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authorPeter Zijlstra <peterz@infradead.org>2010-08-19 13:31:43 +0200
committerIngo Molnar <mingo@elte.hu>2010-08-20 14:59:01 +0200
commit861d034ee814917a83bd5de4b26e3b8336ddeeb8 (patch)
tree6514cb3ebbb58fb0a638e267dfd6da510a5c8a00 /kernel
parent763008c4357b73c8d18396dfd8d79dc58fa3f99d (diff)
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sched: Fix rq->clock synchronization when migrating tasks
sched_fork() -- we do task placement in ->task_fork_fair() ensure we update_rq_clock() so we work with current time. We leave the vruntime in relative state, so the time delay until wake_up_new_task() doesn't matter. wake_up_new_task() -- Since task_fork_fair() left p->vruntime in relative state we can safely migrate, the activate_task() on the remote rq will call update_rq_clock() and causes the clock to be synced (enough). Tested-by: Jack Daniel <wanders.thirst@gmail.com> Tested-by: Philby John <pjohn@mvista.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1281002322.1923.1708.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched_fair.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 806d1b227a2..ab661ebc489 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -3752,6 +3752,8 @@ static void task_fork_fair(struct task_struct *p)
raw_spin_lock_irqsave(&rq->lock, flags);
+ update_rq_clock(rq);
+
if (unlikely(task_cpu(p) != this_cpu))
__set_task_cpu(p, this_cpu);