* [PATCH v3 0/2] Fixes for uclamp and capacity inversion detection @ 2023-01-12 12:27 Qais Yousef 2023-01-12 12:27 ` [PATCH v3 1/2] sched/uclamp: Fix a uninitialized variable warnings Qais Yousef 2023-01-12 12:27 ` [PATCH v3 2/2] sched/fair: Fixes for capacity inversion detection Qais Yousef 0 siblings, 2 replies; 5+ messages in thread From: Qais Yousef @ 2023-01-12 12:27 UTC (permalink / raw) To: Ingo Molnar, Peter Zijlstra, Vincent Guittot, Dietmar Eggemann Cc: Rafael J. Wysocki, Viresh Kumar, linux-kernel, linux-pm, Lukasz Luba, Wei Wang, Xuewen Yan, Hank, Jonathan JMChen, Qais Yousef Patch 1 addresses a smatch warning reported by Dan Carpenter. Patch 2 fixes a couple of issues reported by Dietmar in capacity inversion logic. Patch 3 which was an RFC patch was dropped. The discussion has settled into this patch which is now treated separately from this series https://lore.kernel.org/lkml/20221228165415.3436-1-vincent.guittot@linaro.org/ Changes in v3: * Fix commit message in patch 2. * Drop Patch 3 Changes in v2: * Patch1: Improve indentation as suggested by Dietmar * Patch2: Make sure to hold rcu_read_lock() as we need it's not held in all paths. LINK v1: * https://lore.kernel.org/lkml/20221127141742.1644023-1-qyousef@layalina.io/ LINK v2: Sent in-reply-to v1 * https://lore.kernel.org/lkml/20221208145108.452032-1-qyousef@layalina.io/ * https://lore.kernel.org/lkml/20221208145409.453308-1-qyousef@layalina.io/ Qais Yousef (2): sched/uclamp: Fix a uninitialized variable warnings sched/fair: Fixes for capacity inversion detection kernel/sched/fair.c | 48 +++++++++++++++++++++++++-------------------- 1 file changed, 27 insertions(+), 21 deletions(-) -- 2.25.1 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v3 1/2] sched/uclamp: Fix a uninitialized variable warnings 2023-01-12 12:27 [PATCH v3 0/2] Fixes for uclamp and capacity inversion detection Qais Yousef @ 2023-01-12 12:27 ` Qais Yousef 2023-01-13 8:13 ` Vincent Guittot 2023-01-12 12:27 ` [PATCH v3 2/2] sched/fair: Fixes for capacity inversion detection Qais Yousef 1 sibling, 1 reply; 5+ messages in thread From: Qais Yousef @ 2023-01-12 12:27 UTC (permalink / raw) To: Ingo Molnar, Peter Zijlstra, Vincent Guittot, Dietmar Eggemann Cc: Rafael J. Wysocki, Viresh Kumar, linux-kernel, linux-pm, Lukasz Luba, Wei Wang, Xuewen Yan, Hank, Jonathan JMChen, Qais Yousef, kernel test robot, Dan Carpenter 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@intel.com> Reported-by: Dan Carpenter <error27@gmail.com> Signed-off-by: Qais Yousef (Google) <qyousef@layalina.io> --- kernel/sched/fair.c | 35 ++++++++++++++++------------------- 1 file changed, 16 insertions(+), 19 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index e9d906a9bba9..5a8e75d4a17b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7353,10 +7353,10 @@ 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; @@ -7375,6 +7375,8 @@ 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))) @@ -7393,24 +7395,19 @@ 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))) { - util_min = p_util_min; - util_max = p_util_max; - } else { - /* - * 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; -- 2.25.1 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v3 1/2] sched/uclamp: Fix a uninitialized variable warnings 2023-01-12 12:27 ` [PATCH v3 1/2] sched/uclamp: Fix a uninitialized variable warnings Qais Yousef @ 2023-01-13 8:13 ` Vincent Guittot 0 siblings, 0 replies; 5+ messages in thread From: Vincent Guittot @ 2023-01-13 8:13 UTC (permalink / raw) To: Qais Yousef Cc: Ingo Molnar, Peter Zijlstra, Dietmar Eggemann, Rafael J. Wysocki, Viresh Kumar, linux-kernel, linux-pm, Lukasz Luba, Wei Wang, Xuewen Yan, Hank, Jonathan JMChen, kernel test robot, Dan Carpenter On Thu, 12 Jan 2023 at 13:27, Qais Yousef <qyousef@layalina.io> 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@intel.com> > Reported-by: Dan Carpenter <error27@gmail.com> > Signed-off-by: Qais Yousef (Google) <qyousef@layalina.io> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> > --- > kernel/sched/fair.c | 35 ++++++++++++++++------------------- > 1 file changed, 16 insertions(+), 19 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index e9d906a9bba9..5a8e75d4a17b 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -7353,10 +7353,10 @@ 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; > @@ -7375,6 +7375,8 @@ 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))) > @@ -7393,24 +7395,19 @@ 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))) { > - util_min = p_util_min; > - util_max = p_util_max; > - } else { > - /* > - * 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; > -- > 2.25.1 > ^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v3 2/2] sched/fair: Fixes for capacity inversion detection 2023-01-12 12:27 [PATCH v3 0/2] Fixes for uclamp and capacity inversion detection Qais Yousef 2023-01-12 12:27 ` [PATCH v3 1/2] sched/uclamp: Fix a uninitialized variable warnings Qais Yousef @ 2023-01-12 12:27 ` Qais Yousef 2023-01-13 8:14 ` Vincent Guittot 1 sibling, 1 reply; 5+ messages in thread From: Qais Yousef @ 2023-01-12 12:27 UTC (permalink / raw) To: Ingo Molnar, Peter Zijlstra, Vincent Guittot, Dietmar Eggemann Cc: Rafael J. Wysocki, Viresh Kumar, linux-kernel, linux-pm, Lukasz Luba, Wei Wang, Xuewen Yan, Hank, Jonathan JMChen, Qais Yousef 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> --- kernel/sched/fair.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 5a8e75d4a17b..34239d3118f0 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8992,16 +8992,23 @@ 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); @@ -9026,6 +9033,8 @@ static void update_cpu_capacity(struct sched_domain *sd, int cpu) break; } } + + rcu_read_unlock(); } trace_sched_cpu_capacity_tp(rq); -- 2.25.1 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v3 2/2] sched/fair: Fixes for capacity inversion detection 2023-01-12 12:27 ` [PATCH v3 2/2] sched/fair: Fixes for capacity inversion detection Qais Yousef @ 2023-01-13 8:14 ` Vincent Guittot 0 siblings, 0 replies; 5+ messages in thread From: Vincent Guittot @ 2023-01-13 8:14 UTC (permalink / raw) To: Qais Yousef Cc: Ingo Molnar, Peter Zijlstra, Dietmar Eggemann, Rafael J. Wysocki, Viresh Kumar, linux-kernel, linux-pm, Lukasz Luba, Wei Wang, Xuewen Yan, Hank, Jonathan JMChen On Thu, 12 Jan 2023 at 13:27, Qais Yousef <qyousef@layalina.io> wrote: > > 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> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> > --- > kernel/sched/fair.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 5a8e75d4a17b..34239d3118f0 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -8992,16 +8992,23 @@ 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); > > @@ -9026,6 +9033,8 @@ static void update_cpu_capacity(struct sched_domain *sd, int cpu) > break; > } > } > + > + rcu_read_unlock(); > } > > trace_sched_cpu_capacity_tp(rq); > -- > 2.25.1 > ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2023-01-13 8:16 UTC | newest] Thread overview: 5+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2023-01-12 12:27 [PATCH v3 0/2] Fixes for uclamp and capacity inversion detection Qais Yousef 2023-01-12 12:27 ` [PATCH v3 1/2] sched/uclamp: Fix a uninitialized variable warnings Qais Yousef 2023-01-13 8:13 ` Vincent Guittot 2023-01-12 12:27 ` [PATCH v3 2/2] sched/fair: Fixes for capacity inversion detection Qais Yousef 2023-01-13 8:14 ` Vincent Guittot
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).