From: Linus Torvalds Date: Tue, 30 Apr 2013 15:15:40 +0000 (-0700) Subject: Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel... X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=ab86e974f04b1cd827a9c7c35273834ebcd9ab38;p=deliverable%2Flinux.git Merge branch 'timers-core-for-linus' of git://git./linux/kernel/git/tip/tip Pull core timer updates from Ingo Molnar: "The main changes in this cycle's merge are: - Implement shadow timekeeper to shorten in kernel reader side blocking, by Thomas Gleixner. - Posix timers enhancements by Pavel Emelyanov: - allocate timer ID per process, so that exact timer ID allocations can be re-created be checkpoint/restore code. - debuggability and tooling (/proc/PID/timers, etc.) improvements. - suspend/resume enhancements by Feng Tang: on certain new Intel Atom processors (Penwell and Cloverview), there is a feature that the TSC won't stop in S3 state, so the TSC value won't be reset to 0 after resume. This can be taken advantage of by the generic via the CLOCK_SOURCE_SUSPEND_NONSTOP flag: instead of using the RTC to recover/approximate sleep time, the main (and precise) clocksource can be used. - Fix /proc/timer_list for 4096 CPUs by Nathan Zimmer: on so many CPUs the file goes beyond 4MB of size and thus the current simplistic seqfile approach fails. Convert /proc/timer_list to a proper seq_file with its own iterator. - Cleanups and refactorings of the core timekeeping code by John Stultz. - International Atomic Clock time is managed by the NTP code internally currently but not exposed externally. Separate the TAI code out and add CLOCK_TAI support and TAI support to the hrtimer and posix-timer code, by John Stultz. - Add deep idle support enhacement to the broadcast clockevents core timer code, by Daniel Lezcano: add an opt-in CLOCK_EVT_FEAT_DYNIRQ clockevents feature (which will be utilized by future clockevents driver updates), which allows the use of IRQ affinities to avoid spurious wakeups of idle CPUs - the right CPU with an expiring timer will be woken. - Add new ARM bcm281xx clocksource driver, by Christian Daudt - ... various other fixes and cleanups" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits) clockevents: Set dummy handler on CPU_DEAD shutdown timekeeping: Update tk->cycle_last in resume posix-timers: Remove unused variable clockevents: Switch into oneshot mode even if broadcast registered late timer_list: Convert timer list to be a proper seq_file timer_list: Split timer_list_show_tickdevices posix-timers: Show sigevent info in proc file posix-timers: Introduce /proc/PID/timers file posix timers: Allocate timer id per process (v2) timekeeping: Make sure to notify hrtimers when TAI offset changes hrtimer: Fix ktime_add_ns() overflow on 32bit architectures hrtimer: Add expiry time overflow check in hrtimer_interrupt timekeeping: Shorten seq_count region timekeeping: Implement a shadow timekeeper timekeeping: Delay update of clock->cycle_last timekeeping: Store cycle_last value in timekeeper struct as well ntp: Remove ntp_lock, using the timekeeping locks to protect ntp state timekeeping: Simplify tai updating from do_adjtimex timekeeping: Hold timekeepering locks in do_adjtimex and hardpps timekeeping: Move ADJ_SETOFFSET to top level do_adjtimex() ... --- ab86e974f04b1cd827a9c7c35273834ebcd9ab38 diff --cc init/main.c index 12c366944dbd,b3e061428545..bea1287aecdc --- a/init/main.c +++ b/init/main.c @@@ -495,10 -494,9 +495,9 @@@ asmlinkage void __init start_kernel(voi * Interrupts are still disabled. Do necessary setups, then * enable them */ - tick_init(); boot_cpu_init(); page_address_init(); - printk(KERN_NOTICE "%s", linux_banner); + pr_notice("%s", linux_banner); setup_arch(&command_line); mm_init_owner(&init_mm, &init_task); mm_init_cpumask(&init_mm); diff --cc kernel/cpu/idle.c index 168cf407a254,000000000000..8b86c0c68edf mode 100644,000000..100644 --- a/kernel/cpu/idle.c +++ b/kernel/cpu/idle.c @@@ -1,107 -1,0 +1,116 @@@ +/* + * Generic entry point for the idle threads + */ +#include +#include +#include +#include + +#include + +#include + +static int __read_mostly cpu_idle_force_poll; + +void cpu_idle_poll_ctrl(bool enable) +{ + if (enable) { + cpu_idle_force_poll++; + } else { + cpu_idle_force_poll--; + WARN_ON_ONCE(cpu_idle_force_poll < 0); + } +} + +#ifdef CONFIG_GENERIC_IDLE_POLL_SETUP +static int __init cpu_idle_poll_setup(char *__unused) +{ + cpu_idle_force_poll = 1; + return 1; +} +__setup("nohlt", cpu_idle_poll_setup); + +static int __init cpu_idle_nopoll_setup(char *__unused) +{ + cpu_idle_force_poll = 0; + return 1; +} +__setup("hlt", cpu_idle_nopoll_setup); +#endif + +static inline int cpu_idle_poll(void) +{ + trace_cpu_idle_rcuidle(0, smp_processor_id()); + local_irq_enable(); + while (!need_resched()) + cpu_relax(); + trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id()); + return 1; +} + +/* Weak implementations for optional arch specific functions */ +void __weak arch_cpu_idle_prepare(void) { } +void __weak arch_cpu_idle_enter(void) { } +void __weak arch_cpu_idle_exit(void) { } +void __weak arch_cpu_idle_dead(void) { } +void __weak arch_cpu_idle(void) +{ + cpu_idle_force_poll = 1; +} + +/* + * Generic idle loop implementation + */ +static void cpu_idle_loop(void) +{ + while (1) { + tick_nohz_idle_enter(); + + while (!need_resched()) { + check_pgt_cache(); + rmb(); + + if (cpu_is_offline(smp_processor_id())) + arch_cpu_idle_dead(); + + local_irq_disable(); + arch_cpu_idle_enter(); + - if (cpu_idle_force_poll) { ++ /* ++ * In poll mode we reenable interrupts and spin. ++ * ++ * Also if we detected in the wakeup from idle ++ * path that the tick broadcast device expired ++ * for us, we don't want to go deep idle as we ++ * know that the IPI is going to arrive right ++ * away ++ */ ++ if (cpu_idle_force_poll || tick_check_broadcast_expired()) { + cpu_idle_poll(); + } else { + current_clr_polling(); + if (!need_resched()) { + stop_critical_timings(); + rcu_idle_enter(); + arch_cpu_idle(); + WARN_ON_ONCE(irqs_disabled()); + rcu_idle_exit(); + start_critical_timings(); + } else { + local_irq_enable(); + } + current_set_polling(); + } + arch_cpu_idle_exit(); + } + tick_nohz_idle_exit(); + schedule_preempt_disabled(); + } +} + +void cpu_startup_entry(enum cpuhp_state state) +{ + current_set_polling(); + arch_cpu_idle_prepare(); + cpu_idle_loop(); +}