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Date: Sat, 3 Dec 2022 14:32:34 +0000 From: Qais Yousef <qyousef@...alina.io> To: Dietmar Eggemann <dietmar.eggemann@....com> Cc: Ingo Molnar <mingo@...nel.org>, Peter Zijlstra <peterz@...radead.org>, Vincent Guittot <vincent.guittot@...aro.org>, "Rafael J. Wysocki" <rafael@...nel.org>, Viresh Kumar <viresh.kumar@...aro.org>, linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org, Lukasz Luba <lukasz.luba@....com>, Wei Wang <wvw@...gle.com>, Xuewen Yan <xuewen.yan94@...il.com>, Hank <han.lin@...iatek.com>, Jonathan JMChen <Jonathan.JMChen@...iatek.com>, kernel test robot <lkp@...el.com>, Dan Carpenter <error27@...il.com> Subject: Re: [PATCH 1/3] sched/uclamp: Fix a uninitialized variable warnings On 12/01/22 23:38, Dietmar Eggemann wrote: > On 27/11/2022 15:17, Qais Yousef wrote: > > Addresses the following warnings: > > > >> config: riscv-randconfig-m031-20221111 > >> compiler: riscv64-linux-gcc (GCC) 12.1.0 > >> > >> smatch warnings: > >> kernel/sched/fair.c:7263 find_energy_efficient_cpu() error: uninitialized symbol 'util_min'. > >> kernel/sched/fair.c:7263 find_energy_efficient_cpu() error: uninitialized symbol 'util_max'. > > > > Fixes: 244226035a1f ("sched/uclamp: Fix fits_capacity() check in feec()") > > Reported-by: kernel test robot <lkp@...el.com> > > Reported-by: Dan Carpenter <error27@...il.com> > > Signed-off-by: Qais Yousef (Google) <qyousef@...alina.io> > > --- > > kernel/sched/fair.c | 7 ++----- > > 1 file changed, 2 insertions(+), 5 deletions(-) > > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index 4cc56c91e06e..89dadaafc1ec 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -7217,10 +7217,10 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu) > > eenv_task_busy_time(&eenv, p, prev_cpu); > > > > for (; pd; pd = pd->next) { > > + unsigned long util_min = p_util_min, util_max = p_util_max; > > unsigned long cpu_cap, cpu_thermal_cap, util; > > unsigned long cur_delta, max_spare_cap = 0; > > unsigned long rq_util_min, rq_util_max; > > - unsigned long util_min, util_max; > > unsigned long prev_spare_cap = 0; > > int max_spare_cap_cpu = -1; > > unsigned long base_energy; > > @@ -7258,10 +7258,7 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu) > > * aligned with sched_cpu_util(). > > */ > > if (uclamp_is_used()) { > > - if (uclamp_rq_is_idle(cpu_rq(cpu))) { > > - util_min = p_util_min; > > - util_max = p_util_max; > > - } else { > > + if (!uclamp_rq_is_idle(cpu_rq(cpu))) { > > /* > > * Open code uclamp_rq_util_with() except for > > * the clamp() part. Ie: apply max aggregation > > Can we use `struct rq *rq = cpu_rq(cpu)` to reduce nesting and comply > with 80 columns line length? Yep, that's better! Thanks! -- Qais Yousef > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 89dadaafc1ec..6a2fc2ca5078 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -7239,6 +7239,8 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu) > eenv.pd_cap = 0; > > for_each_cpu(cpu, cpus) { > + struct rq *rq = cpu_rq(cpu); > + > eenv.pd_cap += cpu_thermal_cap; > > if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) > @@ -7257,21 +7259,19 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu) > * much capacity we can get out of the CPU; this is > * aligned with sched_cpu_util(). > */ > - if (uclamp_is_used()) { > - if (!uclamp_rq_is_idle(cpu_rq(cpu))) { > - /* > - * Open code uclamp_rq_util_with() except for > - * the clamp() part. Ie: apply max aggregation > - * only. util_fits_cpu() logic requires to > - * operate on non clamped util but must use the > - * max-aggregated uclamp_{min, max}. > - */ > - rq_util_min = uclamp_rq_get(cpu_rq(cpu), UCLAMP_MIN); > - rq_util_max = uclamp_rq_get(cpu_rq(cpu), UCLAMP_MAX); > - > - util_min = max(rq_util_min, p_util_min); > - util_max = max(rq_util_max, p_util_max); > - } > + if (uclamp_is_used() && !uclamp_rq_is_idle(rq)) { > + /* > + * Open code uclamp_rq_util_with() except for > + * the clamp() part. Ie: apply max aggregation > + * only. util_fits_cpu() logic requires to > + * operate on non clamped util but must use the > + * max-aggregated uclamp_{min, max}. > + */ > + rq_util_min = uclamp_rq_get(rq, UCLAMP_MIN); > + rq_util_max = uclamp_rq_get(rq, UCLAMP_MAX); > + > + util_min = max(rq_util_min, p_util_min); > + util_max = max(rq_util_max, p_util_max); > } > if (!util_fits_cpu(util, util_min, util_max, cpu)) > continue;
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