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* hrtimer: Avoid double seqlockStanislaw Gruszka2010-05-261-1/+1
| | | | | | | | | | | hrtimer_get_softirq_time() has it's own xtime lock protection, so it's safe to use plain __current_kernel_time() and avoid the double seqlock loop. Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl> LKML-Reference: <20100525214912.GA1934@r2bh72.net.upc.cz> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* hrtimers: Provide schedule_hrtimeout for CLOCK_REALTIMECarsten Emde2010-04-061-26/+41
| | | | | | | | | | | | | | | | | | The current version of schedule_hrtimeout() always uses the monotonic clock. Some system calls such as mq_timedsend() and mq_timedreceive(), however, require the use of the wall clock due to the definition of the system call. This patch provides the infrastructure to use schedule_hrtimeout() with a CLOCK_REALTIME timer. Signed-off-by: Carsten Emde <C.Emde@osadl.org> Tested-by: Pradyumna Sampath <pradysam@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arjan van de Veen <arjan@infradead.org> LKML-Reference: <20100402204331.167439615@osadl.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* hrtimers: Convert to raw_spinlocksThomas Gleixner2009-12-141-25/+25
| | | | | | | | | Convert locks which cannot be sleeping locks in preempt-rt to raw_spinlocks. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Ingo Molnar <mingo@elte.hu>
* hrtimer: move timer stats helper functions to hrtimer.cHeiko Carstens2009-12-101-4/+20
| | | | | | | | | | | | There is no reason to make timer_stats_hrtimer_set_start_info and friends visible to the rest of the kernel. So move all of them to hrtimer.c. Also make timer_stats_hrtimer_set_start_info a static inline function so it gets inlined and we avoid another function call. Based on a patch by Thomas Gleixner. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> LKML-Reference: <20091210095629.GC4144@osiris.boeblingen.de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* hrtimer: Tune hrtimer_interrupt hang logicThomas Gleixner2009-12-101-40/+57
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The hrtimer_interrupt hang logic adjusts min_delta_ns based on the execution time of the hrtimer callbacks. This is error-prone for virtual machines, where a guest vcpu can be scheduled out during the execution of the callbacks (and the callbacks themselves can do operations that translate to blocking operations in the hypervisor), which in can lead to large min_delta_ns rendering the system unusable. Replace the current heuristics with something more reliable. Allow the interrupt code to try 3 times to catch up with the lost time. If that fails use the total time spent in the interrupt handler to defer the next timer interrupt so the system can catch up with other things which got delayed. Limit that deferment to 100ms. The retry events and the maximum time spent in the interrupt handler are recorded and exposed via /proc/timer_list Inspired by a patch from Marcelo. Reported-by: Michael Tokarev <mjt@tls.msk.ru> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Marcelo Tosatti <mtosatti@redhat.com> Cc: kvm@vger.kernel.org
* Merge branch 'timers-for-linus' of ↵Linus Torvalds2009-12-081-1/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: timers, init: Limit the number of per cpu calibration bootup messages posix-cpu-timers: optimize and document timer_create callback clockevents: Add missing include to pacify sparse x86: vmiclock: Fix printk format x86: Fix printk format due to variable type change sparc: fix printk for change of variable type clocksource/events: Fix fallout of generic code changes nohz: Allow 32-bit machines to sleep for more than 2.15 seconds nohz: Track last do_timer() cpu nohz: Prevent clocksource wrapping during idle nohz: Type cast printk argument mips: Use generic mult/shift factor calculation for clocks clocksource: Provide a generic mult/shift factor calculation clockevents: Use u32 for mult and shift factors nohz: Introduce arch_needs_cpu nohz: Reuse ktime in sub-functions of tick_check_idle. time: Remove xtime_cache time: Implement logarithmic time accumulation
| * nohz: Allow 32-bit machines to sleep for more than 2.15 secondsJon Hunter2009-11-131-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the dynamic tick code, "max_delta_ns" (member of the "clock_event_device" structure) represents the maximum sleep time that can occur between timer events in nanoseconds. The variable, "max_delta_ns", is defined as an unsigned long which is a 32-bit integer for 32-bit machines and a 64-bit integer for 64-bit machines (if -m64 option is used for gcc). The value of max_delta_ns is set by calling the function "clockevent_delta2ns()" which returns a maximum value of LONG_MAX. For a 32-bit machine LONG_MAX is equal to 0x7fffffff and in nanoseconds this equates to ~2.15 seconds. Hence, the maximum sleep time for a 32-bit machine is ~2.15 seconds, where as for a 64-bit machine it will be many years. This patch changes the type of max_delta_ns to be "u64" instead of "unsigned long" so that this variable is a 64-bit type for both 32-bit and 64-bit machines. It also changes the maximum value returned by clockevent_delta2ns() to KTIME_MAX. Hence this allows a 32-bit machine to sleep for longer than ~2.15 seconds. Please note that this patch also changes "min_delta_ns" to be "u64" too and although this is unnecessary, it makes the patch simpler as it avoids to fixup all callers of clockevent_delta2ns(). [ tglx: changed "unsigned long long" to u64 as we use this data type through out the time code ] Signed-off-by: Jon Hunter <jon-hunter@ti.com> Cc: John Stultz <johnstul@us.ibm.com> LKML-Reference: <1250617512-23567-3-git-send-email-jon-hunter@ti.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | Merge branch 'timers-fixes-for-linus' of ↵Linus Torvalds2009-10-051-2/+0
|\ \ | |/ |/| | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: hrtimer: Remove overly verbose "switch to high res mode" message
| * hrtimer: Remove overly verbose "switch to high res mode" messageRoland Dreier2009-09-261-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | On big systems, printing <number of CPUs> copies of Switched to high resolution mode on CPU nnn clutters up the kernel log for minimal gain. Just get rid of them. Signed-off-by: Roland Dreier <rolandd@cisco.com> LKML-Reference: <ada1vlw126s.fsf_-_@cisco.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | Merge branch 'timers-for-linus' of ↵Linus Torvalds2009-09-271-18/+35
|\ \ | |/ |/| | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: hrtimer: Eliminate needless reprogramming of clock events device
| * hrtimer: Eliminate needless reprogramming of clock events deviceAshwin Chaugule2009-09-151-18/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On NOHZ systems the following timers, - tick_nohz_restart_sched_tick (tick_sched_timer) - hrtimer_start (tick_sched_timer) are reprogramming the clock events device far more often than needed. No specific test case was required to observe this effect. This occurres because there was no check to see if the currently removed or restarted hrtimer was: 1) the one which previously armed the clock events device. 2) going to be replaced by another timer which has the same expiry time. Avoid the reprogramming in hrtimer_force_reprogram when the new expiry value which is evaluated from the clock bases is equal to cpu_base->expires_next. This results in faster application startup time by ~4%. [ tglx: simplified initial solution ] Signed-off-by: Ashwin Chaugule <ashwinc@quicinc.com> LKML-Reference: <4AA00165.90609@codeaurora.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | Merge branch 'timers-for-linus' of ↵Linus Torvalds2009-09-231-8/+32
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: itimers: Add tracepoints for itimer hrtimer: Add tracepoint for hrtimers timers: Add tracepoints for timer_list timers cputime: Optimize jiffies_to_cputime(1) itimers: Simplify arm_timer() code a bit itimers: Fix periodic tics precision itimers: Merge ITIMER_VIRT and ITIMER_PROF Trivial header file include conflicts in kernel/fork.c
| * | hrtimer: Add tracepoint for hrtimersXiao Guangrong2009-08-291-8/+32
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add tracepoints which cover the life cycle of a hrtimer. The tracepoints are integrated with the already existing debug_object debug points as far as possible. [ tglx: Fixed comments, made output conistent, easier to read and parse. Fixed output for 32bit archs which do not use the scalar representation of ktime_t. Hand current time to trace_hrtimer_expiry_entry instead of calling get_time() inside of the trace assignment. ] Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Anton Blanchard <anton@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Zhaolei <zhaolei@cn.fujitsu.com> LKML-Reference: <4A7F8B2B.5020908@cn.fujitsu.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | Merge branch 'timers-for-linus' of ↵Linus Torvalds2009-09-181-57/+0
|\ \ | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (34 commits) time: Prevent 32 bit overflow with set_normalized_timespec() clocksource: Delay clocksource down rating to late boot clocksource: clocksource_select must be called with mutex locked clocksource: Resolve cpu hotplug dead lock with TSC unstable, fix crash timers: Drop a function prototype clocksource: Resolve cpu hotplug dead lock with TSC unstable timer.c: Fix S/390 comments timekeeping: Fix invalid getboottime() value timekeeping: Fix up read_persistent_clock() breakage on sh timekeeping: Increase granularity of read_persistent_clock(), build fix time: Introduce CLOCK_REALTIME_COARSE x86: Do not unregister PIT clocksource on PIT oneshot setup/shutdown clocksource: Avoid clocksource watchdog circular locking dependency clocksource: Protect the watchdog rating changes with clocksource_mutex clocksource: Call clocksource_change_rating() outside of watchdog_lock timekeeping: Introduce read_boot_clock timekeeping: Increase granularity of read_persistent_clock() timekeeping: Update clocksource with stop_machine timekeeping: Add timekeeper read_clock helper functions timekeeping: Move NTP adjusted clock multiplier to struct timekeeper ... Fix trivial conflict due to MIPS lemote -> loongson renaming.
| * Merge branch 'linus' into timers/coreThomas Gleixner2009-08-141-46/+64
| |\ | | | | | | | | | | | | | | | | | | Reason: Martin's timekeeping cleanup series depends on both timers/core and mainline changes. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | hrtimer: Remove cb_entry from struct hrtimerPeter Zijlstra2009-07-221-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | It's unused, remove it. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <new-submission>
| * | timekeeping: Move ktime_get() functions to timekeeping.cThomas Gleixner2009-07-071-60/+0
| | | | | | | | | | | | | | | | | | | | | | | | The ktime_get() functions for GENERIC_TIME=n are still located in hrtimer.c. Move them to time/timekeeping.c where they belong. LKML-Reference: <new-submission> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | timekeeping: optimized ktime_get[_ts] for GENERIC_TIME=yMartin Schwidefsky2009-07-071-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The generic ktime_get function defined in kernel/hrtimer.c is suboptimial for GENERIC_TIME=y: 0) | ktime_get() { 0) | ktime_get_ts() { 0) | getnstimeofday() { 0) | read_tod_clock() { 0) 0.601 us | } 0) 1.938 us | } 0) | set_normalized_timespec() { 0) 0.602 us | } 0) 4.375 us | } 0) 5.523 us | } Overall there are two read_seqbegin/read_seqretry loops and a lot of unnecessary struct timespec calculations. ktime_get returns a nano second value which is the sum of xtime, wall_to_monotonic and the nano second delta from the clock source. ktime_get can be optimized for GENERIC_TIME=y. The new version only calls clocksource_read: 0) | ktime_get() { 0) | read_tod_clock() { 0) 0.610 us | } 0) 1.977 us | } It uses a single read_seqbegin/readseqretry loop and just adds everthing to a nano second value. ktime_get_ts is optimized in a similar fashion. [ tglx: added WARN_ON(timekeeping_suspended) as in getnstimeofday() ] Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Acked-by: john stultz <johnstul@us.ibm.com> LKML-Reference: <20090707112728.3005244d@skybase> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | pktgen: spin using hrtimerStephen Hemminger2009-08-281-0/+2
| |/ |/| | | | | | | | | | | | | | | This changes how the pktgen thread spins/waits between packets if delay is configured. It uses a high res timer to wait for time to arrive. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | hrtimer: Fix migration expiry checkThomas Gleixner2009-07-101-57/+64
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | hrtimer: migration: do not check expiry time on current CPUThomas Gleixner2009-07-101-2/+13
|/ | | | | | | | | | | | | | | | | | | | | | | The timer migration code needs to check whether the expiry time of the timer is before the programmed clock event expiry time when the timer is enqueued on another CPU because we can not reprogram the timer device on the other CPU. The current logic checks the expiry time even if we enqueue on the current CPU when nohz_get_load_balancer() returns current CPU. This might lead to an endless loop in the expiry check code when the expiry time of the timer is before the current programmed next event. Check whether nohz_get_load_balancer() returns current CPU and skip the expiry check if this is the case. The bug was triggered from the networking code. The patch fixes the regression http://bugzilla.kernel.org/show_bug.cgi?id=13738 (Soft-Lockup/Race in networking in 2.6.31-rc1+195) Cc: Arun Bharadwaj <arun@linux.vnet.ibm.com Tested-by: Joao Correia <joaomiguelcorreia@gmail.com> Tested-by: Andres Freund <andres@anarazel.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Merge branch 'linux-next' of git://git.infradead.org/ubifs-2.6Linus Torvalds2009-06-171-0/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | * 'linux-next' of git://git.infradead.org/ubifs-2.6: UBIFS: start using hrtimers hrtimer: export ktime_add_safe UBIFS: do not forget to register BDI device UBIFS: allow sync option in rootflags UBIFS: remove dead code UBIFS: use anonymous device UBIFS: return proper error code if the compr is not present UBIFS: return error if link and unlink race UBIFS: reset no_space flag after inode deletion
| * hrtimer: export ktime_add_safeArtem Bityutskiy2009-06-081-0/+2
| | | | | | | | | | | | | | | | | | We want to use hrtimers in UBIFS (for write-buffer write-back timer). We need the 'hrtimer_set_expires_range_ns()', which is an in-line function which uses 'ktime_add_safe()'. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Acked-by: Ingo Molnar <mingo@elte.hu>
* | timers: Logic to move non pinned timersArun R Bharadwaj2009-05-131-2/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 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>
* | timers: Framework for identifying pinned timersArun R Bharadwaj2009-05-131-3/+4
|/ | | | | | | | | | | | | | | | | | | | | | | | * Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-04-16 12:11:36]: This patch creates a new framework for identifying cpu-pinned timers and hrtimers. This framework is needed because pinned timers are expected to fire on the same CPU on which they are queued. So it is essential to identify these and not migrate them, in case there are any. For regular timers, the currently existing add_timer_on() can be used queue pinned timers and subsequently mod_timer_pinned() can be used to modify the 'expires' field. For hrtimers, new modes HRTIMER_ABS_PINNED and HRTIMER_REL_PINNED are added to queue cpu-pinned hrtimer. [ tglx: use .._PINNED mode argument instead of creating tons of new functions ] Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* hrtimer: fix rq->lock inversion (again)Peter Zijlstra2009-03-311-21/+34
| | | | | | | | | | | | | | | | | | | | It appears I inadvertly introduced rq->lock recursion to the hrtimer_start() path when I delegated running already expired timers to softirq context. This patch fixes it by introducing a __hrtimer_start_range_ns() method that will not use raise_softirq_irqoff() but __raise_softirq_irqoff() which avoids the wakeup. It then also changes schedule() to check for pending softirqs and do the wakeup then, I'm not quite sure I like this last bit, nor am I convinced its really needed. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: paulus@samba.org LKML-Reference: <20090313112301.096138802@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* hrtimer: prevent negative expiry value after clock_was_set()Thomas Gleixner2009-01-301-0/+7
| | | | | | | | | | | | | | | Impact: prevent false positive WARN_ON() in clockevents_program_event() clock_was_set() changes the base->offset of CLOCK_REALTIME and enforces the reprogramming of the clockevent device to expire timers which are based on CLOCK_REALTIME. If the clock change is large enough then the subtraction of the timer expiry value and base->offset can become negative which triggers the warning in clockevents_program_event(). Check the subtraction result and set a negative value to 0. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* hrtimers: allow the hot-unplugging of all cpusSebastien Dugue2009-01-301-0/+4
| | | | | | | | | | | | | | | | | | | | | | | 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>
* hrtimers: increase clock min delta threshold while interrupt hangingFrederic Weisbecker2009-01-301-1/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: avoid timer IRQ hanging slow systems While using the function graph tracer on a virtualized system, the hrtimer_interrupt can hang the system on an infinite loop. This can be caused in several situations: - the hardware is very slow and HZ is set too high - something intrusive is slowing the system down (tracing under emulation) ... and the next clock events to program are always before the current time. This patch implements a reasonable compromise: if such a situation is detected, we share the CPUs time in 1/4 to process the hrtimer interrupts. This is enough to let the system running without serious starvation. It has been successfully tested under VirtualBox with 1000 HZ and 100 HZ with function graph tracer launched. On both cases, the clock events were increased until about 25 ms periodic ticks, which means 40 HZ. So we change a hard to debug hang into a warning message and a system that still manages to limp along. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'timers-fixes-for-linus' of ↵Linus Torvalds2009-01-261-1/+3
|\ | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: hrtimers: fix inconsistent lock state on resume in hres_timers_resume time-sched.c: tick_nohz_update_jiffies should be static locking, hpet: annotate false positive warning kernel/fork.c: unused variable 'ret' itimers: remove the per-cpu-ish-ness
| * hrtimers: fix inconsistent lock state on resume in hres_timers_resumePeter Zijlstra2009-01-181-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Andrey Borzenkov reported this lockdep assert: > [17854.688347] ================================= > [17854.688347] [ INFO: inconsistent lock state ] > [17854.688347] 2.6.29-rc2-1avb #1 > [17854.688347] --------------------------------- > [17854.688347] inconsistent {in-hardirq-W} -> {hardirq-on-W} usage. > [17854.688347] pm-suspend/18240 [HC0[0]:SC0[0]:HE1:SE1] takes: > [17854.688347] (&cpu_base->lock){++..}, at: [<c0136fcc>] retrigger_next_event+0x5c/0xa0 > [17854.688347] {in-hardirq-W} state was registered at: > [17854.688347] [<c01443cd>] __lock_acquire+0x79d/0x1930 > [17854.688347] [<c01455bc>] lock_acquire+0x5c/0x80 > [17854.688347] [<c03092e5>] _spin_lock+0x35/0x70 > [17854.688347] [<c0136e61>] hrtimer_run_queues+0x31/0x140 > [17854.688347] [<c0128d98>] run_local_timers+0x8/0x20 > [17854.688347] [<c0128dd3>] update_process_times+0x23/0x60 > [17854.688347] [<c013e274>] tick_periodic+0x24/0x80 > [17854.688347] [<c013e2e2>] tick_handle_periodic+0x12/0x70 > [17854.688347] [<c0104e24>] timer_interrupt+0x14/0x20 > [17854.688347] [<c01607b9>] handle_IRQ_event+0x29/0x60 > [17854.688347] [<c0161c59>] handle_level_irq+0x69/0xe0 > [17854.688347] [<ffffffff>] 0xffffffff > [17854.688347] irq event stamp: 55771 > [17854.688347] hardirqs last enabled at (55771): [<c0309125>] _spin_unlock_irqrestore+0x35/0x60 > [17854.688347] hardirqs last disabled at (55770): [<c0309419>] _spin_lock_irqsave+0x19/0x80 > [17854.688347] softirqs last enabled at (54836): [<c0124f54>] __do_softirq+0xc4/0x110 > [17854.688347] softirqs last disabled at (54831): [<c01049ae>] do_softirq+0x8e/0xe0 > [17854.688347] > [17854.688347] other info that might help us debug this: > [17854.688347] 3 locks held by pm-suspend/18240: > [17854.688347] #0: (&buffer->mutex){--..}, at: [<c01dd4c5>] sysfs_write_file+0x25/0x100 > [17854.688347] #1: (pm_mutex){--..}, at: [<c015056f>] enter_state+0x4f/0x140 > [17854.688347] #2: (dpm_list_mtx){--..}, at: [<c027880f>] device_pm_lock+0xf/0x20 > [17854.688347] > [17854.688347] stack backtrace: > [17854.688347] Pid: 18240, comm: pm-suspend Not tainted 2.6.29-rc2-1avb #1 > [17854.688347] Call Trace: > [17854.688347] [<c0306248>] ? printk+0x18/0x20 > [17854.688347] [<c0141fac>] print_usage_bug+0x16c/0x1d0 > [17854.688347] [<c0142bcf>] mark_lock+0x8bf/0xc90 > [17854.688347] [<c0106b8f>] ? pit_next_event+0x2f/0x40 > [17854.688347] [<c01441b0>] __lock_acquire+0x580/0x1930 > [17854.688347] [<c030916d>] ? _spin_unlock+0x1d/0x20 > [17854.688347] [<c0106b8f>] ? pit_next_event+0x2f/0x40 > [17854.688347] [<c013dd38>] ? clockevents_program_event+0x98/0x160 > [17854.688347] [<c0142fe8>] ? mark_held_locks+0x48/0x90 > [17854.688347] [<c0309125>] ? _spin_unlock_irqrestore+0x35/0x60 > [17854.688347] [<c0143229>] ? trace_hardirqs_on_caller+0x139/0x190 > [17854.688347] [<c014328b>] ? trace_hardirqs_on+0xb/0x10 > [17854.688347] [<c01455bc>] lock_acquire+0x5c/0x80 > [17854.688347] [<c0136fcc>] ? retrigger_next_event+0x5c/0xa0 > [17854.688347] [<c03092e5>] _spin_lock+0x35/0x70 > [17854.688347] [<c0136fcc>] ? retrigger_next_event+0x5c/0xa0 > [17854.688347] [<c0136fcc>] retrigger_next_event+0x5c/0xa0 > [17854.688347] [<c013711a>] hres_timers_resume+0xa/0x10 > [17854.688347] [<c013aa8e>] timekeeping_resume+0xee/0x150 > [17854.688347] [<c0273384>] __sysdev_resume+0x14/0x50 > [17854.688347] [<c0273407>] sysdev_resume+0x47/0x80 > [17854.688347] [<c02791ab>] device_power_up+0xb/0x20 > [17854.688347] [<c015043f>] suspend_devices_and_enter+0xcf/0x150 > [17854.688347] [<c0150c2f>] ? freeze_processes+0x3f/0x90 > [17854.688347] [<c0150614>] enter_state+0xf4/0x140 > [17854.688347] [<c01506dd>] state_store+0x7d/0xc0 > [17854.688347] [<c0150660>] ? state_store+0x0/0xc0 > [17854.688347] [<c0202da4>] kobj_attr_store+0x24/0x30 > [17854.688347] [<c01dd53c>] sysfs_write_file+0x9c/0x100 > [17854.688347] [<c019916c>] vfs_write+0x9c/0x160 > [17854.688347] [<c0103494>] ? restore_nocheck_notrace+0x0/0xe > [17854.688347] [<c01dd4a0>] ? sysfs_write_file+0x0/0x100 > [17854.688347] [<c01992ed>] sys_write+0x3d/0x70 > [17854.688347] [<c0103371>] sysenter_do_call+0x12/0x31 Andrey's analysis: > timekeeping_resume() is called via class ->resume > method; and according to comments in sysdev_resume() and > device_power_up(), they are called with interrupts disabled. > > Looking at suspend_enter, irqs *are* disabled at this point. > > So it actually looks like something (may be some driver) > unconditionally enabled irqs in resume path. Add a debug check to test this theory. If it triggers then it triggers because the resume code calls it with irqs enabled, which is a no-no not just for timekeeping_resume(), but also bad for a number of other resume handlers. Reported-by: Andrey Borzenkov <arvidjaar@mail.ru> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | [CVE-2009-0029] System call wrappers part 01Heiko Carstens2009-01-141-2/+2
|/ | | | Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* hrtimer: splitout peek ahead functionality, fixIngo Molnar2009-01-051-1/+5
| | | | | | | | | | Impact: build fix on !CONFIG_HIGH_RES_TIMERS Fix: kernel/hrtimer.c:1586: error: implicit declaration of function '__hrtimer_peek_ahead_timers' Signen-off-by: Ingo Molnar <mingo@elte.hu>
* hrtimer: fixup commentsThomas Gleixner2009-01-051-11/+9
| | | | | | | | Clean up the comments Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* hrtimer: fix recursion deadlock by re-introducing the softirqPeter Zijlstra2009-01-051-33/+27
| | | | | | | | | | | | | | | | | | Impact: fix rare runtime deadlock There are a few sites that do: spin_lock_irq(&foo) hrtimer_start(&bar) __run_hrtimer(&bar) func() spin_lock(&foo) which obviously deadlocks. In order to avoid this, never call __run_hrtimer() from hrtimer_start*() context, but instead defer this to softirq context. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* hrtimer: simplify hotplug migrationThomas Gleixner2009-01-051-15/+10
| | | | | | | | | | | | Impact: cleanup No need for a smp function call, which is likely to run on the same CPU anyway. We can just call hrtimers_peek_ahead() in the interrupts disabled section of migrate_hrtimers(). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* hrtimer: fix HOTPLUG_CPU=n compile warningThomas Gleixner2009-01-051-11/+8
| | | | | | | | | | | | | | | | Impact: cleanup kernel/hrtimer.c: In function 'hrtimer_cpu_notify': kernel/hrtimer.c:1574: warning: unused variable 'dcpu' Introduced by commit 37810659ea7d9572c5ac284ade272f806ef8f788 ("hrtimer: removing all ur callback modes, fix hotplug") from the timers. dcpu is only used if CONFIG_HOTPLUG_CPU is set. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* hrtimer: splitout peek ahead functionalityThomas Gleixner2009-01-051-7/+17
| | | | | | | | | | | Impact: cleanup Provide a peek ahead function that assumes irqs disabled, allows for micro optimizations. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'irq-fixes-for-linus-4' of ↵Linus Torvalds2008-12-311-1/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'irq-fixes-for-linus-4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sparseirq: move __weak symbols into separate compilation unit sparseirq: work around __weak alias bug sparseirq: fix hang with !SPARSE_IRQ sparseirq: set lock_class for legacy irq when sparse_irq is selected sparseirq: work around compiler optimizing away __weak functions sparseirq: fix desc->lock init sparseirq: do not printk when migrating IRQ descriptors sparseirq: remove duplicated arch_early_irq_init() irq: simplify for_each_irq_desc() usage proc: remove ifdef CONFIG_SPARSE_IRQ from stat.c irq: for_each_irq_desc() move to irqnr.h hrtimer: remove #include <linux/irq.h>
| * hrtimer: remove #include <linux/irq.h>KOSAKI Motohiro2008-12-261-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | Impact: cleanup <linux/irq.h> can be removed and should be, because: - hrtimer doesn't use any irq feature. - <linux/irq.h> shouldn't be include from generic code. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | hrtimers: fix warning in kernel/hrtimer.cIngo Molnar2008-12-191-1/+5
| | | | | | | | | | | | | | | | | | | | | | this warning: kernel/hrtimer.c: In function ‘hrtimer_cpu_notify’: kernel/hrtimer.c:1574: warning: unused variable ‘dcpu’ is caused because 'dcpu' is only used in the CONFIG_HOTPLUG_CPU case. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | hrtimer: removing all ur callback modes, fixPeter Zijlstra2008-12-081-7/+1
| | | | | | | | | | | | | | | | | | > Ingo, this addition fixes the hotplug issue on my machine And because we're all human... Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | hrtimer: removing all ur callback modes, fix hotplugPeter Zijlstra2008-12-041-28/+37
| | | | | | | | | | | | | | | | | | Impact: fix hrtimer locking (reported by lockdep) in the CPU hotplug case This addition fixes the hotplug locking issue on my machine Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | hrtimer: removing all ur callback modesPeter Zijlstra2008-11-251-249/+31
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* hrtimer: clean up unused callback modesPeter Zijlstra2008-11-121-9/+0
| | | | | | | | | | Impact: cleanup git grep HRTIMER_CB_IRQSAFE revealed half the callback modes are actually unused. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* timers: handle HRTIMER_CB_IRQSAFE_UNLOCKED correctly from softirq contextGautham R Shenoy2008-11-111-1/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix incorrect locking triggered during hotplug-intense stress-tests While migrating the the CB_IRQSAFE_UNLOCKED timers during a cpu-offline, we queue them on the cb_pending list, so that they won't go stale. Thus, when the callbacks of the timers run from the softirq context, they could run into potential deadlocks, since these callbacks assume that they're running with irq's disabled, thereby annoying lockdep! Fix this by emulating hardirq context while running these callbacks from the hrtimer softirq. ================================= [ INFO: inconsistent lock state ] 2.6.27 #2 -------------------------------- inconsistent {in-hardirq-W} -> {hardirq-on-W} usage. ksoftirqd/0/4 [HC0[0]:SC1[1]:HE1:SE0] takes: (&rq->lock){++..}, at: [<c011db84>] sched_rt_period_timer+0x9e/0x1fc {in-hardirq-W} state was registered at: [<c014103c>] __lock_acquire+0x549/0x121e [<c0107890>] native_sched_clock+0x88/0x99 [<c013aa12>] clocksource_get_next+0x39/0x3f [<c0139abc>] update_wall_time+0x616/0x7df [<c0141d6b>] lock_acquire+0x5a/0x74 [<c0121724>] scheduler_tick+0x3a/0x18d [<c047ed45>] _spin_lock+0x1c/0x45 [<c0121724>] scheduler_tick+0x3a/0x18d [<c0121724>] scheduler_tick+0x3a/0x18d [<c012c436>] update_process_times+0x3a/0x44 [<c013c044>] tick_periodic+0x63/0x6d [<c013c062>] tick_handle_periodic+0x14/0x5e [<c010568c>] timer_interrupt+0x44/0x4a [<c0150c9f>] handle_IRQ_event+0x13/0x3d [<c0151c14>] handle_level_irq+0x79/0xbd [<c0105634>] do_IRQ+0x69/0x7d [<c01041e4>] common_interrupt+0x28/0x30 [<c047007b>] aac_probe_one+0x1a3/0x3f3 [<c047ec2d>] _spin_unlock_irqrestore+0x36/0x39 [<c01512b4>] setup_irq+0x1be/0x1f9 [<c065d70b>] start_kernel+0x259/0x2c5 [<ffffffff>] 0xffffffff irq event stamp: 50102 hardirqs last enabled at (50102): [<c047ebf4>] _spin_unlock_irq+0x20/0x23 hardirqs last disabled at (50101): [<c047edc2>] _spin_lock_irq+0xa/0x4b softirqs last enabled at (50088): [<c0128ba6>] do_softirq+0x37/0x4d softirqs last disabled at (50099): [<c0128ba6>] do_softirq+0x37/0x4d other info that might help us debug this: no locks held by ksoftirqd/0/4. stack backtrace: Pid: 4, comm: ksoftirqd/0 Not tainted 2.6.27 #2 [<c013f6cb>] print_usage_bug+0x13e/0x147 [<c013fef5>] mark_lock+0x493/0x797 [<c01410b1>] __lock_acquire+0x5be/0x121e [<c0141d6b>] lock_acquire+0x5a/0x74 [<c011db84>] sched_rt_period_timer+0x9e/0x1fc [<c047ed45>] _spin_lock+0x1c/0x45 [<c011db84>] sched_rt_period_timer+0x9e/0x1fc [<c011db84>] sched_rt_period_timer+0x9e/0x1fc [<c01210fd>] finish_task_switch+0x41/0xbd [<c0107890>] native_sched_clock+0x88/0x99 [<c011dae6>] sched_rt_period_timer+0x0/0x1fc [<c0136dda>] run_hrtimer_pending+0x54/0xe5 [<c011dae6>] sched_rt_period_timer+0x0/0x1fc [<c0128afb>] __do_softirq+0x7b/0xef [<c0128ba6>] do_softirq+0x37/0x4d [<c0128c12>] ksoftirqd+0x56/0xc5 [<c0128bbc>] ksoftirqd+0x0/0xc5 [<c0134649>] kthread+0x38/0x5d [<c0134611>] kthread+0x0/0x5d [<c0104477>] kernel_thread_helper+0x7/0x10 ======================= Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'timers/range-hrtimers' into v28-range-hrtimers-for-linus-v2Thomas Gleixner2008-10-221-21/+185
|\ | | | | | | | | | | | | | | Conflicts: kernel/time/tick-sched.c Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * hrtimers: simplify hrtimer_peek_ahead_timers()Thomas Gleixner2008-10-201-9/+3
| | | | | | | | Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * hrtimers: fix docbook commentsThomas Gleixner2008-10-201-2/+2
| | | | | | | | | | | | | | hrtimer_start() and hrtimer_start_range_ns() handle relative and absolute timers. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * Merge commit 'linus/master' into merge-linusArjan van de Ven2008-10-171-10/+85
| |\ | | | | | | | | | | | | | | | Conflicts: arch/x86/kvm/i8254.c
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