sched/fair: Remove update of blocked load from newidle_balance

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newidle_balance runs with both preempt and irq disabled which prevent
local irq to run during this period. The duration for updating the
blocked load of CPUs varies according to the number of CPU cgroups
with non-decayed load and extends this critical period to an uncontrolled
level.

Remove the update from newidle_balance and trigger a normal ILB that
will take care of the update instead.

This reduces the IRQ latency from O(nr_cgroups * nr_nohz_cpus) to
O(nr_cgroups).

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lkml.kernel.org/r/20210224133007.28644-2-vincent.guittot@linaro.org

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Vincent Guittot 2021-02-24 14:30:01 +01:00 • committed by Ingo Molnar

parent 183f47fcaa

commit 0826530de3

1 changed files with 5 additions and 28 deletions

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kernel/sched/fair.c

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