linux/kernel
Thomas Gleixner d689fe222a NOHZ: Check for nohz active instead of nohz enabled
RCU and the fine grained idle time accounting functions check
tick_nohz_enabled. But that variable is merily telling that NOHZ has
been enabled in the config and not been disabled on the command line.

But it does not tell anything about nohz being active. That's what all
this should check for.

Matthew reported, that the idle accounting on his old P1 machine
showed bogus values, when he enabled NOHZ in the config and did not
disable it on the kernel command line. The reason is that his machine
uses (refined) jiffies as a clocksource which explains why the "fine"
grained accounting went into lala land, because it depends on when the
system goes and leaves idle relative to the jiffies increment.

Provide a tick_nohz_active indicator and let RCU and the accounting
code use this instead of tick_nohz_enable.

Reported-and-tested-by: Matthew Whitehead <tedheadster@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: john.stultz@linaro.org
Cc: mwhitehe@redhat.com
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1311132052240.30673@ionos.tec.linutronix.de
2013-11-19 14:59:50 +01:00
..
cpu sched: Add NEED_RESCHED to the preempt_count 2013-09-25 14:07:49 +02:00
debug kdb: Add support for external NMI handler to call KGDB/KDB 2013-10-03 18:47:54 +02:00
events list: introduce list_next_entry() and list_prev_entry() 2013-11-13 12:09:23 +09:00
gcov gcov: reuse kbasename helper 2013-11-13 12:09:34 +09:00
irq Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-11-15 16:47:22 -08:00
locking locking/lockdep: Mark __lockdep_count_forward_deps() as static 2013-11-13 13:50:17 +01:00
power Merge branch 'pm-sleep' 2013-11-07 19:26:55 +01:00
printk printk.c: comments should refer to /proc/vmcore instead of /proc/vmcoreinfo 2013-11-13 12:09:14 +09:00
rcu NOHZ: Check for nohz active instead of nohz enabled 2013-11-19 14:59:50 +01:00
sched sched/fair: Avoid integer overflow 2013-11-13 13:33:55 +01:00
time NOHZ: Check for nohz active instead of nohz enabled 2013-11-19 14:59:50 +01:00
trace This batch of changes is mostly clean ups and small bug fixes. 2013-11-16 12:23:18 -08:00
.gitignore
acct.c
async.c
audit_tree.c kernel/audit_tree.c:audit_add_tree_rule(): protect `rule' from kill_rules() 2013-06-12 16:29:46 -07:00
audit_watch.c
audit.c audit: fix endless wait in audit_log_start() 2013-09-24 17:00:26 -07:00
audit.h audit: fix mq_open and mq_unlink to add the MQ root as a hidden parent audit_names record 2013-07-09 10:33:19 -07:00
auditfilter.c audit: Fix decimal constant description 2013-07-09 10:33:19 -07:00
auditsc.c audit: fix mq_open and mq_unlink to add the MQ root as a hidden parent audit_names record 2013-07-09 10:33:19 -07:00
backtracetest.c
bounds.c mm: properly separate the bloated ptl from the regular case 2013-11-15 09:32:20 +09:00
capability.c xfs: update for v3.12-rc1 2013-09-09 11:19:09 -07:00
cgroup_freezer.c cgroup: make css_for_each_descendant() and friends include the origin css in the iteration 2013-08-08 20:11:27 -04:00
cgroup.c Merge branch 'for-3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2013-11-13 15:21:53 +09:00
compat.c
configs.c
context_tracking.c Linux 3.12-rc4 2013-10-09 12:36:13 +02:00
cpu_pm.c
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
cpuset.c Merge branch 'for-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2013-09-03 18:25:03 -07:00
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 ptrace: revert "Prepare to fix racy accesses on task breakpoints" 2013-07-09 10:33:26 -07:00
extable.c extable: skip sorting if the table is empty 2013-09-11 15:58:25 -07:00
fork.c mm: implement split page table lock for PMD level 2013-11-15 09:32:15 +09:00
freezer.c freezer: set PF_SUSPEND_TASK flag on tasks that call freeze_processes 2013-07-30 14:05:06 +02:00
futex_compat.c
futex.c locking: Move the rtmutex code to kernel/locking/ 2013-11-06 09:23:59 +01:00
groups.c userns: Kill nsown_capable it makes the wrong thing easy 2013-08-30 23:44:11 -07:00
hrtimer.c kernel: delete __cpuinit usage from all core kernel files 2013-07-14 19:36:59 -04:00
hung_task.c Here are the 3.13 KVM changes. There was a lot of work on the PPC 2013-11-15 13:51:36 +09:00
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 locking: Fix copy/paste errors of "ARCH_INLINE_*_UNLOCK_BH" 2013-05-28 08:50:00 +02:00
Kconfig.preempt
kexec.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-11-15 16:47:22 -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 kernel: replace strict_strto*() with kstrto*() 2013-09-12 15:38:03 -07:00
kthread.c kthread: make kthread_create() killable 2013-11-13 12:08:59 +09:00
latencytop.c
Makefile Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-11-12 10:20:12 +09:00
modsign_certificate.S
modsign_pubkey.c kernel/modsign_pubkey.c: fix init const for module signing code 2013-09-11 15:58:21 -07:00
module_signing.c
module-internal.h
module.c Mainly boring here, too. rmmod --wait finally removed, though. 2013-11-15 13:27:50 +09:00
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 - Register hotcpu notifier after initialization 2013-08-29 14:37:59 +10:00
panic.c kernel/panic.c: reduce 1 byte usage for print tainted buffer 2013-11-13 12:09:35 +09:00
params.c kernel/params: fix handling of signed integer types 2013-09-28 12:35:52 -07:00
pid_namespace.c pid_namespace: make freeing struct pid_namespace rcu-delayed 2013-10-24 23:43:29 -04:00
pid.c pidns: fix free_pid() to handle the first fork failure 2013-09-30 14:31:03 -07:00
posix-cpu-timers.c posix_timers: fix racy timer delta caching on task exit 2013-07-03 16:54:42 +02:00
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 range: Do not add new blank slot with add_range_with_merge 2013-06-18 11:32:10 -05:00
reboot.c kernel/reboot.c: re-enable the function of variable reboot_default 2013-09-24 17:00:26 -07:00
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 kernel/resource.c: remove the unneeded assignment in function __find_resource 2013-07-03 16:08:06 -07:00
seccomp.c
signal.c constify copy_siginfo_to_user{,32}() 2013-11-09 00:16:29 -05:00
smp.c kernel: fix generic_exec_single indentation 2013-11-15 09:32:22 +09:00
smpboot.c kernel: delete __cpuinit usage from all core kernel files 2013-07-14 19:36:59 -04:00
smpboot.h
softirq.c revert "softirq: Add support for triggering softirq work on softirqs" 2013-11-15 09:32:22 +09:00
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_ni.c
sys.c kernel/sys.c: remove obsolete #include <linux/kexec.h> 2013-11-13 12:09:13 +09:00
sysctl_binary.c kernel/sysctl_binary.c: use scnprintf() instead of snprintf() 2013-11-13 12:09:33 +09:00
sysctl.c Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-11-14 16:30:30 +09:00
task_work.c task_work: documentation 2013-09-11 15:58:27 -07:00
taskstats.c kernel/taskstats.c: return -ENOMEM when alloc memory fails in add_del_listener() 2013-11-13 12:09:34 +09:00
test_kprobes.c
time.c sched: Rename sched.c as sched/core.c in comments and Documentation 2013-06-19 12:58:42 +02:00
timeconst.bc
timer.c sched: Introduce preempt_count accessor functions 2013-09-25 14:07:32 +02:00
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_namespace.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
user-return-notifier.c
user.c userns: Better restrictions on when proc and sysfs can be mounted 2013-08-26 19:17:03 -07:00
utsname_sysctl.c
utsname.c userns: Kill nsown_capable it makes the wrong thing easy 2013-08-30 23:44:11 -07:00
watchdog.c watchdog: update watchdog_thresh properly 2013-09-24 17:00:25 -07:00
workqueue_internal.h sched: Rename sched.c as sched/core.c in comments and Documentation 2013-06-19 12:58:42 +02:00
workqueue.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-09-06 09:36:28 -07:00