While being of type unsigned long right now, the ->min_delta_ticks and
->min_delta_ticks_adjusted members of struct clock_event_device aren't
expected to ever overflow an unsigned int.
The latter sits in the first cacheline. For the case of
sizeof(long) > sizeof(int), this is a waste of precious space needed by
later patches.
Degrade the types of ->min_delta_ticks_adjusted and ->min_delta_ticks
from unsigned long to unsigned int.
Change casts in the clockevents core were needed.
Adapt the signature of clockevents_config_and_register() accordingly.
Finally, move ->min_delta_ticks farther down the struct in order to
allow for alignment with other ints, potentially avoiding padding.
Signed-off-by: Nicolai Stange <nicsta...@gmail.com>
---
include/linux/clockchips.h | 8 ++++----
kernel/time/clockevents.c | 6 +++---
2 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h
index 76fc51b..c8dfc7a 100644
--- a/include/linux/clockchips.h
+++ b/include/linux/clockchips.h
@@ -92,9 +92,9 @@ enum clock_event_state {
* @set_state_shutdown: switch state to shutdown
* @tick_resume: resume clkevt device
* @broadcast: function to broadcast events
- * @min_delta_ticks: minimum delta value in ticks stored for reconfiguration
* @max_delta_ticks: maximum delta value in ticks stored for reconfiguration
* @name: ptr to clock event name
+ * @min_delta_ticks: minimum delta value in ticks stored for reconfiguration
* @rating: variable to rate clock event devices
* @irq: IRQ number (only for non CPU local devices)
* @bound_on: Bound on CPU
@@ -108,7 +108,7 @@ struct clock_event_device {
int (*set_next_ktime)(ktime_t expires, struct
clock_event_device *);
ktime_t next_event;
u64 max_delta_ns;
- unsigned long min_delta_ticks_adjusted;
+ unsigned int min_delta_ticks_adjusted;
u32 mult;
u32 shift;
enum clock_event_state state_use_accessors;
@@ -124,10 +124,10 @@ struct clock_event_device {
void (*broadcast)(const struct cpumask *mask);
void (*suspend)(struct clock_event_device *);
void (*resume)(struct clock_event_device *);
- unsigned long min_delta_ticks;
unsigned long max_delta_ticks;
const char *name;
+ unsigned int min_delta_ticks;
int rating;
int irq;
int bound_on;
@@ -189,7 +189,7 @@ extern void clockevents_register_device(struct
clock_event_device *dev);
extern int clockevents_unbind_device(struct clock_event_device *ced, int cpu);
extern void clockevents_config_and_register(struct clock_event_device *dev,
- u32 freq, unsigned long min_delta,
+ u32 freq, unsigned int min_delta,
unsigned long max_delta);
extern int clockevents_update_freq(struct clock_event_device *ce, u32 freq);
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 57b00b0..84639a1 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -228,7 +228,7 @@ static int clockevents_increase_min_delta(struct
clock_event_device *dev)
if (min_delta_ns > MIN_DELTA_LIMIT)
min_delta_ns = MIN_DELTA_LIMIT;
- dev->min_delta_ticks_adjusted = (unsigned long)((min_delta_ns *
+ dev->min_delta_ticks_adjusted = (unsigned int)((min_delta_ns *
dev->mult) >> dev->shift);
printk_deferred(KERN_WARNING
@@ -451,7 +451,7 @@ static void __clockevents_update_bounds(struct
clock_event_device *dev)
*/
dev->min_delta_ticks_adjusted =
max(dev->min_delta_ticks,
- (unsigned long)((1000ULL * dev->mult) >> dev->shift));
+ (unsigned int)((1000ULL * dev->mult) >> dev->shift));
}
/**
@@ -514,7 +514,7 @@ static void clockevents_config(struct clock_event_device
*dev, u32 freq)
* min/max_delta can be 0 for devices which do not support oneshot mode.
*/
void clockevents_config_and_register(struct clock_event_device *dev,
- u32 freq, unsigned long min_delta,
+ u32 freq, unsigned int min_delta,
unsigned long max_delta)
{
dev->min_delta_ticks = min_delta;
--
2.10.2
