pm24.git/kernel/time/tick-broadcast.c, branch v5.1

timers: Mark expected switch fall-throughs

2019-01-29T19:08:42Z

In preparation to enabling -Wimplicit-fallthrough, mark switch cases where fall through is indeed expected. Signed-off-by: Gustavo A. R. Silva Signed-off-by: Thomas Gleixner Cc: Frederic Weisbecker Cc: John Stultz Cc: Stephen Boyd Link: https://lkml.kernel.org/r/20190123081413.GA3949@embeddedor

hrtimers/tick/clockevents: Remove sloppy license references

2018-11-23T10:51:21Z

"For licencing details see kernel-base/COPYING" and similar license references have no value over the SPDX identifier. Remove them. Signed-off-by: Thomas Gleixner Acked-by: Kees Cook Acked-by: Ingo Molnar Acked-by: John Stultz Acked-by: Corey Minyard Cc: Peter Zijlstra Cc: Kate Stewart Cc: Philippe Ombredanne Cc: Peter Anvin Cc: Russell King Cc: Richard Cochran Cc: "Paul E. McKenney" Cc: Nicolas Pitre Cc: David Riley Cc: Colin Cross Cc: Mark Brown Link: https://lkml.kernel.org/r/20181031182252.963632760@linutronix.de

time: Add SPDX license identifiers

2018-11-23T10:51:20Z

Update the time(r) core files files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Philippe Ombredanne, Kate Stewart and myself. The data has been created with two independent license scanners and manual inspection. The following files do not contain any direct license information and have been omitted from the big initial SPDX changes: timeconst.bc: The .bc files were not touched time.c, timer.c, timekeeping.c: Licence was deduced from EXPORT_SYMBOL_GPL As those files do not contain direct license references they fall under the project license, i.e. GPL V2 only. Signed-off-by: Thomas Gleixner Acked-by: Kees Cook Acked-by: Ingo Molnar Acked-by: John Stultz Acked-by: Corey Minyard Cc: Peter Zijlstra Cc: Kate Stewart Cc: Philippe Ombredanne Cc: Russell King Cc: Richard Cochran Cc: Nicolas Pitre Cc: David Riley Cc: Colin Cross Cc: Mark Brown Cc: H. Peter Anvin Cc: Paul E. McKenney Link: https://lkml.kernel.org/r/20181031182252.879109557@linutronix.de

time: Remove useless filenames in top level comments

2018-11-23T10:51:20Z

Remove the pointless filenames in the top level comments. They have no value at all and just occupy space. While at it tidy up some of the comments and remove a stale one. Signed-off-by: Thomas Gleixner Acked-by: Nicolas Pitre Acked-by: Kees Cook Acked-by: Ingo Molnar Acked-by: John Stultz Acked-by: Corey Minyard Cc: Peter Zijlstra Cc: Kate Stewart Cc: Philippe Ombredanne Cc: Peter Anvin Cc: Russell King Cc: Richard Cochran Cc: "Paul E. McKenney" Cc: David Riley Cc: Colin Cross Cc: Mark Brown Link: https://lkml.kernel.org/r/20181031182252.794898238@linutronix.de

tick/broadcast: Remove redundant check

2018-09-28T20:29:35Z

tick_device_is_functional() is called early in tick_broadcast_control(), so no need to call it again later. Signed-off-by: Peng Hao Signed-off-by: Thomas Gleixner Cc: fweisbec@gmail.com Link: https://lkml.kernel.org/r/1538150608-2599-1-git-send-email-penghao122@sina.com.cn

tick/broadcast: Use for_each_cpu() specially on UP kernels

2018-05-15T20:45:54Z

for_each_cpu() unintuitively reports CPU0 as set independent of the actual cpumask content on UP kernels. This causes an unexpected PIT interrupt storm on a UP kernel running in an SMP virtual machine on Hyper-V, and as a result, the virtual machine can suffer from a strange random delay of 1~20 minutes during boot-up, and sometimes it can hang forever. Protect if by checking whether the cpumask is empty before entering the for_each_cpu() loop. [ tglx: Use !IS_ENABLED(CONFIG_SMP) instead of #ifdeffery ] Signed-off-by: Dexuan Cui Signed-off-by: Thomas Gleixner Cc: Josh Poulson Cc: "Michael Kelley (EOSG)" Cc: Peter Zijlstra Cc: Frederic Weisbecker Cc: stable@vger.kernel.org Cc: Rakib Mullick Cc: Jork Loeser Cc: Greg Kroah-Hartman Cc: Andrew Morton Cc: KY Srinivasan Cc: Linus Torvalds Cc: Alexey Dobriyan Cc: Dmitry Vyukov Link: https://lkml.kernel.org/r/KL1P15301MB000678289FE55BA365B3279ABF990@KL1P15301MB0006.APCP153.PROD.OUTLOOK.COM Link: https://lkml.kernel.org/r/KL1P15301MB0006FA63BC22BEB64902EAA0BF930@KL1P15301MB0006.APCP153.PROD.OUTLOOK.COM

tick/broadcast: Make tick_broadcast_setup_oneshot() static

2017-06-12T16:56:01Z

This function isn't used outside of tick-broadcast.c, so let's mark it static. Signed-off-by: Stephen Boyd Link: http://lkml.kernel.org/r/20170608063603.13276-1-sboyd@codeaurora.org Signed-off-by: Thomas Gleixner

Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2017-02-20T18:06:32Z

Pull timer updates from Thomas Gleixner: "Nothing exciting, just the usual pile of fixes, updates and cleanups: - A bunch of clocksource driver updates - Removal of CONFIG_TIMER_STATS and the related /proc file - More posix timer slim down work - A scalability enhancement in the tick broadcast code - Math cleanups" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits) hrtimer: Catch invalid clockids again math64, tile: Fix build failure clocksource/drivers/arm_arch_timer:: Mark cyclecounter __ro_after_init timerfd: Protect the might cancel mechanism proper timer_list: Remove useless cast when printing time: Remove CONFIG_TIMER_STATS clocksource/drivers/arm_arch_timer: Work around Hisilicon erratum 161010101 clocksource/drivers/arm_arch_timer: Introduce generic errata handling infrastructure clocksource/drivers/arm_arch_timer: Remove fsl-a008585 parameter clocksource/drivers/arm_arch_timer: Add dt binding for hisilicon-161010101 erratum clocksource/drivers/ostm: Add renesas-ostm timer driver clocksource/drivers/ostm: Document renesas-ostm timer DT bindings clocksource/drivers/tcb_clksrc: Use 32 bit tcb as sched_clock clocksource/drivers/gemini: Add driver for the Cortina Gemini clocksource: add DT bindings for Cortina Gemini clockevents: Add a clkevt-of mechanism like clksrc-of tick/broadcast: Reduce lock cacheline contention timers: Omit POSIX timer stuff from task_struct when disabled x86/timer: Make delay() work during early bootup delay: Add explanation of udelay() inaccuracy ...

tick/broadcast: Prevent deadlock on tick_broadcast_lock

2017-02-13T08:49:31Z

tick_broadcast_lock is taken from interrupt context, but the following call chain takes the lock without disabling interrupts: [ 12.703736] _raw_spin_lock+0x3b/0x50 [ 12.703738] tick_broadcast_control+0x5a/0x1a0 [ 12.703742] intel_idle_cpu_online+0x22/0x100 [ 12.703744] cpuhp_invoke_callback+0x245/0x9d0 [ 12.703752] cpuhp_thread_fun+0x52/0x110 [ 12.703754] smpboot_thread_fn+0x276/0x320 So the following deadlock can happen: lock(tick_broadcast_lock); lock(tick_broadcast_lock); intel_idle_cpu_online() is the only place which violates the calling convention of tick_broadcast_control(). This was caused by the removal of the smp function call in course of the cpu hotplug rework. Instead of slapping local_irq_disable/enable() at the call site, we can relax the calling convention and handle it in the core code, which makes the whole machinery more robust. Fixes: 29d7bbada98e ("intel_idle: Remove superfluous SMP fuction call") Reported-by: Gabriel C Signed-off-by: Mike Galbraith Cc: Ruslan Ruslichenko Cc: Jiri Slaby Cc: Greg KH Cc: Borislav Petkov Cc: lwn@lwn.net Cc: Andrew Morton Cc: Linus Torvalds Cc: Anna-Maria Gleixner Cc: Sebastian Siewior Cc: stable Link: http://lkml.kernel.org/r/1486953115.5912.4.camel@gmx.de Signed-off-by: Thomas Gleixner

tick/broadcast: Reduce lock cacheline contention

2017-02-04T07:54:46Z

It was observed that on an Intel x86 system without the ARAT (Always running APIC timer) feature and with fairly large number of CPUs as well as CPUs coming in and out of intel_idle frequently, the lock contention on the tick_broadcast_lock can become significant. To reduce contention, the lock is put into its own cacheline and all the cpumask_var_t variables are put into the __read_mostly section. Running the SP benchmark of the NAS Parallel Benchmarks on a 4-socket 16-core 32-thread Nehalam system, the performance number improved from 3353.94 Mop/s to 3469.31 Mop/s when this patch was applied on a 4.9.6 kernel. This is a 3.4% improvement. Signed-off-by: Waiman Long Cc: "Peter Zijlstra (Intel)" Cc: Andrew Morton Link: http://lkml.kernel.org/r/1485799063-20857-1-git-send-email-longman@redhat.com Signed-off-by: Thomas Gleixner