Odin Ugedal 20285dc271 sched/fair: Ensure _sum and _avg values stay consistent ... [ Upstream commit 1c35b07e6d3986474e5635be566e7bc79d97c64d ] The _sum and _avg values are in general sync together with the PELT divider. They are however not always completely in perfect sync, resulting in situations where _sum gets to zero while _avg stays positive. Such situations are undesirable. This comes from the fact that PELT will increase period_contrib, also increasing the PELT divider, without updating _sum and _avg values to stay in perfect sync where (_sum == _avg * divider). However, such PELT change will never lower _sum, making it impossible to end up in a situation where _sum is zero and _avg is not. Therefore, we need to ensure that when subtracting load outside PELT, that when _sum is zero, _avg is also set to zero. This occurs when (_sum < _avg * divider), and the subtracted (_avg * divider) is bigger or equal to the current _sum, while the subtracted _avg is smaller than the current _avg. Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com> Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> Signed-off-by: Odin Ugedal <odin@uged.al> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com> Link: https://lore.kernel.org/r/20210624111815.57937-1-odin@uged.al Signed-off-by: Sasha Levin <sashal@kernel.org>		2021-07-19 09:44:54 +02:00
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autogroup.c
autogroup.h
clock.c
completion.c
core.c	sched/uclamp: Fix uclamp_tg_restrict()	2021-07-14 16:56:10 +02:00
cpuacct.c
cpudeadline.c
cpudeadline.h
cpufreq_schedutil.c
cpufreq.c
cpupri.c
cpupri.h
cputime.c
deadline.c	sched/rt: Fix Deadline utilization tracking during policy change	2021-07-14 16:56:09 +02:00
debug.c	sched/fair: Fix util_est UTIL_AVG_UNCHANGED handling	2021-06-16 12:01:46 +02:00
fair.c	sched/fair: Ensure _sum and _avg values stay consistent	2021-07-19 09:44:54 +02:00
features.h	sched,fair: Alternative sched_slice()	2021-05-11 14:47:31 +02:00
idle.c	rcu/nocb: Perform deferred wake up before last idle's need_resched() check	2021-03-04 11:38:35 +01:00
isolation.c
loadavg.c
Makefile
membarrier.c	sched/membarrier: fix missing local execution of ipi_sync_rq_state()	2021-03-17 17:06:35 +01:00
pelt.c
pelt.h	sched/fair: Fix util_est UTIL_AVG_UNCHANGED handling	2021-06-16 12:01:46 +02:00
psi.c	psi: Fix race between psi_trigger_create/destroy	2021-07-14 16:56:10 +02:00
rt.c	sched/rt: Fix RT utilization tracking during policy change	2021-07-14 16:56:09 +02:00
sched-pelt.h
sched.h	sched/fair: Fix shift-out-of-bounds in load_balance()	2021-05-14 09:50:22 +02:00
smp.h
stats.c
stats.h
stop_task.c
swait.c
topology.c
wait_bit.c
wait.c