| /* |
| * linux/kernel/timer.c |
| * |
| * Kernel internal timers, kernel timekeeping, basic process system calls |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * |
| * 1997-01-28 Modified by Finn Arne Gangstad to make timers scale better. |
| * |
| * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 |
| * "A Kernel Model for Precision Timekeeping" by Dave Mills |
| * 1998-12-24 Fixed a xtime SMP race (we need the xtime_lock rw spinlock to |
| * serialize accesses to xtime/lost_ticks). |
| * Copyright (C) 1998 Andrea Arcangeli |
| * 1999-03-10 Improved NTP compatibility by Ulrich Windl |
| * 2002-05-31 Move sys_sysinfo here and make its locking sane, Robert Love |
| * 2000-10-05 Implemented scalable SMP per-CPU timer handling. |
| * Copyright (C) 2000, 2001, 2002 Ingo Molnar |
| * Designed by David S. Miller, Alexey Kuznetsov and Ingo Molnar |
| */ |
| |
| #include <linux/kernel_stat.h> |
| #include <linux/interrupt.h> |
| #include <linux/percpu.h> |
| #include <linux/init.h> |
| #include <linux/mm.h> |
| #include <linux/swap.h> |
| #include <linux/notifier.h> |
| #include <linux/thread_info.h> |
| #include <linux/time.h> |
| #include <linux/jiffies.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/div64.h> |
| #include <asm/timex.h> |
| |
| /* |
| * per-CPU timer vector definitions: |
| */ |
| #define TVN_BITS 6 |
| #define TVR_BITS 8 |
| #define TVN_SIZE (1 << TVN_BITS) |
| #define TVR_SIZE (1 << TVR_BITS) |
| #define TVN_MASK (TVN_SIZE - 1) |
| #define TVR_MASK (TVR_SIZE - 1) |
| |
| typedef struct tvec_s { |
| struct list_head vec[TVN_SIZE]; |
| } tvec_t; |
| |
| typedef struct tvec_root_s { |
| struct list_head vec[TVR_SIZE]; |
| } tvec_root_t; |
| |
| struct tvec_t_base_s { |
| spinlock_t lock; |
| unsigned long timer_jiffies; |
| struct timer_list *running_timer; |
| tvec_root_t tv1; |
| tvec_t tv2; |
| tvec_t tv3; |
| tvec_t tv4; |
| tvec_t tv5; |
| } ____cacheline_aligned_in_smp; |
| |
| typedef struct tvec_t_base_s tvec_base_t; |
| |
| static inline void set_running_timer(tvec_base_t *base, |
| struct timer_list *timer) |
| { |
| #ifdef CONFIG_SMP |
| base->running_timer = timer; |
| #endif |
| } |
| |
| /* Fake initialization */ |
| static DEFINE_PER_CPU(tvec_base_t, tvec_bases) = { SPIN_LOCK_UNLOCKED }; |
| |
| static void check_timer_failed(struct timer_list *timer) |
| { |
| static int whine_count; |
| if (whine_count < 16) { |
| whine_count++; |
| printk("Uninitialised timer!\n"); |
| printk("This is just a warning. Your computer is OK\n"); |
| printk("function=0x%p, data=0x%lx\n", |
| timer->function, timer->data); |
| dump_stack(); |
| } |
| /* |
| * Now fix it up |
| */ |
| spin_lock_init(&timer->lock); |
| timer->magic = TIMER_MAGIC; |
| } |
| |
| static inline void check_timer(struct timer_list *timer) |
| { |
| if (timer->magic != TIMER_MAGIC) |
| check_timer_failed(timer); |
| } |
| |
| |
| static void internal_add_timer(tvec_base_t *base, struct timer_list *timer) |
| { |
| unsigned long expires = timer->expires; |
| unsigned long idx = expires - base->timer_jiffies; |
| struct list_head *vec; |
| |
| if (idx < TVR_SIZE) { |
| int i = expires & TVR_MASK; |
| vec = base->tv1.vec + i; |
| } else if (idx < 1 << (TVR_BITS + TVN_BITS)) { |
| int i = (expires >> TVR_BITS) & TVN_MASK; |
| vec = base->tv2.vec + i; |
| } else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) { |
| int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK; |
| vec = base->tv3.vec + i; |
| } else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) { |
| int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK; |
| vec = base->tv4.vec + i; |
| } else if ((signed long) idx < 0) { |
| /* |
| * Can happen if you add a timer with expires == jiffies, |
| * or you set a timer to go off in the past |
| */ |
| vec = base->tv1.vec + (base->timer_jiffies & TVR_MASK); |
| } else if (idx <= 0xffffffffUL) { |
| int i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK; |
| vec = base->tv5.vec + i; |
| } else { |
| /* Can only get here on architectures with 64-bit jiffies */ |
| INIT_LIST_HEAD(&timer->entry); |
| return; |
| } |
| /* |
| * Timers are FIFO: |
| */ |
| list_add_tail(&timer->entry, vec); |
| } |
| |
| /*** |
| * add_timer - start a timer |
| * @timer: the timer to be added |
| * |
| * The kernel will do a ->function(->data) callback from the |
| * timer interrupt at the ->expired point in the future. The |
| * current time is 'jiffies'. |
| * |
| * The timer's ->expired, ->function (and if the handler uses it, ->data) |
| * fields must be set prior calling this function. |
| * |
| * Timers with an ->expired field in the past will be executed in the next |
| * timer tick. It's illegal to add an already pending timer. |
| */ |
| void add_timer(struct timer_list *timer) |
| { |
| int cpu = get_cpu(); |
| tvec_base_t *base = &per_cpu(tvec_bases, cpu); |
| unsigned long flags; |
| |
| BUG_ON(timer_pending(timer) || !timer->function); |
| |
| check_timer(timer); |
| |
| spin_lock_irqsave(&base->lock, flags); |
| internal_add_timer(base, timer); |
| timer->base = base; |
| spin_unlock_irqrestore(&base->lock, flags); |
| put_cpu(); |
| } |
| |
| /*** |
| * add_timer_on - start a timer on a particular CPU |
| * @timer: the timer to be added |
| * @cpu: the CPU to start it on |
| * |
| * This is not very scalable on SMP. |
| */ |
| void add_timer_on(struct timer_list *timer, int cpu) |
| { |
| tvec_base_t *base = &per_cpu(tvec_bases, cpu); |
| unsigned long flags; |
| |
| BUG_ON(timer_pending(timer) || !timer->function); |
| |
| check_timer(timer); |
| |
| spin_lock_irqsave(&base->lock, flags); |
| internal_add_timer(base, timer); |
| timer->base = base; |
| spin_unlock_irqrestore(&base->lock, flags); |
| } |
| |
| /*** |
| * mod_timer - modify a timer's timeout |
| * @timer: the timer to be modified |
| * |
| * mod_timer is a more efficient way to update the expire field of an |
| * active timer (if the timer is inactive it will be activated) |
| * |
| * mod_timer(timer, expires) is equivalent to: |
| * |
| * del_timer(timer); timer->expires = expires; add_timer(timer); |
| * |
| * Note that if there are multiple unserialized concurrent users of the |
| * same timer, then mod_timer() is the only safe way to modify the timeout, |
| * since add_timer() cannot modify an already running timer. |
| * |
| * The function returns whether it has modified a pending timer or not. |
| * (ie. mod_timer() of an inactive timer returns 0, mod_timer() of an |
| * active timer returns 1.) |
| */ |
| int mod_timer(struct timer_list *timer, unsigned long expires) |
| { |
| tvec_base_t *old_base, *new_base; |
| unsigned long flags; |
| int ret = 0; |
| |
| BUG_ON(!timer->function); |
| |
| check_timer(timer); |
| |
| /* |
| * This is a common optimization triggered by the |
| * networking code - if the timer is re-modified |
| * to be the same thing then just return: |
| */ |
| if (timer->expires == expires && timer_pending(timer)) |
| return 1; |
| |
| spin_lock_irqsave(&timer->lock, flags); |
| new_base = &per_cpu(tvec_bases, smp_processor_id()); |
| repeat: |
| old_base = timer->base; |
| |
| /* |
| * Prevent deadlocks via ordering by old_base < new_base. |
| */ |
| if (old_base && (new_base != old_base)) { |
| if (old_base < new_base) { |
| spin_lock(&new_base->lock); |
| spin_lock(&old_base->lock); |
| } else { |
| spin_lock(&old_base->lock); |
| spin_lock(&new_base->lock); |
| } |
| /* |
| * The timer base might have been cancelled while we were |
| * trying to take the lock(s): |
| */ |
| if (timer->base != old_base) { |
| spin_unlock(&new_base->lock); |
| spin_unlock(&old_base->lock); |
| goto repeat; |
| } |
| } else |
| spin_lock(&new_base->lock); |
| |
| /* |
| * Delete the previous timeout (if there was any), and install |
| * the new one: |
| */ |
| if (old_base) { |
| list_del(&timer->entry); |
| ret = 1; |
| } |
| timer->expires = expires; |
| internal_add_timer(new_base, timer); |
| timer->base = new_base; |
| |
| if (old_base && (new_base != old_base)) |
| spin_unlock(&old_base->lock); |
| spin_unlock(&new_base->lock); |
| spin_unlock_irqrestore(&timer->lock, flags); |
| |
| return ret; |
| } |
| |
| /*** |
| * del_timer - deactive a timer. |
| * @timer: the timer to be deactivated |
| * |
| * del_timer() deactivates a timer - this works on both active and inactive |
| * timers. |
| * |
| * The function returns whether it has deactivated a pending timer or not. |
| * (ie. del_timer() of an inactive timer returns 0, del_timer() of an |
| * active timer returns 1.) |
| */ |
| int del_timer(struct timer_list *timer) |
| { |
| unsigned long flags; |
| tvec_base_t *base; |
| |
| check_timer(timer); |
| |
| repeat: |
| base = timer->base; |
| if (!base) |
| return 0; |
| spin_lock_irqsave(&base->lock, flags); |
| if (base != timer->base) { |
| spin_unlock_irqrestore(&base->lock, flags); |
| goto repeat; |
| } |
| list_del(&timer->entry); |
| timer->base = NULL; |
| spin_unlock_irqrestore(&base->lock, flags); |
| |
| return 1; |
| } |
| |
| #ifdef CONFIG_SMP |
| /*** |
| * del_timer_sync - deactivate a timer and wait for the handler to finish. |
| * @timer: the timer to be deactivated |
| * |
| * This function only differs from del_timer() on SMP: besides deactivating |
| * the timer it also makes sure the handler has finished executing on other |
| * CPUs. |
| * |
| * Synchronization rules: callers must prevent restarting of the timer, |
| * otherwise this function is meaningless. It must not be called from |
| * interrupt contexts. Upon exit the timer is not queued and the handler |
| * is not running on any CPU. |
| * |
| * The function returns whether it has deactivated a pending timer or not. |
| */ |
| int del_timer_sync(struct timer_list *timer) |
| { |
| tvec_base_t *base; |
| int i, ret = 0; |
| |
| check_timer(timer); |
| |
| del_again: |
| ret += del_timer(timer); |
| |
| for (i = 0; i < NR_CPUS; i++) { |
| if (!cpu_online(i)) |
| continue; |
| |
| base = &per_cpu(tvec_bases, i); |
| if (base->running_timer == timer) { |
| while (base->running_timer == timer) { |
| cpu_relax(); |
| preempt_check_resched(); |
| } |
| break; |
| } |
| } |
| if (timer_pending(timer)) |
| goto del_again; |
| |
| return ret; |
| } |
| #endif |
| |
| |
| static int cascade(tvec_base_t *base, tvec_t *tv, int index) |
| { |
| /* cascade all the timers from tv up one level */ |
| struct list_head *head, *curr; |
| |
| head = tv->vec + index; |
| curr = head->next; |
| /* |
| * We are removing _all_ timers from the list, so we don't have to |
| * detach them individually, just clear the list afterwards. |
| */ |
| while (curr != head) { |
| struct timer_list *tmp; |
| |
| tmp = list_entry(curr, struct timer_list, entry); |
| BUG_ON(tmp->base != base); |
| curr = curr->next; |
| internal_add_timer(base, tmp); |
| } |
| INIT_LIST_HEAD(head); |
| |
| return index; |
| } |
| |
| /*** |
| * __run_timers - run all expired timers (if any) on this CPU. |
| * @base: the timer vector to be processed. |
| * |
| * This function cascades all vectors and executes all expired timer |
| * vectors. |
| */ |
| #define INDEX(N) (base->timer_jiffies >> (TVR_BITS + N * TVN_BITS)) & TVN_MASK |
| |
| static inline void __run_timers(tvec_base_t *base) |
| { |
| struct timer_list *timer; |
| |
| spin_lock_irq(&base->lock); |
| while (time_after_eq(jiffies, base->timer_jiffies)) { |
| struct list_head work_list = LIST_HEAD_INIT(work_list); |
| struct list_head *head = &work_list; |
| int index = base->timer_jiffies & TVR_MASK; |
| |
| /* |
| * Cascade timers: |
| */ |
| if (!index && |
| (!cascade(base, &base->tv2, INDEX(0))) && |
| (!cascade(base, &base->tv3, INDEX(1))) && |
| !cascade(base, &base->tv4, INDEX(2))) |
| cascade(base, &base->tv5, INDEX(3)); |
| ++base->timer_jiffies; |
| list_splice_init(base->tv1.vec + index, &work_list); |
| repeat: |
| if (!list_empty(head)) { |
| void (*fn)(unsigned long); |
| unsigned long data; |
| |
| timer = list_entry(head->next,struct timer_list,entry); |
| fn = timer->function; |
| data = timer->data; |
| |
| list_del(&timer->entry); |
| timer->base = NULL; |
| set_running_timer(base, timer); |
| spin_unlock_irq(&base->lock); |
| fn(data); |
| spin_lock_irq(&base->lock); |
| goto repeat; |
| } |
| } |
| set_running_timer(base, NULL); |
| spin_unlock_irq(&base->lock); |
| } |
| |
| /******************************************************************/ |
| |
| /* |
| * Timekeeping variables |
| */ |
| unsigned long tick_usec = TICK_USEC; /* ACTHZ period (usec) */ |
| unsigned long tick_nsec = TICK_NSEC(TICK_USEC); /* USER_HZ period (nsec) */ |
| |
| /* The current time */ |
| struct timespec xtime __attribute__ ((aligned (16))); |
| |
| /* Don't completely fail for HZ > 500. */ |
| int tickadj = 500/HZ ? : 1; /* microsecs */ |
| |
| |
| /* |
| * phase-lock loop variables |
| */ |
| /* TIME_ERROR prevents overwriting the CMOS clock */ |
| int time_state = TIME_OK; /* clock synchronization status */ |
| int time_status = STA_UNSYNC; /* clock status bits */ |
| long time_offset; /* time adjustment (us) */ |
| long time_constant = 2; /* pll time constant */ |
| long time_tolerance = MAXFREQ; /* frequency tolerance (ppm) */ |
| long time_precision = 1; /* clock precision (us) */ |
| long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */ |
| long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */ |
| long time_phase; /* phase offset (scaled us) */ |
| long time_freq = ((1000000 + HZ/2) % HZ - HZ/2) << SHIFT_USEC; |
| /* frequency offset (scaled ppm)*/ |
| long time_adj; /* tick adjust (scaled 1 / HZ) */ |
| long time_reftime; /* time at last adjustment (s) */ |
| long time_adjust; |
| |
| /* |
| * this routine handles the overflow of the microsecond field |
| * |
| * The tricky bits of code to handle the accurate clock support |
| * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame. |
| * They were originally developed for SUN and DEC kernels. |
| * All the kudos should go to Dave for this stuff. |
| * |
| */ |
| static void second_overflow(void) |
| { |
| long ltemp; |
| |
| /* Bump the maxerror field */ |
| time_maxerror += time_tolerance >> SHIFT_USEC; |
| if ( time_maxerror > NTP_PHASE_LIMIT ) { |
| time_maxerror = NTP_PHASE_LIMIT; |
| time_status |= STA_UNSYNC; |
| } |
| |
| /* |
| * Leap second processing. If in leap-insert state at |
| * the end of the day, the system clock is set back one |
| * second; if in leap-delete state, the system clock is |
| * set ahead one second. The microtime() routine or |
| * external clock driver will insure that reported time |
| * is always monotonic. The ugly divides should be |
| * replaced. |
| */ |
| switch (time_state) { |
| |
| case TIME_OK: |
| if (time_status & STA_INS) |
| time_state = TIME_INS; |
| else if (time_status & STA_DEL) |
| time_state = TIME_DEL; |
| break; |
| |
| case TIME_INS: |
| if (xtime.tv_sec % 86400 == 0) { |
| xtime.tv_sec--; |
| time_state = TIME_OOP; |
| clock_was_set(); |
| printk(KERN_NOTICE "Clock: inserting leap second 23:59:60 UTC\n"); |
| } |
| break; |
| |
| case TIME_DEL: |
| if ((xtime.tv_sec + 1) % 86400 == 0) { |
| xtime.tv_sec++; |
| time_state = TIME_WAIT; |
| clock_was_set(); |
| printk(KERN_NOTICE "Clock: deleting leap second 23:59:59 UTC\n"); |
| } |
| break; |
| |
| case TIME_OOP: |
| time_state = TIME_WAIT; |
| break; |
| |
| case TIME_WAIT: |
| if (!(time_status & (STA_INS | STA_DEL))) |
| time_state = TIME_OK; |
| } |
| |
| /* |
| * Compute the phase adjustment for the next second. In |
| * PLL mode, the offset is reduced by a fixed factor |
| * times the time constant. In FLL mode the offset is |
| * used directly. In either mode, the maximum phase |
| * adjustment for each second is clamped so as to spread |
| * the adjustment over not more than the number of |
| * seconds between updates. |
| */ |
| if (time_offset < 0) { |
| ltemp = -time_offset; |
| if (!(time_status & STA_FLL)) |
| ltemp >>= SHIFT_KG + time_constant; |
| if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE) |
| ltemp = (MAXPHASE / MINSEC) << SHIFT_UPDATE; |
| time_offset += ltemp; |
| time_adj = -ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE); |
| } else { |
| ltemp = time_offset; |
| if (!(time_status & STA_FLL)) |
| ltemp >>= SHIFT_KG + time_constant; |
| if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE) |
| ltemp = (MAXPHASE / MINSEC) << SHIFT_UPDATE; |
| time_offset -= ltemp; |
| time_adj = ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE); |
| } |
| |
| /* |
| * Compute the frequency estimate and additional phase |
| * adjustment due to frequency error for the next |
| * second. When the PPS signal is engaged, gnaw on the |
| * watchdog counter and update the frequency computed by |
| * the pll and the PPS signal. |
| */ |
| pps_valid++; |
| if (pps_valid == PPS_VALID) { /* PPS signal lost */ |
| pps_jitter = MAXTIME; |
| pps_stabil = MAXFREQ; |
| time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER | |
| STA_PPSWANDER | STA_PPSERROR); |
| } |
| ltemp = time_freq + pps_freq; |
| if (ltemp < 0) |
| time_adj -= -ltemp >> |
| (SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE); |
| else |
| time_adj += ltemp >> |
| (SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE); |
| |
| #if HZ == 100 |
| /* Compensate for (HZ==100) != (1 << SHIFT_HZ). |
| * Add 25% and 3.125% to get 128.125; => only 0.125% error (p. 14) |
| */ |
| if (time_adj < 0) |
| time_adj -= (-time_adj >> 2) + (-time_adj >> 5); |
| else |
| time_adj += (time_adj >> 2) + (time_adj >> 5); |
| #endif |
| } |
| |
| /* in the NTP reference this is called "hardclock()" */ |
| static void update_wall_time_one_tick(void) |
| { |
| long time_adjust_step; |
| |
| if ( (time_adjust_step = time_adjust) != 0 ) { |
| /* We are doing an adjtime thing. |
| * |
| * Prepare time_adjust_step to be within bounds. |
| * Note that a positive time_adjust means we want the clock |
| * to run faster. |
| * |
| * Limit the amount of the step to be in the range |
| * -tickadj .. +tickadj |
| */ |
| if (time_adjust > tickadj) |
| time_adjust_step = tickadj; |
| else if (time_adjust < -tickadj) |
| time_adjust_step = -tickadj; |
| |
| /* Reduce by this step the amount of time left */ |
| time_adjust -= time_adjust_step; |
| } |
| xtime.tv_nsec += tick_nsec + time_adjust_step * 1000; |
| /* |
| * Advance the phase, once it gets to one microsecond, then |
| * advance the tick more. |
| */ |
| time_phase += time_adj; |
| if (time_phase <= -FINEUSEC) { |
| long ltemp = -time_phase >> (SHIFT_SCALE - 10); |
| time_phase += ltemp << (SHIFT_SCALE - 10); |
| xtime.tv_nsec -= ltemp; |
| } |
| else if (time_phase >= FINEUSEC) { |
| long ltemp = time_phase >> (SHIFT_SCALE - 10); |
| time_phase -= ltemp << (SHIFT_SCALE - 10); |
| xtime.tv_nsec += ltemp; |
| } |
| } |
| |
| /* |
| * Using a loop looks inefficient, but "ticks" is |
| * usually just one (we shouldn't be losing ticks, |
| * we're doing this this way mainly for interrupt |
| * latency reasons, not because we think we'll |
| * have lots of lost timer ticks |
| */ |
| static void update_wall_time(unsigned long ticks) |
| { |
| do { |
| ticks--; |
| update_wall_time_one_tick(); |
| } while (ticks); |
| |
| if (xtime.tv_nsec >= 1000000000) { |
| xtime.tv_nsec -= 1000000000; |
| xtime.tv_sec++; |
| second_overflow(); |
| } |
| } |
| |
| static inline void do_process_times(struct task_struct *p, |
| unsigned long user, unsigned long system) |
| { |
| unsigned long psecs; |
| |
| psecs = (p->utime += user); |
| psecs += (p->stime += system); |
| if (psecs / HZ > p->rlim[RLIMIT_CPU].rlim_cur) { |
| /* Send SIGXCPU every second.. */ |
| if (!(psecs % HZ)) |
| send_sig(SIGXCPU, p, 1); |
| /* and SIGKILL when we go over max.. */ |
| if (psecs / HZ > p->rlim[RLIMIT_CPU].rlim_max) |
| send_sig(SIGKILL, p, 1); |
| } |
| } |
| |
| static inline void do_it_virt(struct task_struct * p, unsigned long ticks) |
| { |
| unsigned long it_virt = p->it_virt_value; |
| |
| if (it_virt) { |
| it_virt -= ticks; |
| if (!it_virt) { |
| it_virt = p->it_virt_incr; |
| send_sig(SIGVTALRM, p, 1); |
| } |
| p->it_virt_value = it_virt; |
| } |
| } |
| |
| static inline void do_it_prof(struct task_struct *p) |
| { |
| unsigned long it_prof = p->it_prof_value; |
| |
| if (it_prof) { |
| if (--it_prof == 0) { |
| it_prof = p->it_prof_incr; |
| send_sig(SIGPROF, p, 1); |
| } |
| p->it_prof_value = it_prof; |
| } |
| } |
| |
| void update_one_process(struct task_struct *p, unsigned long user, |
| unsigned long system, int cpu) |
| { |
| do_process_times(p, user, system); |
| do_it_virt(p, user); |
| do_it_prof(p); |
| } |
| |
| /* |
| * Called from the timer interrupt handler to charge one tick to the current |
| * process. user_tick is 1 if the tick is user time, 0 for system. |
| */ |
| void update_process_times(int user_tick) |
| { |
| struct task_struct *p = current; |
| int cpu = smp_processor_id(), system = user_tick ^ 1; |
| |
| update_one_process(p, user_tick, system, cpu); |
| run_local_timers(); |
| scheduler_tick(user_tick, system); |
| } |
| |
| /* |
| * Nr of active tasks - counted in fixed-point numbers |
| */ |
| static unsigned long count_active_tasks(void) |
| { |
| return (nr_running() + nr_uninterruptible()) * FIXED_1; |
| } |
| |
| /* |
| * Hmm.. Changed this, as the GNU make sources (load.c) seems to |
| * imply that avenrun[] is the standard name for this kind of thing. |
| * Nothing else seems to be standardized: the fractional size etc |
| * all seem to differ on different machines. |
| * |
| * Requires xtime_lock to access. |
| */ |
| unsigned long avenrun[3]; |
| |
| /* |
| * calc_load - given tick count, update the avenrun load estimates. |
| * This is called while holding a write_lock on xtime_lock. |
| */ |
| static inline void calc_load(unsigned long ticks) |
| { |
| unsigned long active_tasks; /* fixed-point */ |
| static int count = LOAD_FREQ; |
| |
| count -= ticks; |
| if (count < 0) { |
| count += LOAD_FREQ; |
| active_tasks = count_active_tasks(); |
| CALC_LOAD(avenrun[0], EXP_1, active_tasks); |
| CALC_LOAD(avenrun[1], EXP_5, active_tasks); |
| CALC_LOAD(avenrun[2], EXP_15, active_tasks); |
| } |
| } |
| |
| /* jiffies at the most recent update of wall time */ |
| unsigned long wall_jiffies = INITIAL_JIFFIES; |
| |
| /* |
| * This read-write spinlock protects us from races in SMP while |
| * playing with xtime and avenrun. |
| */ |
| #ifndef ARCH_HAVE_XTIME_LOCK |
| seqlock_t xtime_lock __cacheline_aligned_in_smp = SEQLOCK_UNLOCKED; |
| #endif |
| unsigned long last_time_offset; |
| |
| /* |
| * This function runs timers and the timer-tq in bottom half context. |
| */ |
| static void run_timer_softirq(struct softirq_action *h) |
| { |
| tvec_base_t *base = &per_cpu(tvec_bases, smp_processor_id()); |
| |
| if (time_after_eq(jiffies, base->timer_jiffies)) |
| __run_timers(base); |
| } |
| |
| /* |
| * Called by the local, per-CPU timer interrupt on SMP. |
| */ |
| void run_local_timers(void) |
| { |
| raise_softirq(TIMER_SOFTIRQ); |
| } |
| |
| /* |
| * Called by the timer interrupt. xtime_lock must already be taken |
| * by the timer IRQ! |
| */ |
| static inline void update_times(void) |
| { |
| unsigned long ticks; |
| |
| ticks = jiffies - wall_jiffies; |
| if (ticks) { |
| wall_jiffies += ticks; |
| update_wall_time(ticks); |
| } |
| last_time_offset = 0; |
| calc_load(ticks); |
| } |
| |
| /* |
| * The 64-bit jiffies value is not atomic - you MUST NOT read it |
| * without sampling the sequence number in xtime_lock. |
| * jiffies is defined in the linker script... |
| */ |
| |
| void do_timer(struct pt_regs *regs) |
| { |
| jiffies_64++; |
| #ifndef CONFIG_SMP |
| /* SMP process accounting uses the local APIC timer */ |
| |
| update_process_times(user_mode(regs)); |
| #endif |
| update_times(); |
| } |
| |
| #if !defined(__alpha__) && !defined(__ia64__) |
| |
| extern int do_setitimer(int, struct itimerval *, struct itimerval *); |
| |
| /* |
| * For backwards compatibility? This can be done in libc so Alpha |
| * and all newer ports shouldn't need it. |
| */ |
| asmlinkage unsigned long sys_alarm(unsigned int seconds) |
| { |
| struct itimerval it_new, it_old; |
| unsigned int oldalarm; |
| |
| it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0; |
| it_new.it_value.tv_sec = seconds; |
| it_new.it_value.tv_usec = 0; |
| do_setitimer(ITIMER_REAL, &it_new, &it_old); |
| oldalarm = it_old.it_value.tv_sec; |
| /* ehhh.. We can't return 0 if we have an alarm pending.. */ |
| /* And we'd better return too much than too little anyway */ |
| if (it_old.it_value.tv_usec) |
| oldalarm++; |
| return oldalarm; |
| } |
| |
| #endif |
| |
| #ifndef __alpha__ |
| |
| /* |
| * The Alpha uses getxpid, getxuid, and getxgid instead. Maybe this |
| * should be moved into arch/i386 instead? |
| */ |
| |
| /** |
| * sys_getpid - return the thread group id of the current process |
| * |
| * Note, despite the name, this returns the tgid not the pid. The tgid and |
| * the pid are identical unless CLONE_THREAD was specified on clone() in |
| * which case the tgid is the same in all threads of the same group. |
| * |
| * This is SMP safe as current->tgid does not change. |
| */ |
| asmlinkage long sys_getpid(void) |
| { |
| return current->tgid; |
| } |
| |
| /* |
| * Accessing ->group_leader->real_parent is not SMP-safe, it could |
| * change from under us. However, rather than getting any lock |
| * we can use an optimistic algorithm: get the parent |
| * pid, and go back and check that the parent is still |
| * the same. If it has changed (which is extremely unlikely |
| * indeed), we just try again.. |
| * |
| * NOTE! This depends on the fact that even if we _do_ |
| * get an old value of "parent", we can happily dereference |
| * the pointer (it was and remains a dereferencable kernel pointer |
| * no matter what): we just can't necessarily trust the result |
| * until we know that the parent pointer is valid. |
| * |
| * NOTE2: ->group_leader never changes from under us. |
| */ |
| asmlinkage long sys_getppid(void) |
| { |
| int pid; |
| struct task_struct *me = current; |
| struct task_struct *parent; |
| |
| parent = me->group_leader->real_parent; |
| for (;;) { |
| pid = parent->tgid; |
| #if CONFIG_SMP |
| { |
| struct task_struct *old = parent; |
| |
| /* |
| * Make sure we read the pid before re-reading the |
| * parent pointer: |
| */ |
| rmb(); |
| parent = me->group_leader->real_parent; |
| if (old != parent) |
| continue; |
| } |
| #endif |
| break; |
| } |
| return pid; |
| } |
| |
| asmlinkage long sys_getuid(void) |
| { |
| /* Only we change this so SMP safe */ |
| return current->uid; |
| } |
| |
| asmlinkage long sys_geteuid(void) |
| { |
| /* Only we change this so SMP safe */ |
| return current->euid; |
| } |
| |
| asmlinkage long sys_getgid(void) |
| { |
| /* Only we change this so SMP safe */ |
| return current->gid; |
| } |
| |
| asmlinkage long sys_getegid(void) |
| { |
| /* Only we change this so SMP safe */ |
| return current->egid; |
| } |
| |
| #endif |
| |
| static void process_timeout(unsigned long __data) |
| { |
| wake_up_process((task_t *)__data); |
| } |
| |
| /** |
| * schedule_timeout - sleep until timeout |
| * @timeout: timeout value in jiffies |
| * |
| * Make the current task sleep until @timeout jiffies have |
| * elapsed. The routine will return immediately unless |
| * the current task state has been set (see set_current_state()). |
| * |
| * You can set the task state as follows - |
| * |
| * %TASK_UNINTERRUPTIBLE - at least @timeout jiffies are guaranteed to |
| * pass before the routine returns. The routine will return 0 |
| * |
| * %TASK_INTERRUPTIBLE - the routine may return early if a signal is |
| * delivered to the current task. In this case the remaining time |
| * in jiffies will be returned, or 0 if the timer expired in time |
| * |
| * The current task state is guaranteed to be TASK_RUNNING when this |
| * routine returns. |
| * |
| * Specifying a @timeout value of %MAX_SCHEDULE_TIMEOUT will schedule |
| * the CPU away without a bound on the timeout. In this case the return |
| * value will be %MAX_SCHEDULE_TIMEOUT. |
| * |
| * In all cases the return value is guaranteed to be non-negative. |
| */ |
| signed long schedule_timeout(signed long timeout) |
| { |
| struct timer_list timer; |
| unsigned long expire; |
| |
| switch (timeout) |
| { |
| case MAX_SCHEDULE_TIMEOUT: |
| /* |
| * These two special cases are useful to be comfortable |
| * in the caller. Nothing more. We could take |
| * MAX_SCHEDULE_TIMEOUT from one of the negative value |
| * but I' d like to return a valid offset (>=0) to allow |
| * the caller to do everything it want with the retval. |
| */ |
| schedule(); |
| goto out; |
| default: |
| /* |
| * Another bit of PARANOID. Note that the retval will be |
| * 0 since no piece of kernel is supposed to do a check |
| * for a negative retval of schedule_timeout() (since it |
| * should never happens anyway). You just have the printk() |
| * that will tell you if something is gone wrong and where. |
| */ |
| if (timeout < 0) |
| { |
| printk(KERN_ERR "schedule_timeout: wrong timeout " |
| "value %lx from %p\n", timeout, |
| __builtin_return_address(0)); |
| current->state = TASK_RUNNING; |
| goto out; |
| } |
| } |
| |
| expire = timeout + jiffies; |
| |
| init_timer(&timer); |
| timer.expires = expire; |
| timer.data = (unsigned long) current; |
| timer.function = process_timeout; |
| |
| add_timer(&timer); |
| schedule(); |
| del_timer_sync(&timer); |
| |
| timeout = expire - jiffies; |
| |
| out: |
| return timeout < 0 ? 0 : timeout; |
| } |
| |
| /* Thread ID - the internal kernel "pid" */ |
| asmlinkage long sys_gettid(void) |
| { |
| return current->pid; |
| } |
| #ifndef FOLD_NANO_SLEEP_INTO_CLOCK_NANO_SLEEP |
| |
| static long nanosleep_restart(struct restart_block *restart) |
| { |
| unsigned long expire = restart->arg0, now = jiffies; |
| struct timespec *rmtp = (struct timespec *) restart->arg1; |
| long ret; |
| |
| /* Did it expire while we handled signals? */ |
| if (!time_after(expire, now)) |
| return 0; |
| |
| current->state = TASK_INTERRUPTIBLE; |
| expire = schedule_timeout(expire - now); |
| |
| ret = 0; |
| if (expire) { |
| struct timespec t; |
| jiffies_to_timespec(expire, &t); |
| |
| ret = -ERESTART_RESTARTBLOCK; |
| if (rmtp && copy_to_user(rmtp, &t, sizeof(t))) |
| ret = -EFAULT; |
| /* The 'restart' block is already filled in */ |
| } |
| return ret; |
| } |
| |
| asmlinkage long sys_nanosleep(struct timespec *rqtp, struct timespec *rmtp) |
| { |
| struct timespec t; |
| unsigned long expire; |
| long ret; |
| |
| if (copy_from_user(&t, rqtp, sizeof(t))) |
| return -EFAULT; |
| |
| if ((t.tv_nsec >= 1000000000L) || (t.tv_nsec < 0) || (t.tv_sec < 0)) |
| return -EINVAL; |
| |
| expire = timespec_to_jiffies(&t) + (t.tv_sec || t.tv_nsec); |
| current->state = TASK_INTERRUPTIBLE; |
| expire = schedule_timeout(expire); |
| |
| ret = 0; |
| if (expire) { |
| struct restart_block *restart; |
| jiffies_to_timespec(expire, &t); |
| if (rmtp && copy_to_user(rmtp, &t, sizeof(t))) |
| return -EFAULT; |
| |
| restart = ¤t_thread_info()->restart_block; |
| restart->fn = nanosleep_restart; |
| restart->arg0 = jiffies + expire; |
| restart->arg1 = (unsigned long) rmtp; |
| ret = -ERESTART_RESTARTBLOCK; |
| } |
| return ret; |
| } |
| #endif // ! FOLD_NANO_SLEEP_INTO_CLOCK_NANO_SLEEP |
| |
| /* |
| * sys_sysinfo - fill in sysinfo struct |
| */ |
| asmlinkage long sys_sysinfo(struct sysinfo __user *info) |
| { |
| struct sysinfo val; |
| u64 uptime; |
| unsigned long mem_total, sav_total; |
| unsigned int mem_unit, bitcount; |
| unsigned long seq; |
| |
| memset((char *)&val, 0, sizeof(struct sysinfo)); |
| |
| do { |
| seq = read_seqbegin(&xtime_lock); |
| |
| uptime = jiffies_64 - INITIAL_JIFFIES; |
| do_div(uptime, HZ); |
| val.uptime = (unsigned long) uptime; |
| |
| val.loads[0] = avenrun[0] << (SI_LOAD_SHIFT - FSHIFT); |
| val.loads[1] = avenrun[1] << (SI_LOAD_SHIFT - FSHIFT); |
| val.loads[2] = avenrun[2] << (SI_LOAD_SHIFT - FSHIFT); |
| |
| val.procs = nr_threads; |
| } while (read_seqretry(&xtime_lock, seq)); |
| |
| si_meminfo(&val); |
| si_swapinfo(&val); |
| |
| /* |
| * If the sum of all the available memory (i.e. ram + swap) |
| * is less than can be stored in a 32 bit unsigned long then |
| * we can be binary compatible with 2.2.x kernels. If not, |
| * well, in that case 2.2.x was broken anyways... |
| * |
| * -Erik Andersen <andersee@debian.org> |
| */ |
| |
| mem_total = val.totalram + val.totalswap; |
| if (mem_total < val.totalram || mem_total < val.totalswap) |
| goto out; |
| bitcount = 0; |
| mem_unit = val.mem_unit; |
| while (mem_unit > 1) { |
| bitcount++; |
| mem_unit >>= 1; |
| sav_total = mem_total; |
| mem_total <<= 1; |
| if (mem_total < sav_total) |
| goto out; |
| } |
| |
| /* |
| * If mem_total did not overflow, multiply all memory values by |
| * val.mem_unit and set it to 1. This leaves things compatible |
| * with 2.2.x, and also retains compatibility with earlier 2.4.x |
| * kernels... |
| */ |
| |
| val.mem_unit = 1; |
| val.totalram <<= bitcount; |
| val.freeram <<= bitcount; |
| val.sharedram <<= bitcount; |
| val.bufferram <<= bitcount; |
| val.totalswap <<= bitcount; |
| val.freeswap <<= bitcount; |
| val.totalhigh <<= bitcount; |
| val.freehigh <<= bitcount; |
| |
| out: |
| if (copy_to_user(info, &val, sizeof(struct sysinfo))) |
| return -EFAULT; |
| |
| return 0; |
| } |
| |
| static void __devinit init_timers_cpu(int cpu) |
| { |
| int j; |
| tvec_base_t *base; |
| |
| base = &per_cpu(tvec_bases, cpu); |
| spin_lock_init(&base->lock); |
| for (j = 0; j < TVN_SIZE; j++) { |
| INIT_LIST_HEAD(base->tv5.vec + j); |
| INIT_LIST_HEAD(base->tv4.vec + j); |
| INIT_LIST_HEAD(base->tv3.vec + j); |
| INIT_LIST_HEAD(base->tv2.vec + j); |
| } |
| for (j = 0; j < TVR_SIZE; j++) |
| INIT_LIST_HEAD(base->tv1.vec + j); |
| |
| base->timer_jiffies = jiffies; |
| } |
| |
| static int __devinit timer_cpu_notify(struct notifier_block *self, |
| unsigned long action, void *hcpu) |
| { |
| long cpu = (long)hcpu; |
| switch(action) { |
| case CPU_UP_PREPARE: |
| init_timers_cpu(cpu); |
| break; |
| default: |
| break; |
| } |
| return NOTIFY_OK; |
| } |
| |
| static struct notifier_block __devinitdata timers_nb = { |
| .notifier_call = timer_cpu_notify, |
| }; |
| |
| |
| void __init init_timers(void) |
| { |
| timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE, |
| (void *)(long)smp_processor_id()); |
| register_cpu_notifier(&timers_nb); |
| open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL); |
| } |