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sched/uclamp: Fix iowait boost escaping uclamp restriction

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iowait_boost signal is applied independently of util and doesn't take
into account uclamp settings of the rq. An io heavy task that is capped
by uclamp_max could still request higher frequency because
sugov_iowait_apply() doesn't clamp the boost via uclamp_rq_util_with()
like effective_cpu_util() does.

Make sure that iowait_boost honours uclamp requests by calling
uclamp_rq_util_with() when applying the boost.

Fixes: 982d9cdc22 ("sched/cpufreq, sched/uclamp: Add clamps for FAIR and RT tasks")
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20211216225320.2957053-3-qais.yousef@arm.com
This commit is contained in:
Qais Yousef 2021-12-16 22:53:20 +00:00 committed by Peter Zijlstra
parent 7a17e1db12
commit d37aee9018
1 changed files with 1 additions and 0 deletions
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kernel/sched/cpufreq_schedutil.c
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@ -289,6 +289,7 @@ static void sugov_iowait_apply(struct sugov_cpu *sg_cpu, u64 time)
* into the same scale so we can compare.
*/
boost = (sg_cpu->iowait_boost * sg_cpu->max) >> SCHED_CAPACITY_SHIFT;
boost = uclamp_rq_util_with(cpu_rq(sg_cpu->cpu), boost, NULL);
if (sg_cpu->util < boost)
sg_cpu->util = boost;
}