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* Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2017-02-206-167/+115
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: "The main changes in this (fairly busy) cycle were: - There was a class of scheduler bugs related to forgetting to update the rq-clock timestamp which can cause weird and hard to debug problems, so there's a new debug facility for this: which uncovered a whole lot of bugs which convinced us that we want to keep the debug facility. (Peter Zijlstra, Matt Fleming) - Various cputime related updates: eliminate cputime and use u64 nanoseconds directly, simplify and improve the arch interfaces, implement delayed accounting more widely, etc. - (Frederic Weisbecker) - Move code around for better structure plus cleanups (Ingo Molnar) - Move IO schedule accounting deeper into the scheduler plus related changes to improve the situation (Tejun Heo) - ... plus a round of sched/rt and sched/deadline fixes, plus other fixes, updats and cleanups" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (85 commits) sched/core: Remove unlikely() annotation from sched_move_task() sched/autogroup: Rename auto_group.[ch] to autogroup.[ch] sched/topology: Split out scheduler topology code from core.c into topology.c sched/core: Remove unnecessary #include headers sched/rq_clock: Consolidate the ordering of the rq_clock methods delayacct: Include <uapi/linux/taskstats.h> sched/core: Clean up comments sched/rt: Show the 'sched_rr_timeslice' SCHED_RR timeslice tuning knob in milliseconds sched/clock: Add dummy clear_sched_clock_stable() stub function sched/cputime: Remove generic asm headers sched/cputime: Remove unused nsec_to_cputime() s390, sched/cputime: Remove unused cputime definitions powerpc, sched/cputime: Remove unused cputime definitions s390, sched/cputime: Make arch_cpu_idle_time() to return nsecs ia64, sched/cputime: Remove unused cputime definitions ia64: Convert vtime to use nsec units directly ia64, sched/cputime: Move the nsecs based cputime headers to the last arch using it sched/cputime: Remove jiffies based cputime sched/cputime, vtime: Return nsecs instead of cputime_t to account sched/cputime: Complete nsec conversion of tick based accounting ...
| * timers/itimer: Convert internal cputime_t units to nsecFrederic Weisbecker2017-02-012-68/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use the new nsec based cputime accessors as part of the whole cputime conversion from cputime_t to nsecs. Also convert itimers to use nsec based internal counters. This simplifies it and removes the whole game with error/inc_error which served to deal with cputime_t random granularity. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Link: http://lkml.kernel.org/r/1485832191-26889-20-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * timers/posix-timers: Convert internals to use nsecsFrederic Weisbecker2017-02-012-126/+90
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use the new nsec based cputime accessors as part of the whole cputime conversion from cputime_t to nsecs. Also convert posix-cpu-timers to use nsec based internal counters to simplify it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Link: http://lkml.kernel.org/r/1485832191-26889-19-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * timers/posix-timers: Use TICK_NSEC instead of a dynamically ad-hoc ↵Frederic Weisbecker2017-02-011-9/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | calculated version Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Link: http://lkml.kernel.org/r/1485832191-26889-18-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * sched/cputime: Introduce special task_cputime_t() API to return old-typed ↵Frederic Weisbecker2017-02-012-24/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cputime This API returns a task's cputime in cputime_t in order to ease the conversion of cputime internals to use nsecs units instead. Blindly converting all cputime readers to use this API now will later let us convert more smoothly and step by step all these places to use the new nsec based cputime. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Link: http://lkml.kernel.org/r/1485832191-26889-7-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * time: Introduce jiffies64_to_nsecs()Frederic Weisbecker2017-02-012-0/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This will be needed for the cputime_t to nsec conversion. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Link: http://lkml.kernel.org/r/1485832191-26889-2-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * jiffies: Reuse TICK_NSEC instead of NSEC_PER_JIFFYFrederic Weisbecker2017-02-011-16/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | NSEC_PER_JIFFY is an ad-hoc redefinition of TICK_NSEC. Let's rather use a unique and well maintained version. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Link: http://lkml.kernel.org/r/1485832191-26889-1-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * Merge branch 'linus' into sched/core, to pick up fixes and refresh the branchIngo Molnar2017-02-012-2/+9
| |\ | | | | | | | | | Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | sched/clock, clocksource: Add optional cs::mark_unstable() methodThomas Gleixner2017-01-141-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | PeterZ reported that we'd fail to mark the TSC unstable when the clocksource watchdog finds it unsuitable. Allow a clocksource to run a custom action when its being marked unstable and hook up the TSC unstable code. Reported-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | Merge branch 'timers-core-for-linus' of ↵Linus Torvalds2017-02-208-573/+27
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 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 ...
| * | | hrtimer: Catch invalid clockids againMarc Zyngier2017-02-181-5/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 82e88ff1ea94 ("hrtimer: Revert CLOCK_MONOTONIC_RAW support") removed unfortunately a sanity check in the hrtimer code which was part of that MONOTONIC_RAW patch series. It would have caught the bogus usage of CLOCK_MONOTONIC_RAW in the wireless code. So bring it back. It is way too easy to take any random clockid and feed it to the hrtimer subsystem. At best, it gets mapped to a monotonic base, but it would be better to just catch illegal values as early as possible. Detect invalid clockids, map them to CLOCK_MONOTONIC and emit a warning. [ tglx: Replaced the BUG by a WARN and gracefully map to CLOCK_MONOTONIC ] Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Tomasz Nowicki <tn@semihalf.com> Cc: Christoffer Dall <christoffer.dall@linaro.org> Link: http://lkml.kernel.org/r/1452879670-16133-3-git-send-email-marc.zyngier@arm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | timer_list: Remove useless cast when printingMars Cheng2017-02-101-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | hrtimer_resolution is already unsigned int, not necessary to cast it when printing. Signed-off-by: Mars Cheng <mars.cheng@mediatek.com> Cc: CC Hwang <cc.hwang@mediatek.com> Cc: wsd_upstream@mediatek.com Cc: Loda Chou <loda.chou@mediatek.com> Cc: Jades Shih <jades.shih@mediatek.com> Cc: Miles Chen <miles.chen@mediatek.com> Cc: John Stultz <john.stultz@linaro.org> Cc: My Chuang <my.chuang@mediatek.com> Cc: Matthias Brugger <matthias.bgg@gmail.com> Cc: Yingjoe Chen <yingjoe.chen@mediatek.com> Link: http://lkml.kernel.org/r/1486626615-5879-1-git-send-email-mars.cheng@mediatek.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | time: Remove CONFIG_TIMER_STATSKees Cook2017-02-105-520/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently CONFIG_TIMER_STATS exposes process information across namespaces: kernel/time/timer_list.c print_timer(): SEQ_printf(m, ", %s/%d", tmp, timer->start_pid); /proc/timer_list: #11: <0000000000000000>, hrtimer_wakeup, S:01, do_nanosleep, cron/2570 Given that the tracer can give the same information, this patch entirely removes CONFIG_TIMER_STATS. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: linux-doc@vger.kernel.org Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Xing Gao <xgao01@email.wm.edu> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jessica Frazelle <me@jessfraz.com> Cc: kernel-hardening@lists.openwall.com Cc: Nicolas Iooss <nicolas.iooss_linux@m4x.org> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Michal Marek <mmarek@suse.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Olof Johansson <olof@lixom.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-api@vger.kernel.org Cc: Arjan van de Ven <arjan@linux.intel.com> Link: http://lkml.kernel.org/r/20170208192659.GA32582@beast Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | tick/broadcast: Reduce lock cacheline contentionWaiman Long2017-02-041-7/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <longman@redhat.com> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1485799063-20857-1-git-send-email-longman@redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | timekeeping: Remove unused timekeeping_{get,set}_tai_offset()Stephen Boyd2017-01-062-40/+1
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The last caller to timekeeping_set_tai_offset() was in commit 0b5154fb9040 (timekeeping: Simplify tai updating from do_adjtimex, 2013-03-22) and the last caller to timekeeping_get_tai_offset() was in commit 76f4108892d9 (hrtimer: Cleanup hrtimer accessors to the timekepeing state, 2014-07-16). Remove these unused functions now that we handle TAI offsets differently. Cc: John Stultz <john.stultz@linaro.org> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
* | | Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds2017-02-182-10/+9
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fixes from Thomas Gleixner: "Two small fixes:: - Prevent deadlock on the tick broadcast lock. Found and fixed by Mike. - Stop using printk() in the timekeeping debug code to prevent a deadlock against the scheduler" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timekeeping: Use deferred printk() in debug code tick/broadcast: Prevent deadlock on tick_broadcast_lock
| * | | timekeeping: Use deferred printk() in debug codeSergey Senozhatsky2017-02-151-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We cannot do printk() from tk_debug_account_sleep_time(), because tk_debug_account_sleep_time() is called under tk_core seq lock. The reason why printk() is unsafe there is that console_sem may invoke scheduler (up()->wake_up_process()->activate_task()), which, in turn, can return back to timekeeping code, for instance, via get_time()->ktime_get(), deadlocking the system on tk_core seq lock. [ 48.950592] ====================================================== [ 48.950622] [ INFO: possible circular locking dependency detected ] [ 48.950622] 4.10.0-rc7-next-20170213+ #101 Not tainted [ 48.950622] ------------------------------------------------------- [ 48.950622] kworker/0:0/3 is trying to acquire lock: [ 48.950653] (tk_core){----..}, at: [<c01cc624>] retrigger_next_event+0x4c/0x90 [ 48.950683] but task is already holding lock: [ 48.950683] (hrtimer_bases.lock){-.-...}, at: [<c01cc610>] retrigger_next_event+0x38/0x90 [ 48.950714] which lock already depends on the new lock. [ 48.950714] the existing dependency chain (in reverse order) is: [ 48.950714] -> #5 (hrtimer_bases.lock){-.-...}: [ 48.950744] _raw_spin_lock_irqsave+0x50/0x64 [ 48.950775] lock_hrtimer_base+0x28/0x58 [ 48.950775] hrtimer_start_range_ns+0x20/0x5c8 [ 48.950775] __enqueue_rt_entity+0x320/0x360 [ 48.950805] enqueue_rt_entity+0x2c/0x44 [ 48.950805] enqueue_task_rt+0x24/0x94 [ 48.950836] ttwu_do_activate+0x54/0xc0 [ 48.950836] try_to_wake_up+0x248/0x5c8 [ 48.950836] __setup_irq+0x420/0x5f0 [ 48.950836] request_threaded_irq+0xdc/0x184 [ 48.950866] devm_request_threaded_irq+0x58/0xa4 [ 48.950866] omap_i2c_probe+0x530/0x6a0 [ 48.950897] platform_drv_probe+0x50/0xb0 [ 48.950897] driver_probe_device+0x1f8/0x2cc [ 48.950897] __driver_attach+0xc0/0xc4 [ 48.950927] bus_for_each_dev+0x6c/0xa0 [ 48.950927] bus_add_driver+0x100/0x210 [ 48.950927] driver_register+0x78/0xf4 [ 48.950958] do_one_initcall+0x3c/0x16c [ 48.950958] kernel_init_freeable+0x20c/0x2d8 [ 48.950958] kernel_init+0x8/0x110 [ 48.950988] ret_from_fork+0x14/0x24 [ 48.950988] -> #4 (&rt_b->rt_runtime_lock){-.-...}: [ 48.951019] _raw_spin_lock+0x40/0x50 [ 48.951019] rq_offline_rt+0x9c/0x2bc [ 48.951019] set_rq_offline.part.2+0x2c/0x58 [ 48.951049] rq_attach_root+0x134/0x144 [ 48.951049] cpu_attach_domain+0x18c/0x6f4 [ 48.951049] build_sched_domains+0xba4/0xd80 [ 48.951080] sched_init_smp+0x68/0x10c [ 48.951080] kernel_init_freeable+0x160/0x2d8 [ 48.951080] kernel_init+0x8/0x110 [ 48.951080] ret_from_fork+0x14/0x24 [ 48.951110] -> #3 (&rq->lock){-.-.-.}: [ 48.951110] _raw_spin_lock+0x40/0x50 [ 48.951141] task_fork_fair+0x30/0x124 [ 48.951141] sched_fork+0x194/0x2e0 [ 48.951141] copy_process.part.5+0x448/0x1a20 [ 48.951171] _do_fork+0x98/0x7e8 [ 48.951171] kernel_thread+0x2c/0x34 [ 48.951171] rest_init+0x1c/0x18c [ 48.951202] start_kernel+0x35c/0x3d4 [ 48.951202] 0x8000807c [ 48.951202] -> #2 (&p->pi_lock){-.-.-.}: [ 48.951232] _raw_spin_lock_irqsave+0x50/0x64 [ 48.951232] try_to_wake_up+0x30/0x5c8 [ 48.951232] up+0x4c/0x60 [ 48.951263] __up_console_sem+0x2c/0x58 [ 48.951263] console_unlock+0x3b4/0x650 [ 48.951263] vprintk_emit+0x270/0x474 [ 48.951293] vprintk_default+0x20/0x28 [ 48.951293] printk+0x20/0x30 [ 48.951324] kauditd_hold_skb+0x94/0xb8 [ 48.951324] kauditd_thread+0x1a4/0x56c [ 48.951324] kthread+0x104/0x148 [ 48.951354] ret_from_fork+0x14/0x24 [ 48.951354] -> #1 ((console_sem).lock){-.....}: [ 48.951385] _raw_spin_lock_irqsave+0x50/0x64 [ 48.951385] down_trylock+0xc/0x2c [ 48.951385] __down_trylock_console_sem+0x24/0x80 [ 48.951385] console_trylock+0x10/0x8c [ 48.951416] vprintk_emit+0x264/0x474 [ 48.951416] vprintk_default+0x20/0x28 [ 48.951416] printk+0x20/0x30 [ 48.951446] tk_debug_account_sleep_time+0x5c/0x70 [ 48.951446] __timekeeping_inject_sleeptime.constprop.3+0x170/0x1a0 [ 48.951446] timekeeping_resume+0x218/0x23c [ 48.951477] syscore_resume+0x94/0x42c [ 48.951477] suspend_enter+0x554/0x9b4 [ 48.951477] suspend_devices_and_enter+0xd8/0x4b4 [ 48.951507] enter_state+0x934/0xbd4 [ 48.951507] pm_suspend+0x14/0x70 [ 48.951507] state_store+0x68/0xc8 [ 48.951538] kernfs_fop_write+0xf4/0x1f8 [ 48.951538] __vfs_write+0x1c/0x114 [ 48.951538] vfs_write+0xa0/0x168 [ 48.951568] SyS_write+0x3c/0x90 [ 48.951568] __sys_trace_return+0x0/0x10 [ 48.951568] -> #0 (tk_core){----..}: [ 48.951599] lock_acquire+0xe0/0x294 [ 48.951599] ktime_get_update_offsets_now+0x5c/0x1d4 [ 48.951629] retrigger_next_event+0x4c/0x90 [ 48.951629] on_each_cpu+0x40/0x7c [ 48.951629] clock_was_set_work+0x14/0x20 [ 48.951660] process_one_work+0x2b4/0x808 [ 48.951660] worker_thread+0x3c/0x550 [ 48.951660] kthread+0x104/0x148 [ 48.951690] ret_from_fork+0x14/0x24 [ 48.951690] other info that might help us debug this: [ 48.951690] Chain exists of: tk_core --> &rt_b->rt_runtime_lock --> hrtimer_bases.lock [ 48.951721] Possible unsafe locking scenario: [ 48.951721] CPU0 CPU1 [ 48.951721] ---- ---- [ 48.951721] lock(hrtimer_bases.lock); [ 48.951751] lock(&rt_b->rt_runtime_lock); [ 48.951751] lock(hrtimer_bases.lock); [ 48.951751] lock(tk_core); [ 48.951782] *** DEADLOCK *** [ 48.951782] 3 locks held by kworker/0:0/3: [ 48.951782] #0: ("events"){.+.+.+}, at: [<c0156590>] process_one_work+0x1f8/0x808 [ 48.951812] #1: (hrtimer_work){+.+...}, at: [<c0156590>] process_one_work+0x1f8/0x808 [ 48.951843] #2: (hrtimer_bases.lock){-.-...}, at: [<c01cc610>] retrigger_next_event+0x38/0x90 [ 48.951843] stack backtrace: [ 48.951873] CPU: 0 PID: 3 Comm: kworker/0:0 Not tainted 4.10.0-rc7-next-20170213+ [ 48.951904] Workqueue: events clock_was_set_work [ 48.951904] [<c0110208>] (unwind_backtrace) from [<c010c224>] (show_stack+0x10/0x14) [ 48.951934] [<c010c224>] (show_stack) from [<c04ca6c0>] (dump_stack+0xac/0xe0) [ 48.951934] [<c04ca6c0>] (dump_stack) from [<c019b5cc>] (print_circular_bug+0x1d0/0x308) [ 48.951965] [<c019b5cc>] (print_circular_bug) from [<c019d2a8>] (validate_chain+0xf50/0x1324) [ 48.951965] [<c019d2a8>] (validate_chain) from [<c019ec18>] (__lock_acquire+0x468/0x7e8) [ 48.951995] [<c019ec18>] (__lock_acquire) from [<c019f634>] (lock_acquire+0xe0/0x294) [ 48.951995] [<c019f634>] (lock_acquire) from [<c01d0ea0>] (ktime_get_update_offsets_now+0x5c/0x1d4) [ 48.952026] [<c01d0ea0>] (ktime_get_update_offsets_now) from [<c01cc624>] (retrigger_next_event+0x4c/0x90) [ 48.952026] [<c01cc624>] (retrigger_next_event) from [<c01e4e24>] (on_each_cpu+0x40/0x7c) [ 48.952056] [<c01e4e24>] (on_each_cpu) from [<c01cafc4>] (clock_was_set_work+0x14/0x20) [ 48.952056] [<c01cafc4>] (clock_was_set_work) from [<c015664c>] (process_one_work+0x2b4/0x808) [ 48.952087] [<c015664c>] (process_one_work) from [<c0157774>] (worker_thread+0x3c/0x550) [ 48.952087] [<c0157774>] (worker_thread) from [<c015d644>] (kthread+0x104/0x148) [ 48.952087] [<c015d644>] (kthread) from [<c0107830>] (ret_from_fork+0x14/0x24) Replace printk() with printk_deferred(), which does not call into the scheduler. Fixes: 0bf43f15db85 ("timekeeping: Prints the amounts of time spent during suspend") Reported-and-tested-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Rafael J . Wysocki" <rjw@rjwysocki.net> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: John Stultz <john.stultz@linaro.org> Cc: "[4.9+]" <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20170215044332.30449-1-sergey.senozhatsky@gmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | tick/broadcast: Prevent deadlock on tick_broadcast_lockMike Galbraith2017-02-131-8/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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); <Interrupt> 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 <nix.or.die@gmail.com> Signed-off-by: Mike Galbraith <efault@gmx.de> Cc: Ruslan Ruslichenko <rruslich@cisco.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: lwn@lwn.net Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Anna-Maria Gleixner <anna-maria@linutronix.de> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: stable <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/1486953115.5912.4.camel@gmx.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | | Revert "nohz: Fix collision between tick and other hrtimers"Linus Torvalds2017-02-162-14/+2
|/ / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit 24b91e360ef521a2808771633d76ebc68bd5604b and commit 7bdb59f1ad47 ("tick/nohz: Fix possible missing clock reprog after tick soft restart") that depends on it, Pavel reports that it causes occasional boot hangs for him that seem to depend on just how the machine was booted. In particular, his machine hangs at around the PCI fixups of the EHCI USB host controller, but only hangs from cold boot, not from a warm boot. Thomas Gleixner suspecs it's a CPU hotplug interaction, particularly since Pavel also saw suspend/resume issues that seem to be related. We're reverting for now while trying to figure out the root cause. Reported-bisected-and-tested-by: Pavel Machek <pavel@ucw.cz> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@kernel.org # reverted commits were marked for stable Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | / tick/nohz: Fix possible missing clock reprog after tick soft restartFrederic Weisbecker2017-02-101-0/+5
| |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ts->next_tick keeps track of the next tick deadline in order to optimize clock programmation on irq exit and avoid redundant clock device writes. Now if ts->next_tick missed an update, we may spuriously miss a clock reprog later as the nohz code is fooled by an obsolete next_tick value. This is what happens here on a specific path: when we observe an expired timer from the nohz update code on irq exit, we perform a soft tick restart which simply fires the closest possible tick without actually exiting the nohz mode and restoring a periodic state. But we forget to update ts->next_tick accordingly. As a result, after the next tick resulting from such soft tick restart, the nohz code sees a stale value on ts->next_tick which doesn't match the clock deadline that just expired. If that obsolete ts->next_tick value happens to collide with the actual next tick deadline to be scheduled, we may spuriously bypass the clock reprogramming. In the worst case, the tick may never fire again. Fix this with a ts->next_tick reset on soft tick restart. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Reviewed: Wanpeng Li <wanpeng.li@hotmail.com> Acked-by: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1486485894-29173-1-git-send-email-fweisbec@gmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | nohz: Fix collision between tick and other hrtimersFrederic Weisbecker2017-01-112-2/+9
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the tick is stopped and an interrupt occurs afterward, we check on that interrupt exit if the next tick needs to be rescheduled. If it doesn't need any update, we don't want to do anything. In order to check if the tick needs an update, we compare it against the clockevent device deadline. Now that's a problem because the clockevent device is at a lower level than the tick itself if it is implemented on top of hrtimer. Every hrtimer share this clockevent device. So comparing the next tick deadline against the clockevent device deadline is wrong because the device may be programmed for another hrtimer whose deadline collides with the tick. As a result we may end up not reprogramming the tick accidentally. In a worst case scenario under full dynticks mode, the tick stops firing as it is supposed to every 1hz, leaving /proc/stat stalled: Task in a full dynticks CPU ---------------------------- * hrtimer A is queued 2 seconds ahead * the tick is stopped, scheduled 1 second ahead * tick fires 1 second later * on tick exit, nohz schedules the tick 1 second ahead but sees the clockevent device is already programmed to that deadline, fooled by hrtimer A, the tick isn't rescheduled. * hrtimer A is cancelled before its deadline * tick never fires again until an interrupt happens... In order to fix this, store the next tick deadline to the tick_sched local structure and reuse that value later to check whether we need to reprogram the clock after an interrupt. On the other hand, ts->sleep_length still wants to know about the next clock event and not just the tick, so we want to improve the related comment to avoid confusion. Reported-by: James Hartsock <hartsjc@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Rik van Riel <riel@redhat.com> Link: http://lkml.kernel.org/r/1483539124-5693-1-git-send-email-fweisbec@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* ktime: Cleanup ktime_set() usageThomas Gleixner2016-12-254-6/+6
| | | | | | | | | | ktime_set(S,N) was required for the timespec storage type and is still useful for situations where a Seconds and Nanoseconds part of a time value needs to be converted. For anything where the Seconds argument is 0, this is pointless and can be replaced with a simple assignment. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org>
* ktime: Get rid of the unionThomas Gleixner2016-12-2511-83/+83
| | | | | | | | | | | | | | | ktime is a union because the initial implementation stored the time in scalar nanoseconds on 64 bit machine and in a endianess optimized timespec variant for 32bit machines. The Y2038 cleanup removed the timespec variant and switched everything to scalar nanoseconds. The union remained, but become completely pointless. Get rid of the union and just keep ktime_t as simple typedef of type s64. The conversion was done with coccinelle and some manual mopping up. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org>
* clocksource: Use a plain u64 instead of cycle_tThomas Gleixner2016-12-255-39/+36
| | | | | | | | | | | | | | | | | | | | | There is no point in having an extra type for extra confusion. u64 is unambiguous. Conversion was done with the following coccinelle script: @rem@ @@ -typedef u64 cycle_t; @fix@ typedef cycle_t; @@ -cycle_t +u64 Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: John Stultz <john.stultz@linaro.org>
* Replace <asm/uaccess.h> with <linux/uaccess.h> globallyLinus Torvalds2016-12-248-8/+8
| | | | | | | | | | | | | This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds2016-12-181-0/+3
|\ | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fix from Thomas Gleixner: "Prevent NULL pointer dereferencing in the tick broadcast code. Old bug, which got unearthed by the hotplug ordering problem" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tick/broadcast: Prevent NULL pointer dereference
| * tick/broadcast: Prevent NULL pointer dereferenceThomas Gleixner2016-12-151-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a disfunctional timer, e.g. dummy timer, is installed, the tick core tries to setup the broadcast timer. If no broadcast device is installed, the kernel crashes with a NULL pointer dereference in tick_broadcast_setup_oneshot() because the function has no sanity check. Reported-by: Mason <slash.tmp@free.fr> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Anna-Maria Gleixner <anna-maria@linutronix.de> Cc: Richard Cochran <rcochran@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org>, Cc: Sebastian Frias <sf84@laposte.net> Cc: Thibaud Cornic <thibaud_cornic@sigmadesigns.com> Cc: Robin Murphy <robin.murphy@arm.com> Link: http://lkml.kernel.org/r/1147ef90-7877-e4d2-bb2b-5c4fa8d3144b@free.fr
* | posix-timers: give lazy compilers some help optimizing code awayNicolas Pitre2016-12-141-1/+2
|/ | | | | | | | | | | | | | | | | | The OpenRISC compiler (so far) fails to optimize away a large portion of code containing a reference to posix_timer_event in alarmtimer.c when CONFIG_POSIX_TIMERS is unset. Let's give it a direct clue to let the build succeed. This fixes [linux-next:master 6682/7183] alarmtimer.c:undefined reference to `posix_timer_event' reported by kbuild test robot. Signed-off-by: Nicolas Pitre <nico@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'timers-core-for-linus' of ↵Linus Torvalds2016-12-128-94/+275
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner: "The time/timekeeping/timer folks deliver with this update: - Fix a reintroduced signed/unsigned issue and cleanup the whole signed/unsigned mess in the timekeeping core so this wont happen accidentaly again. - Add a new trace clock based on boot time - Prevent injection of random sleep times when PM tracing abuses the RTC for storage - Make posix timers configurable for real tiny systems - Add tracepoints for the alarm timer subsystem so timer based suspend wakeups can be instrumented - The usual pile of fixes and updates to core and drivers" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits) timekeeping: Use mul_u64_u32_shr() instead of open coding it timekeeping: Get rid of pointless typecasts timekeeping: Make the conversion call chain consistently unsigned timekeeping_Force_unsigned_clocksource_to_nanoseconds_conversion alarmtimer: Add tracepoints for alarm timers trace: Update documentation for mono, mono_raw and boot clock trace: Add an option for boot clock as trace clock timekeeping: Add a fast and NMI safe boot clock timekeeping/clocksource_cyc2ns: Document intended range limitation timekeeping: Ignore the bogus sleep time if pm_trace is enabled selftests/timers: Fix spelling mistake "Asyncrhonous" -> "Asynchronous" clocksource/drivers/bcm2835_timer: Unmap region obtained by of_iomap clocksource/drivers/arm_arch_timer: Map frame with of_io_request_and_map() arm64: dts: rockchip: Arch counter doesn't tick in system suspend clocksource/drivers/arm_arch_timer: Don't assume clock runs in suspend posix-timers: Make them configurable posix_cpu_timers: Move the add_device_randomness() call to a proper place timer: Move sys_alarm from timer.c to itimer.c ptp_clock: Allow for it to be optional Kconfig: Regenerate *.c_shipped files after previous changes ...
| * timekeeping: Use mul_u64_u32_shr() instead of open coding itThomas Gleixner2016-12-091-21/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The resume code must deal with a clocksource delta which is potentially big enough to overflow the 64bit mult. Replace the open coded handling with the proper function. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Parit Bhargava <prarit@redhat.com> Cc: Laurent Vivier <lvivier@redhat.com> Cc: "Christopher S. Hall" <christopher.s.hall@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Liav Rehana <liavr@mellanox.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/20161208204228.921674404@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * timekeeping: Get rid of pointless typecastsThomas Gleixner2016-12-091-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cycle_t is defined as u64, so casting it to u64 is a pointless and confusing exercise. cycle_t should simply go away and be replaced with a plain u64 to avoid further confusion. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Parit Bhargava <prarit@redhat.com> Cc: Laurent Vivier <lvivier@redhat.com> Cc: "Christopher S. Hall" <christopher.s.hall@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Liav Rehana <liavr@mellanox.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/20161208204228.844699737@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * timekeeping: Make the conversion call chain consistently unsignedThomas Gleixner2016-12-091-13/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Propagating a unsigned value through signed variables and functions makes absolutely no sense and is just prone to (re)introduce subtle signed vs. unsigned issues as happened recently. Clean it up. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Parit Bhargava <prarit@redhat.com> Cc: Laurent Vivier <lvivier@redhat.com> Cc: "Christopher S. Hall" <christopher.s.hall@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Liav Rehana <liavr@mellanox.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/20161208204228.765843099@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * timekeeping_Force_unsigned_clocksource_to_nanoseconds_conversionThomas Gleixner2016-12-091-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The clocksource delta to nanoseconds conversion is using signed math, but the delta is unsigned. This makes the conversion space smaller than necessary and in case of a multiplication overflow the conversion can become negative. The conversion is done with scaled math: s64 nsec_delta = ((s64)clkdelta * clk->mult) >> clk->shift; Shifting a signed integer right obvioulsy preserves the sign, which has interesting consequences: - Time jumps backwards - __iter_div_u64_rem() which is used in one of the calling code pathes will take forever to piecewise calculate the seconds/nanoseconds part. This has been reported by several people with different scenarios: David observed that when stopping a VM with a debugger: "It was essentially the stopped by debugger case. I forget exactly why, but the guest was being explicitly stopped from outside, it wasn't just scheduling lag. I think it was something in the vicinity of 10 minutes stopped." When lifting the stop the machine went dead. The stopped by debugger case is not really interesting, but nevertheless it would be a good thing not to die completely. But this was also observed on a live system by Liav: "When the OS is too overloaded, delta will get a high enough value for the msb of the sum delta * tkr->mult + tkr->xtime_nsec to be set, and so after the shift the nsec variable will gain a value similar to 0xffffffffff000000." Unfortunately this has been reintroduced recently with commit 6bd58f09e1d8 ("time: Add cycles to nanoseconds translation"). It had been fixed a year ago already in commit 35a4933a8959 ("time: Avoid signed overflow in timekeeping_get_ns()"). Though it's not surprising that the issue has been reintroduced because the function itself and the whole call chain uses s64 for the result and the propagation of it. The change in this recent commit is subtle: s64 nsec; - nsec = (d * m + n) >> s: + nsec = d * m + n; + nsec >>= s; d being type of cycle_t adds another level of obfuscation. This wouldn't have happened if the previous change to unsigned computation would have made the 'nsec' variable u64 right away and a follow up patch had cleaned up the whole call chain. There have been patches submitted which basically did a revert of the above patch leaving everything else unchanged as signed. Back to square one. This spawned a admittedly pointless discussion about potential users which rely on the unsigned behaviour until someone pointed out that it had been fixed before. The changelogs of said patches added further confusion as they made finally false claims about the consequences for eventual users which expect signed results. Despite delta being cycle_t, aka. u64, it's very well possible to hand in a signed negative value and the signed computation will happily return the correct result. But nobody actually sat down and analyzed the code which was added as user after the propably unintended signed conversion. Though in sensitive code like this it's better to analyze it proper and make sure that nothing relies on this than hunting the subtle wreckage half a year later. After analyzing all call chains it stands that no caller can hand in a negative value (which actually would work due to the s64 cast) and rely on the signed math to do the right thing. Change the conversion function to unsigned math. The conversion of all call chains is done in a follow up patch. This solves the starvation issue, which was caused by the negative result, but it does not solve the underlying problem. It merily procrastinates it. When the timekeeper update is deferred long enough that the unsigned multiplication overflows, then time going backwards is observable again. It does neither solve the issue of clocksources with a small counter width which will wrap around possibly several times and cause random time stamps to be generated. But those are usually not found on systems used for virtualization, so this is likely a non issue. I took the liberty to claim authorship for this simply because analyzing all callsites and writing the changelog took substantially more time than just making the simple s/s64/u64/ change and ignore the rest. Fixes: 6bd58f09e1d8 ("time: Add cycles to nanoseconds translation") Reported-by: David Gibson <david@gibson.dropbear.id.au> Reported-by: Liav Rehana <liavr@mellanox.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Parit Bhargava <prarit@redhat.com> Cc: Laurent Vivier <lvivier@redhat.com> Cc: "Christopher S. Hall" <christopher.s.hall@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: John Stultz <john.stultz@linaro.org> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20161208204228.688545601@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * alarmtimer: Add tracepoints for alarm timersBaolin Wang2016-12-011-10/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Alarm timers are one of the mechanisms to wake up a system from suspend, but there exist no tracepoints to analyse which process/thread armed an alarmtimer. Add tracepoints for start/cancel/expire of individual alarm timers and one for tracing the suspend time decision when to resume the system. The following trace excerpt illustrates the new mechanism: Binder:3292_2-3304 [000] d..2 149.981123: alarmtimer_cancel: alarmtimer:ffffffc1319a7800 type:REALTIME expires:1325463120000000000 now:1325376810370370245 Binder:3292_2-3304 [000] d..2 149.981136: alarmtimer_start: alarmtimer:ffffffc1319a7800 type:REALTIME expires:1325376840000000000 now:1325376810370384591 Binder:3292_9-3953 [000] d..2 150.212991: alarmtimer_cancel: alarmtimer:ffffffc1319a5a00 type:BOOTTIME expires:179552000000 now:150154008122 Binder:3292_9-3953 [000] d..2 150.213006: alarmtimer_start: alarmtimer:ffffffc1319a5a00 type:BOOTTIME expires:179551000000 now:150154025622 system_server-3000 [002] ...1 162.701940: alarmtimer_suspend: alarmtimer type:REALTIME expires:1325376840000000000 The wakeup time which is selected at suspend time allows to map it back to the task arming the timer: Binder:3292_2. [ tglx: Store alarm timer expiry time instead of some useless RTC relative information, add proper type information for wakeups which are handled via the clock_nanosleep/freezer and massage the changelog. ] Signed-off-by: Baolin Wang <baolin.wang@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Link: http://lkml.kernel.org/r/1480372524-15181-5-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * timekeeping: Add a fast and NMI safe boot clockJoel Fernandes2016-11-291-0/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This boot clock can be used as a tracing clock and will account for suspend time. To keep it NMI safe since we're accessing from tracing, we're not using a separate timekeeper with updates to monotonic clock and boot offset protected with seqlocks. This has the following minor side effects: (1) Its possible that a timestamp be taken after the boot offset is updated but before the timekeeper is updated. If this happens, the new boot offset is added to the old timekeeping making the clock appear to update slightly earlier: CPU 0 CPU 1 timekeeping_inject_sleeptime64() __timekeeping_inject_sleeptime(tk, delta); timestamp(); timekeeping_update(tk, TK_CLEAR_NTP...); (2) On 32-bit systems, the 64-bit boot offset (tk->offs_boot) may be partially updated. Since the tk->offs_boot update is a rare event, this should be a rare occurrence which postprocessing should be able to handle. Signed-off-by: Joel Fernandes <joelaf@google.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1480372524-15181-6-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * posix-timers: Make them configurableNicolas Pitre2016-11-164-5/+137
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some embedded systems have no use for them. This removes about 25KB from the kernel binary size when configured out. Corresponding syscalls are routed to a stub logging the attempt to use those syscalls which should be enough of a clue if they were disabled without proper consideration. They are: timer_create, timer_gettime: timer_getoverrun, timer_settime, timer_delete, clock_adjtime, setitimer, getitimer, alarm. The clock_settime, clock_gettime, clock_getres and clock_nanosleep syscalls are replaced by simple wrappers compatible with CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only which should cover the vast majority of use cases with very little code. Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: Richard Cochran <richardcochran@gmail.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Cc: Paul Bolle <pebolle@tiscali.nl> Cc: linux-kbuild@vger.kernel.org Cc: netdev@vger.kernel.org Cc: Michal Marek <mmarek@suse.com> Cc: Edward Cree <ecree@solarflare.com> Link: http://lkml.kernel.org/r/1478841010-28605-7-git-send-email-nicolas.pitre@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * posix_cpu_timers: Move the add_device_randomness() call to a proper placeNicolas Pitre2016-11-161-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is no logical relation between add_device_randomness() and posix_cpu_timers_exit(). Let's move the former to where the later is called. This way, when posix-cpu-timers.c is compiled out, there is no need to worry about not losing a call to add_device_randomness(). Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Paul Bolle <pebolle@tiscali.nl> Cc: linux-kbuild@vger.kernel.org Cc: netdev@vger.kernel.org Cc: Richard Cochran <richardcochran@gmail.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Michal Marek <mmarek@suse.com> Cc: Edward Cree <ecree@solarflare.com> Link: http://lkml.kernel.org/r/1478841010-28605-6-git-send-email-nicolas.pitre@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * timer: Move sys_alarm from timer.c to itimer.cNicolas Pitre2016-11-162-14/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move the only user of alarm_setitimer to itimer.c where it is defined. This allows for making alarm_setitimer static, and dropping it from the build when __ARCH_WANT_SYS_ALARM is not defined. Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Paul Bolle <pebolle@tiscali.nl> Cc: linux-kbuild@vger.kernel.org Cc: netdev@vger.kernel.org Cc: Richard Cochran <richardcochran@gmail.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Michal Marek <mmarek@suse.com> Cc: Edward Cree <ecree@solarflare.com> Link: http://lkml.kernel.org/r/1478841010-28605-5-git-send-email-nicolas.pitre@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * timers: Fix documentation for schedule_timeout() and similarDouglas Anderson2016-10-262-10/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The documentation for schedule_timeout(), schedule_hrtimeout(), and schedule_hrtimeout_range() all claim that the routines couldn't possibly return early if the task state was TASK_UNINTERRUPTIBLE. This is simply not true since wake_up_process() will cause those routines to exit early. We cannot make schedule_[hr]timeout() loop until the timeout expires if the task state is uninterruptible because we have users which rely on the existing and designed behaviour. Make the documentation match the (correct) implementation. schedule_hrtimeout() returns -EINTR even when a uninterruptible task was woken up. This might look strange, but making the return code depend on the state is too much of an effort as it would affect all the call sites. There is no value in doing so, but we spell it out clearly in the documentation. Suggested-by: Daniel Kurtz <djkurtz@chromium.org> Signed-off-by: Douglas Anderson <dianders@chromium.org> Cc: huangtao@rock-chips.com Cc: heiko@sntech.de Cc: broonie@kernel.org Cc: briannorris@chromium.org Cc: Andreas Mohr <andi@lisas.de> Cc: linux-rockchip@lists.infradead.org Cc: tony.xie@rock-chips.com Cc: John Stultz <john.stultz@linaro.org> Cc: linux@roeck-us.net Cc: tskd08@gmail.com Link: http://lkml.kernel.org/r/1477065531-30342-2-git-send-email-dianders@chromium.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * timers: Fix usleep_range() in the context of wake_up_process()Douglas Anderson2016-10-261-12/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Users of usleep_range() expect that it will _never_ return in less time than the minimum passed parameter. However, nothing in the code ensures this, when the sleeping task is woken by wake_up_process() or any other mechanism which can wake a task from uninterruptible state. Neither usleep_range() nor schedule_hrtimeout_range*() have any protection against wakeups. schedule_hrtimeout_range*() is designed this way despite the fact that the API documentation does not mention it. msleep() already has code to handle this case since it will loop as long as there was still time left. usleep_range() has no such loop, add it. Presumably this problem was not detected before because usleep_range() is only used in a few places and the function is mostly used in contexts which are not exposed to wakeups of any form. An effort was made to look for users relying on the old behavior by looking for usleep_range() in the same file as wake_up_process(). No problems were found by this search, though it is conceivable that someone could have put the sleep and wakeup in two different files. An effort was made to ask several upstream maintainers if they were aware of people relying on wake_up_process() to wake up usleep_range(). No maintainers were aware of that but they were aware of many people relying on usleep_range() never returning before the minimum. Reported-by: Tao Huang <huangtao@rock-chips.com> Signed-off-by: Douglas Anderson <dianders@chromium.org> Cc: heiko@sntech.de Cc: broonie@kernel.org Cc: briannorris@chromium.org Cc: Andreas Mohr <andi@lisas.de> Cc: linux-rockchip@lists.infradead.org Cc: tony.xie@rock-chips.com Cc: John Stultz <john.stultz@linaro.org> Cc: djkurtz@chromium.org Cc: linux@roeck-us.net Cc: tskd08@gmail.com Link: http://lkml.kernel.org/r/1477065531-30342-1-git-send-email-dianders@chromium.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | Merge branch 'smp-hotplug-for-linus' of ↵Linus Torvalds2016-12-121-19/+14
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull smp hotplug updates from Thomas Gleixner: "This is the final round of converting the notifier mess to the state machine. The removal of the notifiers and the related infrastructure will happen around rc1, as there are conversions outstanding in other trees. The whole exercise removed about 2000 lines of code in total and in course of the conversion several dozen bugs got fixed. The new mechanism allows to test almost every hotplug step standalone, so usage sites can exercise all transitions extensively. There is more room for improvement, like integrating all the pointlessly different architecture mechanisms of synchronizing, setting cpus online etc into the core code" * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (60 commits) tracing/rb: Init the CPU mask on allocation soc/fsl/qbman: Convert to hotplug state machine soc/fsl/qbman: Convert to hotplug state machine zram: Convert to hotplug state machine KVM/PPC/Book3S HV: Convert to hotplug state machine arm64/cpuinfo: Convert to hotplug state machine arm64/cpuinfo: Make hotplug notifier symmetric mm/compaction: Convert to hotplug state machine iommu/vt-d: Convert to hotplug state machine mm/zswap: Convert pool to hotplug state machine mm/zswap: Convert dst-mem to hotplug state machine mm/zsmalloc: Convert to hotplug state machine mm/vmstat: Convert to hotplug state machine mm/vmstat: Avoid on each online CPU loops mm/vmstat: Drop get_online_cpus() from init_cpu_node_state/vmstat_cpu_dead() tracing/rb: Convert to hotplug state machine oprofile/nmi timer: Convert to hotplug state machine net/iucv: Use explicit clean up labels in iucv_init() x86/pci/amd-bus: Convert to hotplug state machine x86/oprofile/nmi: Convert to hotplug state machine ...
| * | sched/nohz: Convert to hotplug state machineSebastian Andrzej Siewior2016-11-221-19/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Install the callbacks via the state machine. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: rt@linuxtronix.de Link: http://lkml.kernel.org/r/20161117183541.8588-14-bigeasy@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2016-12-121-2/+2
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: "The main scheduler changes in this cycle were: - support Intel Turbo Boost Max Technology 3.0 (TBM3) by introducig a notion of 'better cores', which the scheduler will prefer to schedule single threaded workloads on. (Tim Chen, Srinivas Pandruvada) - enhance the handling of asymmetric capacity CPUs further (Morten Rasmussen) - improve/fix load handling when moving tasks between task groups (Vincent Guittot) - simplify and clean up the cputime code (Stanislaw Gruszka) - improve mass fork()ed task spread a.k.a. hackbench speedup (Vincent Guittot) - make struct kthread kmalloc()ed and related fixes (Oleg Nesterov) - add uaccess atomicity debugging (when using access_ok() in the wrong context), under CONFIG_DEBUG_ATOMIC_SLEEP=y (Peter Zijlstra) - implement various fixes, cleanups and other enhancements (Daniel Bristot de Oliveira, Martin Schwidefsky, Rafael J. Wysocki)" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits) sched/core: Use load_avg for selecting idlest group sched/core: Fix find_idlest_group() for fork kthread: Don't abuse kthread_create_on_cpu() in __kthread_create_worker() kthread: Don't use to_live_kthread() in kthread_[un]park() kthread: Don't use to_live_kthread() in kthread_stop() Revert "kthread: Pin the stack via try_get_task_stack()/put_task_stack() in to_live_kthread() function" kthread: Make struct kthread kmalloc'ed x86/uaccess, sched/preempt: Verify access_ok() context sched/x86: Make CONFIG_SCHED_MC_PRIO=y easier to enable sched/x86: Change CONFIG_SCHED_ITMT to CONFIG_SCHED_MC_PRIO x86/sched: Use #include <linux/mutex.h> instead of #include <asm/mutex.h> cpufreq/intel_pstate: Use CPPC to get max performance acpi/bus: Set _OSC for diverse core support acpi/bus: Enable HWP CPPC objects x86/sched: Add SD_ASYM_PACKING flags to x86 ITMT CPU x86/sysctl: Add sysctl for ITMT scheduling feature x86: Enable Intel Turbo Boost Max Technology 3.0 x86/topology: Define x86's arch_update_cpu_topology sched: Extend scheduler's asym packing sched/fair: Clean up the tunable parameter definitions ...
| * | | sched/cputime: Simplify task_cputime()Stanislaw Gruszka2016-11-151-2/+2
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now since fetch_task_cputime() has no other users than task_cputime(), its code could be used directly in task_cputime(). Moreover since only 2 task_cputime() calls of 17 use a NULL argument, we can add dummy variables to those calls and remove NULL checks from task_cputimes(). Also remove NULL checks from task_cputimes_scaled(). Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Neuling <mikey@neuling.org> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1479175612-14718-5-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* / / clocksource: export the clocks_calc_mult_shift to use by timestamp codeMurali Karicheri2016-12-071-0/+1
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The CPSW CPTS driver is capable of doing timestamping on tx/rx packets and requires to know mult and shift factors for timestamp conversion from raw value to nanoseconds (ptp clock). Now these mult and shift factors are calculated manually and provided through DT, which makes very hard to support of a lot number of platforms, especially if CPTS refclk is not the same for some kind of boards and depends on efuse settings (Keystone 2 platforms). Hence, export clocks_calc_mult_shift() to allow drivers like CPSW CPTS (and other ptp drivesr) to benefit from automaitc calculation of mult and shift factors. Cc: John Stultz <john.stultz@linaro.org> Signed-off-by: Murali Karicheri <m-karicheri2@ti.com> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* | timers: Prevent base clock corruption when forwardingThomas Gleixner2016-10-251-13/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a timer is enqueued we try to forward the timer base clock. This mechanism has two issues: 1) Forwarding a remote base unlocked The forwarding function is called from get_target_base() with the current timer base lock held. But if the new target base is a different base than the current base (can happen with NOHZ, sigh!) then the forwarding is done on an unlocked base. This can lead to corruption of base->clk. Solution is simple: Invoke the forwarding after the target base is locked. 2) Possible corruption due to jiffies advancing This is similar to the issue in get_net_timer_interrupt() which was fixed in the previous patch. jiffies can advance between check and assignement and therefore advancing base->clk beyond the next expiry value. So we need to read jiffies into a local variable once and do the checks and assignment with the local copy. Fixes: a683f390b93f("timers: Forward the wheel clock whenever possible") Reported-by: Ashton Holmes <scoopta@gmail.com> Reported-by: Michael Thayer <michael.thayer@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Michal Necasek <michal.necasek@oracle.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: knut.osmundsen@oracle.com Cc: stable@vger.kernel.org Cc: stern@rowland.harvard.edu Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20161022110552.253640125@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | timers: Prevent base clock rewind when forwarding clockThomas Gleixner2016-10-251-5/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ashton and Michael reported, that kernel versions 4.8 and later suffer from USB timeouts which are caused by the timer wheel rework. This is caused by a bug in the base clock forwarding mechanism, which leads to timers expiring early. The scenario which leads to this is: run_timers() while (jiffies >= base->clk) { collect_expired_timers(); base->clk++; expire_timers(); } So base->clk = jiffies + 1. Now the cpu goes idle: idle() get_next_timer_interrupt() nextevt = __next_time_interrupt(); if (time_after(nextevt, base->clk)) base->clk = jiffies; jiffies has not advanced since run_timers(), so this assignment effectively decrements base->clk by one. base->clk is the index into the timer wheel arrays. So let's assume the following state after the base->clk increment in run_timers(): jiffies = 0 base->clk = 1 A timer gets enqueued with an expiry delta of 63 ticks (which is the case with the USB timeout and HZ=250) so the resulting bucket index is: base->clk + delta = 1 + 63 = 64 The timer goes into the first wheel level. The array size is 64 so it ends up in bucket 0, which is correct as it takes 63 ticks to advance base->clk to index into bucket 0 again. If the cpu goes idle before jiffies advance, then the bug in the forwarding mechanism sets base->clk back to 0, so the next invocation of run_timers() at the next tick will index into bucket 0 and therefore expire the timer 62 ticks too early. Instead of blindly setting base->clk to jiffies we must make the forwarding conditional on jiffies > base->clk, but we cannot use jiffies for this as we might run into the following issue: if (time_after(jiffies, base->clk) { if (time_after(nextevt, base->clk)) base->clk = jiffies; jiffies can increment between the check and the assigment far enough to advance beyond nextevt. So we need to use a stable value for checking. get_next_timer_interrupt() has the basej argument which is the jiffies value snapshot taken in the calling code. So we can just that. Thanks to Ashton for bisecting and providing trace data! Fixes: a683f390b93f ("timers: Forward the wheel clock whenever possible") Reported-by: Ashton Holmes <scoopta@gmail.com> Reported-by: Michael Thayer <michael.thayer@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Michal Necasek <michal.necasek@oracle.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: knut.osmundsen@oracle.com Cc: stable@vger.kernel.org Cc: stern@rowland.harvard.edu Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20161022110552.175308322@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | timers: Lock base for same bucket optimizationThomas Gleixner2016-10-251-11/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Linus stumbled over the unlocked modification of the timer expiry value in mod_timer() which is an optimization for timers which stay in the same bucket - due to the bucket granularity - despite their expiry time getting updated. The optimization itself still makes sense even if we take the lock, because in case that the bucket stays the same, we avoid the pointless queue/enqueue dance. Make the check and the modification of timer->expires protected by the base lock and shuffle the remaining code around so we can keep the lock held when we actually have to requeue the timer to a different bucket. Fixes: f00c0afdfa62 ("timers: Implement optimization for same expiry time in mod_timer()") Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1610241711220.4983@nanos Cc: stable@vger.kernel.org Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org>
* | timers: Plug locking race vs. timer migrationThomas Gleixner2016-10-251-1/+8
|/ | | | | | | | | | | | | | | | | | Linus noticed that lock_timer_base() lacks a READ_ONCE() for accessing the timer flags. As a consequence the compiler is allowed to reload the flags between the initial check for TIMER_MIGRATION and the following timer base computation and the spin lock of the base. While this has not been observed (yet), we need to make sure that it never happens. Fixes: 0eeda71bc30d ("timer: Replace timer base by a cpu index") Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1610241711220.4983@nanos Cc: stable@vger.kernel.org Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org>
* alarmtimer: Remove unused but set variableTobias Klauser2016-10-171-2/+0
| | | | | | | | | | | | | | Remove the set but unused variable base in alarm_clock_get to fix the following warning when building with 'W=1': kernel/time/alarmtimer.c: In function ‘alarm_timer_create’: kernel/time/alarmtimer.c:545:21: warning: variable ‘base’ set but not used [-Wunused-but-set-variable] Signed-off-by: Tobias Klauser <tklauser@distanz.ch> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/20161017094702.10873-1-tklauser@distanz.ch Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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