Commit-ID: e0454311903d3fd0f12a86c9e65d7b271c2bb05d
Gitweb: http://git.kernel.org/tip/e0454311903d3fd0f12a86c9e65d7b271c2bb05d
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Tue, 7 Jul 2015 14:07:27 +0200
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue, 7 Jul 2015 18:46:47 +0200
tick/broadcast: Sanity check the shutdown of the local clock_event
The broadcast code shuts down the local clock event unconditionally
even if no broadcast device is installed or if the broadcast device is
hrtimer based.
Add proper sanity checks.
[ Split out from a larger combo patch ]
Reported-and-tested-by: Sudeep Holla <sudeep.holla@xxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Suzuki Poulose <Suzuki.Poulose@xxxxxxx>
Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@xxxxxxx>
Cc: Catalin Marinas <Catalin.Marinas@xxxxxxx>
Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Preeti U Murthy <preeti@xxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
---
kernel/time/tick-broadcast.c | 23 ++++++++++++++++-------
1 file changed, 16 insertions(+), 7 deletions(-)
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index a762040..9877d0b 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -159,7 +159,7 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
{
struct clock_event_device *bc = tick_broadcast_device.evtdev;
unsigned long flags;
- int ret;
+ int ret = 0;
raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
@@ -221,13 +221,14 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
* If we kept the cpu in the broadcast mask,
* tell the caller to leave the per cpu device
* in shutdown state. The periodic interrupt
- * is delivered by the broadcast device.
+ * is delivered by the broadcast device, if
+ * the broadcast device exists and is not
+ * hrtimer based.
*/
- ret = cpumask_test_cpu(cpu, tick_broadcast_mask);
+ if (bc && !(bc->features & CLOCK_EVT_FEAT_HRTIMER))
+ ret = cpumask_test_cpu(cpu, tick_broadcast_mask);
break;
default:
- /* Nothing to do */
- ret = 0;
break;
}
}
@@ -373,8 +374,16 @@ void tick_broadcast_control(enum tick_broadcast_mode mode)
case TICK_BROADCAST_ON:
cpumask_set_cpu(cpu, tick_broadcast_on);
if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_mask)) {
- if (tick_broadcast_device.mode ==
- TICKDEV_MODE_PERIODIC)
+ /*
+ * Only shutdown the cpu local device, if:
+ *
+ * - the broadcast device exists
+ * - the broadcast device is not a hrtimer based one
+ * - the broadcast device is in periodic mode to
+ * avoid a hickup during switch to oneshot mode
+ */
+ if (bc && !(bc->features & CLOCK_EVT_FEAT_HRTIMER) &&
+ tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
clockevents_shutdown(dev);
}
break;
--
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