Messages in this thread Patch in this message | | | From | Patrick Bellasi <> | Subject | [PATCH v8 07/16] sched/core: uclamp: Reset uclamp values on RESET_ON_FORK | Date | Tue, 2 Apr 2019 11:41:43 +0100 |
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A forked tasks gets the same clamp values of its parent however, when the RESET_ON_FORK flag is set on parent, e.g. via:
sys_sched_setattr() sched_setattr() __sched_setscheduler(attr::SCHED_FLAG_RESET_ON_FORK)
the new forked task is expected to start with all attributes reset to default values.
Do that for utilization clamp values too by checking the reset request from the existing uclamp_fork() call which already provides the required initialization for other uclamp related bits.
Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> --- kernel/sched/core.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 68aed32e8ec7..bdebdabe9bc4 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1070,6 +1070,17 @@ static void uclamp_fork(struct task_struct *p) for (clamp_id = 0; clamp_id < UCLAMP_CNT; ++clamp_id) p->uclamp[clamp_id].active = false; + + if (likely(!p->sched_reset_on_fork)) + return; + + for (clamp_id = 0; clamp_id < UCLAMP_CNT; ++clamp_id) { + unsigned int clamp_value = uclamp_none(clamp_id); + + p->uclamp_req[clamp_id].user_defined = false; + p->uclamp_req[clamp_id].value = clamp_value; + p->uclamp_req[clamp_id].bucket_id = uclamp_bucket_id(clamp_value); + } } static void __init init_uclamp(void) -- 2.20.1
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