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sched/core: Avoid double calling update_rq_clock() in __balance_push_cpu_stop()

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There is a double update_rq_clock() invocation:

  __balance_push_cpu_stop()
    update_rq_clock()
    __migrate_task()
      update_rq_clock()

Sadly select_fallback_rq() also needs update_rq_clock() for
__do_set_cpus_allowed(), it is not possible to remove the update from
__balance_push_cpu_stop(). So remove it from __migrate_task() and
ensure all callers of this function call update_rq_clock() prior to
calling it.

Signed-off-by: Hao Jia <jiahao.os@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20230613082012.49615-3-jiahao.os@bytedance.com
This commit is contained in:
Hao Jia 2023-06-13 16:20:10 +08:00 committed by Peter Zijlstra
parent cab3ecaed5
commit 96500560f0
1 changed files with 4 additions and 3 deletions
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7
kernel/sched/core.c
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@ -2546,7 +2546,6 @@ static struct rq *__migrate_task(struct rq *rq, struct rq_flags *rf,
if (!is_cpu_allowed(p, dest_cpu))
return rq;
update_rq_clock(rq);
rq = move_queued_task(rq, rf, p, dest_cpu);
return rq;
@ -2604,10 +2603,12 @@ static int migration_cpu_stop(void *data)
goto out;
}
if (task_on_rq_queued(p))
if (task_on_rq_queued(p)) {
update_rq_clock(rq);
rq = __migrate_task(rq, &rf, p, arg->dest_cpu);
else
} else {
p->wake_cpu = arg->dest_cpu;
}
/*
* XXX __migrate_task() can fail, at which point we might end