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* Merge tag 'staging-3.17-rc1' of ↵Linus Torvalds2014-08-051-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging Pull staging driver updates from Greg KH: "Here's the big pull request for the staging driver tree for 3.17-rc1. Lots of things in here, over 2000 patches, but the best part is this: 1480 files changed, 39070 insertions(+), 254659 deletions(-) Thanks to the great work of Kristina Martšenko, 14 different staging drivers have been removed from the tree as they were obsolete and no one was willing to work on cleaning them up. Other than the driver removals, loads of cleanups are in here (comedi, lustre, etc.) as well as the usual IIO driver updates and additions. All of this has been in the linux-next tree for a while" * tag 'staging-3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (2199 commits) staging: comedi: addi_apci_1564: remove diagnostic interrupt support code staging: comedi: addi_apci_1564: add subdevice to check diagnostic status staging: wlan-ng: coding style problem fix staging: wlan-ng: fixing coding style problems staging: comedi: ii_pci20kc: request and ioremap memory staging: lustre: bitwise vs logical typo staging: dgnc: Remove unneeded dgnc_trace.c and dgnc_trace.h staging: dgnc: rephrase comment staging: comedi: ni_tio: remove some dead code staging: rtl8723au: Fix static symbol sparse warning staging: rtl8723au: usb_dvobj_init(): Remove unused variable 'pdev_desc' staging: rtl8723au: Do not duplicate kernel provided USB macros staging: rtl8723au: Remove never set struct pwrctrl_priv.bHWPowerdown staging: rtl8723au: Remove two never set variables staging: rtl8723au: RSSI_test is never set staging:r8190: coding style: Fixed checkpatch reported Error staging:r8180: coding style: Fixed too long lines staging:r8180: coding style: Fixed commenting style staging: lustre: ptlrpc: lproc_ptlrpc.c - fix dereferenceing user space buffer staging: lustre: ldlm: ldlm_resource.c - fix dereferenceing user space buffer ...
| * alarmtimer: Export symbols of alarmtimer_get_rtcdevPramod Gurav2014-06-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | Export symbol of alarmtimer_get_rtcdev so that it is used by any driver when built as module like, drivers/staging/android/alarm-dev.c. CC: John Stultz <john.stultz@linaro.org> CC: Marcus Gelderie <redmnic@gmail.com> Signed-off-by: Pramod Gurav <pramod.gurav.etc@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2014-08-051-4/+6
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: - Move the nohz kick code out of the scheduler tick to a dedicated IPI, from Frederic Weisbecker. This necessiated quite some background infrastructure rework, including: * Clean up some irq-work internals * Implement remote irq-work * Implement nohz kick on top of remote irq-work * Move full dynticks timer enqueue notification to new kick * Move multi-task notification to new kick * Remove unecessary barriers on multi-task notification - Remove proliferation of wait_on_bit() action functions and allow wait_on_bit_action() functions to support a timeout. (Neil Brown) - Another round of sched/numa improvements, cleanups and fixes. (Rik van Riel) - Implement fast idling of CPUs when the system is partially loaded, for better scalability. (Tim Chen) - Restructure and fix the CPU hotplug handling code that may leave cfs_rq and rt_rq's throttled when tasks are migrated away from a dead cpu. (Kirill Tkhai) - Robustify the sched topology setup code. (Peterz Zijlstra) - Improve sched_feat() handling wrt. static_keys (Jason Baron) - Misc fixes. * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits) sched/fair: Fix 'make xmldocs' warning caused by missing description sched: Use macro for magic number of -1 for setparam sched: Robustify topology setup sched: Fix sched_setparam() policy == -1 logic sched: Allow wait_on_bit_action() functions to support a timeout sched: Remove proliferation of wait_on_bit() action functions sched/numa: Revert "Use effective_load() to balance NUMA loads" sched: Fix static_key race with sched_feat() sched: Remove extra static_key*() function indirection sched/rt: Fix replenish_dl_entity() comments to match the current upstream code sched: Transform resched_task() into resched_curr() sched/deadline: Kill task_struct->pi_top_task sched: Rework check_for_tasks() sched/rt: Enqueue just unthrottled rt_rq back on the stack in __disable_runtime() sched/fair: Disable runtime_enabled on dying rq sched/numa: Change scan period code to match intent sched/numa: Rework best node setting in task_numa_migrate() sched/numa: Examine a task move when examining a task swap sched/numa: Simplify task_numa_compare() sched/numa: Use effective_load() to balance NUMA loads ...
| * \ Merge branch 'sched/urgent' into sched/core, to merge fixes before applying ↵Ingo Molnar2014-07-281-2/+18
| |\ \ | | | | | | | | | | | | | | | | | | | | new changes Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | nohz: Support nohz full remote kickFrederic Weisbecker2014-06-161-4/+6
| | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remotely kicking a full nohz CPU in order to make it re-evaluate its next tick is currently implemented using the scheduler IPI. However this bloats a scheduler fast path with an off-topic feature. The scheduler tick was abused here for its cool "callable anywhere/anytime" properties. But now that the irq work subsystem can queue remote callbacks, it's a perfect fit to safely queue IPIs when interrupts are disabled without worrying about concurrent callers. So lets implement remote kick on top of irq work. This is going to be used when a new event requires the next tick to be recalculated: more than 1 task competing on the CPU, timer armed, ... Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@linaro.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* | | Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds2014-08-051-0/+10
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU changes from Ingo Molar: "The main changes: - torture-test updates - callback-offloading changes - maintainership changes - update RCU documentation - miscellaneous fixes" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (32 commits) rcu: Allow for NULL tick_nohz_full_mask when nohz_full= missing rcu: Fix a sparse warning in rcu_report_unblock_qs_rnp() rcu: Fix a sparse warning in rcu_initiate_boost() rcu: Fix __rcu_reclaim() to use true/false for bool rcu: Remove CONFIG_PROVE_RCU_DELAY rcu: Use __this_cpu_read() instead of per_cpu_ptr() rcu: Don't use NMIs to dump other CPUs' stacks rcu: Bind grace-period kthreads to non-NO_HZ_FULL CPUs rcu: Simplify priority boosting by putting rt_mutex in rcu_node rcu: Check both root and current rcu_node when setting up future grace period rcu: Allow post-unlock reference for rt_mutex rcu: Loosen __call_rcu()'s rcu_head alignment constraint rcu: Eliminate read-modify-write ACCESS_ONCE() calls rcu: Remove redundant ACCESS_ONCE() from tick_do_timer_cpu rcu: Make rcu node arrays static const char * const signal: Explain local_irq_save() call rcu: Handle obsolete references to TINY_PREEMPT_RCU rcu: Document deadlock-avoidance information for rcu_read_unlock() scripts: Teach get_maintainer.pl about the new "R:" tag rcu: Update rcu torture maintainership filename patterns ...
| * | | rcu: Bind grace-period kthreads to non-NO_HZ_FULL CPUsPaul E. McKenney2014-07-091-0/+10
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Binding the grace-period kthreads to the timekeeping CPU resulted in significant performance decreases for some workloads. For more detail, see: https://lkml.org/lkml/2014/6/3/395 for benchmark numbers https://lkml.org/lkml/2014/6/4/218 for CPU statistics It turns out that it is necessary to bind the grace-period kthreads to the timekeeping CPU only when all but CPU 0 is a nohz_full CPU on the one hand or if CONFIG_NO_HZ_FULL_SYSIDLE=y on the other. In other cases, it suffices to bind the grace-period kthreads to the set of non-nohz_full CPUs. This commit therefore creates a tick_nohz_not_full_mask that is the complement of tick_nohz_full_mask, and then binds the grace-period kthread to the set of CPUs indicated by this new mask, which covers the CONFIG_NO_HZ_FULL_SYSIDLE=n case. The CONFIG_NO_HZ_FULL_SYSIDLE=y case still binds the grace-period kthreads to the timekeeping CPU. This commit also includes the tick_nohz_full_enabled() check suggested by Frederic Weisbecker. Reported-by: Jet Chen <jet.chen@intel.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> [ paulmck: Created housekeeping_affine() and housekeeping_mask per fweisbec feedback. ]
* | | timer: Fix lock inversion between hrtimer_bases.lock and scheduler locksJan Kara2014-08-011-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | clockevents_increase_min_delta() calls printk() from under hrtimer_bases.lock. That causes lock inversion on scheduler locks because printk() can call into the scheduler. Lockdep puts it as: ====================================================== [ INFO: possible circular locking dependency detected ] 3.15.0-rc8-06195-g939f04b #2 Not tainted ------------------------------------------------------- trinity-main/74 is trying to acquire lock: (&port_lock_key){-.....}, at: [<811c60be>] serial8250_console_write+0x8c/0x10c but task is already holding lock: (hrtimer_bases.lock){-.-...}, at: [<8103caeb>] hrtimer_try_to_cancel+0x13/0x66 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (hrtimer_bases.lock){-.-...}: [<8104a942>] lock_acquire+0x92/0x101 [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e [<8103c918>] __hrtimer_start_range_ns+0x1c/0x197 [<8107ec20>] perf_swevent_start_hrtimer.part.41+0x7a/0x85 [<81080792>] task_clock_event_start+0x3a/0x3f [<810807a4>] task_clock_event_add+0xd/0x14 [<8108259a>] event_sched_in+0xb6/0x17a [<810826a2>] group_sched_in+0x44/0x122 [<81082885>] ctx_sched_in.isra.67+0x105/0x11f [<810828e6>] perf_event_sched_in.isra.70+0x47/0x4b [<81082bf6>] __perf_install_in_context+0x8b/0xa3 [<8107eb8e>] remote_function+0x12/0x2a [<8105f5af>] smp_call_function_single+0x2d/0x53 [<8107e17d>] task_function_call+0x30/0x36 [<8107fb82>] perf_install_in_context+0x87/0xbb [<810852c9>] SYSC_perf_event_open+0x5c6/0x701 [<810856f9>] SyS_perf_event_open+0x17/0x19 [<8142f8ee>] syscall_call+0x7/0xb -> #4 (&ctx->lock){......}: [<8104a942>] lock_acquire+0x92/0x101 [<8142f04c>] _raw_spin_lock+0x21/0x30 [<81081df3>] __perf_event_task_sched_out+0x1dc/0x34f [<8142cacc>] __schedule+0x4c6/0x4cb [<8142cae0>] schedule+0xf/0x11 [<8142f9a6>] work_resched+0x5/0x30 -> #3 (&rq->lock){-.-.-.}: [<8104a942>] lock_acquire+0x92/0x101 [<8142f04c>] _raw_spin_lock+0x21/0x30 [<81040873>] __task_rq_lock+0x33/0x3a [<8104184c>] wake_up_new_task+0x25/0xc2 [<8102474b>] do_fork+0x15c/0x2a0 [<810248a9>] kernel_thread+0x1a/0x1f [<814232a2>] rest_init+0x1a/0x10e [<817af949>] start_kernel+0x303/0x308 [<817af2ab>] i386_start_kernel+0x79/0x7d -> #2 (&p->pi_lock){-.-...}: [<8104a942>] lock_acquire+0x92/0x101 [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e [<810413dd>] try_to_wake_up+0x1d/0xd6 [<810414cd>] default_wake_function+0xb/0xd [<810461f3>] __wake_up_common+0x39/0x59 [<81046346>] __wake_up+0x29/0x3b [<811b8733>] tty_wakeup+0x49/0x51 [<811c3568>] uart_write_wakeup+0x17/0x19 [<811c5dc1>] serial8250_tx_chars+0xbc/0xfb [<811c5f28>] serial8250_handle_irq+0x54/0x6a [<811c5f57>] serial8250_default_handle_irq+0x19/0x1c [<811c56d8>] serial8250_interrupt+0x38/0x9e [<810510e7>] handle_irq_event_percpu+0x5f/0x1e2 [<81051296>] handle_irq_event+0x2c/0x43 [<81052cee>] handle_level_irq+0x57/0x80 [<81002a72>] handle_irq+0x46/0x5c [<810027df>] do_IRQ+0x32/0x89 [<8143036e>] common_interrupt+0x2e/0x33 [<8142f23c>] _raw_spin_unlock_irqrestore+0x3f/0x49 [<811c25a4>] uart_start+0x2d/0x32 [<811c2c04>] uart_write+0xc7/0xd6 [<811bc6f6>] n_tty_write+0xb8/0x35e [<811b9beb>] tty_write+0x163/0x1e4 [<811b9cd9>] redirected_tty_write+0x6d/0x75 [<810b6ed6>] vfs_write+0x75/0xb0 [<810b7265>] SyS_write+0x44/0x77 [<8142f8ee>] syscall_call+0x7/0xb -> #1 (&tty->write_wait){-.....}: [<8104a942>] lock_acquire+0x92/0x101 [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e [<81046332>] __wake_up+0x15/0x3b [<811b8733>] tty_wakeup+0x49/0x51 [<811c3568>] uart_write_wakeup+0x17/0x19 [<811c5dc1>] serial8250_tx_chars+0xbc/0xfb [<811c5f28>] serial8250_handle_irq+0x54/0x6a [<811c5f57>] serial8250_default_handle_irq+0x19/0x1c [<811c56d8>] serial8250_interrupt+0x38/0x9e [<810510e7>] handle_irq_event_percpu+0x5f/0x1e2 [<81051296>] handle_irq_event+0x2c/0x43 [<81052cee>] handle_level_irq+0x57/0x80 [<81002a72>] handle_irq+0x46/0x5c [<810027df>] do_IRQ+0x32/0x89 [<8143036e>] common_interrupt+0x2e/0x33 [<8142f23c>] _raw_spin_unlock_irqrestore+0x3f/0x49 [<811c25a4>] uart_start+0x2d/0x32 [<811c2c04>] uart_write+0xc7/0xd6 [<811bc6f6>] n_tty_write+0xb8/0x35e [<811b9beb>] tty_write+0x163/0x1e4 [<811b9cd9>] redirected_tty_write+0x6d/0x75 [<810b6ed6>] vfs_write+0x75/0xb0 [<810b7265>] SyS_write+0x44/0x77 [<8142f8ee>] syscall_call+0x7/0xb -> #0 (&port_lock_key){-.....}: [<8104a62d>] __lock_acquire+0x9ea/0xc6d [<8104a942>] lock_acquire+0x92/0x101 [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e [<811c60be>] serial8250_console_write+0x8c/0x10c [<8104e402>] call_console_drivers.constprop.31+0x87/0x118 [<8104f5d5>] console_unlock+0x1d7/0x398 [<8104fb70>] vprintk_emit+0x3da/0x3e4 [<81425f76>] printk+0x17/0x19 [<8105bfa0>] clockevents_program_min_delta+0x104/0x116 [<8105c548>] clockevents_program_event+0xe7/0xf3 [<8105cc1c>] tick_program_event+0x1e/0x23 [<8103c43c>] hrtimer_force_reprogram+0x88/0x8f [<8103c49e>] __remove_hrtimer+0x5b/0x79 [<8103cb21>] hrtimer_try_to_cancel+0x49/0x66 [<8103cb4b>] hrtimer_cancel+0xd/0x18 [<8107f102>] perf_swevent_cancel_hrtimer.part.60+0x2b/0x30 [<81080705>] task_clock_event_stop+0x20/0x64 [<81080756>] task_clock_event_del+0xd/0xf [<81081350>] event_sched_out+0xab/0x11e [<810813e0>] group_sched_out+0x1d/0x66 [<81081682>] ctx_sched_out+0xaf/0xbf [<81081e04>] __perf_event_task_sched_out+0x1ed/0x34f [<8142cacc>] __schedule+0x4c6/0x4cb [<8142cae0>] schedule+0xf/0x11 [<8142f9a6>] work_resched+0x5/0x30 other info that might help us debug this: Chain exists of: &port_lock_key --> &ctx->lock --> hrtimer_bases.lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(hrtimer_bases.lock); lock(&ctx->lock); lock(hrtimer_bases.lock); lock(&port_lock_key); *** DEADLOCK *** 4 locks held by trinity-main/74: #0: (&rq->lock){-.-.-.}, at: [<8142c6f3>] __schedule+0xed/0x4cb #1: (&ctx->lock){......}, at: [<81081df3>] __perf_event_task_sched_out+0x1dc/0x34f #2: (hrtimer_bases.lock){-.-...}, at: [<8103caeb>] hrtimer_try_to_cancel+0x13/0x66 #3: (console_lock){+.+...}, at: [<8104fb5d>] vprintk_emit+0x3c7/0x3e4 stack backtrace: CPU: 0 PID: 74 Comm: trinity-main Not tainted 3.15.0-rc8-06195-g939f04b #2 00000000 81c3a310 8b995c14 81426f69 8b995c44 81425a99 8161f671 8161f570 8161f538 8161f559 8161f538 8b995c78 8b142bb0 00000004 8b142fdc 8b142bb0 8b995ca8 8104a62d 8b142fac 000016f2 81c3a310 00000001 00000001 00000003 Call Trace: [<81426f69>] dump_stack+0x16/0x18 [<81425a99>] print_circular_bug+0x18f/0x19c [<8104a62d>] __lock_acquire+0x9ea/0xc6d [<8104a942>] lock_acquire+0x92/0x101 [<811c60be>] ? serial8250_console_write+0x8c/0x10c [<811c6032>] ? wait_for_xmitr+0x76/0x76 [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e [<811c60be>] ? serial8250_console_write+0x8c/0x10c [<811c60be>] serial8250_console_write+0x8c/0x10c [<8104af87>] ? lock_release+0x191/0x223 [<811c6032>] ? wait_for_xmitr+0x76/0x76 [<8104e402>] call_console_drivers.constprop.31+0x87/0x118 [<8104f5d5>] console_unlock+0x1d7/0x398 [<8104fb70>] vprintk_emit+0x3da/0x3e4 [<81425f76>] printk+0x17/0x19 [<8105bfa0>] clockevents_program_min_delta+0x104/0x116 [<8105cc1c>] tick_program_event+0x1e/0x23 [<8103c43c>] hrtimer_force_reprogram+0x88/0x8f [<8103c49e>] __remove_hrtimer+0x5b/0x79 [<8103cb21>] hrtimer_try_to_cancel+0x49/0x66 [<8103cb4b>] hrtimer_cancel+0xd/0x18 [<8107f102>] perf_swevent_cancel_hrtimer.part.60+0x2b/0x30 [<81080705>] task_clock_event_stop+0x20/0x64 [<81080756>] task_clock_event_del+0xd/0xf [<81081350>] event_sched_out+0xab/0x11e [<810813e0>] group_sched_out+0x1d/0x66 [<81081682>] ctx_sched_out+0xaf/0xbf [<81081e04>] __perf_event_task_sched_out+0x1ed/0x34f [<8104416d>] ? __dequeue_entity+0x23/0x27 [<81044505>] ? pick_next_task_fair+0xb1/0x120 [<8142cacc>] __schedule+0x4c6/0x4cb [<81047574>] ? trace_hardirqs_off_caller+0xd7/0x108 [<810475b0>] ? trace_hardirqs_off+0xb/0xd [<81056346>] ? rcu_irq_exit+0x64/0x77 Fix the problem by using printk_deferred() which does not call into the scheduler. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | sched_clock: Avoid corrupting hrtimer tree during suspendStephen Boyd2014-07-241-1/+3
| |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | During suspend we call sched_clock_poll() to update the epoch and accumulated time and reprogram the sched_clock_timer to fire before the next wrap-around time. Unfortunately, sched_clock_poll() doesn't restart the timer, instead it relies on the hrtimer layer to do that and during suspend we aren't calling that function from the hrtimer layer. Instead, we're reprogramming the expires time while the hrtimer is enqueued, which can cause the hrtimer tree to be corrupted. Furthermore, we restart the timer during suspend but we update the epoch during resume which seems counter-intuitive. Let's fix this by saving the accumulated state and canceling the timer during suspend. On resume we can update the epoch and restart the timer similar to what we would do if we were starting the clock for the first time. Fixes: a08ca5d1089d "sched_clock: Use an hrtimer instead of timer" Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/1406174630-23458-1-git-send-email-john.stultz@linaro.org Cc: Ingo Molnar <mingo@kernel.org> Cc: stable <stable@vger.kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | alarmtimer: Fix bug where relative alarm timers were treated as absoluteJohn Stultz2014-07-081-2/+18
|/ | | | | | | | | | | | | | | | | | | | Sharvil noticed with the posix timer_settime interface, using the CLOCK_REALTIME_ALARM or CLOCK_BOOTTIME_ALARM clockid, if the users tried to specify a relative time timer, it would incorrectly be treated as absolute regardless of the state of the flags argument. This patch corrects this, properly checking the absolute/relative flag, as well as adds further error checking that no invalid flag bits are set. Reported-by: Sharvil Nanavati <sharvil@google.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Sharvil Nanavati <sharvil@google.com> Cc: stable <stable@vger.kernel.org> #3.0+ Link: http://lkml.kernel.org/r/1404767171-6902-1-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Merge branch 'akpm' (patchbomb from Andrew) into nextLinus Torvalds2014-06-052-9/+13
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge misc updates from Andrew Morton: - a few fixes for 3.16. Cc'ed to stable so they'll get there somehow. - various misc fixes and cleanups - most of the ocfs2 queue. Review is slow... - most of MM. The MM queue is pretty huge this time, but not much in the way of feature work. - some tweaks under kernel/ - printk maintenance work - updates to lib/ - checkpatch updates - tweaks to init/ * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (276 commits) fs/autofs4/dev-ioctl.c: add __init to autofs_dev_ioctl_init fs/ncpfs/getopt.c: replace simple_strtoul by kstrtoul init/main.c: remove an ifdef kthreads: kill CLONE_KERNEL, change kernel_thread(kernel_init) to avoid CLONE_SIGHAND init/main.c: add initcall_blacklist kernel parameter init/main.c: don't use pr_debug() fs/binfmt_flat.c: make old_reloc() static fs/binfmt_elf.c: fix bool assignements fs/efs: convert printk(KERN_DEBUG to pr_debug fs/efs: add pr_fmt / use __func__ fs/efs: convert printk to pr_foo() scripts/checkpatch.pl: device_initcall is not the only __initcall substitute checkpatch: check stable email address checkpatch: warn on unnecessary void function return statements checkpatch: prefer kstrto<foo> to sscanf(buf, "%<lhuidx>", &bar); checkpatch: add warning for kmalloc/kzalloc with multiply checkpatch: warn on #defines ending in semicolon checkpatch: make --strict a default for files in drivers/net and net/ checkpatch: always warn on missing blank line after variable declaration block checkpatch: fix wildcard DT compatible string checking ...
| * timekeeping: use printk_deferred when holding timekeeping seqlockJohn Stultz2014-06-052-9/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Jiri Bohac pointed out that there are rare but potential deadlock possibilities when calling printk while holding the timekeeping seqlock. This is due to printk() triggering console sem wakeup, which can cause scheduling code to trigger hrtimers which may try to read the time. Specifically, as Jiri pointed out, that path is: printk vprintk_emit console_unlock up(&console_sem) __up wake_up_process try_to_wake_up ttwu_do_activate ttwu_activate activate_task enqueue_task enqueue_task_fair hrtick_update hrtick_start_fair hrtick_start_fair get_time ktime_get --> endless loop on read_seqcount_retry(&timekeeper_seq, ...) This patch tries to avoid this issue by using printk_deferred (previously named printk_sched) which should defer printing via a irq_work_queue. Signed-off-by: John Stultz <john.stultz@linaro.org> Reported-by: Jiri Bohac <jbohac@suse.cz> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Cc: Jan Kara <jack@suse.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | ntp: Make is_error_status() use its argumentGeorge Spelvin2014-05-121-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | is_error_status() is an inline function always called with the global time_status as an argument, so there's zero functional difference with this change, but the non-CONFIG_NTP_PPS version uses the passed-in argument, while the CONFIG_NTP_PPS one ignores its argument and uses the global. Looks like is_error_status was refactored out, but someone forgot to change the logic to check the local argument value. Thus this patch makes it use the argument always; shorter variable names are good. Signed-off-by: George Spelvin <linux@horizon.com> [jstultz: Tweaked commit message] Signed-off-by: John Stultz <john.stultz@linaro.org>
* | ntp: Convert simple_strtol to kstrtolFabian Frederick2014-05-121-1/+4
| | | | | | | | | | | | | | | | | | | | | | Replace obsolete function simple_strtol w/ kstrtol Inspired-By: Andrew Morton <akpm@linux-foundation.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Fabian Frederick <fabf@skynet.be> [jstultz: Tweak commit message] Signed-off-by: John Stultz <john.stultz@linaro.org>
* | sched_clock: Remove deprecated setup_sched_clock() APIStephen Boyd2014-04-221-13/+0Star
|/ | | | | | | | Remove the 32-bit only setup_sched_clock() API now that all users have been converted to the 64-bit friendly sched_clock_register(). Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
* tick-sched: Check tick_nohz_enabled in tick_nohz_switch_to_nohz()Viresh Kumar2014-04-151-1/+1
| | | | | | | | | | | | | | | | | | Since commit d689fe222 (NOHZ: Check for nohz active instead of nohz enabled) the tick_nohz_switch_to_nohz() function returns because it checks for the tick_nohz_active flag. This can't be set, because the function itself sets it. Undo the change in tick_nohz_switch_to_nohz(). Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: linaro-kernel@lists.linaro.org Cc: fweisbec@gmail.com Cc: Arvind.Chauhan@arm.com Cc: linaro-networking@linaro.org Cc: <stable@vger.kernel.org> # 3.13+ Link: http://lkml.kernel.org/r/40939c05f2d65d781b92b20302b02243d0654224.1397537987.git.viresh.kumar@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* tick-sched: Don't call update_wall_time() when delta is lesser than tick_periodViresh Kumar2014-04-151-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | In tick_do_update_jiffies64() we are processing ticks only if delta is greater than tick_period. This is what we are supposed to do here and it broke a bit with this patch: commit 47a1b796 (tick/timekeeping: Call update_wall_time outside the jiffies lock) With above patch, we might end up calling update_wall_time() even if delta is found to be smaller that tick_period. Fix this by returning when the delta is less than tick period. [ tglx: Made it a 3 liner and massaged changelog ] Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: linaro-kernel@lists.linaro.org Cc: fweisbec@gmail.com Cc: Arvind.Chauhan@arm.com Cc: linaro-networking@linaro.org Cc: John Stultz <john.stultz@linaro.org> Cc: <stable@vger.kernel.org> # v3.14+ Link: http://lkml.kernel.org/r/80afb18a494b0bd9710975bcc4de134ae323c74f.1397537987.git.viresh.kumar@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* tick-common: Fix wrong check in tick_check_replacement()Viresh Kumar2014-04-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | tick_check_replacement() returns if a replacement of clock_event_device is possible or not. It does this as the first check: if (tick_check_percpu(curdev, newdev, smp_processor_id())) return false; Thats wrong. tick_check_percpu() returns true when the device is useable. Check for false instead. [ tglx: Massaged changelog ] Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: <stable@vger.kernel.org> # v3.11+ Cc: linaro-kernel@lists.linaro.org Cc: fweisbec@gmail.com Cc: Arvind.Chauhan@arm.com Cc: linaro-networking@linaro.org Link: http://lkml.kernel.org/r/486a02efe0246635aaba786e24b42d316438bf3b.1397537987.git.viresh.kumar@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* kernel: use macros from compiler.h instead of __attribute__((...))Gideon Israel Dsouza2014-04-081-2/+3
| | | | | | | | | | | | | To increase compiler portability there is <linux/compiler.h> which provides convenience macros for various gcc constructs. Eg: __weak for __attribute__((weak)). I've replaced all instances of gcc attributes with the right macro in the kernel subsystem. Signed-off-by: Gideon Israel Dsouza <gidisrael@gmail.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Ingo Molnar <mingo@elte.hu> 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 Torvalds2014-04-019-36/+236
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer changes from Thomas Gleixner: "This assorted collection provides: - A new timer based timer broadcast feature for systems which do not provide a global accessible timer device. That allows those systems to put CPUs into deep idle states where the per cpu timer device stops. - A few NOHZ_FULL related improvements to the timer wheel - The usual updates to timer devices found in ARM SoCs - Small improvements and updates all over the place" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits) tick: Remove code duplication in tick_handle_periodic() tick: Fix spelling mistake in tick_handle_periodic() x86: hpet: Use proper destructor for delayed work workqueue: Provide destroy_delayed_work_on_stack() clocksource: CMT, MTU2, TMU and STI should depend on GENERIC_CLOCKEVENTS timer: Remove code redundancy while calling get_nohz_timer_target() hrtimer: Rearrange comments in the order struct members are declared timer: Use variable head instead of &work_list in __run_timers() clocksource: exynos_mct: silence a static checker warning arm: zynq: Add support for cpufreq arm: zynq: Don't use arm_global_timer with cpufreq clocksource/cadence_ttc: Overhaul clocksource frequency adjustment clocksource/cadence_ttc: Call clockevents_update_freq() with IRQs enabled clocksource: Add Kconfig entries for CMT, MTU2, TMU and STI sh: Remove Kconfig entries for TMU, CMT and MTU2 ARM: shmobile: Remove CMT, TMU and STI Kconfig entries clocksource: armada-370-xp: Use atomic access for shared registers clocksource: orion: Use atomic access for shared registers clocksource: timer-keystone: Delete unnecessary variable clocksource: timer-keystone: introduce clocksource driver for Keystone ...
| * tick: Remove code duplication in tick_handle_periodic()Viresh Kumar2014-03-261-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | tick_handle_periodic() is calling ktime_add() at two places, first before the infinite loop and then at the end of infinite loop. We can rearrange code a bit to fix code duplication here. It looks quite simple and shouldn't break anything, I guess :) Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: linaro-kernel@lists.linaro.org Cc: fweisbec@gmail.com Link: http://lkml.kernel.org/r/be3481e8f3f71df694a4b43623254fc93ca51b59.1395735873.git.viresh.kumar@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * tick: Fix spelling mistake in tick_handle_periodic()Viresh Kumar2014-03-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | One of the comments in tick_handle_periodic() had 'when' instead of 'which' (My guess :)). Fix it. Also fix spelling mistake in 'Possible'. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: linaro-kernel@lists.linaro.org Cc: skarafotis@gmail.com Link: http://lkml.kernel.org/r/2b29ca4230c163e44179941d7c7a16c1474385c2.1395743878.git.viresh.kumar@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * Merge branch 'fortglx/3.15/time' of ↵Thomas Gleixner2014-03-101-0/+2
| |\ | | | | | | | | | | | | | | | | | | | | | | | | git://git.linaro.org/people/john.stultz/linux into timers/core - support CLOCK_BOOTTIME clock in timerfd - Add missing header file Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| | * kernel: Include appropriate header file in time/timekeeping_debug.cRashika Kheria2014-03-031-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Include appropriate header file kernel/time/timekeeping_internal.h in kernel/time/timekeeping_debug.c because it has prototype declaration of function defined in kernel/time/timekeeping_debug.c. This eliminates the following warning in kernel/time/timekeeping_debug.c: kernel/time/timekeeping_debug.c:68:6: warning: no previous prototype for ‘tk_debug_account_sleep_time’ [-Wmissing-prototypes] Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
| * | nohz: ensure users are aware boot CPU is not NO_HZ_FULLPaul Gortmaker2014-02-141-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This bit of information is in the Kconfig help text: "Note the boot CPU will still be kept outside the range to handle the timekeeping duty." However neither the variable NO_HZ_FULL_ALL, or the prompt convey this important detail, so lets add it to the prompt to make it more explicitly obvious to the average user. Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1391711781-7466-1-git-send-email-paul.gortmaker@windriver.com Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
| * | tick: Fixup more fallout from hrtimer broadcast modePreeti U Murthy2014-02-092-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The hrtimer mode of broadcast is supported only when GENERIC_CLOCKEVENTS_BROADCAST and TICK_ONESHOT config options are enabled. Hence compile in the functions for hrtimer mode of broadcast only when these options are selected. Also fix max_delta_ticks value for the pseudo clock device. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/52F719EE.9010304@linux.vnet.ibm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | time: Fixup fallout from recent clockevent/tick changesThomas Gleixner2014-02-071-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make the stub function static inline instead of static and move the clockevents related function into the proper ifdeffed section. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Soren Brinkmann <soren.brinkmann@xilinx.com> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
| * | tick: Introduce hrtimer based broadcastPreeti U Murthy2014-02-073-4/+158
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On some architectures, in certain CPU deep idle states the local timers stop. An external clock device is used to wakeup these CPUs. The kernel support for the wakeup of these CPUs is provided by the tick broadcast framework by using the external clock device as the wakeup source. However not all implementations of architectures provide such an external clock device. This patch includes support in the broadcast framework to handle the wakeup of the CPUs in deep idle states on such systems by queuing a hrtimer on one of the CPUs, which is meant to handle the wakeup of CPUs in deep idle states. This patchset introduces a pseudo clock device which can be registered by the archs as tick_broadcast_device in the absence of a real external clock device. Once registered, the broadcast framework will work as is for these architectures as long as the archs take care of the BROADCAST_ENTER notification failing for one of the CPUs. This CPU is made the stand by CPU to handle wakeup of the CPUs in deep idle and it *must not enter deep idle states*. The CPU with the earliest wakeup is chosen to be this CPU. Hence this way the stand by CPU dynamically moves around and so does the hrtimer which is queued to trigger at the next earliest wakeup time. This is consistent with the case where an external clock device is present. The smp affinity of this clock device is set to the CPU with the earliest wakeup. This patchset handles the hotplug of the stand by CPU as well by moving the hrtimer on to the CPU handling the CPU_DEAD notification. Originally-from: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: deepthi@linux.vnet.ibm.com Cc: paulmck@linux.vnet.ibm.com Cc: fweisbec@gmail.com Cc: paulus@samba.org Cc: srivatsa.bhat@linux.vnet.ibm.com Cc: svaidy@linux.vnet.ibm.com Cc: peterz@infradead.org Cc: benh@kernel.crashing.org Cc: rafael.j.wysocki@intel.com Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/20140207080632.17187.80532.stgit@preeti.in.ibm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | time: Change the return type of clockevents_notify() to integerPreeti U Murthy2014-02-073-8/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The broadcast framework can potentially be made use of by archs which do not have an external clock device as well. Then, it is required that one of the CPUs need to handle the broadcasting of wakeup IPIs to the CPUs in deep idle. As a result its local timers should remain functional all the time. For such a CPU, the BROADCAST_ENTER notification has to fail indicating that its clock device cannot be shutdown. To make way for this support, change the return type of tick_broadcast_oneshot_control() and hence clockevents_notify() to indicate such scenarios. Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: deepthi@linux.vnet.ibm.com Cc: paulmck@linux.vnet.ibm.com Cc: fweisbec@gmail.com Cc: paulus@samba.org Cc: srivatsa.bhat@linux.vnet.ibm.com Cc: svaidy@linux.vnet.ibm.com Cc: peterz@infradead.org Cc: benh@kernel.crashing.org Cc: rafael.j.wysocki@intel.com Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/20140207080606.17187.78306.stgit@preeti.in.ibm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | clockevents: Adjust timer interval when frequency changesSoren Brinkmann2014-02-071-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | clockevent devices in periodic mode are not updated when the frequency of the device changes. Issue a dev->set_mode() callback which forces the device to reevaluate the timer settings. Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com> Cc: linux-arm-kernel@lists.infradead.org Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Michal Simek <michal.simek@xilinx.com> Link: http://lkml.kernel.org/r/1391466877-28908-3-git-send-email-soren.brinkmann@xilinx.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | clockevents: Serialize calls to clockevents_update_freq() in the coreThomas Gleixner2014-02-073-13/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We can identify the broadcast device in the core and serialize all callers including interrupts on a different CPU against the update. Also, disabling interrupts is moved into the core allowing callers to leave interrutps enabled when calling clockevents_update_freq(). Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com> Cc: linux-arm-kernel@lists.infradead.org Cc: Soeren Brinkmann <soren.brinkmann@xilinx.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Michal Simek <michal.simek@xilinx.com> Link: http://lkml.kernel.org/r/1391466877-28908-2-git-send-email-soren.brinkmann@xilinx.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | timekeeping: Move clock sync work to power efficient workqueueShaibal Dutta2014-02-071-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For better use of CPU idle time, allow the scheduler to select the CPU on which the CMOS clock sync work would be scheduled. This improves idle residency time and conserver power. This functionality is enabled when CONFIG_WQ_POWER_EFFICIENT is selected. Signed-off-by: Shaibal Dutta <shaibal.dutta@broadcom.com> [zoran.markovic@linaro.org: Added commit message. Aligned code.] Signed-off-by: Zoran Markovic <zoran.markovic@linaro.org> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/1391195904-12497-1-git-send-email-zoran.markovic@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | time: Revert to calling clock_was_set_delayed() while in irq contextJohn Stultz2014-03-281-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In commit 47a1b796306356f35 ("tick/timekeeping: Call update_wall_time outside the jiffies lock"), we moved to calling clock_was_set() due to the fact that we were no longer holding the timekeeping or jiffies lock. However, there is still the problem that clock_was_set() triggers an IPI, which cannot be done from the timer's hard irq context, and will generate WARN_ON warnings. Apparently in my earlier testing, I'm guessing I didn't bump the dmesg log level, so I somehow missed the WARN_ONs. Thus we need to revert back to calling clock_was_set_delayed(). Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1395963049-11923-1-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | sched_clock: Prevent callers from seeing half-updated dataStephen Boyd2014-02-191-17/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The generic sched_clock registration function was previously done lockless, due to the fact that it was expected to be called only once. However, now there are systems that may register multiple sched_clock sources, for which the lack of locking has casued problems: If two sched_clock sources are registered we may end up in a situation where a call to sched_clock() may be accessing the epoch cycle count for the old counter and the cycle count for the new counter. This can lead to confusing results where sched_clock() values jump and then are reset to 0 (due to the way the registration function forces the epoch_ns to be 0). Fix this by reorganizing the registration function to hold the seqlock for as short a time as possible while we update the clock_data structure for a new counter. We also put any accumulated time into epoch_ns instead of resetting the time to 0 so that the clock doesn't reset after each successful registration. [jstultz: Added extra context to the commit message] Reported-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Josh Cartwright <joshc@codeaurora.org> Link: http://lkml.kernel.org/r/1392662736-7803-2-git-send-email-john.stultz@linaro.org Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | tick: Clear broadcast pending bit when switching to oneshotThomas Gleixner2014-02-131-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | AMD systems which use the C1E workaround in the amd_e400_idle routine trigger the WARN_ON_ONCE in the broadcast code when onlining a CPU. The reason is that the idle routine of those AMD systems switches the cpu into forced broadcast mode early on before the newly brought up CPU can switch over to high resolution / NOHZ mode. The timer related CPU1 bringup looks like this: clockevent_register_device(local_apic); tick_setup(local_apic); ... idle() tick_broadcast_on_off(FORCE); tick_broadcast_oneshot_control(ENTER) cpumask_set(cpu, broadcast_oneshot_mask); halt(); Now the broadcast interrupt on CPU0 sets CPU1 in the broadcast_pending_mask and wakes CPU1. So CPU1 continues: local_apic_timer_interrupt() tick_handle_periodic(); softirq() tick_init_highres(); cpumask_clr(cpu, broadcast_oneshot_mask); tick_broadcast_oneshot_control(ENTER) WARN_ON(cpumask_test(cpu, broadcast_pending_mask); So while we remove CPU1 from the broadcast_oneshot_mask when we switch over to highres mode, we do not clear the pending bit, which then triggers the warning when we go back to idle. The reason why this is only visible on C1E affected AMD systems is that the other machines enter the deep sleep states via acpi_idle/intel_idle and exit the broadcast mode before executing the remote triggered local_apic_timer_interrupt. So the pending bit is already cleared when the switch over to highres mode is clearing the oneshot mask. The solution is simple: Clear the pending bit together with the mask bit when we switch over to highres mode. Stanislaw came up independently with the same patch by enforcing the C1E workaround and debugging the fallout. I picked mine, because mine has a changelog :) Reported-by: poma <pomidorabelisima@gmail.com> Debugged-by: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Olaf Hering <olaf@aepfle.de> Cc: Dave Jones <davej@redhat.com> Cc: Justin M. Forbes <jforbes@redhat.com> Cc: Josh Boyer <jwboyer@redhat.com> Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1402111434180.21991@ionos.tec.linutronix.de Cc: stable@vger.kernel.org # 3.10+ Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | time: Fix overflow when HZ is smaller than 60Mikulas Patocka2014-02-061-0/+6
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When compiling for the IA-64 ski emulator, HZ is set to 32 because the emulation is slow and we don't want to waste too many cycles processing timers. Alpha also has an option to set HZ to 32. This causes integer underflow in kernel/time/jiffies.c: kernel/time/jiffies.c:66:2: warning: large integer implicitly truncated to unsigned type [-Woverflow] .mult = NSEC_PER_JIFFY << JIFFIES_SHIFT, /* details above */ ^ This patch reduces the JIFFIES_SHIFT value to avoid the overflow. Signed-off-by: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> Link: http://lkml.kernel.org/r/alpine.LRH.2.02.1401241639100.23871@file01.intranet.prod.int.rdu2.redhat.com Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | Merge branch 'timers/core' of ↵Ingo Molnar2014-01-251-13/+14
|\ \ | |/ |/| | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into timers/urgent Pull dynticks cleanups from Frederic Weisbecker. Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * nohz_full: fix code style issue of tick_nohz_full_stop_tickAlex Shi2014-01-151-8/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Code usually starts with 'tab' instead of 7 'space' in kernel Signed-off-by: Alex Shi <alex.shi@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Alex Shi <alex.shi@linaro.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Kevin Hilman <khilman@linaro.org> Link: http://lkml.kernel.org/r/1386074112-30754-2-git-send-email-alex.shi@linaro.org Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
| * nohz: Get timekeeping max deferment outside jiffies_lockFrederic Weisbecker2014-01-151-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We don't need to fetch the timekeeping max deferment under the jiffies_lock seqlock. If the clocksource is updated concurrently while we stop the tick, stop machine is called and the tick will be reevaluated again along with uptodate jiffies and its related values. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Alex Shi <alex.shi@linaro.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Kevin Hilman <khilman@linaro.org> Link: http://lkml.kernel.org/r/1387320692-28460-9-git-send-email-fweisbec@gmail.com Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
| * tick: Rename tick_check_idle() to tick_irq_enter()Frederic Weisbecker2014-01-151-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This makes the code more symetric against the existing tick functions called on irq exit: tick_irq_exit() and tick_nohz_irq_exit(). These function are also symetric as they mirror each other's action: we start to account idle time on irq exit and we stop this accounting on irq entry. Also the tick is stopped on irq exit and timekeeping catches up with the tickless time elapsed until we reach irq entry. This rename was suggested by Peter Zijlstra a long while ago but it got forgotten in the mass. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Alex Shi <alex.shi@linaro.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Kevin Hilman <khilman@linaro.org> Link: http://lkml.kernel.org/r/1387320692-28460-2-git-send-email-fweisbec@gmail.com Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* | Merge branch 'timers-core-for-linus' of ↵Linus Torvalds2014-01-205-55/+50Star
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer changes from Ingo Molnar: - ARM clocksource/clockevent improvements and fixes - generic timekeeping updates: TAI fixes/improvements, cleanups - Posix cpu timer cleanups and improvements - dynticks updates: full dynticks bugfixes, optimizations and cleanups * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (46 commits) clocksource: Timer-sun5i: Switch to sched_clock_register() timekeeping: Remove comment that's mostly out of date rtc-cmos: Add an alarm disable quirk timekeeper: fix comment typo for tk_setup_internals() timekeeping: Fix missing timekeeping_update in suspend path timekeeping: Fix CLOCK_TAI timer/nanosleep delays tick/timekeeping: Call update_wall_time outside the jiffies lock timekeeping: Avoid possible deadlock from clock_was_set_delayed timekeeping: Fix potential lost pv notification of time change timekeeping: Fix lost updates to tai adjustment clocksource: sh_cmt: Add clk_prepare/unprepare support clocksource: bcm_kona_timer: Remove unused bcm_timer_ids clocksource: vt8500: Remove deprecated IRQF_DISABLED clocksource: tegra: Remove deprecated IRQF_DISABLED clocksource: misc drivers: Remove deprecated IRQF_DISABLED clocksource: sh_mtu2: Remove unnecessary platform_set_drvdata() clocksource: sh_tmu: Remove unnecessary platform_set_drvdata() clocksource: armada-370-xp: Enable timer divider only when needed clocksource: clksrc-of: Warn if no clock sources are found clocksource: orion: Switch to sched_clock_register() ...
| * Merge branch 'fortglx/3.14/time' of ↵Ingo Molnar2014-01-124-27/+29
| |\ | | | | | | | | | | | | | | | | | | | | | git://git.linaro.org/people/john.stultz/linux into timers/core Pull timekeeping updates from John Stultz. Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * timekeeping: Remove comment that's mostly out of dateJohn Stultz2013-12-231-10/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Prior to 92bb1fcf57a0c2e45f7e67fbf0a8ed475a749236 (Only do nanosecond rounding on GENERIC_TIME_VSYSCALL_OLD systems), the comment here was accuate, but now we can mostly avoid the extra rounding which causes the unlikey to be actually likely here. So remove the out of date comment. Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * timekeeper: fix comment typo for tk_setup_internals()Yijing Wang2013-12-231-1/+2
| | | | | | | | | | | | | | | | | | | | | Fix trivial comment typo for tk_setup_internals(). Signed-off-by: Yijing Wang <wangyijing@huawei.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * timekeeping: Fix missing timekeeping_update in suspend pathJohn Stultz2013-12-231-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since 48cdc135d4840 (Implement a shadow timekeeper), we have to call timekeeping_update() after any adjustment to the timekeeping structure in order to make sure that any adjustments to the structure persist. In the timekeeping suspend path, we udpate the timekeeper structure, so we should be sure to update the shadow-timekeeper before releasing the timekeeping locks. Currently this isn't done. In most cases, the next time related code to run would be timekeeping_resume, which does update the shadow-timekeeper, but in an abundence of caution, this patch adds the call to timekeeping_update() in the suspend path. Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: stable <stable@vger.kernel.org> #3.10+ Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * timekeeping: Fix CLOCK_TAI timer/nanosleep delaysJohn Stultz2013-12-231-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A think-o in the calculation of the monotonic -> tai time offset results in CLOCK_TAI timers and nanosleeps to expire late (the latency is ~2x the tai offset). Fix this by adding the tai offset from the realtime offset instead of subtracting. Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: stable <stable@vger.kernel.org> #3.10+ Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * tick/timekeeping: Call update_wall_time outside the jiffies lockJohn Stultz2013-12-234-15/+7Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since the xtime lock was split into the timekeeping lock and the jiffies lock, we no longer need to call update_wall_time() while holding the jiffies lock. Thus, this patch splits update_wall_time() out from do_timer(). This allows us to get away from calling clock_was_set_delayed() in update_wall_time() and instead use the standard clock_was_set() call that previously would deadlock, as it causes the jiffies lock to be acquired. Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * timekeeping: Avoid possible deadlock from clock_was_set_delayedJohn Stultz2013-12-231-2/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As part of normal operaions, the hrtimer subsystem frequently calls into the timekeeping code, creating a locking order of hrtimer locks -> timekeeping locks clock_was_set_delayed() was suppoed to allow us to avoid deadlocks between the timekeeping the hrtimer subsystem, so that we could notify the hrtimer subsytem the time had changed while holding the timekeeping locks. This was done by scheduling delayed work that would run later once we were out of the timekeeing code. But unfortunately the lock chains are complex enoguh that in scheduling delayed work, we end up eventually trying to grab an hrtimer lock. Sasha Levin noticed this in testing when the new seqlock lockdep enablement triggered the following (somewhat abrieviated) message: [ 251.100221] ====================================================== [ 251.100221] [ INFO: possible circular locking dependency detected ] [ 251.100221] 3.13.0-rc2-next-20131206-sasha-00005-g8be2375-dirty #4053 Not tainted [ 251.101967] ------------------------------------------------------- [ 251.101967] kworker/10:1/4506 is trying to acquire lock: [ 251.101967] (timekeeper_seq){----..}, at: [<ffffffff81160e96>] retrigger_next_event+0x56/0x70 [ 251.101967] [ 251.101967] but task is already holding lock: [ 251.101967] (hrtimer_bases.lock#11){-.-...}, at: [<ffffffff81160e7c>] retrigger_next_event+0x3c/0x70 [ 251.101967] [ 251.101967] which lock already depends on the new lock. [ 251.101967] [ 251.101967] [ 251.101967] the existing dependency chain (in reverse order) is: [ 251.101967] -> #5 (hrtimer_bases.lock#11){-.-...}: [snipped] -> #4 (&rt_b->rt_runtime_lock){-.-...}: [snipped] -> #3 (&rq->lock){-.-.-.}: [snipped] -> #2 (&p->pi_lock){-.-.-.}: [snipped] -> #1 (&(&pool->lock)->rlock){-.-...}: [ 251.101967] [<ffffffff81194803>] validate_chain+0x6c3/0x7b0 [ 251.101967] [<ffffffff81194d9d>] __lock_acquire+0x4ad/0x580 [ 251.101967] [<ffffffff81194ff2>] lock_acquire+0x182/0x1d0 [ 251.101967] [<ffffffff84398500>] _raw_spin_lock+0x40/0x80 [ 251.101967] [<ffffffff81153e69>] __queue_work+0x1a9/0x3f0 [ 251.101967] [<ffffffff81154168>] queue_work_on+0x98/0x120 [ 251.101967] [<ffffffff81161351>] clock_was_set_delayed+0x21/0x30 [ 251.101967] [<ffffffff811c4bd1>] do_adjtimex+0x111/0x160 [ 251.101967] [<ffffffff811e2711>] compat_sys_adjtimex+0x41/0x70 [ 251.101967] [<ffffffff843a4b49>] ia32_sysret+0x0/0x5 [ 251.101967] -> #0 (timekeeper_seq){----..}: [snipped] [ 251.101967] other info that might help us debug this: [ 251.101967] [ 251.101967] Chain exists of: timekeeper_seq --> &rt_b->rt_runtime_lock --> hrtimer_bases.lock#11 [ 251.101967] Possible unsafe locking scenario: [ 251.101967] [ 251.101967] CPU0 CPU1 [ 251.101967] ---- ---- [ 251.101967] lock(hrtimer_bases.lock#11); [ 251.101967] lock(&rt_b->rt_runtime_lock); [ 251.101967] lock(hrtimer_bases.lock#11); [ 251.101967] lock(timekeeper_seq); [ 251.101967] [ 251.101967] *** DEADLOCK *** [ 251.101967] [ 251.101967] 3 locks held by kworker/10:1/4506: [ 251.101967] #0: (events){.+.+.+}, at: [<ffffffff81154960>] process_one_work+0x200/0x530 [ 251.101967] #1: (hrtimer_work){+.+...}, at: [<ffffffff81154960>] process_one_work+0x200/0x530 [ 251.101967] #2: (hrtimer_bases.lock#11){-.-...}, at: [<ffffffff81160e7c>] retrigger_next_event+0x3c/0x70 [ 251.101967] [ 251.101967] stack backtrace: [ 251.101967] CPU: 10 PID: 4506 Comm: kworker/10:1 Not tainted 3.13.0-rc2-next-20131206-sasha-00005-g8be2375-dirty #4053 [ 251.101967] Workqueue: events clock_was_set_work So the best solution is to avoid calling clock_was_set_delayed() while holding the timekeeping lock, and instead using a flag variable to decide if we should call clock_was_set() once we've released the locks. This works for the case here, where the do_adjtimex() was the deadlock trigger point. Unfortuantely, in update_wall_time() we still hold the jiffies lock, which would deadlock with the ipi triggered by clock_was_set(), preventing us from calling it even after we drop the timekeeping lock. So instead call clock_was_set_delayed() at that point. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: stable <stable@vger.kernel.org> #3.10+ Reported-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * timekeeping: Fix potential lost pv notification of time changeJohn Stultz2013-12-231-9/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In 780427f0e11 (Indicate that clock was set in the pvclock gtod notifier), logic was added to pass a CLOCK_WAS_SET notification to the pvclock notifier chain. While that patch added a action flag returned from accumulate_nsecs_to_secs(), it only uses the returned value in one location, and not in the logarithmic accumulation. This means if a leap second triggered during the logarithmic accumulation (which is most likely where it would happen), the notification that the clock was set would not make it to the pv notifiers. This patch extends the logarithmic_accumulation pass down that action flag so proper notification will occur. This patch also changes the varialbe action -> clock_set per Ingo's suggestion. Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: <xen-devel@lists.xen.org> Cc: stable <stable@vger.kernel.org> #3.11+ Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * timekeeping: Fix lost updates to tai adjustmentJohn Stultz2013-12-231-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since 48cdc135d4840 (Implement a shadow timekeeper), we have to call timekeeping_update() after any adjustment to the timekeeping structure in order to make sure that any adjustments to the structure persist. Unfortunately, the updates to the tai offset via adjtimex do not trigger this update, causing adjustments to the tai offset to be made and then over-written by the previous value at the next update_wall_time() call. This patch resovles the issue by calling timekeeping_update() right after setting the tai offset. Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: stable <stable@vger.kernel.org> #3.10+ Signed-off-by: John Stultz <john.stultz@linaro.org>