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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 <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2007-08-09 11:16:46 +02:00
parent a4ac01c36e
commit b04a0f4c16
1 changed files with 23 additions and 9 deletions
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32
kernel/sched.c
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@ -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 prev_raw = rq->prev_clock_raw;
u64 now = sched_clock(); u64 now = sched_clock();
s64 delta = now - prev_raw; s64 delta = now - prev_raw;
u64 clock = rq->clock; 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: * Protect against sched_clock() occasionally going backwards:
*/ */
@ -349,20 +353,27 @@ static unsigned long long __rq_clock(struct rq *rq)
rq->prev_clock_raw = now; rq->prev_clock_raw = now;
rq->clock = clock; rq->clock = clock;
return clock;
} }
static unsigned long long rq_clock(struct rq *rq) static void update_rq_clock(struct rq *rq)
{ {
int this_cpu = smp_processor_id(); if (likely(smp_processor_id() == cpu_of(rq)))
__update_rq_clock(rq);
}
if (this_cpu == cpu_of(rq)) static u64 __rq_clock(struct rq *rq)
return __rq_clock(rq); {
__update_rq_clock(rq);
return rq->clock; return rq->clock;
} }
static u64 rq_clock(struct rq *rq)
{
update_rq_clock(rq);
return rq->clock;
}
/* /*
* The domain tree (rq->sd) is protected by RCU's quiescent state transition. * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
* See detach_destroy_domains: synchronize_sched for details. * See detach_destroy_domains: synchronize_sched for details.
@ -386,9 +397,12 @@ unsigned long long cpu_clock(int cpu)
{ {
unsigned long long now; unsigned long long now;
unsigned long flags; unsigned long flags;
struct rq *rq;
local_irq_save(flags); 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); local_irq_restore(flags);
return now; return now;