No functional changes ..
I created sched_clock_drift_adjust() which holds similar code from
different places in the scheduler which all appear to do the same thing.
I also added an explicit ifdef on CONFIG_SMP, the comments seemed to
suggest it wasn't needed, but it can't hurt to make it explicit .
Signed-Off-By: Daniel Walker <[email protected]>
---
kernel/sched.c | 31 ++++++++++++++++++++++---------
1 file changed, 22 insertions(+), 9 deletions(-)
Index: linux-2.6.20/kernel/sched.c
===================================================================
--- linux-2.6.20.orig/kernel/sched.c
+++ linux-2.6.20/kernel/sched.c
@@ -659,6 +659,20 @@ sched_info_switch(struct task_struct *pr
#define sched_info_switch(t, next) do { } while (0)
#endif /* CONFIG_SCHEDSTATS || CONFIG_TASK_DELAY_ACCT */
+#ifdef CONFIG_SMP
+static inline unsigned long long
+sched_clock_drift_adjust(unsigned long long timestamp, struct rq *from,
+ struct rq *to)
+{
+ return (timestamp - from->most_recent_timestamp)
+ + to->most_recent_timestamp;
+}
+#else
+static inline unsigned long long
+sched_clock_drift_adjust(unsigned long long timestamp, struct rq *from,
+ struct rq *to) { }
+#endif
+
static inline int task_queued(struct task_struct *task)
{
return !list_empty(&task->run_list);
@@ -1018,10 +1032,10 @@ static void activate_task(struct task_st
#ifdef CONFIG_SMP
if (!local) {
- /* Compensate for drifting sched_clock */
struct rq *this_rq = this_rq();
- now = (now - this_rq->most_recent_timestamp)
- + rq->most_recent_timestamp;
+
+ /* Compensate for drifting sched_clock */
+ now = sched_clock_drift_adjust(now, this_rq, rq);
}
#endif
@@ -1742,8 +1756,8 @@ void fastcall wake_up_new_task(struct ta
* Not the local CPU - must adjust timestamp. This should
* get optimised away in the !CONFIG_SMP case.
*/
- p->timestamp = (p->timestamp - this_rq->most_recent_timestamp)
- + rq->most_recent_timestamp;
+ p->timestamp =
+ sched_clock_drift_adjust(p->timestamp, this_rq, rq);
activate_task(p, rq, 0);
try_preempt(p, rq);
@@ -2118,8 +2132,7 @@ static void pull_task(struct rq *src_rq,
set_task_cpu(p, this_cpu);
inc_nr_running(p, this_rq);
enqueue_task(p, this_rq);
- p->timestamp = (p->timestamp - src_rq->most_recent_timestamp)
- + this_rq->most_recent_timestamp;
+ p->timestamp = sched_clock_drift_adjust(p->timestamp, src_rq, this_rq);
try_preempt(p, this_rq);
}
@@ -5054,8 +5067,8 @@ static int __migrate_task(struct task_st
* afterwards, and pretending it was a local activate.
* This way is cleaner and logically correct.
*/
- p->timestamp = p->timestamp - rq_src->most_recent_timestamp
- + rq_dest->most_recent_timestamp;
+ p->timestamp =
+ sched_clock_drift_adjust(p->timestamp, rq_src, rq_dest);
deactivate_task(p, rq_src);
__activate_task(p, rq_dest);
try_preempt(p, rq_dest);
--
--
-
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