linux-uconsole/kernel
Vincent Guittot 0d9d559b57 sched/fair: handle case of task_h_load() returning 0
commit 01cfcde9c2 upstream.

task_h_load() can return 0 in some situations like running stress-ng
mmapfork, which forks thousands of threads, in a sched group on a 224 cores
system. The load balance doesn't handle this correctly because
env->imbalance never decreases and it will stop pulling tasks only after
reaching loop_max, which can be equal to the number of running tasks of
the cfs. Make sure that imbalance will be decreased by at least 1.

misfit task is the other feature that doesn't handle correctly such
situation although it's probably more difficult to face the problem
because of the smaller number of CPUs and running tasks on heterogenous
system.

We can't simply ensure that task_h_load() returns at least one because it
would imply to handle underflow in other places.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: <stable@vger.kernel.org> # v4.4+
Link: https://lkml.kernel.org/r/20200710152426.16981-1-vincent.guittot@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-22 09:32:13 +02:00
..
bpf bpf: Check correct cred for CAP_SYSLOG in bpf_dump_raw_ok() 2020-07-16 08:17:27 +02:00
cgroup cgroup: fix cgroup_sk_alloc() for sk_clone_lock() 2020-07-22 09:32:00 +02:00
configs kconfig: tinyconfig: remove stale stack protector fixups 2018-06-15 07:15:28 +09:00
debug kgdb: Avoid suspicious RCU usage warning 2020-07-09 09:37:10 +02:00
dma dma-debug: add a schedule point in debug_dma_dump_mappings() 2020-01-04 19:12:43 +01:00
events perf: Add cond_resched() to task_function_call() 2020-06-22 09:05:08 +02:00
gcov kernel/gcov/fs.c: gcov_seq_next() should increase position index 2020-04-29 16:31:12 +02:00
irq genirq/irqdomain: Check pointer in irq_domain_alloc_irqs_hierarchy() 2020-04-17 10:48:41 +02:00
livepatch livepatch: Nullify obj->mod in klp_module_coming()'s error path 2019-10-07 18:57:10 +02:00
locking locktorture: Print ratio of acquisitions, not failures 2020-04-23 10:30:23 +02:00
power PM: hibernate: Freeze kernel threads in software_resume() 2020-05-06 08:13:28 +02:00
printk printk: fix exclusive_console replaying 2020-02-11 04:33:51 -08:00
rcu rcu: Avoid data-race in rcu_gp_fqs_check_wake() 2020-02-11 04:33:55 -08:00
sched sched/fair: handle case of task_h_load() returning 0 2020-07-22 09:32:13 +02:00
time timer: Fix wheel index calculation on last level 2020-07-22 09:32:11 +02:00
trace ring-buffer: Zero out time extend if it is nested and not absolute 2020-06-30 23:17:17 -04:00
.gitignore
acct.c acct_on(): don't mess with freeze protection 2019-05-31 06:46:05 -07:00
async.c
audit.c audit: fix a net reference leak in audit_list_rules_send() 2020-06-22 09:05:13 +02:00
audit.h audit: fix a net reference leak in audit_list_rules_send() 2020-06-22 09:05:13 +02:00
audit_fsnotify.c
audit_tree.c audit: Embed key into chunk 2019-12-13 08:51:11 +01:00
audit_watch.c audit_get_nd(): don't unlock parent too early 2019-12-13 08:51:02 +01:00
auditfilter.c audit: fix a net reference leak in audit_list_rules_send() 2020-06-22 09:05:13 +02:00
auditsc.c audit: print empty EXECVE args 2019-12-01 09:17:17 +01:00
backtracetest.c
bounds.c kbuild: fix kernel/bounds.c 'W=1' warning 2018-11-13 11:08:47 -08:00
capability.c LSM: generalize flag passing to security_capable 2020-01-23 08:21:29 +01:00
compat.c make 'user_access_begin()' do 'access_ok()' 2020-06-22 09:04:58 +02:00
configs.c
context_tracking.c
cpu.c sched/core: Fix illegal RCU from offline CPUs 2020-06-22 09:05:14 +02:00
cpu_pm.c kernel/cpu_pm: Fix uninitted local in cpu_pm 2020-06-22 09:05:28 +02:00
crash_core.c kernel/crash_core.c: print timestamp using time64_t 2018-08-22 10:52:47 -07:00
crash_dump.c
cred.c memcg: account security cred as well to kmemcg 2020-01-09 10:19:00 +01:00
delayacct.c
dma.c
elfcore.c kernel/elfcore.c: include proper prototypes 2019-10-11 18:21:23 +02:00
exec_domain.c
exit.c exit: Move preemption fixup up, move blocking operations down 2020-06-22 09:05:14 +02:00
extable.c
fail_function.c bpf/error-inject/kprobes: Clear current_kprobe and enable preempt in kprobe 2018-06-21 12:33:19 +02:00
fork.c fork,memcg: alloc_thread_stack_node needs to set tsk->stack 2020-01-27 14:50:58 +01:00
freezer.c PM / reboot: Eliminate race between reboot and suspend 2018-08-06 12:35:20 +02:00
futex.c futex: Unbreak futex hashing 2020-03-25 08:06:14 +01:00
groups.c
hung_task.c kernel: hung_task.c: disable on suspend 2019-04-20 09:16:02 +02:00
iomem.c
irq_work.c irq_work: Do not raise an IPI when queueing work on the local CPU 2019-05-31 06:46:19 -07:00
jump_label.c jump_label: move 'asm goto' support test to Kconfig 2019-06-04 08:02:34 +02:00
kallsyms.c kallsyms: Refactor kallsyms_show_value() to take cred 2020-07-16 08:17:26 +02:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt kconfig: include kernel/Kconfig.preempt from init/Kconfig 2018-08-02 08:06:54 +09:00
kcov.c kernel/kcov.c: mark write_comp_data() as notrace 2019-02-12 19:47:20 +01:00
kexec.c kexec: add call to LSM hook in original kexec_load syscall 2018-07-16 12:31:57 -07:00
kexec_core.c kexec: Allocate decrypted control pages for kdump if SME is enabled 2019-11-24 08:20:29 +01:00
kexec_file.c treewide: Use array_size() in vzalloc() 2018-06-12 16:19:22 -07:00
kexec_internal.h
kmod.c kmod: make request_module() return an error when autoloading is disabled 2020-04-17 10:48:52 +02:00
kprobes.c kprobes: Do not expose probe addresses to non-CAP_SYSLOG 2020-07-16 08:17:27 +02:00
ksysfs.c
kthread.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-08-13 11:25:07 -07:00
latencytop.c
Makefile y2038: futex: Move compat implementation into futex.c 2019-12-01 09:17:38 +01:00
memremap.c mm/memory_hotplug: shrink zones when offlining memory 2020-01-29 16:43:27 +01:00
module-internal.h modsign: log module name in the event of an error 2018-07-02 11:36:17 +02:00
module.c module: Do not expose section addresses to non-CAP_SYSLOG 2020-07-16 08:17:26 +02:00
module_signing.c modsign: log module name in the event of an error 2018-07-02 11:36:17 +02:00
notifier.c x86/mm: split vmalloc_sync_all() 2020-03-25 08:06:13 +01:00
nsproxy.c
padata.c padata: purge get_cpu and reorder_via_wq from padata_do_serial 2020-05-27 17:37:36 +02:00
panic.c kernel/panic.c: do not append newline to the stack protector panic string 2019-12-01 09:17:10 +01:00
params.c
pid.c Fix failure path in alloc_pid() 2019-01-13 09:51:06 +01:00
pid_namespace.c signal/pid_namespace: Fix reboot_pid_ns to use send_sig not force_sig 2019-07-26 09:14:01 +02:00
profile.c
ptrace.c ptrace: reintroduce usage of subjective credentials in ptrace_has_cap() 2020-01-23 08:21:29 +01:00
range.c
reboot.c PM / reboot: Eliminate race between reboot and suspend 2018-08-06 12:35:20 +02:00
relay.c kernel/relay.c: handle alloc_percpu returning NULL in relay_open 2020-06-07 13:17:54 +02:00
resource.c resource: fix locking in find_next_iomem_res() 2019-09-16 08:22:20 +02:00
rseq.c rseq: uapi: Declare rseq_cs field as union, update includes 2018-07-10 22:18:52 +02:00
seccomp.c LSM: generalize flag passing to security_capable 2020-01-23 08:21:29 +01:00
signal.c signal: Extend exec_id to 64bits 2020-04-17 10:48:47 +02:00
smp.c cpu/hotplug: Fix "SMT disabled by BIOS" detection for KVM 2019-02-12 19:47:25 +01:00
smpboot.c smpboot: Remove cpumask from the API 2018-07-03 09:20:44 +02:00
smpboot.h
softirq.c nohz: Fix missing tick reprogram when interrupting an inline softirq 2018-08-03 15:52:10 +02:00
stacktrace.c
stop_machine.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-08-13 11:25:07 -07:00
sys.c kernel/sys.c: prctl: fix false positive in validate_prctl_map() 2019-06-15 11:54:01 +02:00
sys_ni.c Merge branch 'core-rseq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-10 10:17:09 -07:00
sysctl.c kernel: sysctl: make drop_caches write-only 2020-01-04 19:13:17 +01:00
sysctl_binary.c
task_work.c
taskstats.c taskstats: fix data-race 2020-01-09 10:18:59 +01:00
test_kprobes.c kprobes: Remove jprobe API implementation 2018-06-21 12:33:05 +02:00
torture.c torture: Keep old-school dmesg format 2018-06-25 11:30:10 -07:00
tracepoint.c tracepoint: Fix tracepoint array element size mismatch 2018-10-17 15:35:29 -04:00
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c coredump: fix crash when umh is disabled 2020-05-14 07:57:21 +02:00
up.c
user-return-notifier.c
user.c userns: use irqsave variant of refcount_dec_and_lock() 2018-08-22 10:52:47 -07:00
user_namespace.c userns: also map extents in the reverse map to kernel IDs 2018-11-13 11:09:00 -08:00
utsname.c
utsname_sysctl.c sys: don't hold uts_sem while accessing userspace memory 2018-08-11 02:05:53 -05:00
watchdog.c watchdog/softlockup: Enforce that timestamp is valid on boot 2020-02-24 08:34:49 +01:00
watchdog_hld.c watchdog: Mark watchdog touch functions as notrace 2018-08-30 12:56:40 +02:00
workqueue.c workqueue: don't use wq_select_unbound_cpu() for bound works 2020-03-18 07:14:20 +01:00
workqueue_internal.h