Merge branch 'perf/core' into perf/uprobes

Merge in latest upstream (and the latest perf development tree),
to prepare for tooling changes, and also to pick up v3.4 MM
changes that the uprobes code needs to take care of.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 17 insertions, 10 deletions

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 14bc092fb12..df30ee08bdd 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -9,6 +9,8 @@
  * to those contributors as well.
  */
 
+#define pr_fmt(fmt) "NMI watchdog: " fmt
+
 #include <linux/mm.h>
 #include <linux/cpu.h>
 #include <linux/nmi.h>
@@ -319,11 +321,9 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
  */
 static int watchdog(void *unused)
 {
-	struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
+	struct sched_param param = { .sched_priority = 0 };
 	struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer);
 
-	sched_setscheduler(current, SCHED_FIFO, &param);
-
 	/* initialize timestamp */
 	__touch_watchdog();
 
@@ -349,8 +349,11 @@ static int watchdog(void *unused)
 
 		set_current_state(TASK_INTERRUPTIBLE);
 	}
+	/*
+	 * Drop the policy/priority elevation during thread exit to avoid a
+	 * scheduling latency spike.
+	 */
 	__set_current_state(TASK_RUNNING);
-	param.sched_priority = 0;
 	sched_setscheduler(current, SCHED_NORMAL, &param);
 	return 0;
 }
@@ -376,18 +379,20 @@ static int watchdog_nmi_enable(int cpu)
 	/* Try to register using hardware perf events */
 	event = perf_event_create_kernel_counter(wd_attr, cpu, NULL, watchdog_overflow_callback, NULL);
 	if (!IS_ERR(event)) {
-		printk(KERN_INFO "NMI watchdog enabled, takes one hw-pmu counter.\n");
+		pr_info("enabled, takes one hw-pmu counter.\n");
 		goto out_save;
 	}
 
 
 	/* vary the KERN level based on the returned errno */
 	if (PTR_ERR(event) == -EOPNOTSUPP)
-		printk(KERN_INFO "NMI watchdog disabled (cpu%i): not supported (no LAPIC?)\n", cpu);
+		pr_info("disabled (cpu%i): not supported (no LAPIC?)\n", cpu);
 	else if (PTR_ERR(event) == -ENOENT)
-		printk(KERN_WARNING "NMI watchdog disabled (cpu%i): hardware events not enabled\n", cpu);
+		pr_warning("disabled (cpu%i): hardware events not enabled\n",
+			 cpu);
 	else
-		printk(KERN_ERR "NMI watchdog disabled (cpu%i): unable to create perf event: %ld\n", cpu, PTR_ERR(event));
+		pr_err("disabled (cpu%i): unable to create perf event: %ld\n",
+			cpu, PTR_ERR(event));
 	return PTR_ERR(event);
 
 	/* success path */
@@ -439,9 +444,10 @@ static int watchdog_enable(int cpu)
 
 	/* create the watchdog thread */
 	if (!p) {
+		struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
 		p = kthread_create_on_node(watchdog, NULL, cpu_to_node(cpu), "watchdog/%d", cpu);
 		if (IS_ERR(p)) {
-			printk(KERN_ERR "softlockup watchdog for %i failed\n", cpu);
+			pr_err("softlockup watchdog for %i failed\n", cpu);
 			if (!err) {
 				/* if hardlockup hasn't already set this */
 				err = PTR_ERR(p);
@@ -450,6 +456,7 @@ static int watchdog_enable(int cpu)
 			}
 			goto out;
 		}
+		sched_setscheduler(p, SCHED_FIFO, &param);
 		kthread_bind(p, cpu);
 		per_cpu(watchdog_touch_ts, cpu) = 0;
 		per_cpu(softlockup_watchdog, cpu) = p;
@@ -496,7 +503,7 @@ static void watchdog_enable_all_cpus(void)
 			watchdog_enabled = 1;
 
 	if (!watchdog_enabled)
-		printk(KERN_ERR "watchdog: failed to be enabled on some cpus\n");
+		pr_err("failed to be enabled on some cpus\n");
 
 }