Viresh Kumar
8ba1465428
timer: Spare IPI when deferrable timer is queued on idle remote targets
...
When a timer is enqueued or modified on a remote target, the latter is
expected to see and handle this timer on its next tick. However if the
target is idle and CONFIG_NO_HZ_IDLE=y, the CPU may be sleeping tickless
and the timer may be ignored.
wake_up_nohz_cpu() takes care of that by setting TIF_NEED_RESCHED and
sending an IPI to idle targets so that the tick is reevaluated on the
idle loop through the tick_nohz_idle_*() APIs.
Now this is all performed regardless of the power properties of the
timer. If the timer is deferrable, idle targets don't need to be woken
up. Only the next buzy tick needs to care about it, and no IPI kick
is needed for that to happen.
So lets spare the IPI on idle targets when the timer is deferrable.
Meanwhile we keep the current behaviour on full dynticks targets. We can
spare IPIs on idle full dynticks targets as well but some tricky races
against idle_cpu() must be dealt all along to make sure that the timer
is well handled after idle exit. We can deal with that later since
NO_HZ_FULL already has more important powersaving issues.
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/CAKohpomMZ0TAN2e6N76_g4ZRzxd5vZ1XfuZfxrP7GMxfTNiLVw@mail.gmail.com
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2014-02-14 17:59:14 +01:00
..
cpu
sched/preempt: Fix up missed PREEMPT_NEED_RESCHED folding
2014-01-13 17:38:55 +01:00
debug
kgdb/kdb: Fix no KDB config problem
2014-01-25 08:55:09 +01:00
events
This pull request has a new feature to ftrace, namely the trace event
2014-01-22 16:35:21 -08:00
gcov
gcov: reuse kbasename helper
2013-11-13 12:09:34 +09:00
irq
Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2013-12-02 10:15:39 -08:00
locking
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-01-20 10:42:08 -08:00
power
Merge branch 'for-3.14/core' of git://git.kernel.dk/linux-block
2014-01-30 11:19:05 -08:00
printk
printk: flush conflicting continuation line
2014-01-23 16:36:56 -08:00
rcu
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2014-01-28 08:38:04 -08:00
sched
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-01-31 09:02:51 -08:00
time
tick: Fixup more fallout from hrtimer broadcast mode
2014-02-09 15:11:47 +01:00
trace
Merge branch 'for-3.14/core' of git://git.kernel.dk/linux-block
2014-01-30 11:19:05 -08:00
.gitignore
Ignore generated file kernel/x509_certificate_list
2013-12-10 18:21:34 +00:00
acct.c
async.c
audit.c
audit: fix location of __net_initdata for audit_net_ops
2014-01-17 17:14:32 -05:00
audit.h
audit: Convert int limit uses to u32
2014-01-14 14:54:00 -05:00
audit_tree.c
fsnotify: remove pointless NULL initializers
2014-01-21 16:19:41 -08:00
audit_watch.c
fsnotify: remove pointless NULL initializers
2014-01-21 16:19:41 -08:00
auditfilter.c
audit: log on errors from filter user rules
2014-01-13 22:32:31 -05:00
auditsc.c
audit: fix dangling keywords in audit_log_set_loginuid() output
2014-01-13 22:32:38 -05:00
backtracetest.c
bounds.c
mm: do not allocate page->ptl dynamically, if spinlock_t fits to long
2013-12-20 12:25:45 -08:00
capability.c
audit: Simplify and correct audit_log_capset
2014-01-13 22:26:48 -05:00
cgroup.c
Merge branch 'for-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
2014-01-21 17:51:34 -08:00
cgroup_freezer.c
cgroup: replace cftype->read_seq_string() with cftype->seq_show()
2013-12-05 12:28:04 -05:00
compat.c
configs.c
context_tracking.c
context_tracking: Wrap static key check into more intuitive function name
2013-12-02 20:43:14 +01:00
cpu.c
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2013-11-14 16:55:11 +09:00
cpu_pm.c
cpuset.c
cgroup: replace cftype->read_seq_string() with cftype->seq_show()
2013-12-05 12:28:04 -05:00
crash_dump.c
cred.c
delayacct.c
kernel/delayacct.c: remove redundant checking in __delayacct_add_tsk()
2013-11-13 12:09:12 +09:00
dma.c
elfcore.c
switch elf_core_write_extra_phdrs() to dump_emit()
2013-11-09 00:16:23 -05:00
exec_domain.c
exit.c
introduce for_each_thread() to replace the buggy while_each_thread()
2014-01-21 16:19:46 -08:00
extable.c
kernel/extable: fix address-checks for core_kernel and init areas
2013-11-28 09:49:41 -08:00
fork.c
exec: kill task_struct->did_exec
2014-01-23 16:37:02 -08:00
freezer.c
libata, freezer: avoid block device removal while system is frozen
2013-12-19 13:50:32 -05:00
futex.c
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-01-20 10:42:08 -08:00
futex_compat.c
groups.c
userns: Kill nsown_capable it makes the wrong thing easy
2013-08-30 23:44:11 -07:00
hrtimer.c
sched/deadline: Add SCHED_DEADLINE structures & implementation
2014-01-13 13:41:06 +01:00
hung_task.c
hung_task: Display every hung task warning
2014-01-25 12:13:33 +01:00
irq_work.c
itimer.c
jump_label.c
static_key: WARN on usage before jump_label_init was called
2013-10-19 19:45:35 -04:00
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
kernel: remove CONFIG_USE_GENERIC_SMP_HELPERS
2013-11-15 09:32:22 +09:00
Kconfig.locks
Kconfig.preempt
kexec.c
kernel/kexec.c: use vscnprintf() instead of vsnprintf() in vmcoreinfo_append_str()
2014-01-27 21:02:40 -08:00
kmod.c
kernel/kmod.c: check for NULL in call_usermodehelper_exec()
2013-09-30 14:31:02 -07:00
kprobes.c
kprobes: use KSYM_NAME_LEN to size identifier buffers
2013-11-13 12:09:26 +09:00
ksysfs.c
kdump: fix exported size of vmcoreinfo note
2014-01-23 16:37:03 -08:00
kthread.c
kthread: make kthread_create() killable
2013-11-13 12:08:59 +09:00
latencytop.c
Makefile
KEYS: Remove files generated when SYSTEM_TRUSTED_KEYRING=y
2013-12-13 15:59:11 +00:00
module-internal.h
KEYS: Separate the kernel signature checking keyring from module signing
2013-09-25 17:17:01 +01:00
module.c
module: Add missing newline in printk call.
2014-01-21 09:59:16 +10:30
module_signing.c
keys: change asymmetric keys to use common hash definitions
2013-10-25 17:15:18 -04:00
notifier.c
nsproxy.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
2013-09-07 14:35:32 -07:00
padata.c
padata: Fix wrong usage of rcu_dereference()
2013-12-05 21:28:42 +08:00
panic.c
panic: Make panic_timeout configurable
2013-11-26 12:12:26 +01:00
params.c
params: improve standard definitions
2013-12-04 14:09:46 +10:30
pid.c
pidns: fix free_pid() to handle the first fork failure
2013-09-30 14:31:03 -07:00
pid_namespace.c
pid_namespace: make freeing struct pid_namespace rcu-delayed
2013-10-24 23:43:29 -04:00
posix-cpu-timers.c
posix-timers: Convert abuses of BUG_ON to WARN_ON
2013-12-09 16:56:29 +01:00
posix-timers.c
profile.c
kernel: delete __cpuinit usage from all core kernel files
2013-07-14 19:36:59 -04:00
ptrace.c
exec/ptrace: fix get_dumpable() incorrect tests
2013-11-13 12:09:33 +09:00
range.c
reboot.c
kexec: migrate to reboot cpu
2013-12-18 19:04:50 -08:00
relay.c
kernel: delete __cpuinit usage from all core kernel files
2013-07-14 19:36:59 -04:00
res_counter.c
memcg: reduce function dereference
2013-09-12 15:38:02 -07:00
resource.c
seccomp.c
signal.c
kernel/signal.c: change do_signal_stop/do_sigaction to use while_each_thread()
2014-01-23 16:37:02 -08:00
smp.c
kernel/smp.c: remove cpumask_ipi
2014-01-30 16:56:54 -08:00
smpboot.c
kernel: delete __cpuinit usage from all core kernel files
2013-07-14 19:36:59 -04:00
smpboot.h
softirq.c
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-01-31 09:02:51 -08:00
stacktrace.c
stop_machine.c
stop_machine: Fix race between stop_two_cpus() and stop_cpus()
2013-11-11 12:43:38 +01:00
sys.c
kernel/sys.c: k_getrusage() can use while_each_thread()
2014-01-23 16:37:02 -08:00
sys_ni.c
sysctl.c
Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-01-31 08:59:46 -08:00
sysctl_binary.c
kernel/sysctl_binary.c: use scnprintf() instead of snprintf()
2013-11-13 12:09:33 +09:00
system_certificates.S
KEYS: correct alignment of system_certificate_list content in assembly file
2013-12-10 18:25:28 +00:00
system_keyring.c
KEYS: correct alignment of system_certificate_list content in assembly file
2013-12-10 18:25:28 +00:00
task_work.c
task_work: documentation
2013-09-11 15:58:27 -07:00
taskstats.c
genetlink: only pass array to genl_register_family_with_ops()
2013-11-19 16:39:05 -05:00
test_kprobes.c
time.c
timeconst.bc
timer.c
timer: Spare IPI when deferrable timer is queued on idle remote targets
2014-02-14 17:59:14 +01:00
tracepoint.c
tsacct.c
uid16.c
userns: Kill nsown_capable it makes the wrong thing easy
2013-08-30 23:44:11 -07:00
up.c
kernel: provide a __smp_call_function_single stub for !CONFIG_SMP
2013-11-15 09:32:22 +09:00
user-return-notifier.c
user.c
KEYS: fix uninitialized persistent_keyring_register_sem
2013-12-13 15:59:11 +00:00
user_namespace.c
KEYS: Add per-user_namespace registers for persistent per-UID kerberos caches
2013-09-24 10:35:19 +01:00
utsname.c
userns: Kill nsown_capable it makes the wrong thing easy
2013-08-30 23:44:11 -07:00
utsname_sysctl.c
watchdog.c
watchdog: update watchdog_thresh properly
2013-09-24 17:00:25 -07:00
workqueue.c
Merge branch 'for-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
2014-01-21 17:46:31 -08:00
workqueue_internal.h