From 2619d7e9c92d524cb155ec89fd72875321512e5b Mon Sep 17 00:00:00 2001 From: John Stultz Date: Wed, 9 Sep 2015 16:07:30 -0700 Subject: time: Fix timekeeping_freqadjust()'s incorrect use of abs() instead of abs64() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The internal clocksteering done for fine-grained error correction uses a logarithmic approximation, so any time adjtimex() adjusts the clock steering, timekeeping_freqadjust() quickly approximates the correct clock frequency over a series of ticks. Unfortunately, the logic in timekeeping_freqadjust(), introduced in commit: dc491596f639 ("timekeeping: Rework frequency adjustments to work better w/ nohz") used the abs() function with a s64 error value to calculate the size of the approximated adjustment to be made. Per include/linux/kernel.h: "abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()". Thus on 32-bit platforms, this resulted in the clocksteering to take a quite dampended random walk trying to converge on the proper frequency, which caused the adjustments to be made much slower then intended (most easily observed when large adjustments are made). This patch fixes the issue by using abs64() instead. Reported-by: Nuno Gonçalves Tested-by: Nuno Goncalves Signed-off-by: John Stultz Cc: # v3.17+ Cc: Linus Torvalds Cc: Miroslav Lichvar Cc: Peter Zijlstra Cc: Prarit Bhargava Cc: Richard Cochran Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1441840051-20244-1-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar --- kernel/time/timekeeping.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/time') diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index f6ee2e6b6f5d..3739ac6aa473 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1614,7 +1614,7 @@ static __always_inline void timekeeping_freqadjust(struct timekeeper *tk, negative = (tick_error < 0); /* Sort out the magnitude of the correction */ - tick_error = abs(tick_error); + tick_error = abs64(tick_error); for (adj = 0; tick_error > interval; adj++) tick_error >>= 1; -- cgit v1.2.3 From eef7635a22f6b144206b5ca2f1398f637acffc4d Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Fri, 11 Sep 2015 09:34:26 +0530 Subject: clockevents: Remove unused set_mode() callback All users are migrated to the per-state callbacks, get rid of the unused interface and the core support code. Signed-off-by: Viresh Kumar Signed-off-by: Thomas Gleixner Cc: linaro-kernel@lists.linaro.org Cc: John Stultz Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/fd60de14cf6d125489c031207567bb255ad946f6.1441943991.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar --- include/linux/clockchips.h | 29 +++++-------------------- kernel/time/clockevents.c | 42 +----------------------------------- kernel/time/tick-common.c | 1 - kernel/time/timer_list.c | 54 +++++++++++++++++++++------------------------- 4 files changed, 30 insertions(+), 96 deletions(-) (limited to 'kernel/time') diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h index 31ce435981fe..bdcf358dfce2 100644 --- a/include/linux/clockchips.h +++ b/include/linux/clockchips.h @@ -18,15 +18,6 @@ struct clock_event_device; struct module; -/* Clock event mode commands for legacy ->set_mode(): OBSOLETE */ -enum clock_event_mode { - CLOCK_EVT_MODE_UNUSED, - CLOCK_EVT_MODE_SHUTDOWN, - CLOCK_EVT_MODE_PERIODIC, - CLOCK_EVT_MODE_ONESHOT, - CLOCK_EVT_MODE_RESUME, -}; - /* * Possible states of a clock event device. * @@ -86,16 +77,14 @@ enum clock_event_state { * @min_delta_ns: minimum delta value in ns * @mult: nanosecond to cycles multiplier * @shift: nanoseconds to cycles divisor (power of two) - * @mode: operating mode, relevant only to ->set_mode(), OBSOLETE * @state_use_accessors:current state of the device, assigned by the core code * @features: features * @retries: number of forced programming retries - * @set_mode: legacy set mode function, only for modes <= CLOCK_EVT_MODE_RESUME. - * @set_state_periodic: switch state to periodic, if !set_mode - * @set_state_oneshot: switch state to oneshot, if !set_mode - * @set_state_oneshot_stopped: switch state to oneshot_stopped, if !set_mode - * @set_state_shutdown: switch state to shutdown, if !set_mode - * @tick_resume: resume clkevt device, if !set_mode + * @set_state_periodic: switch state to periodic + * @set_state_oneshot: switch state to oneshot + * @set_state_oneshot_stopped: switch state to oneshot_stopped + * @set_state_shutdown: switch state to shutdown + * @tick_resume: resume clkevt device * @broadcast: function to broadcast events * @min_delta_ticks: minimum delta value in ticks stored for reconfiguration * @max_delta_ticks: maximum delta value in ticks stored for reconfiguration @@ -116,18 +105,10 @@ struct clock_event_device { u64 min_delta_ns; u32 mult; u32 shift; - enum clock_event_mode mode; enum clock_event_state state_use_accessors; unsigned int features; unsigned long retries; - /* - * State transition callback(s): Only one of the two groups should be - * defined: - * - set_mode(), only for modes <= CLOCK_EVT_MODE_RESUME. - * - set_state_{shutdown|periodic|oneshot|oneshot_stopped}(), tick_resume(). - */ - void (*set_mode)(enum clock_event_mode mode, struct clock_event_device *); int (*set_state_periodic)(struct clock_event_device *); int (*set_state_oneshot)(struct clock_event_device *); int (*set_state_oneshot_stopped)(struct clock_event_device *); diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index 50eb107f1198..a9b76a40319e 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -97,20 +97,6 @@ EXPORT_SYMBOL_GPL(clockevent_delta2ns); static int __clockevents_switch_state(struct clock_event_device *dev, enum clock_event_state state) { - /* Transition with legacy set_mode() callback */ - if (dev->set_mode) { - /* Legacy callback doesn't support new modes */ - if (state > CLOCK_EVT_STATE_ONESHOT) - return -ENOSYS; - /* - * 'clock_event_state' and 'clock_event_mode' have 1-to-1 - * mapping until *_ONESHOT, and so a simple cast will work. - */ - dev->set_mode((enum clock_event_mode)state, dev); - dev->mode = (enum clock_event_mode)state; - return 0; - } - if (dev->features & CLOCK_EVT_FEAT_DUMMY) return 0; @@ -204,12 +190,8 @@ int clockevents_tick_resume(struct clock_event_device *dev) { int ret = 0; - if (dev->set_mode) { - dev->set_mode(CLOCK_EVT_MODE_RESUME, dev); - dev->mode = CLOCK_EVT_MODE_RESUME; - } else if (dev->tick_resume) { + if (dev->tick_resume) ret = dev->tick_resume(dev); - } return ret; } @@ -460,26 +442,6 @@ int clockevents_unbind_device(struct clock_event_device *ced, int cpu) } EXPORT_SYMBOL_GPL(clockevents_unbind_device); -/* Sanity check of state transition callbacks */ -static int clockevents_sanity_check(struct clock_event_device *dev) -{ - /* Legacy set_mode() callback */ - if (dev->set_mode) { - /* We shouldn't be supporting new modes now */ - WARN_ON(dev->set_state_periodic || dev->set_state_oneshot || - dev->set_state_shutdown || dev->tick_resume || - dev->set_state_oneshot_stopped); - - BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED); - return 0; - } - - if (dev->features & CLOCK_EVT_FEAT_DUMMY) - return 0; - - return 0; -} - /** * clockevents_register_device - register a clock event device * @dev: device to register @@ -488,8 +450,6 @@ void clockevents_register_device(struct clock_event_device *dev) { unsigned long flags; - BUG_ON(clockevents_sanity_check(dev)); - /* Initialize state to DETACHED */ clockevent_set_state(dev, CLOCK_EVT_STATE_DETACHED); diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index d11c55b6ab7d..4fcd99e12aa0 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -398,7 +398,6 @@ void tick_shutdown(unsigned int cpu) * the set mode function! */ clockevent_set_state(dev, CLOCK_EVT_STATE_DETACHED); - dev->mode = CLOCK_EVT_MODE_UNUSED; clockevents_exchange_device(dev, NULL); dev->event_handler = clockevents_handle_noop; td->evtdev = NULL; diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c index 129c96033e46..f75e35b60149 100644 --- a/kernel/time/timer_list.c +++ b/kernel/time/timer_list.c @@ -225,7 +225,7 @@ print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu) (unsigned long long) dev->min_delta_ns); SEQ_printf(m, " mult: %u\n", dev->mult); SEQ_printf(m, " shift: %u\n", dev->shift); - SEQ_printf(m, " mode: %d\n", dev->mode); + SEQ_printf(m, " mode: %d\n", clockevent_get_state(dev)); SEQ_printf(m, " next_event: %Ld nsecs\n", (unsigned long long) ktime_to_ns(dev->next_event)); @@ -233,40 +233,34 @@ print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu) print_name_offset(m, dev->set_next_event); SEQ_printf(m, "\n"); - if (dev->set_mode) { - SEQ_printf(m, " set_mode: "); - print_name_offset(m, dev->set_mode); + if (dev->set_state_shutdown) { + SEQ_printf(m, " shutdown: "); + print_name_offset(m, dev->set_state_shutdown); SEQ_printf(m, "\n"); - } else { - if (dev->set_state_shutdown) { - SEQ_printf(m, " shutdown: "); - print_name_offset(m, dev->set_state_shutdown); - SEQ_printf(m, "\n"); - } + } - if (dev->set_state_periodic) { - SEQ_printf(m, " periodic: "); - print_name_offset(m, dev->set_state_periodic); - SEQ_printf(m, "\n"); - } + if (dev->set_state_periodic) { + SEQ_printf(m, " periodic: "); + print_name_offset(m, dev->set_state_periodic); + SEQ_printf(m, "\n"); + } - if (dev->set_state_oneshot) { - SEQ_printf(m, " oneshot: "); - print_name_offset(m, dev->set_state_oneshot); - SEQ_printf(m, "\n"); - } + if (dev->set_state_oneshot) { + SEQ_printf(m, " oneshot: "); + print_name_offset(m, dev->set_state_oneshot); + SEQ_printf(m, "\n"); + } - if (dev->set_state_oneshot_stopped) { - SEQ_printf(m, " oneshot stopped: "); - print_name_offset(m, dev->set_state_oneshot_stopped); - SEQ_printf(m, "\n"); - } + if (dev->set_state_oneshot_stopped) { + SEQ_printf(m, " oneshot stopped: "); + print_name_offset(m, dev->set_state_oneshot_stopped); + SEQ_printf(m, "\n"); + } - if (dev->tick_resume) { - SEQ_printf(m, " resume: "); - print_name_offset(m, dev->tick_resume); - SEQ_printf(m, "\n"); - } + if (dev->tick_resume) { + SEQ_printf(m, " resume: "); + print_name_offset(m, dev->tick_resume); + SEQ_printf(m, "\n"); } SEQ_printf(m, " event_handler: "); -- cgit v1.2.3