[tip:timers/core] hrtimer: Align the hrtimer clock bases as well

[tip-bot for Thomas Gleixner <tipbot@zytor.com>]

Commit-ID:  b8e38413ac2c33c497e72895fcd5da709fd1b908
Gitweb:     http://git.kernel.org/tip/b8e38413ac2c33c497e72895fcd5da709fd1b908
Author:     Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Tue, 14 Apr 2015 21:08:44 +0000
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Wed, 22 Apr 2015 17:06:49 +0200

hrtimer: Align the hrtimer clock bases as well

We don't use cacheline_align here because that might waste lot of
space on 32bit machine with 64 bytes cachelines and on 64bit machines
with 128 bytes cachelines.

The size of struct hrtimer_clock_base is 64byte on 64bit and 32byte on
32bit machines. So we utilize the cache lines proper.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20150414203501.498165771@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/hrtimer.h | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 0853f52..e5c22d6 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -130,6 +130,12 @@ struct hrtimer_sleeper {
 	struct task_struct *task;
 };
 
+#ifdef CONFIG_64BIT
+# define HRTIMER_CLOCK_BASE_ALIGN	64
+#else
+# define HRTIMER_CLOCK_BASE_ALIGN	32
+#endif
+
 /**
  * struct hrtimer_clock_base - the timer base for a specific clock
  * @cpu_base:		per cpu clock base
@@ -147,7 +153,7 @@ struct hrtimer_clock_base {
 	struct timerqueue_head	active;
 	ktime_t			(*get_time)(void);
 	ktime_t			offset;
-};
+} __attribute__((__aligned__(HRTIMER_CLOCK_BASE_ALIGN)));
 
 enum  hrtimer_base_type {
 	HRTIMER_BASE_MONOTONIC,
@@ -195,6 +201,8 @@ struct hrtimer_cpu_base {
 
 static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time)
 {
+	BUILD_BUG_ON(sizeof(struct hrtimer_clock_base) > HRTIMER_CLOCK_BASE_ALIGN);
+
 	timer->node.expires = time;
 	timer->_softexpires = time;
 }