---

yaml
---
r: 205415
b: refs/heads/master
c: 21aa9af
h: refs/heads/master
i:
  205413: f0decd3
  205411: 4f86a3d
  205407: 49d684a
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 9ed3811a6c0d6b66e6cd47a5d7b9136386dce743
+refs/heads/master: 21aa9af03d06cb1d19a3738e5cf12acff984e69b

trunk/include/linux/sched.h

@@ -1696,6 +1696,7 @@ extern void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *
 #define PF_EXITING	0x00000004	/* getting shut down */
 #define PF_EXITPIDONE	0x00000008	/* pi exit done on shut down */
 #define PF_VCPU		0x00000010	/* I'm a virtual CPU */
+#define PF_WQ_WORKER	0x00000020	/* I'm a workqueue worker */
 #define PF_FORKNOEXEC	0x00000040	/* forked but didn't exec */
 #define PF_MCE_PROCESS  0x00000080      /* process policy on mce errors */
 #define PF_SUPERPRIV	0x00000100	/* used super-user privileges */

trunk/kernel/fork.c

@@ -907,7 +907,7 @@ static void copy_flags(unsigned long clone_flags, struct task_struct *p)
 {
 	unsigned long new_flags = p->flags;
 
-	new_flags &= ~PF_SUPERPRIV;
+	new_flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER);
 	new_flags |= PF_FORKNOEXEC;
 	new_flags |= PF_STARTING;
 	p->flags = new_flags;

trunk/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));
 }
 
 /**
@@ -2413,6 +2417,37 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
 	return success;
 }
 
+/**
+ * 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 @@ asmlinkage void __sched schedule(void)
 	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;
 	}
 

trunk/kernel/workqueue_sched.h

@@ -0,0 +1,16 @@
+/*
+ * kernel/workqueue_sched.h
+ *
+ * Scheduler hooks for concurrency managed workqueue.  Only to be
+ * included from sched.c and workqueue.c.
+ */
+static inline void wq_worker_waking_up(struct task_struct *task,
+				       unsigned int cpu)
+{
+}
+
+static inline struct task_struct *wq_worker_sleeping(struct task_struct *task,
+						     unsigned int cpu)
+{
+	return NULL;
+}