Merge branch 'for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

Pull workqueue update from Tejun Heo:
 "Workqueue changes for v4.5.  One cleanup patch and three to improve
  the debuggability.

  Workqueue now has a stall detector which dumps workqueue state if any
  worker pool hasn't made forward progress over a certain amount of time
  (30s by default) and also triggers a warning if a workqueue which can
  be used in memory reclaim path tries to wait on something which can't
  be.

  These should make workqueue hangs a lot easier to debug."

* 'for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: simplify the apply_workqueue_attrs_locked()
  workqueue: implement lockup detector
  watchdog: introduce touch_softlockup_watchdog_sched()
  workqueue: warn if memory reclaim tries to flush !WQ_MEM_RECLAIM workqueue

1 files changed, 17 insertions, 1 deletions

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 84b5035cb6a5..b3ace6ebbba3 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -20,6 +20,7 @@
 #include <linux/smpboot.h>
 #include <linux/sched/rt.h>
 #include <linux/tick.h>
+#include <linux/workqueue.h>
 
 #include <asm/irq_regs.h>
 #include <linux/kvm_para.h>
@@ -225,7 +226,15 @@ static void __touch_watchdog(void)
 	__this_cpu_write(watchdog_touch_ts, get_timestamp());
 }
 
-void touch_softlockup_watchdog(void)
+/**
+ * touch_softlockup_watchdog_sched - touch watchdog on scheduler stalls
+ *
+ * Call when the scheduler may have stalled for legitimate reasons
+ * preventing the watchdog task from executing - e.g. the scheduler
+ * entering idle state.  This should only be used for scheduler events.
+ * Use touch_softlockup_watchdog() for everything else.
+ */
+void touch_softlockup_watchdog_sched(void)
 {
 	/*
 	 * Preemption can be enabled.  It doesn't matter which CPU's timestamp
@@ -233,6 +242,12 @@ void touch_softlockup_watchdog(void)
 	 */
 	raw_cpu_write(watchdog_touch_ts, 0);
 }
+
+void touch_softlockup_watchdog(void)
+{
+	touch_softlockup_watchdog_sched();
+	wq_watchdog_touch(raw_smp_processor_id());
+}
 EXPORT_SYMBOL(touch_softlockup_watchdog);
 
 void touch_all_softlockup_watchdogs(void)
@@ -246,6 +261,7 @@ void touch_all_softlockup_watchdogs(void)
 	 */
 	for_each_watchdog_cpu(cpu)
 		per_cpu(watchdog_touch_ts, cpu) = 0;
+	wq_watchdog_touch(-1);
 }
 
 #ifdef CONFIG_HARDLOCKUP_DETECTOR