[PATCH v2 3/7] sched/fair: Update rq clock in task_hot()

[Matt Fleming]

When determining whether or not a task is likely to be cache hot based
on its execution start time, we need to ensure the runqueue task clock
is accurate and up to date.

Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Mel Gorman <mgor...@techsingularity.net>
Cc: Mike Galbraith <umgwanakikb...@gmail.com>
Signed-off-by: Matt Fleming <m...@codeblueprint.co.uk>
---
 kernel/sched/fair.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 7f8a61e97599..85ca4ddab0d3 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6096,6 +6096,7 @@ static int task_hot(struct task_struct *p, struct lb_env 
*env)
        if (sysctl_sched_migration_cost == 0)
                return 0;
 
+       update_rq_clock(env->src_rq);
        delta = rq_clock_task(env->src_rq) - p->se.exec_start;
 
        return delta < (s64)sysctl_sched_migration_cost;
-- 
2.9.3