Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Fixes and improvements for perf/core:

. Overhaul the tools/ makefiles, gluing them to the top level Makefile, from
  Borislav Petkov.

. Move the UI files from tools/perf/util/ui/ to tools/perf/ui/. Also move
  the GTK+ browser to tools/perf/ui/gtk/, from Namhyung Kim.

. Only fallback to sw cycles counter on ENOENT for the hw cycles, from
  Robert Richter

. Trivial fixes from Robert Richter

. Handle the autogenerated bison/flex files better, from Namhyung and Jiri Olsa.

. Navigate jump instructions in the annotate browser, just press enter or ->,
  still needs support for a jump navigation history, i.e. to go back.

. Search string in the annotate browser: same keys as vim:
     / forward
     n next backward/forward
     ? backward

. Clarify number of events/samples in the report header, from Ashay Rane

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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");
 
 }