mirror_ubuntu-kernels/kernel
Vincent Guittot f6cad8df6b sched/fair: Fix imbalance due to CPU affinity
The load_balance() has a dedicated mecanism to detect when an imbalance
is due to CPU affinity and must be handled at parent level. In this case,
the imbalance field of the parent's sched_group is set.

The description of sg_imbalanced() gives a typical example of two groups
of 4 CPUs each and 4 tasks each with a cpumask covering 1 CPU of the first
group and 3 CPUs of the second group. Something like:

	{ 0 1 2 3 } { 4 5 6 7 }
	        *     * * *

But the load_balance fails to fix this UC on my octo cores system
made of 2 clusters of quad cores.

Whereas the load_balance is able to detect that the imbalanced is due to
CPU affinity, it fails to fix it because the imbalance field is cleared
before letting parent level a chance to run. In fact, when the imbalance is
detected, the load_balance reruns without the CPU with pinned tasks. But
there is no other running tasks in the situation described above and
everything looks balanced this time so the imbalance field is immediately
cleared.

The imbalance field should not be cleared if there is no other task to move
when the imbalance is detected.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1561996022-28829-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-07-25 15:51:52 +02:00
..
bpf Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-20 10:45:15 -07:00
cgroup Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
configs kvm_config: add CONFIG_VIRTIO_MENU 2018-10-24 20:55:56 -04:00
debug treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
dma dma-mapping fixes for 5.3-rc1 2019-07-20 12:09:52 -07:00
events Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 11:35:08 -07:00
gcov gcov: no need to check return value of debugfs_create functions 2019-06-03 16:18:12 +02:00
irq Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 11:22:57 -07:00
livepatch Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching 2019-07-11 15:30:05 -07:00
locking docs: locking: convert docs to ReST and rename to *.rst 2019-07-15 08:53:27 -03:00
power pci-v5.3-changes 2019-07-15 20:44:49 -07:00
printk treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
rcu Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu 2019-06-28 19:46:47 +02:00
sched sched/fair: Fix imbalance due to CPU affinity 2019-07-25 15:51:52 +02:00
time timekeeping/vsyscall: Use __iter_div_u64_rem() 2019-07-10 20:37:49 +02:00
trace Eiichi Tsukata found a small bug from the fixup of the stack code 2019-07-19 12:18:46 -07:00
.gitignore Provide in-kernel headers to make extending kernel easier 2019-04-29 16:48:03 +02:00
acct.c acct_on(): don't mess with freeze protection 2019-04-04 21:04:13 -04:00
async.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
audit_fsnotify.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
audit_tree.c fsnotify: switch send_to_group() and ->handle_event to const struct qstr * 2019-04-26 13:51:03 -04:00
audit_watch.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
audit.c audit/stable-5.3 PR 20190702 2019-07-08 18:55:42 -07:00
audit.h audit/stable-5.3 PR 20190702 2019-07-08 18:55:42 -07:00
auditfilter.c audit/stable-5.3 PR 20190702 2019-07-08 18:55:42 -07:00
auditsc.c audit: enforce op for string fields 2019-05-28 17:46:43 -04:00
backtracetest.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
bounds.c kbuild: fix kernel/bounds.c 'W=1' warning 2018-10-31 08:54:14 -07:00
capability.c LSM: add SafeSetID module that gates setid calls 2019-01-25 11:22:43 -08:00
compat.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
configs.c kernel/configs: use .incbin directive to embed config_data.gz 2019-03-07 18:32:02 -08:00
context_tracking.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
cpu_pm.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282 2019-06-05 17:36:37 +02:00
cpu.c Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 10:39:56 -07:00
crash_core.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230 2019-06-19 17:09:06 +02:00
crash_dump.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
cred.c request_key improvements 2019-07-08 19:19:37 -07:00
delayacct.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 25 2019-05-21 11:52:39 +02:00
dma.c
elfcore.c
exec_domain.c
exit.c pidfd: fix a poll race when setting exit_state 2019-07-22 16:02:03 +02:00
extable.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
fail_function.c fail_function: no need to check return value of debugfs_create functions 2019-06-03 15:49:06 +02:00
fork.c sched/fair: Don't free p->numa_faults with concurrent readers 2019-07-25 15:37:04 +02:00
freezer.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
futex.c Linux 5.2-rc3 2019-06-03 11:50:18 +02:00
gen_kheaders.sh kheaders: include only headers into kheaders_data.tar.xz 2019-07-09 10:10:52 +09:00
groups.c
hung_task.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
iomem.c mm/nvdimm: add is_ioremap_addr and use that to check ioremap address 2019-07-12 11:05:40 -07:00
irq_work.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
jump_label.c jump_label: Batch updates if arch supports it 2019-06-17 12:09:22 +02:00
kallsyms.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
kcmp.c
Kconfig.freezer treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Kconfig.hz treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Kconfig.locks treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Kconfig.preempt sched/rt, Kconfig: Unbreak def/oldconfig with CONFIG_PREEMPT=y 2019-07-22 18:05:11 +02:00
kcov.c kcov: convert kcov.refcount to refcount_t 2019-03-07 18:32:02 -08:00
kexec_core.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230 2019-06-19 17:09:06 +02:00
kexec_file.c Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2019-07-08 20:28:59 -07:00
kexec_internal.h
kexec.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230 2019-06-19 17:09:06 +02:00
kheaders.c kheaders: Move from proc to sysfs 2019-05-24 20:16:01 +02:00
kmod.c
kprobes.c The main changes in this release include: 2019-07-18 11:51:00 -07:00
ksysfs.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 170 2019-05-30 11:26:39 -07:00
kthread.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
latencytop.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
Makefile kheaders: Move from proc to sysfs 2019-05-24 20:16:01 +02:00
memremap.c mm/devm_memremap_pages: enable sub-section remap 2019-07-18 17:08:07 -07:00
module_signing.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
module-internal.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
module.c Modules updates for v5.3 2019-07-18 12:06:57 -07:00
notifier.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
nsproxy.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
padata.c padata: use smp_mb in padata_reorder to avoid orphaned padata jobs 2019-07-18 13:39:54 +08:00
panic.c docs: admin-guide: move sysctl directory to it 2019-07-15 11:03:01 -03:00
params.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
pid_namespace.c proc/sysctl: add shared variables for range check 2019-07-18 17:08:07 -07:00
pid.c kernel/pid.c: convert struct pid count to refcount_t 2019-07-16 19:23:24 -07:00
profile.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
ptrace.c ptrace: add PTRACE_GET_SYSCALL_INFO request 2019-07-16 19:23:24 -07:00
range.c
reboot.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
relay.c Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-03-12 13:27:20 -07:00
resource.c resource: avoid unnecessary lookups in find_next_iomem_res() 2019-07-18 17:08:06 -07:00
rseq.c signal: Remove task parameter from force_sig 2019-05-27 09:36:28 -05:00
seccomp.c signal: Remove the signal number and task parameters from force_sig_info 2019-05-29 09:31:44 -05:00
signal.c signal: simplify set_user_sigmask/restore_user_sigmask 2019-07-16 19:23:24 -07:00
smp.c smp: Warn on function calls from softirq context 2019-07-20 11:27:16 +02:00
smpboot.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
smpboot.h
softirq.c Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 11:01:13 -07:00
stackleak.c stackleak: Mark stackleak_track_stack() as notrace 2018-12-05 19:31:44 -08:00
stacktrace.c stacktrace: Force USER_DS for stack_trace_save_user() 2019-07-18 16:47:24 +02:00
stop_machine.c processor: get rid of cpu_relax_yield 2019-06-15 12:25:55 +02:00
sys_ni.c arch: handle arches who do not yet define clone3 2019-06-21 01:54:53 +02:00
sys.c prctl_set_mm: downgrade mmap_sem to read lock 2019-06-01 15:51:31 -07:00
sysctl_binary.c kernel/sysctl: add panic_print into sysctl 2019-01-04 13:13:47 -08:00
sysctl.c proc/sysctl: add shared variables for range check 2019-07-18 17:08:07 -07:00
task_work.c
taskstats.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
test_kprobes.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 25 2019-05-21 11:52:39 +02:00
torture.c torture: Allow inter-stutter interval to be specified 2019-05-28 09:06:09 -07:00
tracepoint.c The main changes in this release include: 2019-07-18 11:51:00 -07:00
tsacct.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
ucount.c proc/sysctl: add shared variables for range check 2019-07-18 17:08:07 -07:00
uid16.c
uid16.h
umh.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
up.c smp: Remove smp_call_function() and on_each_cpu() return values 2019-06-23 14:26:26 +02:00
user_namespace.c Keyrings namespacing 2019-07-08 19:36:47 -07:00
user-return-notifier.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
user.c Keyrings namespacing 2019-07-08 19:36:47 -07:00
utsname_sysctl.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
utsname.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
watchdog_hld.c kernel/watchdog_hld.c: hard lockup message should end with a newline 2019-04-19 09:46:05 -07:00
watchdog.c watchdog: Fix typo in comment 2019-04-18 14:05:51 +02:00
workqueue_internal.h sched/core, workqueues: Distangle worker accounting from rq lock 2019-04-16 16:55:15 +02:00
workqueue.c workqueue: Remove GPF argument from alloc_workqueue_attrs() 2019-06-27 14:12:19 -07:00