1 files changed, 51 insertions, 2 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 96eafd5f345f..edd5a54b95da 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -77,6 +77,7 @@
 #include <asm/irq_regs.h>
 
 #include "sched_cpupri.h"
+#include "workqueue_sched.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/sched.h>
@@ -2306,6 +2307,9 @@ static inline void ttwu_post_activation(struct task_struct *p, struct rq *rq,
                 rq->idle_stamp = 0;
         }
 #endif
+        /* if a worker is waking up, notify workqueue */
+        if ((p->flags & PF_WQ_WORKER) && success)
+                wq_worker_waking_up(p, cpu_of(rq));
 }
 
 /**
@@ -2414,6 +2418,37 @@ out:
 }
 
 /**
+ * try_to_wake_up_local - try to wake up a local task with rq lock held
+ * @p: the thread to be awakened
+ *
+ * Put @p on the run-queue if it's not alredy there.  The caller must
+ * ensure that this_rq() is locked, @p is bound to this_rq() and not
+ * the current task.  this_rq() stays locked over invocation.
+ */
+static void try_to_wake_up_local(struct task_struct *p)
+{
+        struct rq *rq = task_rq(p);
+        bool success = false;
+
+        BUG_ON(rq != this_rq());
+        BUG_ON(p == current);
+        lockdep_assert_held(&rq->lock);
+
+        if (!(p->state & TASK_NORMAL))
+                return;
+
+        if (!p->se.on_rq) {
+                if (likely(!task_running(rq, p))) {
+                        schedstat_inc(rq, ttwu_count);
+                        schedstat_inc(rq, ttwu_local);
+                }
+                ttwu_activate(p, rq, false, false, true, ENQUEUE_WAKEUP);
+                success = true;
+        }
+        ttwu_post_activation(p, rq, 0, success);
+}
+
+/**
  * wake_up_process - Wake up a specific process
  * @p: The process to be woken up.
  *
@@ -3618,10 +3653,24 @@ need_resched_nonpreemptible:
         clear_tsk_need_resched(prev);
 
         if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
-                if (unlikely(signal_pending_state(prev->state, prev)))
+                if (unlikely(signal_pending_state(prev->state, prev))) {
                         prev->state = TASK_RUNNING;
-                else
+                } else {
+                        /*
+                         * If a worker is going to sleep, notify and
+                         * ask workqueue whether it wants to wake up a
+                         * task to maintain concurrency.  If so, wake
+                         * up the task.
+                         */
+                        if (prev->flags & PF_WQ_WORKER) {
+                                struct task_struct *to_wakeup;
+
+                                to_wakeup = wq_worker_sleeping(prev, cpu);
+                                if (to_wakeup)
+                                        try_to_wake_up_local(to_wakeup);
+                        }
                         deactivate_task(rq, prev, DEQUEUE_SLEEP);
+                }
                 switch_count = &prev->nvcsw;
         }