Messages in this thread Patch in this message |  | | From | Nicolai Stange <> | Subject | [RFC v8 26/28] clockevents: degrade ->retries to unsigned int | Date | Sat, 19 Nov 2016 17:10:34 +0100 |
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Being of type unsigned long, the struct clock_event_device's ->retries member is incremented in clockevents_program_min_delta() and used for diagnostic purposes in /proc/timer_list only.
Turning ->retries' type into unsigned int avoids the introduction of some padding with future reorderings of struct clock_event_device for the case of sizeof(unsigned long) == sizeof(void*) == 8. This is turn prevents these reorganizations from making sizeof(struct clock_event_device) cross a multiple of the cacheline size, assumed to be equal to 64 bytes.
For the case of HZ=1000, this change still allows for 2^32 / HZ / (3600*24) = 49 days without overwrap, even in the highly unrealistic case of one clockevents_program_min_delta() invocation per tick.
Thus, change ->retries' type from unsigned long to unsigned int. Adapt the format specifier or /proc/timer_list accordingly.
Signed-off-by: Nicolai Stange <nicstange@gmail.com> --- include/linux/clockchips.h | 2 +- kernel/time/timer_list.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h index e07f421..878a802 100644 --- a/include/linux/clockchips.h +++ b/include/linux/clockchips.h @@ -115,7 +115,7 @@ struct clock_event_device { u32 shift; enum clock_event_state state_use_accessors:8; unsigned int features:24; - unsigned long retries; + unsigned int retries; int (*set_state_periodic)(struct clock_event_device *); int (*set_state_oneshot)(struct clock_event_device *); diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c index 9067760..6a8d54f 100644 --- a/kernel/time/timer_list.c +++ b/kernel/time/timer_list.c @@ -271,7 +271,7 @@ print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu) SEQ_printf(m, " event_handler: "); print_name_offset(m, dev->event_handler); SEQ_printf(m, "\n"); - SEQ_printf(m, " retries: %lu\n", dev->retries); + SEQ_printf(m, " retries: %u\n", dev->retries); SEQ_printf(m, "\n"); } -- 2.10.2
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