linux/kernel
Thomas Gleixner 6441402b1f clockevents: prevent cpu online to interfere with nohz
Impact: rare hang which can be triggered on CPU online.

tick_do_timer_cpu keeps track of the CPU which updates jiffies
via do_timer. The value -1 is used to signal, that currently no
CPU is doing this. There are two cases, where the variable can 
have this state:

 boot:
    necessary for systems where the boot cpu id can be != 0

 nohz long idle sleep:
    When the CPU which did the jiffies update last goes into
    a long idle sleep it drops the update jiffies duty so
    another CPU which is not idle can pick it up and keep
    jiffies going.

Using the same value for both situations is wrong, as the CPU online
code can see the -1 state when the timer of the newly onlined CPU is
setup. The setup for a newly onlined CPU goes through periodic mode
and can pick up the do_timer duty without being aware of the nohz /
highres mode of the already running system.

Use two separate states and make them constants to avoid magic
numbers confusion. 

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-23 11:38:52 +02:00
..
irq genirq: switch /proc/irq/*/smp_affinity et al to seqfiles 2008-08-12 16:07:30 -07:00
power ftrace: disable tracing for hibernation 2008-08-28 12:27:39 -07:00
time clockevents: prevent cpu online to interfere with nohz 2008-09-23 11:38:52 +02:00
trace Merge branch 'linus' into cpus4096 2008-07-28 23:32:00 +02:00
.gitignore
acct.c bsdacct: fix and add comments around acct_process() 2008-07-25 10:53:47 -07:00
audit_tree.c
audit.c [PATCH] Fix the bug of using AUDIT_STATUS_RATE_LIMIT when set fail, no error output. 2008-08-01 12:15:16 -04:00
audit.h
auditfilter.c Re: [PATCH] the loginuid field should be output in all AUDIT_CONFIG_CHANGE audit messages 2008-08-01 12:15:03 -04:00
auditsc.c [PATCH] audit: Moved variable declaration to beginning of function 2008-09-01 23:06:45 -04:00
backtracetest.c backtrace: replace timer with tasklet + completions 2008-06-27 18:09:16 +02:00
bounds.c
capability.c security: Fix setting of PF_SUPERPRIV by __capable() 2008-08-14 22:59:43 +10:00
cgroup_debug.c
cgroup.c cgroup: uninline cgroup_has_css_refs() 2008-07-30 09:41:44 -07:00
compat.c
configs.c
cpu.c cpu hotplug: s390 doesn't support additional_cpus anymore. 2008-08-12 16:07:28 -07:00
cpuset.c cpuset: avoid changing cpuset's cpus when -errno returned 2008-09-13 14:41:50 -07:00
delayacct.c per-task-delay-accounting: update taskstats for memory reclaim delay 2008-07-25 10:53:47 -07:00
dma-coherent.c DMA: make dma-coherent.c documentation kdoc-friendly 2008-08-07 06:52:01 -07:00
dma.c
exec_domain.c [PATCH] kill altroot 2008-07-26 20:53:20 -04:00
exit.c sched: fix process time monotonicity 2008-09-05 18:14:35 +02:00
extable.c
fork.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
futex_compat.c
futex.c futexes: fix fault handling in futex_lock_pi 2008-06-23 13:31:15 +02:00
hrtimer.c Merge branch 'generic-ipi' into generic-ipi-for-linus 2008-07-15 21:55:59 +02:00
itimer.c
kallsyms.c kallsyms: fix potential overflow in binary search 2008-07-25 10:53:27 -07:00
Kconfig.hz sched: fix SCHED_HRTICK dependency 2008-07-28 14:37:38 +02:00
Kconfig.preempt
kexec.c kexec: use a mutex for locking rather than xchg() 2008-08-15 08:35:43 -07:00
kfifo.c
kgdb.c kgdb: fix gdb serial thread queries 2008-08-01 08:39:35 -05:00
kmod.c call_usermodehelper(): increase reliability 2008-07-25 10:53:28 -07:00
kprobes.c kprobes: remove redundant config check 2008-07-25 10:53:30 -07:00
ksysfs.c
kthread.c tracehook: wait_task_inactive 2008-07-26 12:00:09 -07:00
latencytop.c
lockdep_internals.h lockdep: build fix 2008-08-13 12:55:10 +02:00
lockdep_proc.c lockstat: fix numerical output rounding error 2008-08-26 10:37:46 +02:00
lockdep.c lockdep: fix invalid list_del_rcu in zap_class 2008-08-27 08:40:36 +02:00
Makefile Merge branch 'linus' into core/generic-dma-coherent 2008-07-29 00:07:55 +02:00
marker.c markers: fix markers read barrier for multiple probes 2008-07-30 09:41:45 -07:00
module.c [module] Don't let gcc inline load_module() 2008-08-25 11:10:26 -07:00
mutex-debug.c
mutex-debug.h
mutex.c locking: fix mutex @key parameter kernel-doc notation 2008-07-28 18:12:36 +02:00
mutex.h
notifier.c
ns_cgroup.c cgroup_clone: use pid of newly created task for new cgroup 2008-07-25 10:53:37 -07:00
nsproxy.c removed unused #include <linux/version.h>'s 2008-08-23 12:14:12 -07:00
panic.c Add a WARN() macro; this is WARN_ON() + printk arguments 2008-07-25 10:53:29 -07:00
params.c
pid_namespace.c pid_ns: (BUG 11391) change ->child_reaper when init->group_leader exits 2008-09-02 19:21:38 -07:00
pid.c pidns: remove now unused find_pid function. 2008-07-25 10:53:45 -07:00
pm_qos_params.c pm_qos_requirement might sleep 2008-09-02 19:21:40 -07:00
posix-cpu-timers.c
posix-timers.c Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-08-11 16:46:11 -07:00
printk.c printk: fix comment for printk ratelimiting 2008-07-30 09:41:45 -07:00
profile.c build kernel/profile.o only when requested 2008-07-25 10:53:27 -07:00
ptrace.c security: Fix setting of PF_SUPERPRIV by __capable() 2008-08-14 22:59:43 +10:00
rcuclassic.c stop_machine: Wean existing callers off stop_machine_run() 2008-07-28 12:16:31 +10:00
rcupdate.c rcu: fix synchronize_rcu() so that kernel-doc works 2008-08-21 09:31:44 +02:00
rcupreempt_trace.c
rcupreempt.c Merge branch 'linus' into cpus4096 2008-07-16 00:29:07 +02:00
rcutorture.c rcu: make rcutorture even more vicious: invoke RCU readers from irq handlers (timers) 2008-06-26 09:24:33 +02:00
relay.c relay: fix "full buffer with exactly full last subbuffer" accounting problem 2008-08-05 14:33:46 -07:00
res_counter.c cgroup files: convert res_counter_write() to be a cgroups write_string() handler 2008-07-25 10:53:36 -07:00
resource.c kernel/resource.c: fix new kernel-doc warning 2008-09-02 10:47:30 -07:00
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c sysdev: Pass the attribute to the low level sysdev show/store function 2008-07-21 21:55:02 -07:00
rtmutex.c
rtmutex.h
rwsem.c
sched_clock.c sched_clock: fix cpu_clock() 2008-08-25 17:39:57 +02:00
sched_cpupri.c
sched_cpupri.h
sched_debug.c sched: add full schedstats to /proc/sched_debug 2008-06-27 14:31:31 +02:00
sched_fair.c sched: fix mysql+oltp regression 2008-08-11 14:49:29 +02:00
sched_features.h sched: enable LB_BIAS by default 2008-08-21 08:18:02 +02:00
sched_idletask.c
sched_rt.c sched: fix 2.6.27-rc5 couldn't boot on tulsa machine randomly 2008-09-11 09:34:28 +02:00
sched_stats.h sched: fix accounting in task delay accounting & migration 2008-07-04 12:50:23 +02:00
sched.c sched: fix deadlock in setting scheduler parameter to zero 2008-09-11 09:39:18 +02:00
seccomp.c
semaphore.c semaphore: __down_common: use signal_pending_state() 2008-08-05 14:33:47 -07:00
signal.c tracehook: fix SA_NOCLDWAIT 2008-08-19 20:37:07 -07:00
smp.c smp: have smp_call_function_single() detect invalid CPUs 2008-08-25 17:45:48 -07:00
softirq.c Full conversion to early_initcall() interface, remove old interface 2008-07-26 12:00:04 -07:00
softlockup.c softlockup: minor cleanup, don't check task->state twice 2008-09-02 10:49:51 -07:00
spinlock.c lockdep: spin_lock_nest_lock(), checkpatch fixes 2008-08-13 13:56:51 +02:00
srcu.c
stacktrace.c stacktrace: fix modular build, export print_stack_trace and save_stack_trace 2008-06-30 09:20:55 +02:00
stop_machine.c stop_machine: remove unused variable 2008-08-12 17:52:55 +10:00
sys_ni.c signalfd: fix undefined reference to `compat_sys_signalfd4' when !CONFIG_SIGNALFD 2008-07-25 11:35:41 -07:00
sys.c fix setpriority(PRIO_PGRP) thread iterator breakage 2008-08-20 15:40:32 -07:00
sysctl_check.c sysctl: check for bogus modes 2008-07-25 10:53:45 -07:00
sysctl.c forgotten refcount on sysctl root table 2008-09-04 11:06:21 -07:00
taskstats.c taskstats: remove initialization of static per-cpu variable 2008-07-25 10:53:47 -07:00
test_kprobes.c
time.c
timeconst.pl
timer.c Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm 2008-07-14 16:06:58 -07:00
tsacct.c task IO accounting: move all IO statistics in struct task_io_accounting 2008-07-27 16:12:28 -07:00
uid16.c
user_namespace.c removed unused #include <linux/version.h>'s 2008-08-23 12:14:12 -07:00
user.c
utsname_sysctl.c removed unused #include <linux/version.h>'s 2008-08-23 12:14:12 -07:00
utsname.c removed unused #include <linux/version.h>'s 2008-08-23 12:14:12 -07:00
wait.c
workqueue.c Merge branch 'core/locking' into core/urgent 2008-08-12 00:11:49 +02:00