perf: Kick full dynticks CPU if events rotation is needed

Kick the current CPU's tick by sending it a self IPI when
an event is queued on the rotation list and it is the first
element inserted. This makes sure that perf_event_task_tick()
works on full dynticks CPUs.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephane Eranian <eranian@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index b0cd86501c30..75b58bb75b32 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -18,6 +18,7 @@
 #include <linux/poll.h>
 #include <linux/slab.h>
 #include <linux/hash.h>
+#include <linux/tick.h>
 #include <linux/sysfs.h>
 #include <linux/dcache.h>
 #include <linux/percpu.h>
@@ -655,8 +656,12 @@ static void perf_pmu_rotate_start(struct pmu *pmu)
 
         WARN_ON(!irqs_disabled());
 
-        if (list_empty(&cpuctx->rotation_list))
+        if (list_empty(&cpuctx->rotation_list)) {
+                int was_empty = list_empty(head);
                 list_add(&cpuctx->rotation_list, head);
+                if (was_empty)
+                        tick_nohz_full_kick();
+        }
 }
 
 static void get_ctx(struct perf_event_context *ctx)