diff options
Diffstat (limited to 'kernel/time')
| -rw-r--r-- | kernel/time/clocksource.c | 28 | ||||
| -rw-r--r-- | kernel/time/sched_clock.c | 2 |
2 files changed, 17 insertions, 13 deletions
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index ace95763b3a6..fc2a9de43ca1 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -469,11 +469,13 @@ static u32 clocksource_max_adjustment(struct clocksource *cs) * @shift: cycle to nanosecond divisor (power of two) * @maxadj: maximum adjustment value to mult (~11%) * @mask: bitmask for two's complement subtraction of non 64 bit counters + * @max_cyc: maximum cycle value before potential overflow (does not include + * any safety margin) * * NOTE: This function includes a safety margin of 50%, so that bad clock values * can be detected. */ -u64 clocks_calc_max_nsecs(u32 mult, u32 shift, u32 maxadj, u64 mask) +u64 clocks_calc_max_nsecs(u32 mult, u32 shift, u32 maxadj, u64 mask, u64 *max_cyc) { u64 max_nsecs, max_cycles; @@ -493,6 +495,10 @@ u64 clocks_calc_max_nsecs(u32 mult, u32 shift, u32 maxadj, u64 mask) max_cycles = min(max_cycles, mask); max_nsecs = clocksource_cyc2ns(max_cycles, mult - maxadj, shift); + /* return the max_cycles value as well if requested */ + if (max_cyc) + *max_cyc = max_cycles; + /* Return 50% of the actual maximum, so we can detect bad values */ max_nsecs >>= 1; @@ -500,17 +506,15 @@ u64 clocks_calc_max_nsecs(u32 mult, u32 shift, u32 maxadj, u64 mask) } /** - * clocksource_max_deferment - Returns max time the clocksource should be deferred - * @cs: Pointer to clocksource + * clocksource_update_max_deferment - Updates the clocksource max_idle_ns & max_cycles + * @cs: Pointer to clocksource to be updated * */ -static u64 clocksource_max_deferment(struct clocksource *cs) +static inline void clocksource_update_max_deferment(struct clocksource *cs) { - u64 max_nsecs; - - max_nsecs = clocks_calc_max_nsecs(cs->mult, cs->shift, cs->maxadj, - cs->mask); - return max_nsecs; + cs->max_idle_ns = clocks_calc_max_nsecs(cs->mult, cs->shift, + cs->maxadj, cs->mask, + &cs->max_cycles); } #ifndef CONFIG_ARCH_USES_GETTIMEOFFSET @@ -684,7 +688,7 @@ void __clocksource_updatefreq_scale(struct clocksource *cs, u32 scale, u32 freq) cs->maxadj = clocksource_max_adjustment(cs); } - cs->max_idle_ns = clocksource_max_deferment(cs); + clocksource_update_max_deferment(cs); } EXPORT_SYMBOL_GPL(__clocksource_updatefreq_scale); @@ -730,8 +734,8 @@ int clocksource_register(struct clocksource *cs) "Clocksource %s might overflow on 11%% adjustment\n", cs->name); - /* calculate max idle time permitted for this clocksource */ - cs->max_idle_ns = clocksource_max_deferment(cs); + /* Update max idle time permitted for this clocksource */ + clocksource_update_max_deferment(cs); mutex_lock(&clocksource_mutex); clocksource_enqueue(cs); diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c index 3b8ae45020c1..ca3bc5c7027c 100644 --- a/kernel/time/sched_clock.c +++ b/kernel/time/sched_clock.c @@ -126,7 +126,7 @@ void __init sched_clock_register(u64 (*read)(void), int bits, new_mask = CLOCKSOURCE_MASK(bits); /* calculate how many nanosecs until we risk wrapping */ - wrap = clocks_calc_max_nsecs(new_mult, new_shift, 0, new_mask); + wrap = clocks_calc_max_nsecs(new_mult, new_shift, 0, new_mask, NULL); new_wrap_kt = ns_to_ktime(wrap); /* update epoch for new counter and update epoch_ns from old counter*/ |