Merge tag 'sched-core-2020-06-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:
 "The changes in this cycle are:

   - Optimize the task wakeup CPU selection logic, to improve
     scalability and reduce wakeup latency spikes

   - PELT enhancements

   - CFS bandwidth handling fixes

   - Optimize the wakeup path by remove rq->wake_list and replacing it
     with ->ttwu_pending

   - Optimize IPI cross-calls by making flush_smp_call_function_queue()
     process sync callbacks first.

   - Misc fixes and enhancements"

* tag 'sched-core-2020-06-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
  irq_work: Define irq_work_single() on !CONFIG_IRQ_WORK too
  sched/headers: Split out open-coded prototypes into kernel/sched/smp.h
  sched: Replace rq::wake_list
  sched: Add rq::ttwu_pending
  irq_work, smp: Allow irq_work on call_single_queue
  smp: Optimize send_call_function_single_ipi()
  smp: Move irq_work_run() out of flush_smp_call_function_queue()
  smp: Optimize flush_smp_call_function_queue()
  sched: Fix smp_call_function_single_async() usage for ILB
  sched/core: Offload wakee task activation if it the wakee is descheduling
  sched/core: Optimize ttwu() spinning on p->on_cpu
  sched: Defend cfs and rt bandwidth quota against overflow
  sched/cpuacct: Fix charge cpuacct.usage_sys
  sched/fair: Replace zero-length array with flexible-array
  sched/pelt: Sync util/runnable_sum with PELT window when propagating
  sched/cpuacct: Use __this_cpu_add() instead of this_cpu_ptr()
  sched/fair: Optimize enqueue_task_fair()
  sched: Make scheduler_ipi inline
  sched: Clean up scheduler_ipi()
  sched/core: Simplify sched_init()
  ...

1 files changed, 8 insertions, 1 deletions

diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h
index 3b752e80c017..2735da5f839e 100644
--- a/include/linux/irq_work.h
+++ b/include/linux/irq_work.h
@@ -13,6 +13,8 @@
  * busy      NULL, 2 -> {free, claimed} : callback in progress, can be claimed
  */
 
+/* flags share CSD_FLAG_ space */
+
 #define IRQ_WORK_PENDING	BIT(0)
 #define IRQ_WORK_BUSY		BIT(1)
 
@@ -23,9 +25,12 @@
 
 #define IRQ_WORK_CLAIMED	(IRQ_WORK_PENDING | IRQ_WORK_BUSY)
 
+/*
+ * structure shares layout with single_call_data_t.
+ */
 struct irq_work {
-	atomic_t flags;
 	struct llist_node llnode;
+	atomic_t flags;
 	void (*func)(struct irq_work *);
 };
 
@@ -53,9 +58,11 @@ void irq_work_sync(struct irq_work *work);
 
 void irq_work_run(void);
 bool irq_work_needs_cpu(void);
+void irq_work_single(void *arg);
 #else
 static inline bool irq_work_needs_cpu(void) { return false; }
 static inline void irq_work_run(void) { }
+static inline void irq_work_single(void *arg) { }
 #endif
 
 #endif /* _LINUX_IRQ_WORK_H */