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

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