From b04a0f4c1651a553ee1a03dc70297d66ec74db5c Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Thu, 9 Aug 2007 11:16:46 +0200 Subject: sched: add [__]update_rq_clock(rq) add the [__]update_rq_clock(rq) functions. (No change in functionality, just reorganization to prepare for elimination of the heavy 64-bit timestamp-passing in the scheduler.) Signed-off-by: Ingo Molnar --- kernel/sched.c | 30 ++++++++++++++++++++++-------- 1 file changed, 22 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 1fa07c14624..d613723f324 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -318,15 +318,19 @@ static inline int cpu_of(struct rq *rq) } /* - * Per-runqueue clock, as finegrained as the platform can give us: + * Update the per-runqueue clock, as finegrained as the platform can give + * us, but without assuming monotonicity, etc.: */ -static unsigned long long __rq_clock(struct rq *rq) +static void __update_rq_clock(struct rq *rq) { u64 prev_raw = rq->prev_clock_raw; u64 now = sched_clock(); s64 delta = now - prev_raw; u64 clock = rq->clock; +#ifdef CONFIG_SCHED_DEBUG + WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); +#endif /* * Protect against sched_clock() occasionally going backwards: */ @@ -349,17 +353,24 @@ static unsigned long long __rq_clock(struct rq *rq) rq->prev_clock_raw = now; rq->clock = clock; +} - return clock; +static void update_rq_clock(struct rq *rq) +{ + if (likely(smp_processor_id() == cpu_of(rq))) + __update_rq_clock(rq); } -static unsigned long long rq_clock(struct rq *rq) +static u64 __rq_clock(struct rq *rq) { - int this_cpu = smp_processor_id(); + __update_rq_clock(rq); - if (this_cpu == cpu_of(rq)) - return __rq_clock(rq); + return rq->clock; +} +static u64 rq_clock(struct rq *rq) +{ + update_rq_clock(rq); return rq->clock; } @@ -386,9 +397,12 @@ unsigned long long cpu_clock(int cpu) { unsigned long long now; unsigned long flags; + struct rq *rq; local_irq_save(flags); - now = rq_clock(cpu_rq(cpu)); + rq = cpu_rq(cpu); + update_rq_clock(rq); + now = rq->clock; local_irq_restore(flags); return now; -- cgit v1.2.3