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authorIngo Molnar <mingo@elte.hu>2007-08-09 11:16:46 +0200
committerIngo Molnar <mingo@elte.hu>2007-08-09 11:16:46 +0200
commitb04a0f4c1651a553ee1a03dc70297d66ec74db5c (patch)
tree25a0721d639f244f61bba84edf296b8442e373a4 /kernel/sched.c
parenta4ac01c36e286dd1b9a1d5cd7422c5af51dc55f8 (diff)
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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>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c30
1 files changed, 22 insertions, 8 deletions
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;