Commit Graph

159 Commits

Author SHA1 Message Date
Linus Torvalds
e69a9ac596 Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  hrtimer: Remove overly verbose "switch to high res mode" message
2009-10-05 12:04:16 -07:00
Linus Torvalds
6f5071020d Merge branch 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  hrtimer: Eliminate needless reprogramming of clock events device
2009-09-27 10:39:04 -07:00
Roland Dreier
d3f6302e7e hrtimer: Remove overly verbose "switch to high res mode" message
On big systems, printing <number of CPUs> copies of

    Switched to high resolution mode on CPU nnn

clutters up the kernel log for minimal gain.  Just get rid of them.

Signed-off-by: Roland Dreier <rolandd@cisco.com>
LKML-Reference: <ada1vlw126s.fsf_-_@cisco.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-26 16:58:09 +02:00
Linus Torvalds
31bbb9b58d Merge branch 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  itimers: Add tracepoints for itimer
  hrtimer: Add tracepoint for hrtimers
  timers: Add tracepoints for timer_list timers
  cputime: Optimize jiffies_to_cputime(1)
  itimers: Simplify arm_timer() code a bit
  itimers: Fix periodic tics precision
  itimers: Merge ITIMER_VIRT and ITIMER_PROF

Trivial header file include conflicts in kernel/fork.c
2009-09-23 09:46:15 -07:00
Linus Torvalds
a03fdb7612 Merge branch 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (34 commits)
  time: Prevent 32 bit overflow with set_normalized_timespec()
  clocksource: Delay clocksource down rating to late boot
  clocksource: clocksource_select must be called with mutex locked
  clocksource: Resolve cpu hotplug dead lock with TSC unstable, fix crash
  timers: Drop a function prototype
  clocksource: Resolve cpu hotplug dead lock with TSC unstable
  timer.c: Fix S/390 comments
  timekeeping: Fix invalid getboottime() value
  timekeeping: Fix up read_persistent_clock() breakage on sh
  timekeeping: Increase granularity of read_persistent_clock(), build fix
  time: Introduce CLOCK_REALTIME_COARSE
  x86: Do not unregister PIT clocksource on PIT oneshot setup/shutdown
  clocksource: Avoid clocksource watchdog circular locking dependency
  clocksource: Protect the watchdog rating changes with clocksource_mutex
  clocksource: Call clocksource_change_rating() outside of watchdog_lock
  timekeeping: Introduce read_boot_clock
  timekeeping: Increase granularity of read_persistent_clock()
  timekeeping: Update clocksource with stop_machine
  timekeeping: Add timekeeper read_clock helper functions
  timekeeping: Move NTP adjusted clock multiplier to struct timekeeper
  ...

Fix trivial conflict due to MIPS lemote -> loongson renaming.
2009-09-18 09:15:24 -07:00
Ashwin Chaugule
7403f41f19 hrtimer: Eliminate needless reprogramming of clock events device
On NOHZ systems the following timers,

-  tick_nohz_restart_sched_tick (tick_sched_timer)
-  hrtimer_start (tick_sched_timer)

are reprogramming the clock events device far more often than needed.
No specific test case was required to observe this effect. This
occurres because there was no check to see if the currently removed or
restarted hrtimer was:

1) the one which previously armed the clock events device.
2) going to be replaced by another timer which has the same expiry time.

Avoid the reprogramming in hrtimer_force_reprogram when the new expiry
value which is evaluated from the clock bases is equal to
cpu_base->expires_next. This results in faster application startup
time by ~4%.

[ tglx: simplified initial solution ]

Signed-off-by: Ashwin Chaugule <ashwinc@quicinc.com>
LKML-Reference: <4AA00165.90609@codeaurora.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-09-15 17:09:44 +02:00
Xiao Guangrong
c6a2a17702 hrtimer: Add tracepoint for hrtimers
Add tracepoints which cover the life cycle of a hrtimer. The
tracepoints are integrated with the already existing debug_object
debug points as far as possible.

[ tglx: Fixed comments, made output conistent, easier to read and
  	parse. Fixed output for 32bit archs which do not use the
  	scalar representation of ktime_t. Hand current time to
  	trace_hrtimer_expiry_entry instead of calling get_time()
  	inside of the trace assignment. ]

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Anton Blanchard <anton@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Zhaolei <zhaolei@cn.fujitsu.com>
LKML-Reference: <4A7F8B2B.5020908@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-08-29 14:10:06 +02:00
Stephen Hemminger
2bc481cf43 pktgen: spin using hrtimer
This changes how the pktgen thread spins/waits between
packets if delay is configured. It uses a high res timer to
wait for time to arrive.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-08-28 23:41:29 -07:00
Thomas Gleixner
4cd1993f00 Merge branch 'linus' into timers/core
Reason: Martin's timekeeping cleanup series depends on both
timers/core and mainline changes.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-08-14 15:59:30 +02:00
Peter Zijlstra
fbd90375d7 hrtimer: Remove cb_entry from struct hrtimer
It's unused, remove it.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <new-submission>
2009-07-22 17:12:32 +02:00
Thomas Gleixner
6ff7041dbf hrtimer: Fix migration expiry check
The timer migration expiry check should prevent the migration of a
timer to another CPU when the timer expires before the next event is
scheduled on the other CPU. Migrating the timer might delay it because
we can not reprogram the clock event device on the other CPU. But the
code implementing that check has two flaws:

- for !HIGHRES the check compares the expiry value with the clock
  events device expiry value which is wrong for CLOCK_REALTIME based
  timers.

- the check is racy. It holds the hrtimer base lock of the target CPU,
  but the clock event device expiry value can be modified
  nevertheless, e.g. by an timer interrupt firing.

The !HIGHRES case is easy to fix as we can enqueue the timer on the
cpu which was selected by the load balancer. It runs the idle
balancing code once per jiffy anyway. So the maximum delay for the
timer is the same as when we keep the tick on the current cpu going.

In the HIGHRES case we can get the next expiry value from the hrtimer
cpu_base of the target CPU and serialize the update with the cpu_base
lock. This moves the lock section in hrtimer_interrupt() so we can set
next_event to KTIME_MAX while we are handling the expired timers and
set it to the next expiry value after we handled the timers under the
base lock. While the expired timers are processed timer migration is
blocked because the expiry time of the timer is always <= KTIME_MAX.

Also remove the now useless clockevents_get_next_event() function.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-07-10 17:32:55 +02:00
Thomas Gleixner
7e0c5086c1 hrtimer: migration: do not check expiry time on current CPU
The timer migration code needs to check whether the expiry time of the
timer is before the programmed clock event expiry time when the timer
is enqueued on another CPU because we can not reprogram the timer
device on the other CPU. The current logic checks the expiry time even
if we enqueue on the current CPU when nohz_get_load_balancer() returns
current CPU. This might lead to an endless loop in the expiry check
code when the expiry time of the timer is before the current
programmed next event.

Check whether nohz_get_load_balancer() returns current CPU and skip
the expiry check if this is the case.

The bug was triggered from the networking code. The patch fixes the
regression http://bugzilla.kernel.org/show_bug.cgi?id=13738
(Soft-Lockup/Race in networking in 2.6.31-rc1+195)

Cc: Arun Bharadwaj <arun@linux.vnet.ibm.com
Tested-by: Joao Correia <joaomiguelcorreia@gmail.com>
Tested-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-07-10 17:22:20 +02:00
Thomas Gleixner
a40f262cc2 timekeeping: Move ktime_get() functions to timekeeping.c
The ktime_get() functions for GENERIC_TIME=n are still located in
hrtimer.c. Move them to time/timekeeping.c where they belong.

LKML-Reference: <new-submission>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-07-07 13:00:31 +02:00
Martin Schwidefsky
951ed4d36b timekeeping: optimized ktime_get[_ts] for GENERIC_TIME=y
The generic ktime_get function defined in kernel/hrtimer.c is suboptimial
for GENERIC_TIME=y:

 0)               |  ktime_get() {
 0)               |    ktime_get_ts() {
 0)               |      getnstimeofday() {
 0)               |        read_tod_clock() {
 0)   0.601 us    |        }
 0)   1.938 us    |      }
 0)               |      set_normalized_timespec() {
 0)   0.602 us    |      }
 0)   4.375 us    |    }
 0)   5.523 us    |  }

Overall there are two read_seqbegin/read_seqretry loops and a lot of
unnecessary struct timespec calculations. ktime_get returns a nano second
value which is the sum of xtime, wall_to_monotonic and the nano second
delta from the clock source.

ktime_get can be optimized for GENERIC_TIME=y. The new version only calls
clocksource_read:

 0)               |  ktime_get() {
 0)               |    read_tod_clock() {
 0)   0.610 us    |    }
 0)   1.977 us    |  }

It uses a single read_seqbegin/readseqretry loop and just adds everthing
to a nano second value.

ktime_get_ts is optimized in a similar fashion.

[ tglx: added WARN_ON(timekeeping_suspended) as in getnstimeofday() ]

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Acked-by: john stultz <johnstul@us.ibm.com>
LKML-Reference: <20090707112728.3005244d@skybase>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-07-07 12:47:33 +02:00
Linus Torvalds
b7c142dbf1 Merge branch 'linux-next' of git://git.infradead.org/ubifs-2.6
* 'linux-next' of git://git.infradead.org/ubifs-2.6:
  UBIFS: start using hrtimers
  hrtimer: export ktime_add_safe
  UBIFS: do not forget to register BDI device
  UBIFS: allow sync option in rootflags
  UBIFS: remove dead code
  UBIFS: use anonymous device
  UBIFS: return proper error code if the compr is not present
  UBIFS: return error if link and unlink race
  UBIFS: reset no_space flag after inode deletion
2009-06-17 09:46:33 -07:00
Artem Bityutskiy
8daa21e61b hrtimer: export ktime_add_safe
We want to use hrtimers in UBIFS (for write-buffer write-back timer).
We need the 'hrtimer_set_expires_range_ns()', which is an in-line
function which uses 'ktime_add_safe()'.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
2009-06-08 11:14:58 +03:00
Arun R Bharadwaj
eea08f32ad timers: Logic to move non pinned timers
* Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-04-16 12:11:36]:

This patch migrates all non pinned timers and hrtimers to the current
idle load balancer, from all the idle CPUs. Timers firing on busy CPUs
are not migrated.

While migrating hrtimers, care should be taken to check if migrating
a hrtimer would result in a latency or not. So we compare the expiry of the
hrtimer with the next timer interrupt on the target cpu and migrate the
hrtimer only if it expires *after* the next interrupt on the target cpu.
So, added a clockevents_get_next_event() helper function to return the
next_event on the target cpu's clock_event_device.

[ tglx: cleanups and simplifications ]

Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-05-13 16:52:42 +02:00
Arun R Bharadwaj
597d027573 timers: Framework for identifying pinned timers
* Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-04-16 12:11:36]:

This patch creates a new framework for identifying cpu-pinned timers
and hrtimers.

This framework is needed because pinned timers are expected to fire on
the same CPU on which they are queued. So it is essential to identify
these and not migrate them, in case there are any.

For regular timers, the currently existing add_timer_on() can be used
queue pinned timers and subsequently mod_timer_pinned() can be used
to modify the 'expires' field.

For hrtimers, new modes HRTIMER_ABS_PINNED and HRTIMER_REL_PINNED are
added to queue cpu-pinned hrtimer.

[ tglx: use .._PINNED mode argument instead of creating tons of new
functions ]

Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-05-13 16:52:42 +02:00
Peter Zijlstra
7f1e2ca9f0 hrtimer: fix rq->lock inversion (again)
It appears I inadvertly introduced rq->lock recursion to the
hrtimer_start() path when I delegated running already expired
timers to softirq context.

This patch fixes it by introducing a __hrtimer_start_range_ns()
method that will not use raise_softirq_irqoff() but
__raise_softirq_irqoff() which avoids the wakeup.

It then also changes schedule() to check for pending softirqs and
do the wakeup then, I'm not quite sure I like this last bit, nor
am I convinced its really needed.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: paulus@samba.org
LKML-Reference: <20090313112301.096138802@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-31 14:52:52 +02:00
Thomas Gleixner
b0a9b5111a hrtimer: prevent negative expiry value after clock_was_set()
Impact: prevent false positive WARN_ON() in clockevents_program_event()

clock_was_set() changes the base->offset of CLOCK_REALTIME and
enforces the reprogramming of the clockevent device to expire timers
which are based on CLOCK_REALTIME. If the clock change is large enough
then the subtraction of the timer expiry value and base->offset can
become negative which triggers the warning in
clockevents_program_event().

Check the subtraction result and set a negative value to 0.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-01-30 22:35:34 +01:00
Sebastien Dugue
94df7de028 hrtimers: allow the hot-unplugging of all cpus
Impact: fix CPU hotplug hang on Power6 testbox

On architectures that support offlining all cpus (at least powerpc/pseries),
hot-unpluging the tick_do_timer_cpu can result in a system hang.

This comes from the fact that if the cpu going down happens to be the
cpu doing the tick, then as the tick_do_timer_cpu handover happens after the
cpu is dead (via the CPU_DEAD notification), we're left without ticks,
jiffies are frozen and any task relying on timers (msleep, ...) is stuck.
That's particularly the case for the cpu looping in __cpu_die() waiting
for the dying cpu to be dead.

This patch addresses this by having the tick_do_timer_cpu handover happen
earlier during the CPU_DYING notification. For this, a new clockevent
notification type is introduced (CLOCK_EVT_NOTIFY_CPU_DYING) which is triggered
in hrtimer_cpu_notify().

Signed-off-by: Sebastien Dugue <sebastien.dugue@bull.net>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-30 22:35:29 +01:00
Frederic Weisbecker
7f22391cbe hrtimers: increase clock min delta threshold while interrupt hanging
Impact: avoid timer IRQ hanging slow systems

While using the function graph tracer on a virtualized system, the
hrtimer_interrupt can hang the system on an infinite loop.

This can be caused in several situations:

 - the hardware is very slow and HZ is set too high

 - something intrusive is slowing the system down (tracing under emulation)

... and the next clock events to program are always before the current time.

This patch implements a reasonable compromise: if such a situation is
detected, we share the CPUs time in 1/4 to process the hrtimer interrupts.
This is enough to let the system running without serious starvation.

It has been successfully tested under VirtualBox with 1000 HZ and 100 HZ
with function graph tracer launched. On both cases, the clock events were
increased until about 25 ms periodic ticks, which means 40 HZ.

So we change a hard to debug hang into a warning message and a system that
still manages to limp along.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-30 22:35:10 +01:00
Linus Torvalds
1e70c7f7a9 Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  hrtimers: fix inconsistent lock state on resume in hres_timers_resume
  time-sched.c: tick_nohz_update_jiffies should be static
  locking, hpet: annotate false positive warning
  kernel/fork.c: unused variable 'ret'
  itimers: remove the per-cpu-ish-ness
2009-01-26 09:47:43 -08:00
Peter Zijlstra
1d4a7f1c4f hrtimers: fix inconsistent lock state on resume in hres_timers_resume
Andrey Borzenkov reported this lockdep assert:

> [17854.688347] =================================
> [17854.688347] [ INFO: inconsistent lock state ]
> [17854.688347] 2.6.29-rc2-1avb #1
> [17854.688347] ---------------------------------
> [17854.688347] inconsistent {in-hardirq-W} -> {hardirq-on-W} usage.
> [17854.688347] pm-suspend/18240 [HC0[0]:SC0[0]:HE1:SE1] takes:
> [17854.688347]  (&cpu_base->lock){++..}, at: [<c0136fcc>] retrigger_next_event+0x5c/0xa0
> [17854.688347] {in-hardirq-W} state was registered at:
> [17854.688347]   [<c01443cd>] __lock_acquire+0x79d/0x1930
> [17854.688347]   [<c01455bc>] lock_acquire+0x5c/0x80
> [17854.688347]   [<c03092e5>] _spin_lock+0x35/0x70
> [17854.688347]   [<c0136e61>] hrtimer_run_queues+0x31/0x140
> [17854.688347]   [<c0128d98>] run_local_timers+0x8/0x20
> [17854.688347]   [<c0128dd3>] update_process_times+0x23/0x60
> [17854.688347]   [<c013e274>] tick_periodic+0x24/0x80
> [17854.688347]   [<c013e2e2>] tick_handle_periodic+0x12/0x70
> [17854.688347]   [<c0104e24>] timer_interrupt+0x14/0x20
> [17854.688347]   [<c01607b9>] handle_IRQ_event+0x29/0x60
> [17854.688347]   [<c0161c59>] handle_level_irq+0x69/0xe0
> [17854.688347]   [<ffffffff>] 0xffffffff
> [17854.688347] irq event stamp: 55771
> [17854.688347] hardirqs last  enabled at (55771): [<c0309125>] _spin_unlock_irqrestore+0x35/0x60
> [17854.688347] hardirqs last disabled at (55770): [<c0309419>] _spin_lock_irqsave+0x19/0x80
> [17854.688347] softirqs last  enabled at (54836): [<c0124f54>] __do_softirq+0xc4/0x110
> [17854.688347] softirqs last disabled at (54831): [<c01049ae>] do_softirq+0x8e/0xe0
> [17854.688347]
> [17854.688347] other info that might help us debug this:
> [17854.688347] 3 locks held by pm-suspend/18240:
> [17854.688347]  #0:  (&buffer->mutex){--..}, at: [<c01dd4c5>] sysfs_write_file+0x25/0x100
> [17854.688347]  #1:  (pm_mutex){--..}, at: [<c015056f>] enter_state+0x4f/0x140
> [17854.688347]  #2:  (dpm_list_mtx){--..}, at: [<c027880f>] device_pm_lock+0xf/0x20
> [17854.688347]
> [17854.688347] stack backtrace:
> [17854.688347] Pid: 18240, comm: pm-suspend Not tainted 2.6.29-rc2-1avb #1
> [17854.688347] Call Trace:
> [17854.688347]  [<c0306248>] ? printk+0x18/0x20
> [17854.688347]  [<c0141fac>] print_usage_bug+0x16c/0x1d0
> [17854.688347]  [<c0142bcf>] mark_lock+0x8bf/0xc90
> [17854.688347]  [<c0106b8f>] ? pit_next_event+0x2f/0x40
> [17854.688347]  [<c01441b0>] __lock_acquire+0x580/0x1930
> [17854.688347]  [<c030916d>] ? _spin_unlock+0x1d/0x20
> [17854.688347]  [<c0106b8f>] ? pit_next_event+0x2f/0x40
> [17854.688347]  [<c013dd38>] ? clockevents_program_event+0x98/0x160
> [17854.688347]  [<c0142fe8>] ? mark_held_locks+0x48/0x90
> [17854.688347]  [<c0309125>] ? _spin_unlock_irqrestore+0x35/0x60
> [17854.688347]  [<c0143229>] ? trace_hardirqs_on_caller+0x139/0x190
> [17854.688347]  [<c014328b>] ? trace_hardirqs_on+0xb/0x10
> [17854.688347]  [<c01455bc>] lock_acquire+0x5c/0x80
> [17854.688347]  [<c0136fcc>] ? retrigger_next_event+0x5c/0xa0
> [17854.688347]  [<c03092e5>] _spin_lock+0x35/0x70
> [17854.688347]  [<c0136fcc>] ? retrigger_next_event+0x5c/0xa0
> [17854.688347]  [<c0136fcc>] retrigger_next_event+0x5c/0xa0
> [17854.688347]  [<c013711a>] hres_timers_resume+0xa/0x10
> [17854.688347]  [<c013aa8e>] timekeeping_resume+0xee/0x150
> [17854.688347]  [<c0273384>] __sysdev_resume+0x14/0x50
> [17854.688347]  [<c0273407>] sysdev_resume+0x47/0x80
> [17854.688347]  [<c02791ab>] device_power_up+0xb/0x20
> [17854.688347]  [<c015043f>] suspend_devices_and_enter+0xcf/0x150
> [17854.688347]  [<c0150c2f>] ? freeze_processes+0x3f/0x90
> [17854.688347]  [<c0150614>] enter_state+0xf4/0x140
> [17854.688347]  [<c01506dd>] state_store+0x7d/0xc0
> [17854.688347]  [<c0150660>] ? state_store+0x0/0xc0
> [17854.688347]  [<c0202da4>] kobj_attr_store+0x24/0x30
> [17854.688347]  [<c01dd53c>] sysfs_write_file+0x9c/0x100
> [17854.688347]  [<c019916c>] vfs_write+0x9c/0x160
> [17854.688347]  [<c0103494>] ? restore_nocheck_notrace+0x0/0xe
> [17854.688347]  [<c01dd4a0>] ? sysfs_write_file+0x0/0x100
> [17854.688347]  [<c01992ed>] sys_write+0x3d/0x70
> [17854.688347]  [<c0103371>] sysenter_do_call+0x12/0x31

Andrey's analysis:

> timekeeping_resume() is called via class ->resume
> method; and according to comments in sysdev_resume() and
> device_power_up(), they are called with interrupts disabled.
>
> Looking at suspend_enter, irqs *are* disabled at this point.
>
> So it actually looks like something (may be some driver)
> unconditionally enabled irqs in resume path.

Add a debug check to test this theory. If it triggers then it
triggers because the resume code calls it with irqs enabled,
which is a no-no not just for timekeeping_resume(), but also
bad for a number of other resume handlers.

Reported-by: Andrey Borzenkov <arvidjaar@mail.ru>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-18 21:31:37 +01:00
Heiko Carstens
58fd3aa288 [CVE-2009-0029] System call wrappers part 01
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:18 +01:00
Ingo Molnar
82c5b7b527 hrtimer: splitout peek ahead functionality, fix
Impact: build fix on !CONFIG_HIGH_RES_TIMERS

Fix:

  kernel/hrtimer.c:1586: error: implicit declaration of function '__hrtimer_peek_ahead_timers'

Signen-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-05 14:11:10 +01:00
Thomas Gleixner
e3f1d88374 hrtimer: fixup comments
Clean up the comments

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-05 13:14:34 +01:00
Peter Zijlstra
a6037b61c2 hrtimer: fix recursion deadlock by re-introducing the softirq
Impact: fix rare runtime deadlock

There are a few sites that do:

  spin_lock_irq(&foo)
  hrtimer_start(&bar)
    __run_hrtimer(&bar)
      func()
        spin_lock(&foo)

which obviously deadlocks. In order to avoid this, never call __run_hrtimer()
from hrtimer_start*() context, but instead defer this to softirq context.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-05 13:14:33 +01:00
Thomas Gleixner
731a55ba0f hrtimer: simplify hotplug migration
Impact: cleanup

No need for a smp function call, which is likely to run on the same
CPU anyway. We can just call hrtimers_peek_ahead() in the interrupts
disabled section of migrate_hrtimers().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-05 13:14:33 +01:00
Thomas Gleixner
d5fd43c4ae hrtimer: fix HOTPLUG_CPU=n compile warning
Impact: cleanup

 kernel/hrtimer.c: In function 'hrtimer_cpu_notify':
 kernel/hrtimer.c:1574: warning: unused variable 'dcpu'

Introduced by commit 37810659ea
("hrtimer: removing all ur callback modes, fix hotplug") from the
timers.  dcpu is only used if CONFIG_HOTPLUG_CPU is set.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-05 13:14:32 +01:00
Thomas Gleixner
8bdec955b0 hrtimer: splitout peek ahead functionality
Impact: cleanup

Provide a peek ahead function that assumes irqs disabled, allows for micro
optimizations.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-05 13:14:32 +01:00
Linus Torvalds
db200df0b3 Merge branch 'irq-fixes-for-linus-4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'irq-fixes-for-linus-4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sparseirq: move __weak symbols into separate compilation unit
  sparseirq: work around __weak alias bug
  sparseirq: fix hang with !SPARSE_IRQ
  sparseirq: set lock_class for legacy irq when sparse_irq is selected
  sparseirq: work around compiler optimizing away __weak functions
  sparseirq: fix desc->lock init
  sparseirq: do not printk when migrating IRQ descriptors
  sparseirq: remove duplicated arch_early_irq_init()
  irq: simplify for_each_irq_desc() usage
  proc: remove ifdef CONFIG_SPARSE_IRQ from stat.c
  irq: for_each_irq_desc() move to irqnr.h
  hrtimer: remove #include <linux/irq.h>
2008-12-31 09:00:59 -08:00
KOSAKI Motohiro
51bc39f4ba hrtimer: remove #include <linux/irq.h>
Impact: cleanup

<linux/irq.h> can be removed and should be, because:

  - hrtimer doesn't use any irq feature.
  - <linux/irq.h> shouldn't be include from generic code.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-26 09:48:16 +01:00
Ingo Molnar
b2e3c0adec hrtimers: fix warning in kernel/hrtimer.c
this warning:

  kernel/hrtimer.c: In function ‘hrtimer_cpu_notify’:
  kernel/hrtimer.c:1574: warning: unused variable ‘dcpu’

is caused because 'dcpu' is only used in the CONFIG_HOTPLUG_CPU case.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-19 00:45:32 +01:00
Peter Zijlstra
a0a99b227d hrtimer: removing all ur callback modes, fix
> Ingo, this addition fixes the hotplug issue on my machine

And because we're all human...

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-08 17:20:38 +01:00
Peter Zijlstra
37810659ea hrtimer: removing all ur callback modes, fix hotplug
Impact: fix hrtimer locking (reported by lockdep) in the CPU hotplug case

This addition fixes the hotplug locking issue on my machine

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-04 11:31:25 +01:00
Peter Zijlstra
ca109491f6 hrtimer: removing all ur callback modes
Impact: cleanup, move all hrtimer processing into hardirq context

This is an attempt at removing some of the hrtimer complexity by
reducing the number of callback modes to 1.

This means that all hrtimer callback functions will be ran from HARD-irq
context.

I went through all the 30 odd hrtimer callback functions in the kernel
and saw only one that I'm not quite sure of, which is the one in
net/can/bcm.c - hence I'm CC-ing the folks responsible for that code.

Furthermore, the hrtimer core now calls callbacks directly with IRQs
disabled in case you try to enqueue an expired timer. If this timer is a
periodic timer (which should use hrtimer_forward() to advance its time)
then it might be possible to end up in an inf. recursive loop due to the
fact that hrtimer_forward() doesn't round up to the next timer
granularity, and therefore keeps on calling the callback - obviously
this needs a fix.

Aside from that, this seems to compile and actually boot on my dual core
test box - although I'm sure there are some bugs in, me not hitting any
makes me certain :-)

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-25 15:45:46 +01:00
Peter Zijlstra
621a0d5207 hrtimer: clean up unused callback modes
Impact: cleanup

git grep HRTIMER_CB_IRQSAFE revealed half the callback modes are actually
unused.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-12 09:54:40 +01:00
Gautham R Shenoy
5d5254f0d3 timers: handle HRTIMER_CB_IRQSAFE_UNLOCKED correctly from softirq context
Impact: fix incorrect locking triggered during hotplug-intense stress-tests

While migrating the the CB_IRQSAFE_UNLOCKED timers during a cpu-offline,
we queue them on the cb_pending list, so that they won't go
stale.

Thus, when the callbacks of the timers run from the softirq context,
they could run into potential deadlocks, since these callbacks
assume that they're running with irq's disabled, thereby annoying
lockdep!

Fix this by emulating hardirq context while running these callbacks from
the hrtimer softirq.

=================================
[ INFO: inconsistent lock state ]
2.6.27 #2
--------------------------------
inconsistent {in-hardirq-W} -> {hardirq-on-W} usage.
ksoftirqd/0/4 [HC0[0]:SC1[1]:HE1:SE0] takes:
 (&rq->lock){++..}, at: [<c011db84>] sched_rt_period_timer+0x9e/0x1fc
{in-hardirq-W} state was registered at:
  [<c014103c>] __lock_acquire+0x549/0x121e
  [<c0107890>] native_sched_clock+0x88/0x99
  [<c013aa12>] clocksource_get_next+0x39/0x3f
  [<c0139abc>] update_wall_time+0x616/0x7df
  [<c0141d6b>] lock_acquire+0x5a/0x74
  [<c0121724>] scheduler_tick+0x3a/0x18d
  [<c047ed45>] _spin_lock+0x1c/0x45
  [<c0121724>] scheduler_tick+0x3a/0x18d
  [<c0121724>] scheduler_tick+0x3a/0x18d
  [<c012c436>] update_process_times+0x3a/0x44
  [<c013c044>] tick_periodic+0x63/0x6d
  [<c013c062>] tick_handle_periodic+0x14/0x5e
  [<c010568c>] timer_interrupt+0x44/0x4a
  [<c0150c9f>] handle_IRQ_event+0x13/0x3d
  [<c0151c14>] handle_level_irq+0x79/0xbd
  [<c0105634>] do_IRQ+0x69/0x7d
  [<c01041e4>] common_interrupt+0x28/0x30
  [<c047007b>] aac_probe_one+0x1a3/0x3f3
  [<c047ec2d>] _spin_unlock_irqrestore+0x36/0x39
  [<c01512b4>] setup_irq+0x1be/0x1f9
  [<c065d70b>] start_kernel+0x259/0x2c5
  [<ffffffff>] 0xffffffff
irq event stamp: 50102
hardirqs last  enabled at (50102): [<c047ebf4>] _spin_unlock_irq+0x20/0x23
hardirqs last disabled at (50101): [<c047edc2>] _spin_lock_irq+0xa/0x4b
softirqs last  enabled at (50088): [<c0128ba6>] do_softirq+0x37/0x4d
softirqs last disabled at (50099): [<c0128ba6>] do_softirq+0x37/0x4d

other info that might help us debug this:
no locks held by ksoftirqd/0/4.

stack backtrace:
Pid: 4, comm: ksoftirqd/0 Not tainted 2.6.27 #2
 [<c013f6cb>] print_usage_bug+0x13e/0x147
 [<c013fef5>] mark_lock+0x493/0x797
 [<c01410b1>] __lock_acquire+0x5be/0x121e
 [<c0141d6b>] lock_acquire+0x5a/0x74
 [<c011db84>] sched_rt_period_timer+0x9e/0x1fc
 [<c047ed45>] _spin_lock+0x1c/0x45
 [<c011db84>] sched_rt_period_timer+0x9e/0x1fc
 [<c011db84>] sched_rt_period_timer+0x9e/0x1fc
 [<c01210fd>] finish_task_switch+0x41/0xbd
 [<c0107890>] native_sched_clock+0x88/0x99
 [<c011dae6>] sched_rt_period_timer+0x0/0x1fc
 [<c0136dda>] run_hrtimer_pending+0x54/0xe5
 [<c011dae6>] sched_rt_period_timer+0x0/0x1fc
 [<c0128afb>] __do_softirq+0x7b/0xef
 [<c0128ba6>] do_softirq+0x37/0x4d
 [<c0128c12>] ksoftirqd+0x56/0xc5
 [<c0128bbc>] ksoftirqd+0x0/0xc5
 [<c0134649>] kthread+0x38/0x5d
 [<c0134611>] kthread+0x0/0x5d
 [<c0104477>] kernel_thread_helper+0x7/0x10
 =======================

Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-11 10:46:42 +01:00
Thomas Gleixner
268a3dcfea Merge branch 'timers/range-hrtimers' into v28-range-hrtimers-for-linus-v2
Conflicts:

	kernel/time/tick-sched.c

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-10-22 09:48:06 +02:00
Thomas Gleixner
643bdf68f9 hrtimers: simplify hrtimer_peek_ahead_timers()
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-10-20 13:38:11 +02:00
Thomas Gleixner
e1dd7bc585 hrtimers: fix docbook comments
hrtimer_start() and hrtimer_start_range_ns() handle relative and
absolute timers.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-10-20 13:33:36 +02:00
Thomas Gleixner
c465a76af6 Merge branches 'timers/clocksource', 'timers/hrtimers', 'timers/nohz', 'timers/ntp', 'timers/posixtimers' and 'timers/debug' into v28-timers-for-linus 2008-10-20 13:14:06 +02:00
Arjan van de Ven
651dab4264 Merge commit 'linus/master' into merge-linus
Conflicts:

	arch/x86/kvm/i8254.c
2008-10-17 09:20:26 -07:00
Arjan van de Ven
dc4304f7de rangetimers: fix the bug reported by Ingo for real
and please hand me a brown paper bag

(thanks to Thomas for pointing out this very obvious bug)

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2008-10-13 11:08:34 -04:00
Arjan van de Ven
030aebd2e4 rangetimer: fix BUG_ON reported by Ingo
There's a small race/chance that, while hrtimers are enabled globally,
they're later not enabled when we're calling the hrtimer_interrupt() function,
which then BUG_ON()'s for that. This patch closes that race/gap.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2008-10-11 12:25:45 -07:00
Thomas Gleixner
ccc7dadf73 hrtimer: prevent migration of per CPU hrtimers
Impact: per CPU hrtimers can be migrated from a dead CPU

The hrtimer code has no knowledge about per CPU timers, but we need to
prevent the migration of such timers and warn when such a timer is
active at migration time.

Explicitely mark the timers as per CPU and use a more understandable
mode descriptor for the interrupts safe unlocked callback mode, which
is used by hrtimer_sleeper and the scheduler code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-29 17:09:14 +02:00
Thomas Gleixner
b00c1a99e7 hrtimer: mark migration state
Impact: during migration active hrtimers can be seen as inactive

The migration code removes the hrtimers from the queues of the dead
CPU and sets the state temporary to INACTIVE. The enqueue code sets it
to ACTIVE/PENDING again.

Prevent that the wrong state can be seen by using a separate migration
state bit.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-29 17:09:14 +02:00
Thomas Gleixner
41e1022eae hrtimer: fix migration of CB_IRQSAFE_NO_SOFTIRQ hrtimers
Impact: Stale timers after a CPU went offline.

commit 37bb6cb409
       hrtimer: unlock hrtimer_wakeup

changed the hrtimer sleeper callback mode to CB_IRQSAFE_NO_SOFTIRQ due
to locking problems. A result of this change is that when enqueue is
called for an already expired hrtimer the callback function is not
longer called directly from the enqueue code. The normal callers have
been fixed in the code, but the migration code which moves hrtimers
from a dead CPU to a live CPU was not made aware of this.

This can be fixed by checking the timer state after the call to
enqueue in the migration code.


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-29 17:09:14 +02:00
Thomas Gleixner
7659e34967 hrtimer: migrate pending list on cpu offline
Impact: hrtimers which are on the pending list are not migrated at cpu
	offline and can be stale forever

Add the pending list migration when CONFIG_HIGH_RES_TIMERS is enabled

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-29 17:09:13 +02:00