linux/kernel
Peter Zijlstra c1de45ca83 sched/idle: Add support for tasks that inject idle
Idle injection drivers such as Intel powerclamp and ACPI PAD drivers use
realtime tasks to take control of CPU then inject idle. There are two
issues with this approach:

 1. Low efficiency: injected idle task is treated as busy so sched ticks
    do not stop during injected idle period, the result of these
    unwanted wakeups can be ~20% loss in power savings.

 2. Idle accounting: injected idle time is presented to user as busy.

This patch addresses the issues by introducing a new PF_IDLE flag which
allows any given task to be treated as idle task while the flag is set.
Therefore, idle injection tasks can run through the normal flow of NOHZ
idle enter/exit to get the correct accounting as well as tick stop when
possible.

The implication is that idle task is then no longer limited to PID == 0.

Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 14:02:21 +01:00
..
bpf Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-10-10 20:16:43 -07:00
configs config: android: enable CONFIG_SECCOMP 2016-10-11 15:06:32 -07:00
debug
events Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2016-10-05 10:11:24 -07:00
gcov gcov: add support for gcc version >= 6 2016-07-15 14:54:27 +09:00
irq genirq: Make function __irq_do_set_handler() static 2016-09-25 16:46:52 -04:00
livepatch livepatch/module: make TAINT_LIVEPATCH module-specific 2016-08-26 14:42:08 +02:00
locking locking/lglock: Remove lglock implementation 2016-09-22 15:25:56 +02:00
power oom, suspend: fix oom_killer_disable vs. pm suspend properly 2016-10-07 18:46:27 -07:00
printk Merge branch 'printk-cleanups' 2016-10-10 09:29:50 -07:00
rcu This adds a new gcc plugin named "latent_entropy". It is designed to 2016-10-15 10:03:15 -07:00
sched sched/idle: Add support for tasks that inject idle 2016-11-29 14:02:21 +01:00
time This adds a new gcc plugin named "latent_entropy". It is designed to 2016-10-15 10:03:15 -07:00
trace Disable the __builtin_return_address() warning globally after all 2016-10-12 10:23:41 -07:00
.gitignore
acct.c
async.c
audit_fsnotify.c
audit_tree.c audit: cleanup prune_tree_thread 2016-04-04 09:46:47 -04:00
audit_watch.c Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit 2016-09-01 15:55:56 -07:00
audit.c Merge branch 'stable-4.9' of git://git.infradead.org/users/pcmoore/audit 2016-10-04 14:21:41 -07:00
audit.h Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit 2016-07-29 17:54:17 -07:00
auditfilter.c audit: add fields to exclude filter by reusing user filter 2016-06-27 11:01:00 -04:00
auditsc.c Merge branch 'stable-4.9' of git://git.infradead.org/users/pcmoore/audit 2016-10-04 14:21:41 -07:00
backtracetest.c
bounds.c
capability.c kernel: Add noaudit variant of ns_capable() 2016-06-06 20:16:18 +10:00
cgroup_freezer.c
cgroup_pids.c cgroup: Use lld instead of ld when printing pids controller events_limit 2016-06-21 15:03:36 -04:00
cgroup.c Merge branch 'for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2016-10-14 12:18:50 -07:00
compat.c
configs.c
context_tracking.c
cpu_pm.c
cpu.c Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-10-03 19:43:08 -07:00
cpuset.c Merge branch 'for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2016-10-14 12:18:50 -07:00
crash_dump.c
cred.c cred: Reject inodes with invalid ids in set_create_file_as() 2016-06-30 18:05:09 -05:00
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c mm, oom: enforce exit_oom_victim on current task 2016-10-07 18:46:28 -07:00
extable.c
fork.c sched/idle: Add support for tasks that inject idle 2016-11-29 14:02:21 +01:00
freezer.c freezer, oom: check TIF_MEMDIE on the correct task 2016-07-28 16:07:41 -07:00
futex_compat.c
futex.c futex: Add some more function commentry 2016-09-05 17:20:18 +02:00
groups.c cred: simpler, 1D supplementary groups 2016-10-07 18:46:30 -07:00
hung_task.c hung_task: allow hung_task_panic when hung_task_warnings is 0 2016-10-11 15:06:33 -07:00
irq_work.c
jump_label.c powerpc updates for 4.8 #2 2016-08-05 09:00:54 -04:00
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c kernel/kcov: unproxify debugfs file's fops 2016-06-15 04:56:35 -07:00
kexec_core.c kexec: add restriction on kexec_load() segment sizes 2016-08-02 19:35:31 -04:00
kexec_file.c kexec: fix double-free when failing to relocate the purgatory 2016-09-01 17:52:01 -07:00
kexec_internal.h
kexec.c kexec: allow architectures to override boot mapping 2016-08-02 19:35:27 -04:00
kmod.c
kprobes.c kprobes: include <asm/sections.h> instead of <asm-generic/sections.h> 2016-10-11 15:06:31 -07:00
ksysfs.c kexec: add a kexec_crash_loaded() function 2016-08-02 19:35:30 -04:00
kthread.c kthread: better support freezable kthread workers 2016-10-11 15:06:33 -07:00
latencytop.c
Makefile userns: Add per user namespace sysctls. 2016-08-08 13:18:58 -05:00
membarrier.c
memremap.c mm: fix cache mode of dax pmd mappings 2016-09-09 17:34:46 -07:00
module_signing.c KEYS: Move the point of trust determination to __key_link() 2016-04-11 22:43:43 +01:00
module-internal.h
module.c livepatch/module: make TAINT_LIVEPATCH module-specific 2016-08-26 14:42:08 +02:00
notifier.c
nsproxy.c
padata.c padata: Convert to hotplug state machine 2016-09-19 21:44:30 +02:00
panic.c x86/panic: replace smp_send_stop() with kdump friendly version in panic path 2016-10-11 15:06:32 -07:00
params.c
pid_namespace.c Merge branch 'nsfs-ioctls' into HEAD 2016-09-22 20:00:36 -05:00
pid.c remove lots of IS_ERR_VALUE abuses 2016-05-27 15:26:11 -07:00
profile.c profile: Convert to hotplug state machine 2016-07-15 10:41:42 +02:00
ptrace.c ptrace: clear TIF_SYSCALL_TRACE on ptrace detach 2016-10-11 15:06:32 -07:00
range.c
reboot.c
relay.c relay: Use irq_work instead of plain timer for deferred wakeup 2016-10-11 15:06:32 -07:00
resource.c /proc/iomem: only expose physical resource addresses to privileged users 2016-04-14 12:56:09 -07:00
seccomp.c seccomp: Fix tracer exit notifications during fatal signals 2016-08-30 16:12:46 -07:00
signal.c x86/signal: Add SA_{X32,IA32}_ABI sa_flags 2016-09-14 21:28:11 +02:00
smp.c smp: Allocate smp_call_on_cpu() workqueue on stack too 2016-09-22 14:49:10 +02:00
smpboot.c kthread/smpboot: do not park in kthread_create_on_cpu() 2016-10-11 15:06:33 -07:00
smpboot.h
softirq.c This adds a new gcc plugin named "latent_entropy". It is designed to 2016-10-15 10:03:15 -07:00
stacktrace.c
stop_machine.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-10-03 13:39:00 -07:00
sys_ni.c x86/pkeys: Fix pkeys build breakage for some non-x86 arches 2016-09-13 14:41:36 +02:00
sys.c prctl: make PR_SET_THP_DISABLE wait for mmap_sem killable 2016-05-23 17:04:14 -07:00
sysctl_binary.c kernel/sysctl_binary.c: use generic UUID library 2016-05-20 17:58:30 -07:00
sysctl.c Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-10-10 13:04:49 -07:00
task_work.c task_work: use READ_ONCE/lockless_dereference, avoid pi_lock if !task_works 2016-08-02 19:35:02 -04:00
taskstats.c taskstats: use the libnl API to align nlattr on 64-bit 2016-04-23 20:13:25 -04:00
test_kprobes.c
torture.c torture: Convert torture_shutdown() to hrtimer 2016-08-22 10:01:49 -07:00
tracepoint.c
tsacct.c
ucount.c mntns: Add a limit on the number of mount namespaces. 2016-08-31 07:28:35 -05:00
uid16.c cred: simpler, 1D supplementary groups 2016-10-07 18:46:30 -07:00
up.c smp: Add function to execute a function synchronously on a CPU 2016-09-05 13:52:39 +02:00
user_namespace.c Merge branch 'nsfs-ioctls' into HEAD 2016-09-22 20:00:36 -05:00
user-return-notifier.c
user.c
utsname_sysctl.c
utsname.c Merge branch 'nsfs-ioctls' into HEAD 2016-09-22 20:00:36 -05:00
watchdog.c Revert "perf/x86/intel, watchdog: Switch NMI watchdog to ref cycles on x86" 2016-07-10 20:58:36 +02:00
workqueue_internal.h
workqueue.c kthread: rename probe_kthread_data() to kthread_probe_data() 2016-10-11 15:06:33 -07:00