linux/kernel
Thomas Gleixner 1cf12e08bc sched/hotplug: Consolidate task migration on CPU unplug
With the new mechanism which kicks tasks off the outgoing CPU at the end of
schedule() the situation on an outgoing CPU right before the stopper thread
brings it down completely is:

 - All user tasks and all unbound kernel threads have either been migrated
   away or are not running and the next wakeup will move them to a online CPU.

 - All per CPU kernel threads, except cpu hotplug thread and the stopper
   thread have either been unbound or parked by the responsible CPU hotplug
   callback.

That means that at the last step before the stopper thread is invoked the
cpu hotplug thread is the last legitimate running task on the outgoing
CPU.

Add a final wait step right before the stopper thread is kicked which
ensures that any still running tasks on the way to park or on the way to
kick themself of the CPU are either sleeping or gone.

This allows to remove the migrate_tasks() crutch in sched_cpu_dying(). If
sched_cpu_dying() detects that there is still another running task aside of
the stopper thread then it will explode with the appropriate fireworks.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Link: https://lkml.kernel.org/r/20201023102346.547163969@infradead.org
2020-11-10 18:38:58 +01:00
..
bpf Fixes for 5.10-rc1 from the networking tree: 2020-10-23 12:05:49 -07:00
cgroup kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
configs compiler: remove CONFIG_OPTIMIZE_INLINING entirely 2020-04-07 10:43:42 -07:00
debug kdb: Fix pager search for multi-line strings 2020-10-01 14:44:08 +01:00
dma dma-mapping: move more functions to dma-map-ops.h 2020-10-20 10:41:07 +02:00
entry arch-cleanup-2020-10-22 2020-10-23 10:06:38 -07:00
events task_work: cleanup notification modes 2020-10-17 15:05:30 -06:00
gcov gcov: add support for GCC 10.1 2020-09-11 09:33:54 -07:00
irq task_work: cleanup notification modes 2020-10-17 15:05:30 -06:00
kcsan kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
livepatch kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
locking Merge tag 'core-rcu-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2020-10-18 14:34:50 -07:00
power kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
printk Urgent printk fix for 5.10 2020-10-16 12:52:37 -07:00
rcu Merge tag 'core-rcu-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2020-10-18 14:34:50 -07:00
sched sched/hotplug: Consolidate task migration on CPU unplug 2020-11-10 18:38:58 +01:00
time random32: add noise from network and scheduling activity 2020-10-24 20:21:57 +02:00
trace Fix synthetic event "strcat" overrun 2020-10-28 12:05:14 -07:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
acct.c kernel: acct.c: fix some kernel-doc nits 2020-10-16 11:11:19 -07:00
async.c treewide: Remove uninitialized_var() usage 2020-07-16 12:35:15 -07:00
audit_fsnotify.c fsnotify: create method handle_inode_event() in fsnotify_operations 2020-07-27 23:25:50 +02:00
audit_tree.c \n 2020-08-06 19:29:51 -07:00
audit_watch.c fsnotify: create method handle_inode_event() in fsnotify_operations 2020-07-27 23:25:50 +02:00
audit.c audit: Remove redundant null check 2020-08-26 09:10:39 -04:00
audit.h audit: change unnecessary globals into statics 2020-08-17 20:26:58 -04:00
auditfilter.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
auditsc.c audit/stable-5.9 PR 20200803 2020-08-04 14:20:26 -07:00
backtracetest.c treewide: Replace DECLARE_TASKLET() with DECLARE_TASKLET_OLD() 2020-07-30 11:15:58 -07:00
bounds.c
capability.c LSM: Signal to SafeSetID when setting group IDs 2020-10-13 09:17:34 -07:00
compat.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
configs.c
context_tracking.c context_tracking: Ensure that the critical path cannot be instrumented 2020-06-11 15:14:36 +02:00
cpu_pm.c notifier: Fix broken error handling pattern 2020-09-01 09:58:03 +02:00
cpu.c sched/hotplug: Consolidate task migration on CPU unplug 2020-11-10 18:38:58 +01:00
crash_core.c kdump: append kernel build-id string to VMCOREINFO 2020-08-12 10:58:01 -07:00
crash_dump.c crash_dump: Remove no longer used saved_max_pfn 2020-04-15 11:21:54 +02:00
cred.c exec: Teach prepare_exec_creds how exec treats uids & gids 2020-05-20 14:44:21 -05:00
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c pid: move pidfd_get_pid() to pid.c 2020-10-18 09:27:10 -07:00
extable.c kernel/extable.c: use address-of operator on section symbols 2020-04-07 10:43:42 -07:00
fail_function.c
fork.c kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
freezer.c
futex.c futex: Adjust absolute futex timeouts with per time namespace offset 2020-10-20 17:02:57 +02:00
gen_kheaders.sh kbuild: add variables for compression tools 2020-06-06 23:42:01 +09:00
groups.c LSM: Signal to SafeSetID when setting group IDs 2020-10-13 09:17:34 -07:00
hung_task.c kernel/hung_task.c: introduce sysctl to print all traces when a hung task is detected 2020-06-08 11:05:56 -07:00
iomem.c
irq_work.c irq_work, smp: Allow irq_work on call_single_queue 2020-05-28 10:54:15 +02:00
jump_label.c kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
kallsyms.c treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
kcmp.c kernel/kcmp.c: Use new infrastructure to fix deadlocks in execve 2020-03-25 10:04:01 -05:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c kcov: make some symbols static 2020-08-12 10:58:02 -07:00
kexec_core.c kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
kexec_elf.c
kexec_file.c kernel/resource: move and rename IORESOURCE_MEM_DRIVER_MANAGED 2020-10-16 11:11:18 -07:00
kexec_internal.h
kexec.c LSM: Introduce kernel_post_load_data() hook 2020-10-05 13:37:03 +02:00
kheaders.c
kmod.c kmod: remove redundant "be an" in the comment 2020-08-12 10:58:01 -07:00
kprobes.c Updates for tracing and bootconfig: 2020-10-15 15:51:28 -07:00
ksysfs.c
kthread.c kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
latencytop.c sysctl: pass kernel pointers to ->proc_handler 2020-04-27 02:07:40 -04:00
Makefile Kbuild updates for v5.10 2020-10-22 13:13:57 -07:00
module_signature.c
module_signing.c
module-internal.h
module.c Modules updates for v5.10 2020-10-22 13:08:57 -07:00
notifier.c notifier: Fix broken error handling pattern 2020-09-01 09:58:03 +02:00
nsproxy.c nsproxy: support CLONE_NEWTIME with setns() 2020-07-08 11:14:22 +02:00
padata.c padata: fix possible padata_works_lock deadlock 2020-09-04 17:51:55 +10:00
panic.c panic: dump registers on panic_on_warn 2020-10-16 11:11:22 -07:00
params.c moduleparams: Add hexint type parameter 2020-07-28 13:44:53 +02:00
pid_namespace.c kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
pid.c pid: move pidfd_get_pid() to pid.c 2020-10-18 09:27:10 -07:00
profile.c
ptrace.c
range.c kernel.h: split out min()/max() et al. helpers 2020-10-16 11:11:19 -07:00
reboot.c arch: remove unicore32 port 2020-07-01 12:09:13 +03:00
regset.c regset: kill ->get() 2020-07-27 14:31:12 -04:00
relay.c kernel/relay.c: drop unneeded initialization 2020-10-16 11:11:22 -07:00
resource.c kernel/resource: make iomem_resource implicit in release_mem_region_adjustable() 2020-10-16 11:11:18 -07:00
rseq.c
scftorture.c scftorture: Add cond_resched() to test loop 2020-08-24 18:38:38 -07:00
scs.c mm: memcontrol: account kernel stack per node 2020-08-07 11:33:25 -07:00
seccomp.c seccomp: Make duplicate listener detection non-racy 2020-10-08 13:17:47 -07:00
signal.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
smp.c Merge tag 'core-rcu-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2020-10-18 14:34:50 -07:00
smpboot.c
smpboot.h
softirq.c softirq: Add debug check to __raise_softirq_irqoff() 2020-09-16 15:18:56 +02:00
stackleak.c stackleak: let stack_erasing_sysctl take a kernel pointer buffer 2020-09-19 13:13:39 -07:00
stacktrace.c stacktrace: Remove reliable argument from arch_stack_walk() callback 2020-09-18 14:24:16 +01:00
static_call.c static_call: Fix return type of static_call_init 2020-10-02 21:18:25 +02:00
stop_machine.c stop_machine: Add function and caller debug info 2020-11-10 18:38:57 +01:00
sys_ni.c mm/madvise: introduce process_madvise() syscall: an external memory hinting API 2020-10-18 09:27:10 -07:00
sys.c kernel/sys.c: fix prototype of prctl_get_tid_address() 2020-10-25 11:44:16 -07:00
sysctl-test.c
sysctl.c mm: allow a controlled amount of unfairness in the page lock 2020-09-17 10:26:41 -07:00
task_work.c task_work: cleanup notification modes 2020-10-17 15:05:30 -06:00
taskstats.c taskstats: move specifying netlink policy back to ops 2020-10-02 19:11:12 -07:00
test_kprobes.c
torture.c torture: Dump ftrace at shutdown only if requested 2020-06-29 12:01:45 -07:00
tracepoint.c tracepoint: Fix out of sync data passing by static caller 2020-10-02 21:18:25 +02:00
tsacct.c
ucount.c ucount: Make sure ucounts in /proc/sys/user don't regress again 2020-04-07 21:51:27 +02:00
uid16.c
uid16.h
umh.c usermodehelper: reset umask to default before executing user process 2020-10-06 10:31:52 -07:00
up.c
user_namespace.c kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
user-return-notifier.c
user.c user.c: make uidhash_table static 2020-06-04 19:06:24 -07:00
usermode_driver.c umd: Stop using split_argv 2020-07-07 11:58:59 -05:00
utsname_sysctl.c sysctl: pass kernel pointers to ->proc_handler 2020-04-27 02:07:40 -04:00
utsname.c nsproxy: add struct nsset 2020-05-09 13:57:12 +02:00
watch_queue.c watch_queue: Limit the number of watches a user can hold 2020-08-17 09:39:18 -07:00
watchdog_hld.c
watchdog.c kernel/watchdog.c: convert {soft/hard}lockup boot parameters to sysctl aliases 2020-06-08 11:05:56 -07:00
workqueue_internal.h
workqueue.c workqueue: Manually break affinity on hotplug 2020-11-10 18:38:58 +01:00