kernel_optimize_test/kernel/sched
Qais Yousef 7226017ad3 sched/uclamp: Fix a bug in propagating uclamp value in new cgroups
When a new cgroup is created, the effective uclamp value wasn't updated
with a call to cpu_util_update_eff() that looks at the hierarchy and
update to the most restrictive values.

Fix it by ensuring to call cpu_util_update_eff() when a new cgroup
becomes online.

Without this change, the newly created cgroup uses the default
root_task_group uclamp values, which is 1024 for both uclamp_{min, max},
which will cause the rq to to be clamped to max, hence cause the
system to run at max frequency.

The problem was observed on Ubuntu server and was reproduced on Debian
and Buildroot rootfs.

By default, Ubuntu and Debian create a cpu controller cgroup hierarchy
and add all tasks to it - which creates enough noise to keep the rq
uclamp value at max most of the time. Imitating this behavior makes the
problem visible in Buildroot too which otherwise looks fine since it's a
minimal userspace.

Fixes: 0b60ba2dd3 ("sched/uclamp: Propagate parent clamps")
Reported-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Doug Smythies <dsmythies@telus.net>
Link: https://lore.kernel.org/lkml/000701d5b965$361b6c60$a2524520$@net/
2020-01-17 10:19:20 +01:00
..
autogroup.c sched/autogroup: Make autogroup_path() always available 2019-06-24 19:23:40 +02:00
autogroup.h
clock.c sched/clock: Use static_branch_likely() with sched_clock_running 2019-11-29 08:10:54 +01:00
completion.c
core.c sched/uclamp: Fix a bug in propagating uclamp value in new cgroups 2020-01-17 10:19:20 +01:00
cpuacct.c
cpudeadline.c Linux 5.2-rc5 2019-06-17 12:12:27 +02:00
cpudeadline.h
cpufreq_schedutil.c sched/uclamp: Rename uclamp_util_with() into uclamp_rq_util_with() 2019-12-25 10:42:08 +01:00
cpufreq.c cpufreq: Avoid leaving stale IRQ work items during CPU offline 2019-12-12 17:59:43 +01:00
cpupri.c sched/rt: Make RT capacity-aware 2019-12-25 10:42:10 +01:00
cpupri.h sched/rt: Make RT capacity-aware 2019-12-25 10:42:10 +01:00
cputime.c sched/vtime: Bring up complete kcpustat accessor 2019-11-21 07:33:24 +01:00
deadline.c sched/core: Further clarify sched_class::set_next_task() 2019-11-11 08:35:21 +01:00
debug.c Linux 5.2-rc6 2019-06-24 19:19:53 +02:00
fair.c sched/fair: Load balance aggressively for SCHED_IDLE CPUs 2020-01-17 10:19:20 +01:00
features.h sched/fair/util_est: Implement faster ramp-up EWMA on utilization increases 2019-10-29 10:01:07 +01:00
idle.c Power management updates for 5.5-rc1 2019-11-26 19:06:44 -08:00
isolation.c sched/isolation: Prefer housekeeping CPU in local node 2019-07-25 15:51:55 +02:00
loadavg.c
Makefile
membarrier.c membarrier: Fix RCU locking bug caused by faulty merge 2019-10-01 21:27:50 +02:00
pelt.c schied/fair: Skip calculating @contrib without load 2019-12-17 13:32:51 +01:00
pelt.h sched/topology: Remove unused 'sd' parameter from arch_scale_cpu_capacity() 2019-06-24 19:23:39 +02:00
psi.c psi: Fix a division error in psi poll() 2019-12-17 13:32:48 +01:00
rt.c sched/rt: Make RT capacity-aware 2019-12-25 10:42:10 +01:00
sched-pelt.h sched/fair: Fix "runnable_avg_yN_inv" not used warnings 2019-06-17 12:15:58 +02:00
sched.h sched/uclamp: Rename uclamp_util_with() into uclamp_rq_util_with() 2019-12-25 10:42:08 +01:00
stats.c
stats.h sched/stats: Fix unlikely() use of sched_info_on() 2019-07-25 15:51:55 +02:00
stop_task.c sched/core: Further clarify sched_class::set_next_task() 2019-11-11 08:35:21 +01:00
swait.c kernel/sched/: remove caller signal_pending branch predictions 2019-01-04 13:13:48 -08:00
topology.c Linux 5.4-rc7 2019-11-11 08:34:59 +01:00
wait_bit.c sched/wait: fix ___wait_var_event(exclusive) 2019-12-17 13:32:50 +01:00
wait.c Add wake_up_interruptible_sync_poll_locked() 2019-10-31 15:12:23 +00:00