Thomas Gleixner
332962f2c8
clocksource: Reselect clocksource when watchdog validated high-res capability
...
Up to commit 5d33b883a (clocksource: Always verify highres capability)
we had no sanity check when selecting a clocksource, which prevented
that a non highres capable clocksource is used when the system already
switched to highres/nohz mode.
The new sanity check works as Alex and Tim found out. It prevents the
TSC from being used. This happens because on x86 the boot process
looks like this:
tsc_start_freqency_validation(TSC);
clocksource_register(HPET);
clocksource_done_booting();
clocksource_select()
Selects HPET which is valid for high-res
switch_to_highres();
clocksource_register(TSC);
TSC is not selected, because it is not yet
flagged as VALID_HIGH_RES
clocksource_watchdog()
Validates TSC for highres, but that does not make TSC
the current clocksource.
Before the sanity check was added, we installed TSC unvalidated which
worked most of the time. If the TSC was really detected as unstable,
then the unstable logic removed it and installed HPET again.
The sanity check is correct and needed. So the watchdog needs to kick
a reselection of the clocksource, when it qualifies TSC as a valid
high res clocksource.
To solve this, we mark the clocksource which got the flag
CLOCK_SOURCE_VALID_FOR_HRES set by the watchdog with an new flag
CLOCK_SOURCE_RESELECT and trigger the watchdog thread. The watchdog
thread evaluates the flag and invokes clocksource_select() when set.
To avoid that the clocksource_done_booting() code, which is about to
install the first real clocksource anyway, needs to go through
clocksource_select and tick_oneshot_notify() pointlessly, split out
the clocksource_watchdog_kthread() list walk code and invoke the
select/notify only when called from clocksource_watchdog_kthread().
So clocksource_done_booting() can utilize the same splitout code
without the select/notify invocation and the clocksource_mutex
unlock/relock dance.
Reported-and-tested-by: Alex Shi <alex.shi@intel.com>
Cc: Hans Peter Anvin <hpa@linux.intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Tested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1307042239150.11637@ionos.tec.linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-07-05 11:09:28 +02:00
..
cpu
idle: Enable interrupts in the weak arch_cpu_idle() implementation
2013-06-14 23:01:05 +02:00
debug
kgdb/sysrq: fix inconstistent help message of sysrq key
2013-04-30 17:04:10 -07:00
events
hw_breakpoint: Use cpu_possible_mask in {reserve,release}_bp_slot()
2013-06-20 17:57:01 +02:00
gcov
kernel/gcov: remove depends on CONFIG_EXPERIMENTAL
2013-01-11 11:39:33 -08:00
irq
irqdomain: document the simple domain first_irq
2013-06-08 21:15:09 +01:00
power
Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux
2013-05-02 19:40:34 -07:00
sched
posix-cpu-timers: don't account cpu timer after stopped thread runtime accounting
2013-07-04 18:02:30 +02:00
time
clocksource: Reselect clocksource when watchdog validated high-res capability
2013-07-05 11:09:28 +02:00
trace
tracing: Fix outputting formats of x86-tsc and counter when use trace_clock
2013-06-11 13:58:46 -04:00
.gitignore
kernel/hz.bc: ignore.
2013-04-22 07:09:06 -07:00
acct.c
fs: Fix hang with BSD accounting on frozen filesystem
2013-05-04 14:57:58 -04:00
async.c
async: rename and redefine async_func_ptr
2013-03-12 13:59:14 -07:00
audit.c
audit: wait_for_auditd() should use TASK_UNINTERRUPTIBLE
2013-06-12 16:29:45 -07:00
audit.h
Merge git://git.infradead.org/users/eparis/audit
2013-05-11 14:29:11 -07:00
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: catch possible NULL audit buffers
2013-01-11 14:54:55 -08:00
auditfilter.c
auditfilter.c: fix kernel-doc warnings
2013-05-24 16:22:52 -07:00
auditsc.c
audit: Make testing for a valid loginuid explicit.
2013-05-07 22:27:15 -04:00
backtracetest.c
bounds.c
capability.c
Add file_ns_capable() helper function for open-time capability checking
2013-04-14 10:06:31 -07:00
cgroup.c
cgroup: warn about mismatching options of a new mount of an existing hierarchy
2013-05-29 07:59:39 +09:00
cgroup_freezer.c
cgroup: rename ->create/post_create/pre_destroy/destroy() to ->css_alloc/online/offline/free()
2012-11-19 08:13:38 -08:00
compat.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal
2013-05-01 07:21:43 -07:00
configs.c
proc: Supply PDE attribute setting accessor functions
2013-05-01 17:29:18 -04:00
context_tracking.c
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2013-06-20 08:18:35 -10:00
cpu.c
CPU hotplug: provide a generic helper to disable/enable CPU hotplug
2013-06-12 16:29:44 -07:00
cpu_pm.c
cpuset.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2013-05-01 17:51:54 -07:00
crash_dump.c
cred.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
2012-12-18 10:55:28 -08:00
delayacct.c
cputime: Use accessors to read task cputime stats
2013-01-27 19:23:31 +01:00
dma.c
elfcore.c
exec_domain.c
exit.c
move exit_task_namespaces() outside of exit_notify()
2013-06-15 05:39:08 +04:00
extable.c
extable: Flip the sorting message
2013-04-15 13:25:16 +02:00
fork.c
Merge branch 'for-3.10/drivers' of git://git.kernel.dk/linux-block
2013-05-08 11:51:05 -07:00
freezer.c
freezer: change ptrace_stop/do_signal_stop to use freezable_schedule()
2012-10-26 14:27:49 -07:00
futex.c
futex: fix kernel-doc notation and spello
2013-03-12 20:42:10 -07:00
futex_compat.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal
2013-02-23 18:50:11 -08:00
groups.c
hrtimer.c
hrtimers: Support resuming with two or more CPUs online (but stopped)
2013-06-28 23:15:06 +02:00
hung_task.c
irq_work.c
Merge branch 'nohz/printk-v8' into irq/core
2013-02-05 00:48:46 +01:00
itimer.c
jump_label.c
jump_label: Export jump_label_rate_limit()
2012-08-06 19:00:35 +03:00
kallsyms.c
kernel: kallsyms: memory override issue, need check destination buffer length
2013-04-15 15:17:26 +09:30
kcmp.c
kcmp: include linux/ptrace.h
2012-12-20 17:40:19 -08:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
locking: Adjust spin lock inlining Kconfig options
2012-09-13 17:56:13 +02:00
Kconfig.preempt
kexec.c
kexec: Use min() and min_t() to simplify logic
2013-04-30 17:04:07 -07:00
kmod.c
usermodehelper: check subprocess_info->path != NULL
2013-05-16 12:01:11 -07:00
kprobes.c
kprobes: Fix to free gone and unused optprobes
2013-05-28 10:37:59 +02:00
ksysfs.c
Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2012-12-11 18:10:49 -08:00
kthread.c
kthread: implement probe_kthread_data()
2013-04-30 17:04:02 -07:00
latencytop.c
lglock.c
lockdep.c
Merge branch 'for-3.10/drivers' of git://git.kernel.dk/linux-block
2013-05-08 11:51:05 -07:00
lockdep_internals.h
lockdep_proc.c
lockdep: Use KSYM_NAME_LEN'ed buffer for __get_key_name()
2012-10-24 12:39:09 +02:00
lockdep_states.h
Makefile
We get rid of the general module prefix confusion with a binary config option,
2013-05-05 10:58:06 -07:00
modsign_certificate.S
CONFIG_SYMBOL_PREFIX: cleanup.
2013-03-15 15:09:43 +10:30
modsign_pubkey.c
keys: use keyring_alloc() to create module signing keyring
2012-12-20 17:40:21 -08:00
module-internal.h
MODSIGN: Move the magic string to the end of a module and eliminate the search
2012-10-19 17:30:40 -07:00
module.c
kmemleak: No need for scanning specific module sections
2013-05-17 09:53:36 +01:00
module_signing.c
MODSIGN: Don't use enum-type bitfields in module signature info block
2012-12-05 11:27:24 +10:30
mutex-debug.c
mutex-debug.h
mutex.c
mutex: Back out architecture specific check for negative mutex count
2013-04-19 09:33:36 +02:00
mutex.h
notifier.c
nsproxy.c
proc: Split the namespace stuff out into linux/proc_ns.h
2013-05-01 17:29:39 -04:00
padata.c
padata: use __this_cpu_read per-cpu helper
2012-12-06 17:16:23 +08:00
panic.c
dump_stack: implement arch-specific hardware description in task dumps
2013-04-30 17:04:02 -07:00
params.c
params: Fix potential memory leak in add_sysfs_param()
2013-03-18 11:40:21 +00:00
pid.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2013-05-01 17:51:54 -07:00
pid_namespace.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2013-05-01 17:51:54 -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
posix-timers: Remove unused variable
2013-04-18 12:51:19 +02:00
printk.c
kmsg: honor dmesg_restrict sysctl on /dev/kmsg
2013-06-12 16:29:44 -07:00
profile.c
proc: Supply PDE attribute setting accessor functions
2013-05-01 17:29:18 -04:00
ptrace.c
Fix: kernel/ptrace.c: ptrace_peek_siginfo() missing __put_user() validation
2013-06-29 11:29:08 -07:00
range.c
range: Do not add new blank slot with add_range_with_merge
2013-06-18 11:32:10 -05:00
rcu.h
rcu: Provide RCU CPU stall warnings for tiny RCU
2013-01-28 22:06:21 -08:00
rcupdate.c
Merge branches 'doctorture.2013.01.29a', 'fixes.2013.01.26a', 'tagcb.2013.01.24a' and 'tiny.2013.01.29b' into HEAD
2013-01-28 22:25:21 -08:00
rcutiny.c
Merge branches 'doctorture.2013.01.29a', 'fixes.2013.01.26a', 'tagcb.2013.01.24a' and 'tiny.2013.01.29b' into HEAD
2013-01-28 22:25:21 -08:00
rcutiny_plugin.h
rcu: Provide RCU CPU stall warnings for tiny RCU
2013-01-28 22:06:21 -08:00
rcutorture.c
rcu: Allow rcutorture to be built at low optimization levels
2013-02-04 12:18:20 -08:00
rcutree.c
rcu: Fix deadlock with CPU hotplug, RCU GP init, and timer migration
2013-06-10 13:37:12 -07:00
rcutree.h
rcu: Don't call wakeup() with rcu_node structure ->lock held
2013-06-10 13:37:11 -07:00
rcutree_plugin.h
rcu: Don't allocate bootmem from rcu_init()
2013-05-15 10:41:12 -07:00
rcutree_trace.c
rcutrace: single_open() leaks
2013-05-05 00:16:35 -04:00
relay.c
Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block
2013-05-08 10:13:35 -07:00
res_counter.c
res_counter: return amount of charges after res_counter_uncharge()
2012-12-18 15:02:12 -08:00
resource.c
mem hotunplug: fix kfree() of bootmem memory
2013-04-29 15:54:40 -07:00
rtmutex-debug.c
sched/rt: Move rt specific bits into new header file
2013-02-07 20:51:08 +01:00
rtmutex-debug.h
rtmutex-tester.c
locking/rtmutex/tester: Set correct permissions on sysfs files
2013-04-10 14:48:37 +02:00
rtmutex.c
sched/rt: Move rt specific bits into new header file
2013-02-07 20:51:08 +01:00
rtmutex.h
rtmutex_common.h
rwsem.c
Revert "rw_semaphore: remove up/down_read_non_owner"
2013-03-23 15:53:52 -07:00
seccomp.c
seccomp: allow BPF_XOR based ALU instructions.
2013-03-26 11:07:19 +11:00
semaphore.c
semaphore: use `bool' type for semaphore_waiter's up
2013-04-30 17:04:08 -07:00
signal.c
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
2013-05-01 14:08:52 -07:00
smp.c
kernel/smp.c: cleanups
2013-04-30 17:04:03 -07:00
smpboot.c
kthread: Prevent unpark race which puts threads on the wrong cpu
2013-04-12 14:18:43 +02:00
smpboot.h
smpboot: Provide infrastructure for percpu hotplug threads
2012-08-13 17:01:07 +02:00
softirq.c
Fix lockup related to stop_machine being stuck in __do_softirq.
2013-06-10 17:46:57 -07:00
spinlock.c
srcu.c
srcu: use ACCESS_ONCE() to access sp->completed in srcu_read_lock()
2013-02-07 15:19:36 -08:00
stacktrace.c
stop_machine.c
stop_machine: Mark per cpu stopper enabled early
2013-02-26 22:25:17 +01:00
sys.c
reboot: rigrate shutdown/reboot to boot cpu
2013-06-12 16:29:44 -07:00
sys_ni.c
unify compat fanotify_mark(2), switch to COMPAT_SYSCALL_DEFINE
2013-05-09 13:46:38 -04:00
sysctl.c
mm: replace hardcoded 3% with admin_reserve_pages knob
2013-04-29 15:54:36 -07:00
sysctl_binary.c
switch compat_sys_sysctl to COMPAT_SYSCALL_DEFINE
2013-05-09 14:53:20 -04:00
task_work.c
task_work: task_work_add() should not succeed after exit_task_work()
2012-09-13 16:47:34 +02:00
taskstats.c
taskstats: cgroupstats_user_cmd() may leak on error
2012-10-06 03:05:31 +09:00
test_kprobes.c
kernel/: rename random32() to prandom_u32()
2013-04-29 18:28:42 -07:00
time.c
timekeeping: Use inject_offset in warp_clock
2013-03-15 16:50:20 -07:00
timeconst.bc
kernel: Replace timeconst.pl with a bc script
2013-02-16 23:17:25 +01:00
timer.c
timer: Fix jiffies wrap behavior of round_jiffies_common()
2013-06-28 17:10:11 +02:00
tracepoint.c
Tracing updates for Linux 3.10
2013-04-29 13:55:38 -07:00
tsacct.c
cputime: Use accessors to read task cputime stats
2013-01-27 19:23:31 +01:00
uid16.c
make SYSCALL_DEFINE<n>-generated wrappers do asmlinkage_protect
2013-03-03 22:58:33 -05:00
up.c
user-return-notifier.c
hlist: drop the node parameter from iterators
2013-02-27 19:10:24 -08:00
user.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2013-05-01 17:51:54 -07:00
user_namespace.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2013-05-01 17:51:54 -07:00
utsname.c
proc: Split the namespace stuff out into linux/proc_ns.h
2013-05-01 17:29:39 -04:00
utsname_sysctl.c
kernel/utsname_sysctl.c: put get/get_uts() into CONFIG_PROC_SYSCTL code block
2013-02-27 19:10:22 -08:00
wait.c
propagate name change to comments in kernel source
2012-12-06 10:39:54 +01:00
watchdog.c
watchdog: Add comments to explain the watchdog_disabled variable
2013-03-14 08:24:05 +01:00
workqueue.c
workqueue: don't perform NUMA-aware allocations on offline nodes in wq_numa_init()
2013-05-15 14:24:24 -07:00
workqueue_internal.h
workqueue: include workqueue info when printing debug dump of a worker task
2013-04-30 17:04:02 -07:00