[PATCH] hrtimers: cleanup locking
Improve kernel/hrtimers.c locking: use a per-CPU base with a lock to control
locking of all clocks belonging to a CPU. This simplifies code that needs to
lock all clocks at once. This makes life easier for high-res timers and
dyntick.
No functional changes.
[ optimization change from Andrew Morton <akpm@osdl.org> ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 44c7d28..e00fc4d 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -21,6 +21,9 @@
#include <linux/list.h>
#include <linux/wait.h>
+struct hrtimer_clock_base;
+struct hrtimer_cpu_base;
+
/*
* Mode arguments of xxx_hrtimer functions:
*/
@@ -37,8 +40,6 @@
HRTIMER_RESTART, /* Timer must be restarted */
};
-struct hrtimer_base;
-
/**
* struct hrtimer - the basic hrtimer structure
* @node: red black tree node for time ordered insertion
@@ -51,10 +52,10 @@
* The hrtimer structure must be initialized by init_hrtimer_#CLOCKTYPE()
*/
struct hrtimer {
- struct rb_node node;
- ktime_t expires;
- enum hrtimer_restart (*function)(struct hrtimer *);
- struct hrtimer_base *base;
+ struct rb_node node;
+ ktime_t expires;
+ enum hrtimer_restart (*function)(struct hrtimer *);
+ struct hrtimer_clock_base *base;
};
/**
@@ -71,29 +72,41 @@
/**
* struct hrtimer_base - the timer base for a specific clock
- * @index: clock type index for per_cpu support when moving a timer
- * to a base on another cpu.
- * @lock: lock protecting the base and associated timers
+ * @index: clock type index for per_cpu support when moving a
+ * timer to a base on another cpu.
* @active: red black tree root node for the active timers
* @first: pointer to the timer node which expires first
* @resolution: the resolution of the clock, in nanoseconds
* @get_time: function to retrieve the current time of the clock
* @get_softirq_time: function to retrieve the current time from the softirq
- * @curr_timer: the timer which is executing a callback right now
* @softirq_time: the time when running the hrtimer queue in the softirq
- * @lock_key: the lock_class_key for use with lockdep
*/
-struct hrtimer_base {
+struct hrtimer_clock_base {
+ struct hrtimer_cpu_base *cpu_base;
clockid_t index;
- spinlock_t lock;
struct rb_root active;
struct rb_node *first;
ktime_t resolution;
ktime_t (*get_time)(void);
ktime_t (*get_softirq_time)(void);
- struct hrtimer *curr_timer;
ktime_t softirq_time;
- struct lock_class_key lock_key;
+};
+
+#define HRTIMER_MAX_CLOCK_BASES 2
+
+/*
+ * struct hrtimer_cpu_base - the per cpu clock bases
+ * @lock: lock protecting the base and associated clock bases
+ * and timers
+ * @lock_key: the lock_class_key for use with lockdep
+ * @clock_base: array of clock bases for this cpu
+ * @curr_timer: the timer which is executing a callback right now
+ */
+struct hrtimer_cpu_base {
+ spinlock_t lock;
+ struct lock_class_key lock_key;
+ struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
+ struct hrtimer *curr_timer;
};
/*