clocksource: Restructure clocksource struct members
Group the hot path members of struct clocksource together so we have a
better cache line footprint. Make it cacheline aligned.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Link: http://lkml.kernel.org/r/%3C20110518210136.003081882%40linutronix.de%3E
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 0fb0b7e..c918fbd 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -159,42 +159,38 @@
*/
struct clocksource {
/*
- * First part of structure is read mostly
+ * Hotpath data, fits in a single cache line when the
+ * clocksource itself is cacheline aligned.
*/
- const char *name;
- struct list_head list;
- int rating;
cycle_t (*read)(struct clocksource *cs);
- int (*enable)(struct clocksource *cs);
- void (*disable)(struct clocksource *cs);
+ cycle_t cycle_last;
cycle_t mask;
u32 mult;
u32 shift;
u64 max_idle_ns;
- unsigned long flags;
- cycle_t (*vread)(void);
- void (*suspend)(struct clocksource *cs);
- void (*resume)(struct clocksource *cs);
+
#ifdef CONFIG_IA64
void *fsys_mmio; /* used by fsyscall asm code */
#define CLKSRC_FSYS_MMIO_SET(mmio, addr) ((mmio) = (addr))
#else
#define CLKSRC_FSYS_MMIO_SET(mmio, addr) do { } while (0)
#endif
-
- /*
- * Second part is written at each timer interrupt
- * Keep it in a different cache line to dirty no
- * more than one cache line.
- */
- cycle_t cycle_last ____cacheline_aligned_in_smp;
+ const char *name;
+ struct list_head list;
+ int rating;
+ cycle_t (*vread)(void);
+ int (*enable)(struct clocksource *cs);
+ void (*disable)(struct clocksource *cs);
+ unsigned long flags;
+ void (*suspend)(struct clocksource *cs);
+ void (*resume)(struct clocksource *cs);
#ifdef CONFIG_CLOCKSOURCE_WATCHDOG
/* Watchdog related data, used by the framework */
struct list_head wd_list;
cycle_t wd_last;
#endif
-};
+} ____cacheline_aligned;
/*
* Clock source flags bits::