diff options
| author | Qais Yousef <qyousef@layalina.io> | 2023-01-12 12:27:08 +0000 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2023-01-13 11:40:21 +0100 |
| commit | da07d2f9c153e457e845d4dcfdd13568d71d18a4 (patch) | |
| tree | d1e735a84b3ab5d88477552881f4ad6d82fe4260 /kernel | |
| parent | e26fd28db82899be71b4b949527373d0a6be1e65 (diff) | |
| download | linux-da07d2f9c153e457e845d4dcfdd13568d71d18a4.tar.bz2 | |
sched/fair: Fixes for capacity inversion detection
Traversing the Perf Domains requires rcu_read_lock() to be held and is
conditional on sched_energy_enabled(). Ensure right protections applied.
Also skip capacity inversion detection for our own pd; which was an
error.
Fixes: 44c7b80bffc3 ("sched/fair: Detect capacity inversion")
Reported-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Qais Yousef (Google) <qyousef@layalina.io>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20230112122708.330667-3-qyousef@layalina.io
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/fair.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index be43731b147d..0f8736991427 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8868,16 +8868,23 @@ static void update_cpu_capacity(struct sched_domain *sd, int cpu) * * Thermal pressure will impact all cpus in this perf domain * equally. */ - if (static_branch_unlikely(&sched_asym_cpucapacity)) { + if (sched_energy_enabled()) { unsigned long inv_cap = capacity_orig - thermal_load_avg(rq); - struct perf_domain *pd = rcu_dereference(rq->rd->pd); + struct perf_domain *pd; + + rcu_read_lock(); + pd = rcu_dereference(rq->rd->pd); rq->cpu_capacity_inverted = 0; for (; pd; pd = pd->next) { struct cpumask *pd_span = perf_domain_span(pd); unsigned long pd_cap_orig, pd_cap; + /* We can't be inverted against our own pd */ + if (cpumask_test_cpu(cpu_of(rq), pd_span)) + continue; + cpu = cpumask_any(pd_span); pd_cap_orig = arch_scale_cpu_capacity(cpu); @@ -8902,6 +8909,8 @@ static void update_cpu_capacity(struct sched_domain *sd, int cpu) break; } } + + rcu_read_unlock(); } trace_sched_cpu_capacity_tp(rq); |