08 Sep, 2011
1 commit
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The automatic increase of the min_delta_ns of a clockevents device
should be done in the clockevents code as the minimum delay is an
attribute of the clockevents device.In addition not all architectures want the automatic adjustment, on a
massively virtualized system it can happen that the programming of a
clock event fails several times in a row because the virtual cpu has
been rescheduled quickly enough. In that case the minimum delay will
erroneously be increased with no way back. The new config symbol
GENERIC_CLOCKEVENTS_MIN_ADJUST is used to enable the automatic
adjustment. The config option is selected only for x86.Signed-off-by: Martin Schwidefsky
Cc: john stultz
Link: http://lkml.kernel.org/r/20110823133142.494157493@de.ibm.com
Signed-off-by: Thomas Gleixner
16 Mar, 2011
1 commit
-
…l/git/tip/linux-2.6-tip
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (62 commits)
posix-clocks: Check write permissions in posix syscalls
hrtimer: Remove empty hrtimer_init_hres_timer()
hrtimer: Update hrtimer->state documentation
hrtimer: Update base[CLOCK_BOOTTIME].offset correctly
timers: Export CLOCK_BOOTTIME via the posix timers interface
timers: Add CLOCK_BOOTTIME hrtimer base
time: Extend get_xtime_and_monotonic_offset() to also return sleep
time: Introduce get_monotonic_boottime and ktime_get_boottime
hrtimers: extend hrtimer base code to handle more then 2 clockids
ntp: Remove redundant and incorrect parameter check
mn10300: Switch do_timer() to xtimer_update()
posix clocks: Introduce dynamic clocks
posix-timers: Cleanup namespace
posix-timers: Add support for fd based clocks
x86: Add clock_adjtime for x86
posix-timers: Introduce a syscall for clock tuning.
time: Splitout compat timex accessors
ntp: Add ADJ_SETOFFSET mode bit
time: Introduce timekeeping_inject_offset
posix-timer: Update comment
...Fix up new system-call-related conflicts in
arch/x86/ia32/ia32entry.S
arch/x86/include/asm/unistd_32.h
arch/x86/include/asm/unistd_64.h
arch/x86/kernel/syscall_table_32.S
(name_to_handle_at()/open_by_handle_at() vs clock_adjtime()), and some
due to movement of get_jiffies_64() in:
kernel/time.c
26 Feb, 2011
1 commit
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When the per cpu timer is marked CLOCK_EVT_FEAT_C3STOP, then we only
can switch into oneshot mode, when the backup broadcast device
supports oneshot mode as well. Otherwise we would try to switch the
broadcast device into an unsupported mode unconditionally. This went
unnoticed so far as the current available broadcast devices support
oneshot mode. Seth unearthed this problem while debugging and working
around an hpet related BIOS wreckage.Add the necessary check to tick_is_oneshot_available().
Reported-and-tested-by: Seth Forshee
Signed-off-by: Thomas Gleixner
LKML-Reference:
Cc: stable@kernel.org # .21 ->
01 Feb, 2011
1 commit
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All callers of do_timer() are converted to xtime_update(). The only
users of xtime_lock are in kernel/time/. Make both local to
kernel/time/ and remove them from the global header files.[ tglx: Reuse tick-internal.h instead of creating another local header
file. Massaged changelog ]Signed-off-by: Torben Hohn
Cc: Peter Zijlstra
Cc: johnstul@us.ibm.com
Cc: yong.zhang0@gmail.com
Cc: hch@infradead.org
Signed-off-by: Thomas Gleixner
17 Dec, 2010
1 commit
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__get_cpu_var() can be replaced with this_cpu_read and will then use a
single read instruction with implied address calculation to access the
correct per cpu instance.However, the address of a per cpu variable passed to __this_cpu_read()
cannot be determined (since it's an implied address conversion through
segment prefixes). Therefore apply this only to uses of __get_cpu_var
where the address of the variable is not used.Cc: Pekka Enberg
Cc: Hugh Dickins
Cc: Thomas Gleixner
Acked-by: H. Peter Anvin
Signed-off-by: Christoph Lameter
Signed-off-by: Tejun Heo
15 Dec, 2009
2 commits
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Convert locks which cannot be sleeping locks in preempt-rt to
raw_spinlocks.Signed-off-by: Thomas Gleixner
Acked-by: Peter Zijlstra
Acked-by: Ingo Molnar -
Signed-off-by: Thomas Gleixner
Acked-by: Peter Zijlstra
Acked-by: Ingo Molnar
02 May, 2009
1 commit
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tick_handle_periodic() can lock up hard when a one shot clock event
device is used in combination with jiffies clocksource.Avoid an endless loop issue by requiring that a highres valid
clocksource be installed before we call tick_periodic() in a loop when
using ONESHOT mode. The result is we will only increment jiffies once
per interrupt until a continuous hardware clocksource is available.Without this, we can run into a endless loop, where each cycle through
the loop, jiffies is updated which increments time by tick_period or
more (due to clock steering), which can cause the event programming to
think the next event was before the newly incremented time and fail
causing tick_periodic() to be called again and the whole process loops
forever.[ Impact: prevent hard lock up ]
Signed-off-by: John Stultz
Signed-off-by: Andrew Morton
Signed-off-by: Thomas Gleixner
Cc: stable@kernel.org
31 Jan, 2009
1 commit
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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
Cc:
Signed-off-by: Ingo Molnar
01 Jan, 2009
1 commit
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Impact: Use new APIs
Convert kernel/time functions to use struct cpumask *.
Note the ugly bitmap declarations in tick-broadcast.c. These should
be cpumask_var_t, but there was no obvious initialization function to
put the alloc_cpumask_var() calls in. This was safe.(Eventually 'struct cpumask' will be undefined for CONFIG_CPUMASK_OFFSTACK,
so we use a bitmap here to show we really mean it).Signed-off-by: Rusty Russell
Signed-off-by: Mike Travis
13 Dec, 2008
2 commits
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Impact: change calling convention of existing clock_event APIs
struct clock_event_timer's cpumask field gets changed to take pointer,
as does the ->broadcast function.Another single-patch change. For safety, we BUG_ON() in
clockevents_register_device() if it's not set.Signed-off-by: Rusty Russell
Cc: Ingo Molnar -
Impact: change existing irq_chip API
Not much point with gentle transition here: the struct irq_chip's
setaffinity method signature needs to change.Fortunately, not widely used code, but hits a few architectures.
Note: In irq_select_affinity() I save a temporary in by mangling
irq_desc[irq].affinity directly. Ingo, does this break anything?(Folded in fix from KOSAKI Motohiro)
Signed-off-by: Rusty Russell
Signed-off-by: Mike Travis
Reviewed-by: Grant Grundler
Acked-by: Ingo Molnar
Cc: ralf@linux-mips.org
Cc: grundler@parisc-linux.org
Cc: jeremy@xensource.com
Cc: KOSAKI Motohiro
23 Sep, 2008
2 commits
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Impact: timer hang on CPU online observed on AMD C1E systems
When a CPU is brought online then the broadcast machinery can
be in the one shot state already. Check this and setup the timer
device of the new CPU in one shot mode so the broadcast code
can pick up the next_event value correctly.Another AMD C1E oddity, as we switch to broadcast immediately and
not after the full bring up via the ACPI cpu idle code.Signed-off-by: Thomas Gleixner
-
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 != 0nohz 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
17 Sep, 2008
1 commit
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The device shut down does not cleanup the next_event variable of the
clock event device. So when the device is reactivated the possible
stale next_event value can prevent the device to be reprogrammed as it
claims to wait on a event already.This is the root cause of the resurfacing suspend/resume problem,
where systems need key press to come back to life.Fix this by setting next_event to KTIME_MAX when the device is shut
down. Use a separate function for shutdown which takes care of that
and only keep the direct set mode call in the broadcast code, where we
can not touch the next_event value.Signed-off-by: Thomas Gleixner
05 Sep, 2008
1 commit
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There is a ordering related problem with clockevents code, due to which
clockevents_register_device() called after tickless/highres switch
will not work. The new clockevent ends up with clockevents_handle_noop as
event handler, resulting in no timer activity.The problematic path seems to be
* old device already has hrtimer_interrupt as the event_handler
* new clockevent device registers with a higher rating
* tick_check_new_device() is called
* clockevents_exchange_device() gets called
* old->event_handler is set to clockevents_handle_noop
* tick_setup_device() is called for the new device
* which sets new->event_handler using the old->event_handler which is noop.Change the ordering so that new device inherits the proper handler.
This does not have any issue in normal case as most likely all the clockevent
devices are setup before the highres switch. But, can potentially be affecting
some corner case where HPET force detect happens after the highres switch.
This was a problem with HPET in MSI mode code that we have been experimenting
with.Signed-off-by: Venkatesh Pallipadi
Signed-off-by: Shaohua Li
Signed-off-by: Thomas Gleixner
Signed-off-by: Ingo Molnar
26 Jul, 2008
1 commit
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* Replace previous instances of the cpumask_of_cpu_ptr* macros
with a the new (lvalue capable) generic cpumask_of_cpu().Signed-off-by: Mike Travis
Cc: Andrew Morton
Cc: Jack Steiner
Cc: Rusty Russell
Signed-off-by: Ingo Molnar
19 Jul, 2008
1 commit
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* Optimize various places where a pointer to the cpumask_of_cpu value
will result in reducing stack pressure.Signed-off-by: Mike Travis
Signed-off-by: Ingo Molnar
17 Apr, 2008
1 commit
-
> Generic code is not supposed to include irq.h. Replace this include
> by linux/hardirq.h instead and add/replace an include of linux/irq.h
> in asm header files where necessary.
> This change should only matter for architectures that make use of
> GENERIC_CLOCKEVENTS.
> Architectures in question are mips, x86, arm, sh, powerpc, uml and sparc64.
>
> I did some cross compile tests for mips, x86_64, arm, powerpc and sparc64.
> This patch fixes also build breakages caused by the include replacement in
> tick-common.h.I generally dislike adding optional linux/* includes in asm/* includes -
I'm nervous about this causing include loops.However, there's a separate point to be discussed here.
That is, what interfaces are expected of every architecture in the kernel.
If generic code wants to be able to set the affinity of interrupts, then
that needs to become part of the interfaces listed in linux/interrupt.h
rather than linux/irq.h.So what I suggest is this approach instead (against Linus' tree of a
couple of days ago) - we move irq_set_affinity() and irq_can_set_affinity()
to linux/interrupt.h, change the linux/irq.h includes to linux/interrupt.h
and include asm/irq_regs.h where needed (asm/irq_regs.h is supposed to be
rarely used include since not much touches the stacked parent context
registers.)Build tested on ARM PXA family kernels and ARM's Realview platform
kernels which both use genirq.[ tglx@linutronix.de: add GENERIC_HARDIRQ dependencies ]
Signed-off-by: Russell King
Signed-off-by: Thomas Gleixner
Signed-off-by: Martin Schwidefsky
Signed-off-by: Heiko Carstens
15 Oct, 2007
1 commit
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The 64bit SMP bootup is slightly different to the 32bit one. It enables
the boot CPU local APIC timer before all CPUs are brought up. Some AMD C1E
systems have the C1E feature flag only set in the secondary CPU. Due to
the early enable of the boot CPU local APIC timer the APIC timer is
registered as a fully functional device. When we detect the wreckage during
the bringup of the secondary CPU, we need to force the boot CPU into
broadcast mode.Add a new notifier reason and implement the force broadcast in the clock
events layer.Signed-off-by: Thomas Gleixner
13 Oct, 2007
1 commit
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Change the broadcast timer, if a timer with higher rating becomes available.
Signed-off-by: Venkatesh Pallipadi
Cc: Andi Kleen
Cc: john stultz
Cc: Greg KH
Signed-off-by: Andrew Morton
Signed-off-by: Ingo Molnar
Signed-off-by: Arjan van de Ven
Signed-off-by: Thomas Gleixner
22 Jul, 2007
1 commit
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We need to make sure, that the clockevent devices are resumed, before
the tick is resumed. The current resume logic does not guarantee this.Add CLOCK_EVT_MODE_RESUME and call the set mode functions of the clock
event devices before resuming the tick / oneshot functionality.Fixup the existing users.
Thanks to Nigel Cunningham for tracking down a long standing thinko,
which affected the jinxed VAIO.[akpm@linux-foundation.org: xen build fix]
Signed-off-by: Thomas Gleixner
Cc: john stultz
Cc: Rusty Russell
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
09 May, 2007
1 commit
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While the !highres/!dyntick code assigns the duty of the do_timer() call to
one specific CPU, this was dropped in the highres/dyntick part during
development.Steven Rostedt discovered the xtime lock contention on highres/dyntick due
to several CPUs trying to update jiffies.Add the single CPU assignement back. In the dyntick case this needs to be
handled carefully, as the CPU which has the do_timer() duty must drop the
assignement and let it be grabbed by another CPU, which is active.
Otherwise the do_timer() calls would not happen during the long sleep.Signed-off-by: Thomas Gleixner
Acked-by: Ingo Molnar
Cc: Steven Rostedt
Acked-by: Mark Lord
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Mar, 2007
1 commit
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I finally found a dual core box, which survives suspend/resume without
crashing in the middle of nowhere. Sigh, I never figured out from the
code and the bug reports what's going on.The observed hangs are caused by a stale state transition of the clock
event devices, which keeps the RCU synchronization away from completion,
when the non boot CPU is brought back up.The suspend/resume in oneshot mode needs the similar care as the
periodic mode during suspend to RAM. My assumption that the state
transitions during the different shutdown/bringups of s2disk would go
through the periodic boot phase and then switch over to highres resp.
nohz mode were simply wrong.Add the appropriate suspend / resume handling for the non periodic
modes.Signed-off-by: Thomas Gleixner
Signed-off-by: Linus Torvalds
07 Mar, 2007
1 commit
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The programming of periodic tick devices needs to be saved/restored
across suspend/resume - otherwise we might end up with a system coming
up that relies on getting a PIT (or HPET) interrupt, while those devices
default to 'no interrupts' after powerup. (To confuse things it worked
to a certain degree on some systems because the lapic gets initialized
as a side-effect of SMP bootup.)This suspend / resume thing was dropped unintentionally during the
last-minute -mm code reshuffling.Signed-off-by: Thomas Gleixner
Signed-off-by: Ingo Molnar
Signed-off-by: Linus Torvalds
27 Feb, 2007
1 commit
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When clockevents_program_event() is given an expire time in the
past, it does not update dev->next_event, so this looping code
would loop forever once the first in-the-past expiration time
was used.Keep advancing "next" locally to fix this bug.
Acked-by: Thomas Gleixner
Signed-off-by: David S. Miller
17 Feb, 2007
4 commits
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add /proc/timer_list, which prints all currently pending (high-res) timers,
all clock-event sources and their parameters in a human-readable form.Sample output:
Timer List Version: v0.1
HRTIMER_MAX_CLOCK_BASES: 2
now at 4246046273872 nsecscpu: 0
clock 0:
.index: 0
.resolution: 1 nsecs
.get_time: ktime_get_real
.offset: 1273998312645738432 nsecs
active timers:
clock 1:
.index: 1
.resolution: 1 nsecs
.get_time: ktime_get
.offset: 0 nsecs
active timers:
#0: , hrtimer_sched_tick, hrtimer_stop_sched_tick, swapper/0
# expires at 4246432689566 nsecs [in 386415694 nsecs]
#1: , hrtimer_wakeup, do_nanosleep, pcscd/2050
# expires at 4247018194689 nsecs [in 971920817 nsecs]
#2: , hrtimer_wakeup, do_nanosleep, irqbalance/1909
# expires at 4247351358392 nsecs [in 1305084520 nsecs]
#3: , hrtimer_wakeup, do_nanosleep, crond/2157
# expires at 4249097614968 nsecs [in 3051341096 nsecs]
#4: , it_real_fn, do_setitimer, syslogd/1888
# expires at 4251329900926 nsecs [in 5283627054 nsecs]
.expires_next : 4246432689566 nsecs
.hres_active : 1
.check_clocks : 0
.nr_events : 31306
.idle_tick : 4246020791890 nsecs
.tick_stopped : 1
.idle_jiffies : 986504
.idle_calls : 40700
.idle_sleeps : 36014
.idle_entrytime : 4246019418883 nsecs
.idle_sleeptime : 4178181972709 nsecscpu: 1
clock 0:
.index: 0
.resolution: 1 nsecs
.get_time: ktime_get_real
.offset: 1273998312645738432 nsecs
active timers:
clock 1:
.index: 1
.resolution: 1 nsecs
.get_time: ktime_get
.offset: 0 nsecs
active timers:
#0: , hrtimer_sched_tick, hrtimer_restart_sched_tick, swapper/0
# expires at 4246050084568 nsecs [in 3810696 nsecs]
#1: , hrtimer_wakeup, do_nanosleep, atd/2227
# expires at 4261010635003 nsecs [in 14964361131 nsecs]
#2: , hrtimer_wakeup, do_nanosleep, smartd/2332
# expires at 5469485798970 nsecs [in 1223439525098 nsecs]
.expires_next : 4246050084568 nsecs
.hres_active : 1
.check_clocks : 0
.nr_events : 24043
.idle_tick : 4246046084568 nsecs
.tick_stopped : 0
.idle_jiffies : 986510
.idle_calls : 26360
.idle_sleeps : 22551
.idle_entrytime : 4246043874339 nsecs
.idle_sleeptime : 4170763761184 nsecstick_broadcast_mask: 00000003
event_broadcast_mask: 00000001CPU#0's local event device:
Clock Event Device: lapic
capabilities: 0000000e
max_delta_ns: 807385544
min_delta_ns: 1443
mult: 44624025
shift: 32
set_next_event: lapic_next_event
set_mode: lapic_timer_setup
event_handler: hrtimer_interrupt
.installed: 1
.expires: 4246432689566 nsecsCPU#1's local event device:
Clock Event Device: lapic
capabilities: 0000000e
max_delta_ns: 807385544
min_delta_ns: 1443
mult: 44624025
shift: 32
set_next_event: lapic_next_event
set_mode: lapic_timer_setup
event_handler: hrtimer_interrupt
.installed: 1
.expires: 4246050084568 nsecsClock Event Device: hpet
capabilities: 00000007
max_delta_ns: 2147483647
min_delta_ns: 3352
mult: 61496110
shift: 32
set_next_event: hpet_next_event
set_mode: hpet_set_mode
event_handler: handle_nextevt_broadcastSigned-off-by: Ingo Molnar
Signed-off-by: Thomas Gleixner
Cc: john stultz
Cc: Roman Zippel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
With Ingo Molnar
Add functions to provide dynamic ticks and high resolution timers. The code
which keeps track of jiffies and handles the long idle periods is shared
between tick based and high resolution timer based dynticks. The dyntick
functionality can be disabled on the kernel commandline. Provide also the
infrastructure to support high resolution timers.Signed-off-by: Thomas Gleixner
Signed-off-by: Ingo Molnar
Cc: john stultz
Cc: Roman Zippel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
With Ingo Molnar
Add broadcast functionality, so per cpu clock event devices can be registered
as dummy devices or switched from/to broadcast on demand. The broadcast
function distributes the events via the broadcast function of the clock event
device. This is primarily designed to replace the switch apic timer to / from
IPI in power states, where the apic stops.Signed-off-by: Thomas Gleixner
Signed-off-by: Ingo Molnar
Cc: john stultz
Cc: Roman Zippel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
With Ingo Molnar
The tick-management code is the first user of the clockevents layer. It takes
clock event devices from the clock events core and uses them to provide the
periodic tick.Signed-off-by: Thomas Gleixner
Signed-off-by: Ingo Molnar
Cc: john stultz
Cc: Roman Zippel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
