summaryrefslogtreecommitdiff
path: root/kernel/time
AgeCommit message (Collapse)Author
2009-01-07Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial * '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 ...
2009-01-06trivial: fix then -> than typos in comments and documentationFrederik Schwarzer
- (better, more, bigger ...) then -> (...) than Signed-off-by: Frederik Schwarzer <schwarzerf@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-01-06Merge branches 'sched/clock', 'sched/cleanups' and 'linus' into sched/urgentIngo Molnar
2009-01-03Merge branch 'cpus4096-for-linus-3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/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/ ...
2009-01-03Merge branch 'cputime' of git://git390.osdl.marist.edu/pub/scm/linux-2.6Linus Torvalds
* '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
2009-01-03Merge branch 'master' of ↵Mike Travis
git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-cpumask into merge-rr-cpumask Conflicts: arch/x86/kernel/io_apic.c kernel/rcuclassic.c kernel/sched.c kernel/time/tick-sched.c Signed-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>
2009-01-02Merge branch 'cpus4096-for-linus-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/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
2008-12-31cpumask: replace for_each_cpu_mask_nr with for_each_cpu in kernel/time/Rusty Russell
Impact: cleanup Simple replacement, now the _nr is redundant. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Mike Travis <travis@sgi.com> Cc: Ingo Molnar <mingo@redhat.com>
2008-12-31cpumask: convert kernel time functionsRusty Russell
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 <rusty@rustcorp.com.au> Signed-off-by: Mike Travis <travis@sgi.com>
2008-12-31[PATCH] idle cputime accountingMartin Schwidefsky
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 <schwidefsky@de.ibm.com>
2008-12-31[PATCH] fix scaled & unscaled cputime accountingMartin Schwidefsky
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 <benh@kernel.crashing.org> Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Michael Neuling <mikey@neuling.org> Acked-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-31Merge branch 'master' of ↵Rusty Russell
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 Conflicts: arch/x86/kernel/io_apic.c
2008-12-31sched_clock: prevent scd->clock from moving backwards, take #2Thomas Gleixner
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: <stable@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-25Merge branches 'timers/clocksource', 'timers/hpet', 'timers/hrtimers', ↵Ingo Molnar
'timers/nohz', 'timers/ntp', 'timers/posixtimers' and 'timers/rtc' into timers/core
2008-12-13Merge ../linux-2.6-x86Rusty Russell
Conflicts: arch/x86/kernel/io_apic.c kernel/sched.c kernel/sched_stats.h
2008-12-13cpumask: convert struct clock_event_device to cpumask pointers.Rusty Russell
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 <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@elte.hu>
2008-12-13cpumask: make irq_set_affinity() take a const struct cpumaskRusty Russell
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 <rusty@rustcorp.com.au> Signed-off-by: Mike Travis <travis@sgi.com> Reviewed-by: Grant Grundler <grundler@parisc-linux.org> Acked-by: Ingo Molnar <mingo@redhat.com> Cc: ralf@linux-mips.org Cc: grundler@parisc-linux.org Cc: jeremy@xensource.com Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
2008-12-12nohz: suppress needless timer reprogrammingWoodruff, Richard
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 <r-woodruff2@ti.com> Cc: johnstul@us.ibm.com Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-12-12Merge branch 'sched/core' into cpus4096Ingo Molnar
Conflicts: include/linux/ftrace.h kernel/sched.c
2008-12-12nohz: no softirq pending warnings for offline cpusHeiko Carstens
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 <heiko.carstens@de.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-04time: catch xtime_nsec underflows and fix themjohn stultz
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=11970 Reported-by: alex.shi@intel.com Signed-off-by: John Stultz <johnstul@us.ibm.com> Acked-by: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com> Tested-by: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-25hrtimer: removing all ur callback modesPeter Zijlstra
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>
2008-11-24sched: convert nohz_cpu_mask to cpumask_var_t.Rusty Russell
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 <rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-10nohz: disable tick_nohz_kick_tick() for nowThomas Gleixner
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 <tglx@linutronix.de>
2008-10-22Merge branch 'timers/range-hrtimers' into v28-range-hrtimers-for-linus-v2Thomas Gleixner
Conflicts: kernel/time/tick-sched.c Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-10-21NOHZ: fix thinko in the timer restart code pathThomas 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 <tglx@linutronix.de> Tested-by: Venkatesch Pallipadi <venkatesh.pallipadi@intel.com>
2008-10-20Merge branches 'timers/clocksource', 'timers/hrtimers', 'timers/nohz', ↵Thomas Gleixner
'timers/ntp', 'timers/posixtimers' and 'timers/debug' into v28-timers-for-linus
2008-10-20timer_list: add base address to clock baseThomas Gleixner
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 <tglx@linutronix.de>
2008-10-20timer_list: print cpu number of clockevents deviceThomas 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 <tglx@linutronix.de>
2008-10-20timer_list: print real timer addressThomas Gleixner
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 <tglx@linutronix.de>
2008-10-17Merge commit 'linus/master' into merge-linusArjan van de Ven
Conflicts: arch/x86/kvm/i8254.c
2008-10-17NOHZ: restart tick device from irq_enter()Thomas Gleixner
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 runs This 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 <eo@nebensachen.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Elias Oltmanns <eo@nebensachen.de>
2008-10-17NOHZ: split tick_nohz_restart_sched_tick()Thomas Gleixner
Split out the clock event device reprogramming. Preparatory patch. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-10-17NOHZ: unify the nohz function calls in irq_enter()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 <tglx@linutronix.de>
2008-10-16Merge branch 'core-v28-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * '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 printk Fixed up conflicts in: arch/powerpc/include/asm/types.h arch/powerpc/platforms/Kconfig.cputype manually.
2008-10-16Kconfig: eliminate "def_bool n" constructsJan Beulich
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 <jbeulich@novell.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Tony Luck <tony.luck@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-15Merge branches 'core/softlockup', 'core/softirq', 'core/resources', ↵Ingo Molnar
'core/printk' and 'core/misc' into core-v28-for-linus
2008-10-09[CPUFREQ][5/6] cpufreq: Changes to get_cpu_idle_time_us(), used by ondemand ↵venkatesh.pallipadi@intel.com
governor 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 <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2008-10-04clockevents: check broadcast tick device not the clock events deviceThomas Gleixner
Impact: jiffies increment too fast. Hugh Dickins noted that with NOHZ=n and HIGHRES=n jiffies get incremented too fast. The reason is a wrong check in the broadcast enter/exit code, which keeps the local apic timer in periodic mode when the switch happens. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-29hrtimer: prevent migration of per CPU hrtimersThomas Gleixner
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>
2008-09-24ntp: improve adjtimex frequency roundingRoman Zippel
Change PPM_SCALE_INV_SHIFT so that it doesn't throw away any input bits (19 is the amount of the factor 2 in PPM_SCALE), the output frequency can then be calculated back to its input value, as the inverse divide produce a slightly larger value, which is then correctly rounded by the final shift. Reported-by: Martin Ziegler <ziegler@uni-freiburg.de> Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Cc: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-24timekeeping: fix rounding problem during clock updateRoman Zippel
Due to a rounding problem during a clock update it's possible for readers to observe the clock jumping back by 1nsec. The following simplified example demonstrates the problem: cycle xtime 0 0 1000 999999.6 2000 1999999.2 3000 2999998.8 ... 1500 = 1499999.4 = 0.0 + 1499999.4 = 999999.6 + 499999.8 When reading the clock only the full nanosecond part is used, while timekeeping internally keeps nanosecond fractions. If the clock is now updated at cycle 1500 here, a nanosecond is missing due to the truncation. The simple fix is to round up the xtime value during the update, this also changes the distance to the reference time, but the adjustment will automatically take care that it stays under control. Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-24ntp: let update_persistent_clock() sleepMaciej W. Rozycki
This is a change that makes the 11-minute RTC update be run in the process context. This is so that update_persistent_clock() can sleep, which may be required for certain types of RTC hardware -- most notably I2C devices. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Rik van Riel <riel@redhat.com> Cc: David Brownell <david-b@pacbell.net> Acked-by: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-23timers: fix build error in !oneshot caseIngo Molnar
kernel/time/tick-common.c: In function ‘tick_setup_periodic’: kernel/time/tick-common.c:113: error: implicit declaration of function ‘tick_broadcast_oneshot_active’ Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-23clockevents: prevent mode mismatch on cpu onlineThomas Gleixner
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 <tglx@linutronix.de>
2008-09-23clockevents: check broadcast device not tick deviceThomas Gleixner
Impact: Possible hang on CPU online observed on AMD C1E machines. The broadcast setup code looks at the mode of the tick device to determine whether it needs to be shut down or setup. This is wrong when the broadcast mode is set to one shot already. This can happen when a CPU is brought online as it goes through the periodic setup first. The problem went unnoticed as sane systems do not call into that code before the switch to one shot for the clock event device happens. The AMD C1E idle routine switches over immediately and thereby shuts down the just setup device before the first interrupt happens. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-23clockevents: prevent stale tick_next_period for onlining CPUsThomas Gleixner
Impact: possible hang on CPU onlining in timer one shot mode. The tick_next_period variable is only used during boot on nohz/highres enabled systems, but for CPU onlining it needs to be maintained when the per cpu clock events device operates in one shot mode. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-23clockevents: prevent cpu online to interfere with nohzThomas 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 != 0 nohz 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 <tglx@linutronix.de>
2008-09-16clockevents: make device shutdown robustThomas Gleixner
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 <tglx@linutronix.de>
2008-09-09clockevents: remove WARN_ON which was used to gather informationThomas Gleixner
The issue of the endless reprogramming loop due to a too small min_delta_ns was fixed with the previous updates of the clock events code, but we had no information about the spread of this problem. I added a WARN_ON to get automated information via kerneloops.org and to get some direct reports, which allowed me to analyse the affected machines. The WARN_ON has served its purpose and would be annoying for a release kernel. Remove it and just keep the information about the increase of the min_delta_ns value. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>