[RFC PATCH 07/11] nohz,timer: designate timer housekeeping cpu

From: riel
Date: Wed Jun 24 2015 - 11:00:22 EST


From: Rik van Riel <riel@xxxxxxxxxx>

The timer housekeeping CPU can do tick based sampling for remote
CPUs. For now this is the first CPU in the housekeeping_mask.

Eventually we could move to having one timer housekeeping cpu per
socket, if needed.

Signed-off-by: Rik van Riel <riel@xxxxxxxxxx>
---
include/linux/tick.h | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/include/linux/tick.h b/include/linux/tick.h
index f8492da57ad3..2fb51030587b 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -158,6 +158,15 @@ static inline bool is_housekeeping_cpu(int cpu)
return true;
}

+static inline bool is_timer_housekeeping_cpu(int cpu)
+{
+#ifdef CONFIG_NO_HZ_FULL
+ if (tick_nohz_full_running)
+ return (cpumask_first(housekeeping_mask) == cpu);
+#endif
+ return false;
+}
+
static inline void housekeeping_affine(struct task_struct *t)
{
#ifdef CONFIG_NO_HZ_FULL
--
2.1.0

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