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
15 Jan, 2009
1 commit
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Impact: cleanup, reduce kernel size a bit, avoid sparse warning
Fixes sparse warning:
kernel/time/tick-sched.c:137:6: warning: symbol 'tick_nohz_update_jiffies' was not declared. Should it be static?
Signed-off-by: Jaswinder Singh Rajput
Signed-off-by: Ingo Molnar
08 Jan, 2009
1 commit
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* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (24 commits)
trivial: chack -> check typo fix in main Makefile
trivial: Add a space (and a comma) to a printk in 8250 driver
trivial: Fix misspelling of "firmware" in docs for ncr53c8xx/sym53c8xx
trivial: Fix misspelling of "firmware" in powerpc Makefile
trivial: Fix misspelling of "firmware" in usb.c
trivial: Fix misspelling of "firmware" in qla1280.c
trivial: Fix misspelling of "firmware" in a100u2w.c
trivial: Fix misspelling of "firmware" in megaraid.c
trivial: Fix misspelling of "firmware" in ql4_mbx.c
trivial: Fix misspelling of "firmware" in acpi_memhotplug.c
trivial: Fix misspelling of "firmware" in ipw2100.c
trivial: Fix misspelling of "firmware" in atmel.c
trivial: Fix misspelled firmware in Kconfig
trivial: fix an -> a typos in documentation and comments
trivial: fix then -> than typos in comments and documentation
trivial: update Jesper Juhl CREDITS entry with new email
trivial: fix singal -> signal typo
trivial: Fix incorrect use of "loose" in event.c
trivial: printk: fix indentation of new_text_line declaration
trivial: rtc-stk17ta8: fix sparse warning
...
06 Jan, 2009
2 commits
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- (better, more, bigger ...) then -> (...) than
Signed-off-by: Frederik Schwarzer
Signed-off-by: Jiri Kosina
04 Jan, 2009
3 commits
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…/git/tip/linux-2.6-tip
* 'cpus4096-for-linus-3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (77 commits)
x86: setup_per_cpu_areas() cleanup
cpumask: fix compile error when CONFIG_NR_CPUS is not defined
cpumask: use alloc_cpumask_var_node where appropriate
cpumask: convert shared_cpu_map in acpi_processor* structs to cpumask_var_t
x86: use cpumask_var_t in acpi/boot.c
x86: cleanup some remaining usages of NR_CPUS where s/b nr_cpu_ids
sched: put back some stack hog changes that were undone in kernel/sched.c
x86: enable cpus display of kernel_max and offlined cpus
ia64: cpumask fix for is_affinity_mask_valid()
cpumask: convert RCU implementations, fix
xtensa: define __fls
mn10300: define __fls
m32r: define __fls
h8300: define __fls
frv: define __fls
cris: define __fls
cpumask: CONFIG_DISABLE_OBSOLETE_CPUMASK_FUNCTIONS
cpumask: zero extra bits in alloc_cpumask_var_node
cpumask: replace for_each_cpu_mask_nr with for_each_cpu in kernel/time/
cpumask: convert mm/
... -
* 'cputime' of git://git390.osdl.marist.edu/pub/scm/linux-2.6:
[PATCH] fast vdso implementation for CLOCK_THREAD_CPUTIME_ID
[PATCH] improve idle cputime accounting
[PATCH] improve precision of idle time detection.
[PATCH] improve precision of process accounting.
[PATCH] idle cputime accounting
[PATCH] fix scaled & unscaled cputime accounting -
…ux-2.6-cpumask into merge-rr-cpumask
Conflicts:
arch/x86/kernel/io_apic.c
kernel/rcuclassic.c
kernel/sched.c
kernel/time/tick-sched.cSigned-off-by: Mike Travis <travis@sgi.com>
[ mingo@elte.hu: backmerged typo fix for io_apic.c ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
03 Jan, 2009
1 commit
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…/git/tip/linux-2.6-tip
* 'cpus4096-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (66 commits)
x86: export vector_used_by_percpu_irq
x86: use logical apicid in x2apic_cluster's x2apic_cpu_mask_to_apicid_and()
sched: nominate preferred wakeup cpu, fix
x86: fix lguest used_vectors breakage, -v2
x86: fix warning in arch/x86/kernel/io_apic.c
sched: fix warning in kernel/sched.c
sched: move test_sd_parent() to an SMP section of sched.h
sched: add SD_BALANCE_NEWIDLE at MC and CPU level for sched_mc>0
sched: activate active load balancing in new idle cpus
sched: bias task wakeups to preferred semi-idle packages
sched: nominate preferred wakeup cpu
sched: favour lower logical cpu number for sched_mc balance
sched: framework for sched_mc/smt_power_savings=N
sched: convert BALANCE_FOR_xx_POWER to inline functions
x86: use possible_cpus=NUM to extend the possible cpus allowed
x86: fix cpu_mask_to_apicid_and to include cpu_online_mask
x86: update io_apic.c to the new cpumask code
x86: Introduce topology_core_cpumask()/topology_thread_cpumask()
x86: xen: use smp_call_function_many()
x86: use work_on_cpu in x86/kernel/cpu/mcheck/mce_amd_64.c
...Fixed up trivial conflict in kernel/time/tick-sched.c manually
01 Jan, 2009
2 commits
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Impact: cleanup
Simple replacement, now the _nr is redundant.
Signed-off-by: Rusty Russell
Signed-off-by: Mike Travis
Cc: Ingo Molnar -
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
31 Dec, 2008
4 commits
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The cpu time spent by the idle process actually doing something is
currently accounted as idle time. This is plain wrong, the architectures
that support VIRT_CPU_ACCOUNTING=y can do better: distinguish between the
time spent doing nothing and the time spent by idle doing work. The first
is accounted with account_idle_time and the second with account_system_time.
The architectures that use the account_xxx_time interface directly and not
the account_xxx_ticks interface now need to do the check for the idle
process in their arch code. In particular to improve the system vs true
idle time accounting the arch code needs to measure the true idle time
instead of just testing for the idle process.
To improve the tick based accounting as well we would need an architecture
primitive that can tell us if the pt_regs of the interrupted context
points to the magic instruction that halts the cpu.In addition idle time is no more added to the stime of the idle process.
This field now contains the system time of the idle process as it should
be. On systems without VIRT_CPU_ACCOUNTING this will always be zero as
every tick that occurs while idle is running will be accounted as idle
time.This patch contains the necessary common code changes to be able to
distinguish idle system time and true idle time. The architectures with
support for VIRT_CPU_ACCOUNTING need some changes to exploit this.Signed-off-by: Martin Schwidefsky
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The utimescaled / stimescaled fields in the task structure and the
global cpustat should be set on all architectures. On s390 the calls
to account_user_time_scaled and account_system_time_scaled never have
been added. In addition system time that is accounted as guest time
to the user time of a process is accounted to the scaled system time
instead of the scaled user time.
To fix the bugs and to prevent future forgetfulness this patch merges
account_system_time_scaled into account_system_time and
account_user_time_scaled into account_user_time.Cc: Benjamin Herrenschmidt
Cc: Hidetoshi Seto
Cc: Tony Luck
Cc: Jeremy Fitzhardinge
Cc: Chris Wright
Cc: Michael Neuling
Acked-by: Paul Mackerras
Signed-off-by: Martin Schwidefsky -
Conflicts:
arch/x86/kernel/io_apic.c
-
Redo:
5b7dba4: sched_clock: prevent scd->clock from moving backwards
which had to be reverted due to s2ram hangs:
ca7e716: Revert "sched_clock: prevent scd->clock from moving backwards"
... this time with resume restoring GTOD later in the sequence
taken into account as well.The "timekeeping_suspended" flag is not very nice but we cannot call into
GTOD before it has been properly resumed and the scheduler will run very
early in the resume sequence.Cc:
Signed-off-by: Ingo Molnar
26 Dec, 2008
1 commit
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…ohz', 'timers/ntp', 'timers/posixtimers' and 'timers/rtc' into timers/core
13 Dec, 2008
3 commits
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Conflicts:
arch/x86/kernel/io_apic.c
kernel/sched.c
kernel/sched_stats.h -
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
12 Dec, 2008
3 commits
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In my device I get many interrupts from a high speed USB device in a very
short period of time. The system spends a lot of time reprogramming the
hardware timer which is in a slower timing domain as compared to the CPU.
This results in the CPU spending a huge amount of time waiting for the
timer posting to be done. All of this reprogramming is useless as the
wake up time has not changed.As measured using ETM trace this drops my reprogramming penalty from
almost 60% CPU load down to 15% during high interrupt rate. I can send
traces to show this.Suppress setting of duplicate timer event when timer already stopped.
Timer programming can be very costly and can result in long cpu stall/wait
times.[akpm@linux-foundation.org: coding-style fixes]
[tglx@linutronix.de: move the check to the right place and avoid raising
the softirq for nothing]Signed-off-by: Richard Woodruff
Cc: johnstul@us.ibm.com
Signed-off-by: Andrew Morton
Signed-off-by: Thomas Gleixner -
Conflicts:
include/linux/ftrace.h
kernel/sched.c -
Impact: remove false positive warning
After a cpu was taken down during cpu hotplug (read: disabled for interrupts)
it still might have pending softirqs. However take_cpu_down makes sure
that the idle task will run next instead of ksoftirqd on the taken down cpu.
The idle task will call tick_nohz_stop_sched_tick which might warn about
pending softirqs just before the cpu kills itself completely.However the pending softirqs on the dead cpu aren't a problem because they
will be moved to an online cpu during CPU_DEAD handling.So make sure we warn only for online cpus.
Signed-off-by: Heiko Carstens
Signed-off-by: Ingo Molnar
04 Dec, 2008
1 commit
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Impact: fix time warp bug
Alex Shi, along with Yanmin Zhang have been noticing occasional time
inconsistencies recently. Through their great diagnosis, they found that
the xtime_nsec value used in update_wall_time was occasionally going
negative. After looking through the code for awhile, I realized we have
the possibility for an underflow when three conditions are met in
update_wall_time():1) We have accumulated a second's worth of nanoseconds, so we
incremented xtime.tv_sec and appropriately decrement xtime_nsec.
(This doesn't cause xtime_nsec to go negative, but it can cause it
to be small).2) The remaining offset value is large, but just slightly less then
cycle_interval.3) clocksource_adjust() is speeding up the clock, causing a
corrective amount (compensating for the increase in the multiplier
being multiplied against the unaccumulated offset value) to be
subtracted from xtime_nsec.This can cause xtime_nsec to underflow.
Unfortunately, since we notify the NTP subsystem via second_overflow()
whenever we accumulate a full second, and this effects the error
accumulation that has already occured, we cannot simply revert the
accumulated second from xtime nor move the second accumulation to after
the clocksource_adjust call without a change in behavior.This leaves us with (at least) two options:
1) Simply return from clocksource_adjust() without making a change if we
notice the adjustment would cause xtime_nsec to go negative.This would work, but I'm concerned that if a large adjustment was needed
(due to the error being large), it may be possible to get stuck with an
ever increasing error that becomes too large to correct (since it may
always force xtime_nsec negative). This may just be paranoia on my part.2) Catch xtime_nsec if it is negative, then add back the amount its
negative to both xtime_nsec and the error.This second method is consistent with how we've handled earlier rounding
issues, and also has the benefit that the error being added is always in
the oposite direction also always equal or smaller then the correction
being applied. So the risk of a corner case where things get out of
control is lessened.This patch fixes bug 11970, as tested by Yanmin Zhang
http://bugzilla.kernel.org/show_bug.cgi?id=11970Reported-by: alex.shi@intel.com
Signed-off-by: John Stultz
Acked-by: "Zhang, Yanmin"
Tested-by: "Zhang, Yanmin"
Signed-off-by: Ingo Molnar
25 Nov, 2008
2 commits
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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
Signed-off-by: Ingo Molnar -
Impact: (future) size reduction for large NR_CPUS.
Dynamically allocating cpumasks (when CONFIG_CPUMASK_OFFSTACK) saves
space for small nr_cpu_ids but big CONFIG_NR_CPUS. cpumask_var_t
is just a struct cpumask for !CONFIG_CPUMASK_OFFSTACK.Signed-off-by: Rusty Russell
Signed-off-by: Ingo Molnar
11 Nov, 2008
1 commit
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Impact: nohz powersavings and wakeup regression
commit fb02fbc14d17837b4b7b02dbb36142c16a7bf208 (NOHZ: restart tick
device from irq_enter()) causes a serious wakeup regression.While the patch is correct it does not take into account that spurious
wakeups happen on x86. A fix for this issue is available, but we just
revert to the .27 behaviour and let long running softirqs screw
themself.Disable it for now.
Signed-off-by: Thomas Gleixner
22 Oct, 2008
2 commits
-
Conflicts:
kernel/time/tick-sched.c
Signed-off-by: Thomas Gleixner
-
commit fb02fbc14d17837b4b7b02dbb36142c16a7bf208 (NOHZ: restart tick
device from irq_enter())solves the problem of stale jiffies when long running softirqs happen
in a long idle sleep period, but it has a major thinko in it:When the interrupt which came in _is_ the timer interrupt which should
expire ts->sched_timer then we cancel and rearm the timer _before_ it
gets expired in hrtimer_interrupt() to the next period. That means the
call back function is not called. This game can go on for ever :(Prevent this by making sure to only rearm the timer when the expiry
time is more than one tick_period away. Otherwise keep it running as
it is either already expired or will expiry at the right point to
update jiffies.Signed-off-by: Thomas Gleixner
Tested-by: Venkatesch Pallipadi
20 Oct, 2008
4 commits
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…tp', 'timers/posixtimers' and 'timers/debug' into v28-timers-for-linus
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The base address of a (per cpu) clock base is a useful debug info.
Add it and bump the version number of timer_lists.Signed-off-by: Thomas Gleixner
-
The per cpu clock events device output of timer_list lacks an
association of the device to the cpu which is annoying when looking at
the output of /proc/timer_list from a 128 way system.Add the CPU number info and mark the broadcast device in the device
list printout.Signed-off-by: Thomas Gleixner
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The current timer_list output prints the address of the on stack copy
of the active hrtimer instead of the hrtimer itself.Print the address of the real timer instead.
Signed-off-by: Thomas Gleixner
18 Oct, 2008
4 commits
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Conflicts:
arch/x86/kvm/i8254.c
-
We did not restart the tick device from irq_enter() to avoid double
reprogramming and extra events in the return immediate to idle case.But long lasting softirqs can lead to a situation where jiffies become
stale:idle()
tick stopped (reprogrammed to next pending timer)
halt()
interrupt
jiffies updated from irq_enter()
interrupt handler
softirq function 1 runs 20ms
softirq function 2 arms a 10ms timer with a stale jiffies value
jiffies updated from irq_exit()
timer wheel has now an already expired timer
(the one added in function 2)
timer fires and timer softirq runsThis was discovered when debugging a timer problem which happend only
when the ath5k driver is active. The debugging proved that there is a
softirq function running for more than 20ms, which is a bug by itself.To solve this we restart the tick timer right from irq_enter(), but do
not go through the other functions which are necessary to return from
idle when need_resched() is set.Reported-by: Elias Oltmanns
Signed-off-by: Thomas Gleixner
Tested-by: Elias Oltmanns -
Split out the clock event device reprogramming. Preparatory
patch.Signed-off-by: Thomas Gleixner
-
We have two separate nohz function calls in irq_enter() for no good
reason. Just call a single NOHZ function from irq_enter() and call
the bits in the tick code.Signed-off-by: Thomas Gleixner
17 Oct, 2008
2 commits
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* 'core-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
do_generic_file_read: s/EINTR/EIO/ if lock_page_killable() fails
softirq, warning fix: correct a format to avoid a warning
softirqs, debug: preemption check
x86, pci-hotplug, calgary / rio: fix EBDA ioremap()
IO resources, x86: ioremap sanity check to catch mapping requests exceeding, fix
IO resources, x86: ioremap sanity check to catch mapping requests exceeding the BAR sizes
softlockup: Documentation/sysctl/kernel.txt: fix softlockup_thresh description
dmi scan: warn about too early calls to dmi_check_system()
generic: redefine resource_size_t as phys_addr_t
generic: make PFN_PHYS explicitly return phys_addr_t
generic: add phys_addr_t for holding physical addresses
softirq: allocate less vectors
IO resources: fix/remove printk
printk: robustify printk, update comment
printk: robustify printk, fix #2
printk: robustify printk, fix
printk: robustify printkFixed up conflicts in:
arch/powerpc/include/asm/types.h
arch/powerpc/platforms/Kconfig.cputype
manually. -
Using "def_bool n" is pointless, simply using bool here appears more
appropriate.Further, retaining such options that don't have a prompt and aren't
selected by anything seems also at least questionable.Signed-off-by: Jan Beulich
Cc: Ingo Molnar
Cc: Tony Luck
Cc: Thomas Gleixner
Cc: Bartlomiej Zolnierkiewicz
Cc: Sam Ravnborg
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
15 Oct, 2008
1 commit
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…' and 'core/misc' into core-v28-for-linus
10 Oct, 2008
1 commit
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export get_cpu_idle_time_us() for it to be used in ondemand governor.
Last update time can be current time when the CPU is currently non-idle,
accounting for the busy time since last idle.Signed-off-by: Venkatesh Pallipadi
Signed-off-by: Dave Jones
