user/sven/linux.git/kernel/time, branch v4.4.2

hrtimer: Handle remaining time proper for TIME_LOW_RES

2016-02-17T20:30:57Z

commit 203cbf77de59fc8f13502dcfd11350c6d4a5c95f upstream. If CONFIG_TIME_LOW_RES is enabled we add a jiffie to the relative timeout to prevent short sleeps, but we do not account for that in interfaces which retrieve the remaining time. Helge observed that timerfd can return a remaining time larger than the relative timeout. That's not expected and breaks userland test programs. Store the information that the timer was armed relative and provide functions to adjust the remaining time. To avoid bloating the hrtimer struct make state a u8, which as a bonus results in better code on x86 at least. Reported-and-tested-by: Helge Deller Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: John Stultz Cc: linux-m68k@lists.linux-m68k.org Cc: dhowells@redhat.com Link: http://lkml.kernel.org/r/20160114164159.273328486@linutronix.de Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

Merge branches 'irq-urgent-for-linus' and 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2015-11-15T17:30:48Z

Pull irq and timer fixes from Thomas Gleixner: - An irq regression fix to restore the wakeup behaviour of chained interrupts. - A timer fix for a long standing race versus timers scheduled on a target cpu which got exposed by recent changes in the workqueue implementation. * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: genirq/PM: Restore system wake up from chained interrupts * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timers: Use proper base migration in add_timer_on()

remove abs64()

2015-11-09T23:11:24Z

Switch everything to the new and more capable implementation of abs(). Mainly to give the new abs() a bit of a workout. Cc: Michal Nazarewicz Cc: John Stultz Cc: Ingo Molnar Cc: Steven Rostedt Cc: Peter Zijlstra Cc: Masami Hiramatsu Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

timers: Use proper base migration in add_timer_on()

2015-11-04T19:23:19Z

Regardless of the previous CPU a timer was on, add_timer_on() currently simply sets timer->flags to the new CPU. As the caller must be seeing the timer as idle, this is locally fine, but the timer leaving the old base while unlocked can lead to race conditions as follows. Let's say timer was on cpu 0. cpu 0 cpu 1 ----------------------------------------------------------------------------- del_timer(timer) succeeds del_timer(timer) lock_timer_base(timer) locks cpu_0_base add_timer_on(timer, 1) spin_lock(&cpu_1_base->lock) timer->flags set to cpu_1_base operates on @timer operates on @timer This triggered with mod_delayed_work_on() which contains "if (del_timer()) add_timer_on()" sequence eventually leading to the following oops. BUG: unable to handle kernel NULL pointer dereference at (null) IP: [] detach_if_pending+0x69/0x1a0 ... Workqueue: wqthrash wqthrash_workfunc [wqthrash] task: ffff8800172ca680 ti: ffff8800172d0000 task.ti: ffff8800172d0000 RIP: 0010:[] [] detach_if_pending+0x69/0x1a0 ... Call Trace: [] del_timer+0x44/0x60 [] try_to_grab_pending+0xb6/0x160 [] mod_delayed_work_on+0x33/0x80 [] wqthrash_workfunc+0x61/0x90 [wqthrash] [] process_one_work+0x1e8/0x650 [] worker_thread+0x4e/0x450 [] kthread+0xef/0x110 [] ret_from_fork+0x3f/0x70 Fix it by updating add_timer_on() to perform proper migration as __mod_timer() does. Reported-and-tested-by: Jeff Layton Signed-off-by: Tejun Heo Cc: Chris Worley Cc: bfields@fieldses.org Cc: Michael Skralivetsky Cc: Trond Myklebust Cc: Shaohua Li Cc: Jeff Layton Cc: kernel-team@fb.com Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20151029103113.2f893924@tlielax.poochiereds.net Link: http://lkml.kernel.org/r/20151104171533.GI5749@mtj.duckdns.org Signed-off-by: Thomas Gleixner

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

2015-11-03T22:13:41Z

Pull timer updates from Thomas Gleixner: "The timer departement provides: - More y2038 work in the area of ntp and pps. - Optimization of posix cpu timers - New time related selftests - Some new clocksource drivers - The usual pile of fixes, cleanups and improvements" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits) timeconst: Update path in comment timers/x86/hpet: Type adjustments clocksource/drivers/armada-370-xp: Implement ARM delay timer clocksource/drivers/tango_xtal: Add new timer for Tango SoCs clocksource/drivers/imx: Allow timer irq affinity change clocksource/drivers/exynos_mct: Use container_of() instead of this_cpu_ptr() clocksource/drivers/h8300_*: Remove unneeded memset()s clocksource/drivers/sh_cmt: Remove unneeded memset() in sh_cmt_setup() clocksource/drivers/em_sti: Remove unneeded memset()s clocksource/drivers/mediatek: Use GPT as sched clock source clockevents/drivers/mtk: Fix spurious interrupt leading to crash posix_cpu_timer: Reduce unnecessary sighand lock contention posix_cpu_timer: Convert cputimer->running to bool posix_cpu_timer: Check thread timers only when there are active thread timers posix_cpu_timer: Optimize fastpath_timer_check() timers, kselftest: Add 'adjtick' test to validate adjtimex() tick adjustments timers: Use __fls in apply_slack() clocksource: Remove return statement from void functions net: sfc: avoid using timespec ntp/pps: use y2038 safe types in pps_event_time ...

timeconst: Update path in comment

2015-10-26T01:06:06Z

Signed-off-by: Jason A. Donenfeld Cc: hofrat@osadl.org Link: http://lkml.kernel.org/r/1436894685-5868-1-git-send-email-Jason@zx2c4.com Signed-off-by: Thomas Gleixner

Merge branch 'fortglx/4.4/time' of https://git.linaro.org/people/john.stultz/linux into timers/core

2015-10-20T10:36:37Z

Time updates from John Stultz: - More 2038 work from Arnd Bergmann around ntp and pps

timekeeping: Increment clock_was_set_seq in timekeeping_init()

2015-10-16T13:50:22Z

timekeeping_init() can set the wall time offset, so we need to increment the clock_was_set_seq counter. That way hrtimers will pick up the early offset immediately. Otherwise on a machine which does not set wall time later in the boot process the hrtimer offset is stale at 0 and wall time timers are going to expire with a delay of 45 years. Fixes: 868a3e915f7f "hrtimer: Make offset update smarter" Reported-and-tested-by: Heiko Carstens Signed-off-by: Thomas Gleixner Cc: Stefan Liebler Cc: Peter Zijlstra Cc: John Stultz

posix_cpu_timer: Reduce unnecessary sighand lock contention

2015-10-15T09:23:41Z

It was found while running a database workload on large systems that significant time was spent trying to acquire the sighand lock. The issue was that whenever an itimer expired, many threads ended up simultaneously trying to send the signal. Most of the time, nothing happened after acquiring the sighand lock because another thread had just already sent the signal and updated the "next expire" time. The fastpath_timer_check() didn't help much since the "next expire" time was updated after the threads exit fastpath_timer_check(). This patch addresses this by having the thread_group_cputimer structure maintain a boolean to signify when a thread in the group is already checking for process wide timers, and adds extra logic in the fastpath to check the boolean. Signed-off-by: Jason Low Reviewed-by: Oleg Nesterov Reviewed-by: George Spelvin Cc: Paul E. McKenney Cc: Frederic Weisbecker Cc: Davidlohr Bueso Cc: Steven Rostedt Cc: hideaki.kimura@hpe.com Cc: terry.rudd@hpe.com Cc: scott.norton@hpe.com Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1444849677-29330-5-git-send-email-jason.low2@hp.com Signed-off-by: Thomas Gleixner

posix_cpu_timer: Convert cputimer->running to bool

2015-10-15T09:23:41Z

In the next patch in this series, a new field 'checking_timer' will be added to 'struct thread_group_cputimer'. Both this and the existing 'running' integer field are just used as boolean values. To save space in the structure, we can make both of these fields booleans. This is a preparatory patch to convert the existing running integer field to a boolean. Suggested-by: George Spelvin Signed-off-by: Jason Low Reviewed: George Spelvin Cc: Oleg Nesterov Cc: Paul E. McKenney Cc: Frederic Weisbecker Cc: Davidlohr Bueso Cc: Steven Rostedt Cc: hideaki.kimura@hpe.com Cc: terry.rudd@hpe.com Cc: scott.norton@hpe.com Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1444849677-29330-4-git-send-email-jason.low2@hp.com Signed-off-by: Thomas Gleixner