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2009-08-19clockevent: Prevent dead lock on clockevents_lockSuresh Siddha
Currently clockevents_notify() is called with interrupts enabled at some places and interrupts disabled at some other places. This results in a deadlock in this scenario. cpu A holds clockevents_lock in clockevents_notify() with irqs enabled cpu B waits for clockevents_lock in clockevents_notify() with irqs disabled cpu C doing set_mtrr() which will try to rendezvous of all the cpus. This will result in C and A come to the rendezvous point and waiting for B. B is stuck forever waiting for the spinlock and thus not reaching the rendezvous point. Fix the clockevents code so that clockevents_lock is taken with interrupts disabled and thus avoid the above deadlock. Also call lapic_timer_propagate_broadcast() on the destination cpu so that we avoid calling smp_call_function() in the clockevents notifier chain. This issue left us wondering if we need to change the MTRR rendezvous logic to use stop machine logic (instead of smp_call_function) or add a check in spinlock debug code to see if there are other spinlocks which gets taken under both interrupts enabled/disabled conditions. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: "Pallipadi Venkatesh" <venkatesh.pallipadi@intel.com> Cc: "Brown Len" <len.brown@intel.com> LKML-Reference: <1250544899.2709.210.camel@sbs-t61.sc.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-08-17timers: Drop write permission on /proc/timer_listAmerigo Wang
/proc/timer_list and /proc/slabinfo are not supposed to be written, so there should be no write permissions on it. Signed-off-by: WANG Cong <amwang@redhat.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Vegard Nossum <vegard.nossum@gmail.com> Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> Cc: linux-mm@kvack.org Cc: Christoph Lameter <cl@linux-foundation.org> Cc: David Rientjes <rientjes@google.com> Cc: Amerigo Wang <amwang@redhat.com> Cc: Matt Mackall <mpm@selenic.com> Cc: Arjan van de Ven <arjan@linux.intel.com> LKML-Reference: <20090817094525.6355.88682.sendpatchset@localhost.localdomain> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-19clocksource: Prevent NULL pointer dereferenceThomas Gleixner
Writing a zero length string to sys/.../current_clocksource will cause a NULL pointer dereference if the clock events system is in one shot (highres or nohz) mode. Pointed-out-by: Dan Carpenter <error27@gmail.com> LKML-Reference: <alpine.DEB.2.00.0907191545580.12306@bicker> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-07-10hrtimer: Fix migration expiry checkThomas Gleixner
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>
2009-06-24timer stats: Optimize by adding quick check to avoid function callsHeiko Carstens
When the kernel is configured with CONFIG_TIMER_STATS but timer stats are runtime disabled we still get calls to __timer_stats_timer_set_start_info which initializes some fields in the corresponding struct timer_list. So add some quick checks in the the timer stats setup functions to avoid function calls to __timer_stats_timer_set_start_info when timer stats are disabled. In an artificial workload that does nothing but playing ping pong with a single tcp packet via loopback this decreases cpu consumption by 1 - 1.5%. This is part of a modified function trace output on SLES11: perl-2497 [00] 28630647177732388 [+ 125]: sk_reset_timer <-tcp_v4_rcv perl-2497 [00] 28630647177732513 [+ 125]: mod_timer <-sk_reset_timer perl-2497 [00] 28630647177732638 [+ 125]: __timer_stats_timer_set_start_info <-mod_timer perl-2497 [00] 28630647177732763 [+ 125]: __mod_timer <-mod_timer perl-2497 [00] 28630647177732888 [+ 125]: __timer_stats_timer_set_start_info <-__mod_timer perl-2497 [00] 28630647177733013 [+ 93]: lock_timer_base <-__mod_timer Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Mustafa Mesanovic <mustafa.mesanovic@de.ibm.com> Cc: Arjan van de Ven <arjan@infradead.org> LKML-Reference: <20090623153811.GA4641@osiris.boeblingen.de.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-20Merge branch 'timers-fixes-for-linus' of ↵Linus Torvalds
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: NOHZ: Properly feed cpufreq ondemand governor
2009-06-15Merge branch 'timers-for-linus-migration' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-for-linus-migration' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: timers: Logic to move non pinned timers timers: /proc/sys sysctl hook to enable timer migration timers: Identifying the existing pinned timers timers: Framework for identifying pinned timers timers: allow deferrable timers for intervals tv2-tv5 to be deferred Fix up conflicts in kernel/sched.c and kernel/timer.c manually
2009-06-15Merge branch 'timers-for-linus-clockevents' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-for-linus-clockevents' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: clockevent: export register_device and delta2ns clockevents: tick_broadcast_device can become static
2009-06-15Merge branch 'timers-for-linus-clocksource' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-for-linus-clocksource' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: clocksource: prevent selection of low resolution clocksourse also for nohz=on clocksource: sanity check sysfs clocksource changes
2009-06-13clocksource: prevent selection of low resolution clocksourse also for nohz=onThomas Gleixner
commit 3f68535adad (clocksource: sanity check sysfs clocksource changes) prevents selection of non high resolution capable clocksources when high resolution mode is active, but did not take into account that the same rules apply for highres=off nohz=on. Check the tick device mode instead of hrtimer_hres_active() to verify whether the system needs to be protected from a switch to jiffies or other non highres capable clock sources. Reported-by: Luming Yu <luming.yu@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-06-11clocksource: sanity check sysfs clocksource changesjohn stultz
Thomas, Andrew and Ingo pointed out that we don't have any safety checks in the clocksource sysfs entries to make sure sysadmins don't try to change the clocksource to a non high-res timer capable clocksource (such as jiffies) when high-res timers (HRT) is enabled. Doing so will likely hang a system. Correct this by filtering non HRT clocksources from available_clocksources and not accepting non HRT clocksources with HRT enabled. 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>
2009-06-11Merge branch 'master' of ↵Paul Mundt
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
2009-05-27NOHZ: Properly feed cpufreq ondemand governorEero Nurkkala
A call from irq_exit() may occasionally pause the timing info for cpufreq ondemand governor. This results in the cpufreq ondemand governor to fail to calculate the system load properly. Thus, relocate the checks for this particular case to keep the governor always functional. Signed-off-by: Eero Nurkkala <ext-eero.nurkkala@nokia.com> Reported-by: Tero Kristo <tero.kristo@nokia.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-05-22Merge branches 'sh/stable-updates' and 'sh/sparseirq'Paul Mundt
2009-05-15sched, timers: move calc_load() to schedulerThomas Gleixner
Dimitri Sivanich noticed that xtime_lock is held write locked across calc_load() which iterates over all online CPUs. That can cause long latencies for xtime_lock readers on large SMP systems. The load average calculation is an rough estimate anyway so there is no real need to protect the readers vs. the update. It's not a problem when the avenrun array is updated while a reader copies the values. Instead of iterating over all online CPUs let the scheduler_tick code update the number of active tasks shortly before the avenrun update happens. The avenrun update itself is handled by the CPU which calls do_timer(). [ Impact: reduce xtime_lock write locked section ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org>
2009-05-13timers: Logic to move non pinned timersArun R Bharadwaj
* 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>
2009-05-13timers: Identifying the existing pinned timersArun R Bharadwaj
* Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-04-16 12:11:36]: The following pinned hrtimers have been identified and marked: 1)sched_rt_period_timer 2)tick_sched_timer 3)stack_trace_timer_fn [ tglx: fixup the hrtimer pinned mode ] Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-05-02clockevent: export register_device and delta2nsMagnus Damm
Export the following symbols using EXPORT_SYMBOL_GPL: - clockevent_delta2ns - clockevents_register_device This allows us to build SuperH clockevent and clocksource drivers as modules, see drivers/clocksource/sh_*.c [ Impact: allow modular build of clockevent drivers ] Signed-off-by: Magnus Damm <damm@igel.co.jp> LKML-Reference: <20090501055247.8286.64067.sendpatchset@rx1.opensource.se> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-05-02timekeeping: create arch_gettimeoffset infrastructurejohn stultz
Some arches don't supply their own clocksource. This is mainly the case in architectures that get their inter-tick times by reading the counter on their interval timer. Since these timers wrap every tick, they're not really useful as clocksources. Wrapping them to act like one is possible but not very efficient. So we provide a callout these arches can implement for use with the jiffies clocksource to provide finer then tick granular time. [ Impact: ease the migration to generic time keeping ] 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>
2009-05-02clocksource: setup mult_orig in clocksource_enable()Magnus Damm
Setup clocksource mult_orig in clocksource_enable(). Clocksource drivers can save power by using keeping the device clock disabled while the clocksource is unused. In practice this means that the enable() and disable() callbacks perform clk_enable() and clk_disable(). The enable() callback may also use clk_get_rate() to get the clock rate from the clock framework. This information can then be used to calculate the shift and mult variables. Currently the mult_orig variable is setup from mult at registration time only. This is conflicting with the above case since the clock is disabled and the mult variable is not yet calculated at the time of registration. Moving the mult_orig setup code to clocksource_enable() allows us to both handle the common case with no enable() callback and the mult-changed-after-enable() case. [ Impact: allow dynamic clock source usage ] Signed-off-by: Magnus Damm <damm@igel.co.jp> LKML-Reference: <20090501054546.8193.10688.sendpatchset@rx1.opensource.se> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-05-02clockevents: tick_broadcast_device can become staticDmitri Vorobiev
The variable tick_broadcast_device is not used outside of the file where it is defined, so let's make it static. Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@movial.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-05-02clockevents: prevent endless loop in tick_handle_periodic()john stultz
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 <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@kernel.org
2009-04-21clocksource: add enable() and disable() callbacksMagnus Damm
Add enable() and disable() callbacks for clocksources. This allows us to put unused clocksources in power save mode. The functions clocksource_enable() and clocksource_disable() wrap the callbacks and are inserted in the timekeeping code to enable before use and disable after switching to a new clocksource. Signed-off-by: Magnus Damm <damm@igel.co.jp> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-21clocksource: pass clocksource to read() callbackMagnus Damm
Pass clocksource pointer to the read() callback for clocksources. This allows us to share the callback between multiple instances. [hugh@veritas.com: fix powerpc build of clocksource pass clocksource mods] [akpm@linux-foundation.org: cleanup] Signed-off-by: Magnus Damm <damm@igel.co.jp> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-26Merge branch 'timers-for-linus' of ↵Linus Torvalds
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: (26 commits) posix timers: fix RLIMIT_CPU && fork() time: ntp: fix bug in ntp_update_offset() & do_adjtimex(), fix time: ntp: clean up second_overflow() time: ntp: simplify ntp_tick_adj calculations time: ntp: make 64-bit constants more robust time: ntp: refactor do_adjtimex() some more time: ntp: refactor do_adjtimex() time: ntp: fix bug in ntp_update_offset() & do_adjtimex() time: ntp: micro-optimize ntp_update_offset() time: ntp: simplify ntp_update_offset_fll() time: ntp: refactor and clean up ntp_update_offset() time: ntp: refactor up ntp_update_frequency() time: ntp: clean up ntp_update_frequency() time: ntp: simplify the MAX_TICKADJ_SCALED definition time: ntp: simplify the second_overflow() code flow time: ntp: clean up kernel/time/ntp.c x86: hpet: stop HPET_COUNTER when programming periodic mode x86: hpet: provide separate functions to stop and start the counter x86: hpet: print HPET registers during setup (if hpet=verbose is used) time: apply NTP frequency/tick changes immediately ...
2009-03-26Merge branches 'timers/new-apis', 'timers/ntp' and 'timers/urgent' into ↵Ingo Molnar
timers/core
2009-02-26time: ntp: fix bug in ntp_update_offset() & do_adjtimex(), fixJohn Stultz
The time_status conditional was accidentally placed right after we clear the checked time_status bits, which causes us to take the conditional every time through. This fixes it by moving the conditional to before we clear the time_status bits. Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Clark Williams <williams@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25time: ntp: clean up second_overflow()Ingo Molnar
Impact: cleanup, no functionality changed The 'time_adj' local variable is named in a very confusing way because it almost shadows the 'time_adjust' global variable - which is used in this same function. Rename it to 'delta' - to make them stand apart more clearly. kernel/time/ntp.o: text data bss dec hex filename 2545 114 144 2803 af3 ntp.o.before 2545 114 144 2803 af3 ntp.o.after md5: 1bf0b3be564512279ba7cee299d1d2be ntp.o.before.asm 1bf0b3be564512279ba7cee299d1d2be ntp.o.after.asm Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25time: ntp: simplify ntp_tick_adj calculationsIngo Molnar
Impact: micro-optimization Convert the (internal) ntp_tick_adj value we store from unscaled units to scaled units. This is a constant that we never modify, so scaling it up once during bootup is enough - we dont have to do it for every adjustment step. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25time: ntp: make 64-bit constants more robustIngo Molnar
Impact: cleanup, no functionality changed - make PPM_SCALE an explicit s64 constant, to remove (s64) casts from usage sites. kernel/time/ntp.o: text data bss dec hex filename 2536 114 136 2786 ae2 ntp.o.before 2536 114 136 2786 ae2 ntp.o.after md5: 40a7728d1188aa18e83e21a81fa7b150 ntp.o.before.asm 40a7728d1188aa18e83e21a81fa7b150 ntp.o.after.asm Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25time: ntp: refactor do_adjtimex() some moreIngo Molnar
Impact: cleanup, no functionality changed Further simplify do_adjtimex(): - introduce the ntp_start_leap_timer() helper function - eliminate the goto adj_done complication Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25time: ntp: refactor do_adjtimex()Ingo Molnar
Impact: cleanup, no functionality changed do_adjtimex() is currently a monster function with a maze of branches. Refactor the txc->modes setting aspects of it into two new helper functions: process_adj_status() process_adjtimex_modes() kernel/time/ntp.o: text data bss dec hex filename 2512 114 136 2762 aca ntp.o.before 2512 114 136 2762 aca ntp.o.after Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25time: ntp: fix bug in ntp_update_offset() & do_adjtimex()Ingo Molnar
Impact: change (fix) the way the NTP PLL seconds offset is initialized/tracked Fix a bug and do a micro-optimization: When PLL is enabled we do not reset time_reftime. If the PLL was off for a long time (for example after bootup), this is arguably the wrong thing to do. We already had a hack for the common boot-time case in ntp_update_offset(), in form of: if (unlikely(time_status & STA_FREQHOLD || time_reftime == 0)) secs = 0; But the update delta should be reset later on too - not just when the PLL is enabled for the first time after bootup. So do it on !STA_PLL -> STA_PLL transitions. This changes behavior, as previously if ntpd was disabled for a long time and we restarted it, we'd run from that last update, with a very large delta. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25time: ntp: micro-optimize ntp_update_offset()Ingo Molnar
Impact: cleanup, no functionality changed The time_reftime update in ntp_update_offset() to xtime.tv_sec is a convoluted way of saying that we want to freeze the frequency and want the 'secs' delta to be 0. Also make this branch unlikely. This shaves off 8 bytes from the code size: text data bss dec hex filename 2504 114 136 2754 ac2 ntp.o.before 2496 114 136 2746 aba ntp.o.after Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25time: ntp: simplify ntp_update_offset_fll()Ingo Molnar
Impact: cleanup, no functionality changed Change ntp_update_offset_fll() to delta logic instead of absolute value logic. This eliminates 'freq_adj' from the function. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25time: ntp: refactor and clean up ntp_update_offset()Ingo Molnar
Impact: cleanup, no functionality changed - introduce the ntp_update_offset_fll() helper - clean up the flow and variable naming kernel/time/ntp.o: text data bss dec hex filename 2504 114 136 2754 ac2 ntp.o.before 2504 114 136 2754 ac2 ntp.o.after md5: 01f7b8e1a5472a3056f9e4ae84d46315 ntp.o.before.asm 01f7b8e1a5472a3056f9e4ae84d46315 ntp.o.after.asm Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25time: ntp: refactor up ntp_update_frequency()Ingo Molnar
Impact: cleanup, no functionality changed Change ntp_update_frequency() from a hard to follow code flow that uses global variables as temporaries, to a clean input+output flow. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25time: ntp: clean up ntp_update_frequency()Ingo Molnar
Impact: cleanup, no functionality changed Prepare a refactoring of ntp_update_frequency(). kernel/time/ntp.o: text data bss dec hex filename 2504 114 136 2754 ac2 ntp.o.before 2504 114 136 2754 ac2 ntp.o.after md5: 41f3009debc9b397d7394dd77d912f0a ntp.o.before.asm 41f3009debc9b397d7394dd77d912f0a ntp.o.after.asm Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25time: ntp: simplify the MAX_TICKADJ_SCALED definitionIngo Molnar
Impact: cleanup, no functionality changed There's an ugly u64 typecase in the MAX_TICKADJ_SCALED definition, this can be eliminated by making the MAX_TICKADJ constant's type 64-bit (signed). kernel/time/ntp.o: text data bss dec hex filename 2504 114 136 2754 ac2 ntp.o.before 2504 114 136 2754 ac2 ntp.o.after md5: 41f3009debc9b397d7394dd77d912f0a ntp.o.before.asm 41f3009debc9b397d7394dd77d912f0a ntp.o.after.asm Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25time: ntp: simplify the second_overflow() code flowIngo Molnar
Impact: cleanup, no functionality changed Instead of a hierarchy of conditions, transform them to clean gradual conditions and return's. This makes the flow easier to read and makes the purpose of the function easier to understand. kernel/time/ntp.o: text data bss dec hex filename 2552 170 168 2890 b4a ntp.o.before 2552 170 168 2890 b4a ntp.o.after md5: eae1275df0b7d6290c13f6f6f8f05c8c ntp.o.before.asm eae1275df0b7d6290c13f6f6f8f05c8c ntp.o.after.asm Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25time: ntp: clean up kernel/time/ntp.cIngo Molnar
Impact: cleanup, no functionality changed Make this file a bit more readable by applying a consistent coding style. No code changed: kernel/time/ntp.o: text data bss dec hex filename 2552 170 168 2890 b4a ntp.o.before 2552 170 168 2890 b4a ntp.o.after md5: eae1275df0b7d6290c13f6f6f8f05c8c ntp.o.before.asm eae1275df0b7d6290c13f6f6f8f05c8c ntp.o.after.asm Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-19time: apply NTP frequency/tick changes immediatelyjohn stultz
Since the GENERIC_TIME changes landed, the adjtimex behavior changed for struct timex.tick and .freq changed. When the tick or freq value is set, we adjust the tick_length_base in ntp_update_frequency(). However, this new value doesn't get applied to tick_length until the next second (via second_overflow). This means some applications that do quick time tweaking do not see the requested change made as quickly as expected. I've run a few tests with this change, and ntpd still functions fine. Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-15timecompare: generic infrastructure to map between two time basesPatrick Ohly
Mapping from a struct timecounter to a time returned by functions like ktime_get_real() is implemented. This is sufficient to use this code in a network device driver which wants to support hardware time stamping and transformation of hardware time stamps to system time. The interface could have been made more versatile by not depending on a time counter, but this wasn't done to avoid writing glue code elsewhere. The method implemented here is the one used and analyzed under the name "assisted PTP" in the LCI PTP paper: http://www.linuxclustersinstitute.org/conferences/archive/2008/PDF/Ohly_92221.pdf Acked-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Patrick Ohly <patrick.ohly@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-15clocksource: allow usage independent of timekeeping.cPatrick Ohly
So far struct clocksource acted as the interface between time/timekeeping.c and hardware. This patch generalizes the concept so that a similar interface can also be used in other contexts. For that it introduces new structures and related functions *without* touching the existing struct clocksource. The reasons for adding these new structures to clocksource.[ch] are * the APIs are clearly related * struct clocksource could be cleaned up to use the new structs * avoids proliferation of files with similar names (timesource.h? timecounter.h?) As outlined in the discussion with John Stultz, this patch adds * struct cyclecounter: stateless API to hardware which counts clock cycles * struct timecounter: stateful utility code built on a cyclecounter which provides a nanosecond counter * only the function to read the nanosecond counter; deltas are used internally and not exposed to users of timecounter The code does no locking of the shared state. It must be called at least as often as the cycle counter wraps around to detect these wrap arounds. Both is the responsibility of the timecounter user. Acked-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Patrick Ohly <patrick.ohly@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-08Merge branches 'timers/clockevents', 'timers/hpet', 'timers/hrtimers' and ↵Ingo Molnar
'timers/urgent' into timers/core
2009-01-30hrtimers: allow the hot-unplugging of all cpusSebastien Dugue
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>
2009-01-16clockevents: let set_mode() setup delta informationMagnus Damm
Allow the set_mode() clockevent callback to decide and fill in delta details such as shift, mult, max_delta_ns and min_delta_ns. With this change the clockevent can be registered without delta details which allows us to keep the parent clock disabled until the clockevent gets setup using set_mode(). Letting set_mode() fill in or update delta details allows us to save power by disabling the parent clock while the clockevent is unused. This may however make the parent clock rate change, so next time the clockevent gets enabled we need let set_mode() to update the detla details accordingly. Doing it at registration time is not enough. Furthermore, the delta details seem unused in the case of periodic-only clockevent drivers, so this change also allows registration of such drivers without the delta details filled in. Signed-off-by: Magnus Damm <damm@igel.co.jp> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-01-15time-sched.c: tick_nohz_update_jiffies should be staticJaswinder Singh Rajput
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 <jaswinderrajput@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-12Merge commit 'v2.6.29-rc1' into timers/hrtimersIngo Molnar
Conflicts: kernel/time/tick-common.c
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 ...