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2016-09-02tick/nohz: Fix softlockup on scheduler stalls in kvm guestWanpeng Li
tick_nohz_start_idle() is prevented to be called if the idle tick can't be stopped since commit 1f3b0f8243cb934 ("tick/nohz: Optimize nohz idle enter"). As a result, after suspend/resume the host machine, full dynticks kvm guest will softlockup: NMI watchdog: BUG: soft lockup - CPU#0 stuck for 26s! [swapper/0:0] Call Trace: default_idle+0x31/0x1a0 arch_cpu_idle+0xf/0x20 default_idle_call+0x2a/0x50 cpu_startup_entry+0x39b/0x4d0 rest_init+0x138/0x140 ? rest_init+0x5/0x140 start_kernel+0x4c1/0x4ce ? set_init_arg+0x55/0x55 ? early_idt_handler_array+0x120/0x120 x86_64_start_reservations+0x24/0x26 x86_64_start_kernel+0x142/0x14f In addition, cat /proc/stat | grep cpu in guest or host: cpu 398 16 5049 15754 5490 0 1 46 0 0 cpu0 206 5 450 0 0 0 1 14 0 0 cpu1 81 0 3937 3149 1514 0 0 9 0 0 cpu2 45 6 332 6052 2243 0 0 11 0 0 cpu3 65 2 328 6552 1732 0 0 11 0 0 The idle and iowait states are weird 0 for cpu0(housekeeping). The bug is present in both guest and host kernels, and they both have cpu0's idle and iowait states issue, however, host kernel's suspend/resume path etc will touch watchdog to avoid the softlockup. - The watchdog will not be touched in tick_nohz_stop_idle path (need be touched since the scheduler stall is expected) if idle_active flags are not detected. - The idle and iowait states will not be accounted when exit idle loop (resched or interrupt) if idle start time and idle_active flags are not set. This patch fixes it by reverting commit 1f3b0f8243cb934 since can't stop idle tick doesn't mean can't be idle. Fixes: 1f3b0f8243cb934 ("tick/nohz: Optimize nohz idle enter") Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Cc: Sanjeev Yadav<sanjeev.yadav@spreadtrum.com> Cc: Gaurav Jindal<gaurav.jindal@spreadtrum.com> Cc: stable@vger.kernel.org Cc: kvm@vger.kernel.org Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Link: http://lkml.kernel.org/r/1472798303-4154-1-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-08-24timekeeping: Cap array access in timekeeping_debugJohn Stultz
It was reported that hibernation could fail on the 2nd attempt, where the system hangs at hibernate() -> syscore_resume() -> i8237A_resume() -> claim_dma_lock(), because the lock has already been taken. However there is actually no other process would like to grab this lock on that problematic platform. Further investigation showed that the problem is triggered by setting /sys/power/pm_trace to 1 before the 1st hibernation. Since once pm_trace is enabled, the rtc becomes unmeaningful after suspend, and meanwhile some BIOSes would like to adjust the 'invalid' RTC (e.g, smaller than 1970) to the release date of that motherboard during POST stage, thus after resumed, it may seem that the system had a significant long sleep time which is a completely meaningless value. Then in timekeeping_resume -> tk_debug_account_sleep_time, if the bit31 of the sleep time happened to be set to 1, fls() returns 32 and we add 1 to sleep_time_bin[32], which causes an out of bounds array access and therefor memory being overwritten. As depicted by System.map: 0xffffffff81c9d080 b sleep_time_bin 0xffffffff81c9d100 B dma_spin_lock the dma_spin_lock.val is set to 1, which caused this problem. This patch adds a sanity check in tk_debug_account_sleep_time() to ensure we don't index past the sleep_time_bin array. [jstultz: Problem diagnosed and original patch by Chen Yu, I've solved the issue slightly differently, but borrowed his excelent explanation of the issue here.] Fixes: 5c83545f24ab "power: Add option to log time spent in suspend" Reported-by: Janek Kozicki <cosurgi@gmail.com> Reported-by: Chen Yu <yu.c.chen@intel.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: linux-pm@vger.kernel.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: Xunlei Pang <xpang@redhat.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: stable <stable@vger.kernel.org> Cc: Zhang Rui <rui.zhang@intel.com> Link: http://lkml.kernel.org/r/1471993702-29148-3-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-08-24timekeeping: Avoid taking lock in NMI path with CONFIG_DEBUG_TIMEKEEPINGJohn Stultz
When I added some extra sanity checking in timekeeping_get_ns() under CONFIG_DEBUG_TIMEKEEPING, I missed that the NMI safe __ktime_get_fast_ns() method was using timekeeping_get_ns(). Thus the locking added to the debug checks broke the NMI-safety of __ktime_get_fast_ns(). This patch open-codes the timekeeping_get_ns() logic for __ktime_get_fast_ns(), so can avoid any deadlocks in NMI. Fixes: 4ca22c2648f9 "timekeeping: Add warnings when overflows or underflows are observed" Reported-by: Steven Rostedt <rostedt@goodmis.org> Reported-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: stable <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/1471993702-29148-2-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-08-09timers: Fix get_next_timer_interrupt() computationChris Metcalf
The tick_nohz_stop_sched_tick() routine is not properly canceling the sched timer when nothing is pending, because get_next_timer_interrupt() is no longer returning KTIME_MAX in that case. This causes periodic interrupts when none are needed. When determining the next interrupt time, we first use __next_timer_interrupt() to get the first expiring timer in the timer wheel. If no timer is found, we return the base clock value plus NEXT_TIMER_MAX_DELTA to indicate there is no timer in the timer wheel. Back in get_next_timer_interrupt(), we set the "expires" value by converting the timer wheel expiry (in ticks) to a nsec value. But we don't want to do this if the timer wheel expiry value indicates no timer; we want to return KTIME_MAX. Prior to commit 500462a9de65 ("timers: Switch to a non-cascading wheel") we checked base->active_timers to see if any timers were active, and if not, we didn't touch the expiry value and so properly returned KTIME_MAX. Now we don't have active_timers. To fix this, we now just check the timer wheel expiry value to see if it is "now + NEXT_TIMER_MAX_DELTA", and if it is, we don't try to compute a new value based on it, but instead simply let the KTIME_MAX value in expires remain. Fixes: 500462a9de65 "timers: Switch to a non-cascading wheel" Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Christoph Lameter <cl@linux.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/1470688147-22287-1-git-send-email-cmetcalf@mellanox.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-07-29Merge branch 'smp-hotplug-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull smp hotplug updates from Thomas Gleixner: "This is the next part of the hotplug rework. - Convert all notifiers with a priority assigned - Convert all CPU_STARTING/DYING notifiers The final removal of the STARTING/DYING infrastructure will happen when the merge window closes. Another 700 hundred line of unpenetrable maze gone :)" * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits) timers/core: Correct callback order during CPU hot plug leds/trigger/cpu: Move from CPU_STARTING to ONLINE level powerpc/numa: Convert to hotplug state machine arm/perf: Fix hotplug state machine conversion irqchip/armada: Avoid unused function warnings ARC/time: Convert to hotplug state machine clocksource/atlas7: Convert to hotplug state machine clocksource/armada-370-xp: Convert to hotplug state machine clocksource/exynos_mct: Convert to hotplug state machine clocksource/arm_global_timer: Convert to hotplug state machine rcu: Convert rcutree to hotplug state machine KVM/arm/arm64/vgic-new: Convert to hotplug state machine smp/cfd: Convert core to hotplug state machine x86/x2apic: Convert to CPU hotplug state machine profile: Convert to hotplug state machine timers/core: Convert to hotplug state machine hrtimer: Convert to hotplug state machine x86/tboot: Convert to hotplug state machine arm64/armv8 deprecated: Convert to hotplug state machine hwtracing/coresight-etm4x: Convert to hotplug state machine ...
2016-07-25Merge branch 'timers-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner: "This update provides the following changes: - The rework of the timer wheel which addresses the shortcomings of the current wheel (cascading, slow search for next expiring timer, etc). That's the first major change of the wheel in almost 20 years since Finn implemted it. - A large overhaul of the clocksource drivers init functions to consolidate the Device Tree initialization - Some more Y2038 updates - A capability fix for timerfd - Yet another clock chip driver - The usual pile of updates, comment improvements all over the place" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (130 commits) tick/nohz: Optimize nohz idle enter clockevents: Make clockevents_subsys static clocksource/drivers/time-armada-370-xp: Fix return value check timers: Implement optimization for same expiry time in mod_timer() timers: Split out index calculation timers: Only wake softirq if necessary timers: Forward the wheel clock whenever possible timers/nohz: Remove pointless tick_nohz_kick_tick() function timers: Optimize collect_expired_timers() for NOHZ timers: Move __run_timers() function timers: Remove set_timer_slack() leftovers timers: Switch to a non-cascading wheel timers: Reduce the CPU index space to 256k timers: Give a few structs and members proper names hlist: Add hlist_is_singular_node() helper signals: Use hrtimer for sigtimedwait() timers: Remove the deprecated mod_timer_pinned() API timers, net/ipv4/inet: Initialize connection request timers as pinned timers, drivers/tty/mips_ejtag: Initialize the poll timer as pinned timers, drivers/tty/metag_da: Initialize the poll timer as pinned ...
2016-07-24Merge tag 'staging-4.8-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging Pull staging and IIO driver updates from Greg KH: "Here is the big Staging and IIO driver update for 4.8-rc1. We ended up adding more code than removing, again, but it's not all that bad. Lots of cleanups all over the staging tree, and new IIO drivers, full details in the shortlog. All of these have been in linux-next for a while with no reported issues" * tag 'staging-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (417 commits) drivers:iio:accel:mma8452: removed unwanted return statements drivers:iio:accel:mma8452: added cleanup provision in case of failure. iio: Add iio.git tree to MAINTAINERS iio:st_pressure: clean useless static channel initializers iio:st_pressure:lps22hb: temperature support iio:st_pressure:lps22hb: open drain support iio:st_pressure: temperature triggered buffering iio:st_pressure: document sampling gains iio:st_pressure: align storagebits on power of 2 iio:st_sensors: align on storagebits boundaries staging:iio:lis3l02dq drop separate driver iio: accel: st_accel: Add lis3l02dq support iio: adc: add missing of_node references to iio_dev iio: adc: ti-ads1015: add indio_dev->dev.of_node reference iio: potentiometer: Fix typo in Kconfig iio: potentiometer: mcp4531: Add device tree binding iio: potentiometer: mcp4531: Add device tree binding documentation iio: potentiometer: mcp4531: Add support for MCP454x, MCP456x, MCP464x and MCP466x iio:imu:mpu6050: icm20608 initial support iio: adc: max1363: Add device tree binding ...
2016-07-19tick/nohz: Optimize nohz idle enterGaurav Jindal
tick_nohz_start_idle is called before checking whether the idle tick can be stopped. If the tick cannot be stopped, calling tick_nohz_start_idle() is pointless and just wasting CPU cycles. Only invoke tick_nohz_start_idle() when can_stop_idle_tick() returns true. A short one minute observation of the effect on ARM64 shows a reduction of calls by 1.5% thus optimizing the idle entry sequence. [tglx: Massaged changelog ] Co-developed-by: Sanjeev Yadav<sanjeev.yadav@spreadtrum.com> Signed-off-by: Gaurav Jindal<gaurav.jindal@spreadtrum.com> Link: http://lkml.kernel.org/r/20160714120416.GB21099@gaurav.jindal@spreadtrum.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-07-19clockevents: Make clockevents_subsys staticBen Dooks
The clockevents_subsys struct is used for sysfs support and is not declared or used outside the file it is defined in. Fix the following warning by making it static: kernel/time/clockevents.c:648:17: warning: symbol 'clockevents_subsys' was not declared. Should it be static? Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Cc: linux-kernel@lists.codethink.co.uk Link: http://lkml.kernel.org/r/1466178974-7105-1-git-send-email-ben.dooks@codethink.co.uk Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-07-15timers/core: Convert to hotplug state machineRichard Cochran
When tearing down, call timers_dead_cpu() before notify_dead(). There is a hidden dependency between: - timers - block multiqueue - rcutree If timers_dead_cpu() comes later than blk_mq_queue_reinit_notify() that latter function causes a RCU stall. Signed-off-by: Richard Cochran <rcochran@linutronix.de> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160713153337.566790058@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-15hrtimer: Convert to hotplug state machineThomas Gleixner
Split out the clockevents callbacks instead of piggybacking them on hrtimers. This gets rid of a POST_DEAD user. See commit: 54e88fad223c ("sched: Make sure timers have migrated before killing the migration_thread") We just move the callback state to the proper place in the state machine. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160713153337.485419196@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-11posix_cpu_timer: Exit early when process has been reapedAlexey Dobriyan
Variable "now" seems to be genuinely used unintialized if branch if (CPUCLOCK_PERTHREAD(timer->it_clock)) { is not taken and branch if (unlikely(sighand == NULL)) { is taken. In this case the process has been reaped and the timer is marked as disarmed anyway. So none of the postprocessing of the sample is required. Return right away. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20160707223911.GA26483@p183.telecom.by Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-07-07Merge branch 'timers/fast-wheel' into timers/coreIngo Molnar
2016-07-07timers: Implement optimization for same expiry time in mod_timer()Anna-Maria Gleixner
The existing optimization for same expiry time in mod_timer() checks whether the timer expiry time is the same as the new requested expiry time. In the old timer wheel implementation this does not take the slack batching into account, neither does the new implementation evaluate whether the new expiry time will requeue the timer to the same bucket. To optimize that, we can calculate the resulting bucket and check if the new expiry time is different from the current expiry time. This calculation happens outside the base lock held region. If the resulting bucket is the same we can avoid taking the base lock and requeueing the timer. If the timer needs to be requeued then we have to check under the base lock whether the base time has changed between the lockless calculation and taking the lock. If it has changed we need to recalculate under the lock. This optimization takes effect for timers which are enqueued into the less granular wheel levels (1 and above). With a simple test case the functionality has been verified: Before After Match: 5.5% 86.6% Requeue: 94.5% 13.4% Recalc: <0.01% In the non optimized case the timer is requeued in 94.5% of the cases. With the index optimization in place the requeue rate drops to 13.4%. The case where the lockless index calculation has to be redone is less than 0.01%. With a real world test case (networking) we observed the following changes: Before After Match: 97.8% 99.7% Requeue: 2.2% 0.3% Recalc: <0.001% That means two percent fewer lock/requeue/unlock operations done in one of the hot path use cases of timers. Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Chris Mason <clm@fb.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160704094342.778527749@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-07timers: Split out index calculationAnna-Maria Gleixner
For further optimizations we need to seperate index calculation from queueing. No functional change. Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Chris Mason <clm@fb.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160704094342.691159619@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-07timers: Only wake softirq if necessaryThomas Gleixner
With the wheel forwading in place and with the HZ=1000 4ms folding we can avoid running the softirq at all. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Chris Mason <clm@fb.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160704094342.607650550@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-07timers: Forward the wheel clock whenever possibleThomas Gleixner
The wheel clock is stale when a CPU goes into a long idle sleep. This has the side effect that timers which are queued end up in the outer wheel levels. That results in coarser granularity. To solve this, we keep track of the idle state and forward the wheel clock whenever possible. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Chris Mason <clm@fb.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160704094342.512039360@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-07timers/nohz: Remove pointless tick_nohz_kick_tick() functionThomas Gleixner
This was a failed attempt to optimize the timer expiry in idle, which was disabled and never revisited. Remove the cruft. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Chris Mason <clm@fb.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160704094342.431073782@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-07timers: Optimize collect_expired_timers() for NOHZAnna-Maria Gleixner
After a NOHZ idle sleep the timer wheel must be forwarded to current jiffies. There might be expired timers so the current code loops and checks the expired buckets for timers. This can take quite some time for long NOHZ idle periods. The pending bitmask in the timer base allows us to do a quick search for the next expiring timer and therefore a fast forward of the base time which prevents pointless long lasting loops. For a 3 seconds idle sleep this reduces the catchup time from ~1ms to 5us. Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Chris Mason <clm@fb.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160704094342.351296290@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-07timers: Move __run_timers() functionAnna-Maria Gleixner
Move __run_timers() below __next_timer_interrupt() and next_pending_bucket() in preparation for __run_timers() NOHZ optimization. No functional change. Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Chris Mason <clm@fb.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160704094342.271872665@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-07timers: Remove set_timer_slack() leftoversThomas Gleixner
We now have implicit batching in the timer wheel. The slack API is no longer used, so remove it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Andrew F. Davis <afd@ti.com> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Chris Mason <clm@fb.com> Cc: David S. Miller <davem@davemloft.net> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jaehoon Chung <jh80.chung@samsung.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: John Stultz <john.stultz@linaro.org> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathias Nyman <mathias.nyman@intel.com> Cc: Pali Rohár <pali.rohar@gmail.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Sebastian Reichel <sre@kernel.org> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: linux-block@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-mmc@vger.kernel.org Cc: linux-pm@vger.kernel.org Cc: linux-usb@vger.kernel.org Cc: netdev@vger.kernel.org Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160704094342.189813118@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-07timers: Switch to a non-cascading wheelThomas Gleixner
The current timer wheel has some drawbacks: 1) Cascading: Cascading can be an unbound operation and is completely pointless in most cases because the vast majority of the timer wheel timers are canceled or rearmed before expiration. (They are used as timeout safeguards, not as real timers to measure time.) 2) No fast lookup of the next expiring timer: In NOHZ scenarios the first timer soft interrupt after a long NOHZ period must fast forward the base time to the current value of jiffies. As we have no way to find the next expiring timer fast, the code loops linearly and increments the base time one by one and checks for expired timers in each step. This causes unbound overhead spikes exactly in the moment when we should wake up as fast as possible. After a thorough analysis of real world data gathered on laptops, workstations, webservers and other machines (thanks Chris!) I came to the conclusion that the current 'classic' timer wheel implementation can be modified to address the above issues. The vast majority of timer wheel timers is canceled or rearmed before expiry. Most of them are timeouts for networking and other I/O tasks. The nature of timeouts is to catch the exception from normal operation (TCP ack timed out, disk does not respond, etc.). For these kinds of timeouts the accuracy of the timeout is not really a concern. Timeouts are very often approximate worst-case values and in case the timeout fires, we already waited for a long time and performance is down the drain already. The few timers which actually expire can be split into two categories: 1) Short expiry times which expect halfways accurate expiry 2) Long term expiry times are inaccurate today already due to the batching which is done for NOHZ automatically and also via the set_timer_slack() API. So for long term expiry timers we can avoid the cascading property and just leave them in the less granular outer wheels until expiry or cancelation. Timers which are armed with a timeout larger than the wheel capacity are no longer cascaded. We expire them with the longest possible timeout (6+ days). We have not observed such timeouts in our data collection, but at least we handle them, applying the rule of the least surprise. To avoid extending the wheel levels for HZ=1000 so we can accomodate the longest observed timeouts (5 days in the network conntrack code) we reduce the first level granularity on HZ=1000 to 4ms, which effectively is the same as the HZ=250 behaviour. From our data analysis there is nothing which relies on that 1ms granularity and as a side effect we get better batching and timer locality for the networking code as well. Contrary to the classic wheel the granularity of the next wheel is not the capacity of the first wheel. The granularities of the wheels are in the currently chosen setting 8 times the granularity of the previous wheel. So for HZ=250 we end up with the following granularity levels: Level Offset Granularity Range 0 0 4 ms 0 ms - 252 ms 1 64 32 ms 256 ms - 2044 ms (256ms - ~2s) 2 128 256 ms 2048 ms - 16380 ms (~2s - ~16s) 3 192 2048 ms (~2s) 16384 ms - 131068 ms (~16s - ~2m) 4 256 16384 ms (~16s) 131072 ms - 1048572 ms (~2m - ~17m) 5 320 131072 ms (~2m) 1048576 ms - 8388604 ms (~17m - ~2h) 6 384 1048576 ms (~17m) 8388608 ms - 67108863 ms (~2h - ~18h) 7 448 8388608 ms (~2h) 67108864 ms - 536870911 ms (~18h - ~6d) That's a worst case inaccuracy of 12.5% for the timers which are queued at the beginning of a level. So the new wheel concept addresses the old issues: 1) Cascading is avoided completely 2) By keeping the timers in the bucket until expiry/cancelation we can track the buckets which have timers enqueued in a bucket bitmap and therefore can look up the next expiring timer very fast and O(1). A further benefit of the concept is that the slack calculation which is done on every timer start is no longer necessary because the granularity levels provide natural batching already. Our extensive testing with various loads did not show any performance degradation vs. the current wheel implementation. This patch does not address the 'fast lookup' issue as we wanted to make sure that there is no regression introduced by the wheel redesign. The optimizations are in follow up patches. This patch contains fixes from Anna-Maria Gleixner and Richard Cochran. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Chris Mason <clm@fb.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160704094342.108621834@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-07timers: Give a few structs and members proper namesThomas Gleixner
Some of the names in the internal implementation of the timer code are not longer correct and others are simply too long to type. Clean it up before we switch the wheel implementation over to the new scheme. No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Chris Mason <clm@fb.com> Cc: Eric Dumazet <edumazet@google.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160704094341.948752516@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-07timers: Remove the deprecated mod_timer_pinned() APIThomas Gleixner
We switched all users to initialize the timers as pinned and call mod_timer(). Remove the now unused timer API function. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Chris Mason <clm@fb.com> Cc: Eric Dumazet <edumazet@google.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160704094341.706205231@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-07timers: Make 'pinned' a timer propertyThomas Gleixner
We want to move the timer migration logic from a 'push' to a 'pull' model. Under the current 'push' model pinned timers are handled via a runtime API variant: mod_timer_pinned(). The 'pull' model requires us to store the pinned attribute of a timer in the timer_list structure itself, as a new TIMER_PINNED bit in timer->flags. This flag must be set at initialization time and the timer APIs recognize the flag. This patch: - Implements the new flag and associated new-style initialization methods - makes mod_timer() recognize new-style pinned timers, - and adds some migration helper facility to allow step by step conversion of old-style to new-style pinned timers. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Chris Mason <clm@fb.com> Cc: Eric Dumazet <edumazet@google.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160704094341.049338558@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-05tick/broadcast-hrtimer: Set name of the ce_broadcast_hrtimerJisheng Zhang
This is to avoid the "null" name when we either ~ # cat /sys/devices/system/clockevents/broadcast/current_device (null) or ~ # cat /proc/timer_list ... Tick Device: mode: 1 Broadcast device Clock Event Device: (null) ... Signed-off-by: Jisheng Zhang <jszhang@marvell.com> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1467709071-3667-1-git-send-email-jszhang@marvell.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-07-01timers/nohz: Capitalize 'CPU' consistentlyIngo Molnar
While reviewing another patch I noticed that kernel/time/tick-sched.c had a charmingly (confusingly, annoyingly) rich set of variants for spelling 'CPU': cpu cpus CPU CPUs per CPU per-CPU per cpu ... sometimes these were mixed even within the same comment block! Compress these variants down to a single consistent set of: CPU CPUs per-CPU Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-01timers/nohz: Fix several typosWei Jiangang
Signed-off-by: Wei Jiangang <weijg.fnst@cn.fujitsu.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: fenghua.yu@intel.com Link: http://lkml.kernel.org/r/1467175910-2966-2-git-send-email-weijg.fnst@cn.fujitsu.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-30timekeeping: export get_monotonic_coarse64 symbolGregor Boirie
EXPORT_SYMBOL() get_monotonic_coarse64 for new IIO timestamping clock selection usage. This provides user apps the ability to request a particular IIO device to timestamp samples using a monotonic coarse clock granularity. Signed-off-by: Gregor Boirie <gregor.boirie@parrot.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2016-06-21Merge branch 'fortglx/4.8/time' of ↵Thomas Gleixner
https://git.linaro.org/people/john.stultz/linux into timers/core Pull time(keeping) updates from John Stultz: - Handle the 1ns issue with the old refusing to die vsyscall machinery - More y2038 updates - Documentation fixes - Simplify clocksource handling
2016-06-20timer: Avoid using timespecArnd Bergmann
The tstats_show() function prints a ktime_t variable by converting it to struct timespec first. The algorithm is ok, but we want to stop using timespec in general because of the 32-bit time_t overflow problem. This changes the code to use struct timespec64, without any functional change. Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-06-20time: Avoid timespec in udelay_testArnd Bergmann
udelay_test_single() uses ktime_get_ts() to get two timespec values and calculate the difference between them, while udelay_test_show() uses the same to printk() the current monotonic time. Both of these are y2038 safe on all machines, but we want to get rid of struct timespec anyway, so this converts the code to use ktime_get_ns() and ktime_get_ts64() respectively. Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-06-20time: Add time64_to_tm()Deepa Dinamani
time_to_tm() takes time_t as an argument. time_t is not y2038 safe. Add time64_to_tm() that takes time64_t as an argument which is y2038 safe. The plan is to eventually replace all calls to time_to_tm() by time64_to_tm(). Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-06-20alarmtimer: Fix comments describing structure fieldsPratyush Patel
Updated struct alarm and struct alarm_timer descriptions. Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Pratyush Patel <pratyushpatel.1995@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-06-20timekeeping: Fix 1ns/tick drift with GENERIC_TIME_VSYSCALL_OLDThomas Graziadei
The user notices the problem in a raw and real time drift, calling clock_gettime with CLOCK_REALTIME / CLOCK_MONOTONIC_RAW on a system with no ntp correction taking place (no ntpd or ptp stuff running). The problem is, that old_vsyscall_fixup adds an extra 1ns even though xtime_nsec is already held in full nsecs and the remainder in this case is 0. Do the rounding up buisness only if needed. Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Thomas Graziadei <thomas.graziadei@omicronenergy.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-06-20clocksource: Make clocksource insert entry more efficientMinfei Huang
In clocksource_enqueue(), it is unnecessary to continue looping the list, if we find there is an entry that the value of rating is smaller than the new one. It is safe to be out the loop, because all of entry are inserted in descending order. Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Minfei Huang <mnghuan@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-06-10hrtimer: Remove redundant #ifdef blockPratyush Patel
Only need CONFIG_NO_HZ_COMMON as this block is already in a CONFIG_SMP block. Signed-off-by: Pratyush Patel <pratyushpatel.1995@gmail.com> Link: http://lkml.kernel.org/r/20160301172849.GA18152@cyborg Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-06-10timers: Clarify usleep_range() function commentBjorn Helgaas
Update the usleep_range() function comment to make it clear that it can only be used in non-atomic context. Previously we claimed usleep_range() was a drop-in replacement for udelay() where wakeup is flexible. But that's only true in non-atomic contexts, where it's possible to sleep instead of delay. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/20160531212302.28502.44995.stgit@bhelgaas-glaptop2.roam.corp.google.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-31timer: Export destroy_hrtimer_on_stack()Guenter Roeck
hrtimer_init_on_stack() needs a matching call to destroy_hrtimer_on_stack(), so both need to be exported. Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-19debugobjects: insulate non-fixup logic related to static obj from fixup ↵Du, Changbin
callbacks When activating a static object we need make sure that the object is tracked in the object tracker. If it is a non-static object then the activation is illegal. In previous implementation, each subsystem need take care of this in their fixup callbacks. Actually we can put it into debugobjects core. Thus we can save duplicated code, and have *pure* fixup callbacks. To achieve this, a new callback "is_static_object" is introduced to let the type specific code decide whether a object is static or not. If yes, we take it into object tracker, otherwise give warning and invoke fixup callback. This change has paassed debugobjects selftest, and I also do some test with all debugobjects supports enabled. At last, I have a concern about the fixups that can it change the object which is in incorrect state on fixup? Because the 'addr' may not point to any valid object if a non-static object is not tracked. Then Change such object can overwrite someone's memory and cause unexpected behaviour. For example, the timer_fixup_activate bind timer to function stub_timer. Link: http://lkml.kernel.org/r/1462576157-14539-1-git-send-email-changbin.du@intel.com [changbin.du@intel.com: improve code comments where invoke the new is_static_object callback] Link: http://lkml.kernel.org/r/1462777431-8171-1-git-send-email-changbin.du@intel.com Signed-off-by: Du, Changbin <changbin.du@intel.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Triplett <josh@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tejun Heo <tj@kernel.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19timer: update debugobjects fixup callbacks return typeDu, Changbin
Update the return type to use bool instead of int, corresponding to cheange (debugobjects: make fixup functions return bool instead of int). Signed-off-by: Du, Changbin <changbin.du@intel.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Triplett <josh@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tejun Heo <tj@kernel.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19time: remove timespec_add_safe()Deepa Dinamani
All references to timespec_add_safe() now use timespec64_add_safe(). The plan is to replace struct timespec references with struct timespec64 throughout the kernel as timespec is not y2038 safe. Drop timespec_add_safe() and use timespec64_add_safe() for all architectures. Link: http://lkml.kernel.org/r/1461947989-21926-4-git-send-email-deepa.kernel@gmail.com Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19time: add missing implementation for timespec64_add_safe()Deepa Dinamani
timespec64_add_safe() has been defined in time64.h for 64 bit systems. But, 32 bit systems only have an extern function prototype defined. Provide a definition for the above function. The function will be necessary as part of y2038 changes. struct timespec is not y2038 safe. All references to timespec will be replaced by struct timespec64. The function is meant to be a replacement for timespec_add_safe(). The implementation is similar to timespec_add_safe(). Link: http://lkml.kernel.org/r/1461947989-21926-2-git-send-email-deepa.kernel@gmail.com Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-17Merge branch 'timers-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner: "A rather small set of patches from the timer departement: - Some more y2038 work - Yet another new clocksource driver - The usual set of small fixes, cleanups and enhancements" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: clocksource/drivers/tegra: Remove unused suspend/resume code clockevents/driversi/mps2: add MPS2 Timer driver dt-bindings: document the MPS2 timer bindings clocksource/drivers/mtk_timer: Add __init attribute clockevents/drivers/dw_apb_timer: Implement ->set_state_oneshot_stopped() time: Introduce do_sys_settimeofday64() security: Introduce security_settime64() clocksource: Add missing include of of.h.
2016-05-16Merge branch 'sched-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: - massive CPU hotplug rework (Thomas Gleixner) - improve migration fairness (Peter Zijlstra) - CPU load calculation updates/cleanups (Yuyang Du) - cpufreq updates (Steve Muckle) - nohz optimizations (Frederic Weisbecker) - switch_mm() micro-optimization on x86 (Andy Lutomirski) - ... lots of other enhancements, fixes and cleanups. * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (66 commits) ARM: Hide finish_arch_post_lock_switch() from modules sched/core: Provide a tsk_nr_cpus_allowed() helper sched/core: Use tsk_cpus_allowed() instead of accessing ->cpus_allowed sched/loadavg: Fix loadavg artifacts on fully idle and on fully loaded systems sched/fair: Correct unit of load_above_capacity sched/fair: Clean up scale confusion sched/nohz: Fix affine unpinned timers mess sched/fair: Fix fairness issue on migration sched/core: Kill sched_class::task_waking to clean up the migration logic sched/fair: Prepare to fix fairness problems on migration sched/fair: Move record_wakee() sched/core: Fix comment typo in wake_q_add() sched/core: Remove unused variable sched: Make hrtick_notifier an explicit call sched/fair: Make ilb_notifier an explicit call sched/hotplug: Make activate() the last hotplug step sched/hotplug: Move migration CPU_DYING to sched_cpu_dying() sched/migration: Move CPU_ONLINE into scheduler state sched/migration: Move calc_load_migrate() into CPU_DYING sched/migration: Move prepare transition to SCHED_STARTING state ...
2016-05-05locking/atomics: Flip atomic_fetch_or() argumentsPeter Zijlstra
All the atomic operations have their arguments the wrong way around; make atomic_fetch_or() consistent and flip them. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-23sched/fair: Correctly handle nohz ticks CPU load accountingFrederic Weisbecker
Ticks can happen while the CPU is in dynticks-idle or dynticks-singletask mode. In fact "nohz" or "dynticks" only mean that we exit the periodic mode and we try to minimize the ticks as much as possible. The nohz subsystem uses a confusing terminology with the internal state "ts->tick_stopped" which is also available through its public interface with tick_nohz_tick_stopped(). This is a misnomer as the tick is instead reduced with the best effort rather than stopped. In the best case the tick can indeed be actually stopped but there is no guarantee about that. If a timer needs to fire one second later, a tick will fire while the CPU is in nohz mode and this is a very common scenario. Now this confusion happens to be a problem with CPU load updates: cpu_load_update_active() doesn't handle nohz ticks correctly because it assumes that ticks are completely stopped in nohz mode and that cpu_load_update_active() can't be called in dynticks mode. When that happens, the whole previous tickless load is ignored and the function just records the load for the current tick, ignoring potentially long idle periods behind. In order to solve this, we could account the current load for the previous nohz time but there is a risk that we account the load of a task that got freshly enqueued for the whole nohz period. So instead, lets record the dynticks load on nohz frame entry so we know what to record in case of nohz ticks, then use this record to account the tickless load on nohz ticks and nohz frame end. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Byungchul Park <byungchul.park@lge.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1460555812-25375-3-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-23sched/fair: Gather CPU load functions under a more conventional namespaceFrederic Weisbecker
The CPU load update related functions have a weak naming convention currently, starting with update_cpu_load_*() which isn't ideal as "update" is a very generic concept. Since two of these functions are public already (and a third is to come) that's enough to introduce a more conventional naming scheme. So let's do the following rename instead: update_cpu_load_*() -> cpu_load_update_*() Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Byungchul Park <byungchul.park@lge.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1460555812-25375-2-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-22time: Introduce do_sys_settimeofday64()Baolin Wang
The do_sys_settimeofday() function uses a timespec, which is not year 2038 safe on 32bit systems. Thus this patch introduces do_sys_settimeofday64(), which allows us to transition users of do_sys_settimeofday() to using 64bit time types. Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Baolin Wang <baolin.wang@linaro.org> [jstultz: Include errno-base.h to avoid build issue on some arches] Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-03-29timers/nohz: Convert tick dependency mask to atomic_tFrederic Weisbecker
The tick dependency mask was intially unsigned long because this is the type on which clear_bit() operates on and fetch_or() accepts it. But now that we have atomic_fetch_or(), we can instead use atomic_andnot() to clear the bit. This consolidates the type of our tick dependency mask, reduce its size on structures and benefit from possible architecture optimizations on atomic_t operations. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1458830281-4255-3-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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