linux/kernel
Paul E. McKenney 67182ae1c4 rcu, debug: detect stalled grace periods
this is a diagnostic patch for Classic RCU.

The approach is to record a timestamp at the beginning
of the grace period (in rcu_start_batch()), then have
rcu_check_callbacks() complain if:

 1.	it is running on a CPU that has holding up grace periods for
 	a long time (say one second).  This will identify the culprit
 	assuming that the culprit has not disabled hardware irqs,
 	instruction execution, or some such.

 2.	it is running on a CPU that is not holding up grace periods,
 	but grace periods have been held up for an even longer time
 	(say two seconds).

It is enabled via the default-off CONFIG_DEBUG_RCU_STALL kernel parameter.

Rather than exponential backoff, it backs off to once per 30 seconds.
My feeling upon thinking on it was that if you have stalled RCU grace
periods for that long, a few extra printk() messages are probably the
least of your worries...

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: David Witbrodt <dawitbro@sbcglobal.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-11 13:35:18 +02:00
..
irq genirq: better warning on irqchip->set_type() failure 2008-08-05 14:33:47 -07:00
power kexec jump: save/restore device state 2008-07-26 12:00:04 -07:00
time cpumask: change cpumask_of_cpu_ptr to use new cpumask_of_cpu 2008-07-26 16:40:33 +02:00
trace Merge branch 'linus' into cpus4096 2008-07-28 23:32:00 +02:00
.gitignore Update kernel/.gitignore with new auto-generated files 2008-02-09 23:27:01 -08:00
acct.c bsdacct: fix and add comments around acct_process() 2008-07-25 10:53:47 -07:00
audit_tree.c [PATCH] list_for_each_rcu must die: audit 2008-05-17 03:30:23 -04:00
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 [PATCH 1/2] audit: move extern declarations to audit.h 2008-04-28 06:28:04 -04:00
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 Re: [PATCH] Fix the kernel panic of audit_filter_task when key field is set 2008-08-04 06:13:50 -04:00
backtracetest.c backtrace: replace timer with tasklet + completions 2008-06-27 18:09:16 +02:00
bounds.c Add kbuild.h that contains common definitions for kbuild users 2008-04-29 08:06:29 -07:00
capability.c security: filesystem capabilities refactor kernel code 2008-07-24 10:47:22 -07:00
cgroup_debug.c CGroup API files: move "releasable" to cgroup_debug subsystem 2008-04-29 08:06:09 -07:00
cgroup.c cgroup: uninline cgroup_has_css_refs() 2008-07-30 09:41:44 -07:00
compat.c ntp: support for TAI 2008-05-01 08:03:59 -07:00
configs.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
cpu.c Merge branch 'linus' into cpus4096 2008-07-28 23:32:00 +02:00
cpuset.c cpuset: clean up cpuset hierarchy traversal code 2008-07-30 09:41:44 -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: fix order calculation in dma_mark_declared_memory_occupied() 2008-08-05 14:33:49 -07:00
dma.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
exec_domain.c [PATCH] kill altroot 2008-07-26 20:53:20 -04:00
exit.c tracehook: fix exit_signal=0 case 2008-08-01 12:01:11 -07:00
extable.c module: Don't report discarded init pages as kernel text. 2008-01-29 17:13:18 +11:00
fork.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
futex_compat.c futex_compat __user annotation 2008-03-30 14:18:41 -07:00
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 ITIMER_REAL: convert to use struct pid 2008-02-08 09:22:29 -08:00
kallsyms.c kallsyms: fix potential overflow in binary search 2008-07-25 10:53:27 -07:00
Kconfig.hz sched: fix hrtick & generic-ipi dependency 2008-07-23 11:18:28 +02:00
Kconfig.preempt rcu: move PREEMPT_RCU config option back under PREEMPT 2008-03-10 18:01:20 -07:00
kexec.c kexec jump: save/restore device state 2008-07-26 12:00:04 -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 Kobject: convert remaining kobject_unregister() to kobject_put() 2008-01-24 20:40:40 -08:00
kthread.c tracehook: wait_task_inactive 2008-07-26 12:00:09 -07:00
latencytop.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
lockdep_internals.h lockdep: add lock_class information to lock_chain and output it 2008-06-24 01:28:20 +02:00
lockdep_proc.c lockdep: add lock_class information to lock_chain and output it 2008-06-24 01:28:20 +02:00
lockdep.c Merge branch 'core/locking' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-07-14 14:55:13 -07:00
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 stop_machine: Wean existing callers off stop_machine_run() 2008-07-28 12:16:31 +10:00
mutex-debug.c mutex-debug: check mutex magic before owner 2008-05-16 16:53:35 +02:00
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 ipc: re-enable msgmni automatic recomputing msgmni if set to negative 2008-04-29 08:06:13 -07:00
ns_cgroup.c cgroup_clone: use pid of newly created task for new cgroup 2008-07-25 10:53:37 -07:00
nsproxy.c cgroup_clone: use pid of newly created task for new cgroup 2008-07-25 10:53:37 -07:00
panic.c Add a WARN() macro; this is WARN_ON() + printk arguments 2008-07-25 10:53:29 -07:00
params.c Add new string functions strict_strto* and convert kernel params to use them 2008-02-08 09:22:41 -08:00
pid_namespace.c bsdacct: switch from global bsd_acct_struct instance to per-pidns one 2008-07-25 10:53:47 -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: spelling fixes 2008-08-05 14:33:50 -07:00
posix-cpu-timers.c posix-timers: print RT watchdog message 2008-05-24 18:49:22 +02:00
posix-timers.c posix timers: release_posix_timer: kill the bogus put_task_struct(->it_process); 2008-07-25 10:53:38 -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 tracehook: wait_task_inactive 2008-07-26 12:00:09 -07:00
rcuclassic.c rcu, debug: detect stalled grace periods 2008-08-11 13:35:18 +02:00
rcupdate.c Merge branch 'generic-ipi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-07-15 14:12:03 -07:00
rcupreempt_trace.c rcu: remove duplicated include in kernel/rcupreempt_trace.c 2008-05-19 10:03:39 +02:00
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 resource: add resource_size() 2008-07-30 09:41:43 -07:00
rtmutex_common.h Don't operate with pid_t in rtmutex tester 2008-02-08 09:22:41 -08:00
rtmutex-debug.c Don't operate with pid_t in rtmutex tester 2008-02-08 09:22:41 -08:00
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 hrtimer: more hrtimer_init_sleeper() fallout. 2008-02-13 15:45:36 +01:00
rtmutex.h
rwsem.c sched: mark rwsem functions as __sched for wchan/profiling 2007-12-18 15:21:13 +01:00
sched_clock.c Merge branch 'sched/clock' into sched/devel 2008-07-14 12:19:13 +02:00
sched_cpupri.c sched: use a 2-d bitmap for searching lowest-pri CPU 2008-06-06 15:19:28 +02:00
sched_cpupri.h sched: fix the cpuprio count really 2008-06-06 15:19:44 +02:00
sched_debug.c sched: add full schedstats to /proc/sched_debug 2008-06-27 14:31:31 +02:00
sched_fair.c Merge branch 'sched/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-07-23 19:36:53 -07:00
sched_features.h sched: bias effective_load() error towards failing wake_affine(). 2008-06-27 14:31:47 +02:00
sched_idletask.c sched: make rt_sched_class, idle_sched_class static 2008-05-05 23:56:17 +02:00
sched_rt.c Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-07-24 12:53:51 -07:00
sched_stats.h sched: fix accounting in task delay accounting & migration 2008-07-04 12:50:23 +02:00
sched.c __sched_setscheduler: don't do any policy checks when not "user" 2008-08-04 17:16:20 -07:00
seccomp.c
semaphore.c semaphore: __down_common: use signal_pending_state() 2008-08-05 14:33:47 -07:00
signal.c tracehook: force signal_pending() 2008-07-26 12:00:09 -07:00
smp.c Full conversion to early_initcall() interface, remove old interface 2008-07-26 12:00:04 -07:00
softirq.c Full conversion to early_initcall() interface, remove old interface 2008-07-26 12:00:04 -07:00
softlockup.c Full conversion to early_initcall() interface, remove old interface 2008-07-26 12:00:04 -07:00
spinlock.c ftrace: lockdep notrace annotations 2008-05-23 20:39:40 +02:00
srcu.c make srcu_readers_active() static 2008-02-06 10:41:02 -08:00
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(): stop_machine_run() changed to use cpu mask 2008-07-28 12:16:30 +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 kexec jump 2008-07-26 12:00:04 -07:00
sysctl_check.c sysctl: check for bogus modes 2008-07-25 10:53:45 -07:00
sysctl.c lost sysctl fix 2008-07-27 09:45:34 -07:00
taskstats.c taskstats: remove initialization of static per-cpu variable 2008-07-25 10:53:47 -07:00
test_kprobes.c kprobes: kretprobe user entry-handler 2008-02-06 10:41:11 -08:00
time.c Make constants in kernel/timeconst.h fixed 64 bits 2008-05-02 16:18:42 -07:00
timeconst.pl Make constants in kernel/timeconst.h fixed 64 bits 2008-05-02 16:18:42 -07:00
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 asmlinkage_protect replaces prevent_tail_call 2008-04-10 17:28:26 -07:00
user_namespace.c eCryptfs: make key module subsystem respect namespaces 2008-04-29 08:06:07 -07:00
user.c alloc_uid: cleanup 2008-04-30 08:29:53 -07:00
utsname_sysctl.c
utsname.c kernel: explicitly include required header files under kernel/ 2008-04-29 08:06:04 -07:00
wait.c kernel: remove fastcall in kernel/* 2008-02-08 09:22:31 -08:00
workqueue.c workqueues: add comments to __create_workqueue_key() 2008-07-30 09:41:47 -07:00