequeue(struct task_struct *p)