diff options
| author | Vincent Guittot <vincent.guittot@linaro.org> | 2021-02-24 14:30:06 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2021-03-06 12:40:22 +0100 |
| commit | c6f886546cb8a38617cdbe755fe50d3acd2463e4 (patch) | |
| tree | 7bc2bc591b13312964251693f7a005f00f616f59 /kernel/sched/fair.c | |
| parent | 6553fc18179113a11835d5fde1735259f8943a55 (diff) | |
sched/fair: Trigger the update of blocked load on newly idle cpu
Instead of waking up a random and already idle CPU, we can take advantage
of this_cpu being about to enter idle to run the ILB and update the
blocked load.
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/20210224133007.28644-7-vincent.guittot@linaro.org
Diffstat (limited to 'kernel/sched/fair.c')
| -rw-r--r-- | kernel/sched/fair.c | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 356a2456c5e9..e87e1b3bcdca 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -10453,6 +10453,24 @@ static bool nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) return true; } +/* + * Check if we need to run the ILB for updating blocked load before entering + * idle state. + */ +void nohz_run_idle_balance(int cpu) +{ + unsigned int flags; + + flags = atomic_fetch_andnot(NOHZ_NEWILB_KICK, nohz_flags(cpu)); + + /* + * Update the blocked load only if no SCHED_SOFTIRQ is about to happen + * (ie NOHZ_STATS_KICK set) and will do the same. + */ + if ((flags == NOHZ_NEWILB_KICK) && !need_resched()) + _nohz_idle_balance(cpu_rq(cpu), NOHZ_STATS_KICK, CPU_IDLE); +} + static void nohz_newidle_balance(struct rq *this_rq) { int this_cpu = this_rq->cpu; @@ -10474,10 +10492,10 @@ static void nohz_newidle_balance(struct rq *this_rq) return; /* - * Blocked load of idle CPUs need to be updated. - * Kick an ILB to update statistics. + * Set the need to trigger ILB in order to update blocked load + * before entering idle state. */ - kick_ilb(NOHZ_STATS_KICK); + atomic_or(NOHZ_NEWILB_KICK, nohz_flags(this_cpu)); } #else /* !CONFIG_NO_HZ_COMMON */ |