diff -urP -I '\$Id:.*Exp \$' -X /usr/src/patch.exclude linux-2.6.6-kbdw/include/linux/posix-timers.h linux/include/linux/posix-timers.h --- linux-2.6.6-kbdw/include/linux/posix-timers.h 2003-11-10 17:09:04.000000000 -0800 +++ linux/include/linux/posix-timers.h 2004-06-28 19:16:44.000000000 -0700 @@ -1,8 +1,16 @@ #ifndef _linux_POSIX_TIMERS_H #define _linux_POSIX_TIMERS_H +#include +#include + +struct k_clock_abs { + struct list_head list; + spinlock_t lock; +}; struct k_clock { int res; /* in nano seconds */ + struct k_clock_abs *abs_struct; int (*clock_set) (struct timespec * tp); int (*clock_get) (struct timespec * tp); int (*nsleep) (int flags, @@ -23,8 +31,14 @@ #define posix_time_before(timer, now) \ time_before((timer)->expires, (now)->jiffies) -#define posix_bump_timer(timr) do { \ - (timr)->it_timer.expires += (timr)->it_incr; \ - (timr)->it_overrun++; \ - }while (0) +#define posix_bump_timer(timr, now) \ + do { \ + long delta, orun; \ + delta = now.jiffies - (timr)->it_timer.expires; \ + if (delta >= 0) { \ + orun = 1 + (delta / (timr)->it_incr); \ + (timr)->it_timer.expires += orun * (timr)->it_incr; \ + (timr)->it_overrun += orun; \ + } \ + }while (0) #endif diff -urP -I '\$Id:.*Exp \$' -X /usr/src/patch.exclude linux-2.6.6-kbdw/include/linux/sched.h linux/include/linux/sched.h --- linux-2.6.6-kbdw/include/linux/sched.h 2004-05-11 17:39:10.000000000 -0700 +++ linux/include/linux/sched.h 2004-06-14 17:40:35.000000000 -0700 @@ -342,6 +342,8 @@ struct task_struct *it_process; /* process to send signal to */ struct timer_list it_timer; struct sigqueue *sigq; /* signal queue entry. */ + struct list_head abs_timer_entry; /* clock abs_timer_list */ + struct timespec wall_to_prev; /* wall_to_monotonic used when set */ }; diff -urP -I '\$Id:.*Exp \$' -X /usr/src/patch.exclude linux-2.6.6-kbdw/kernel/posix-timers.c linux/kernel/posix-timers.c --- linux-2.6.6-kbdw/kernel/posix-timers.c 2004-05-11 17:39:11.000000000 -0700 +++ linux/kernel/posix-timers.c 2004-06-28 17:18:30.000000000 -0700 @@ -7,6 +7,9 @@ * * Copyright (C) 2002 2003 by MontaVista Software. * + * 2004-06-01 Fix CLOCK_REALTIME clock/timer TIMER_ABSTIME bug. + * Copyright (C) 2004 Boris Hu + * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or (at @@ -41,6 +44,7 @@ #include #include #include +#include #ifndef div_long_long_rem #include @@ -169,6 +173,12 @@ */ static struct k_clock posix_clocks[MAX_CLOCKS]; +/* + * We only have one real clock that can be set so we need only one abs list, + * even if we should want to have several clocks with differing resolutions. + */ +static struct k_clock_abs abs_list = {.list = LIST_HEAD_INIT(abs_list.list), + .lock = SPIN_LOCK_UNLOCKED}; #define if_clock_do(clock_fun,alt_fun,parms) \ (!clock_fun) ? alt_fun parms : clock_fun parms @@ -200,8 +210,11 @@ */ static __init int init_posix_timers(void) { - struct k_clock clock_realtime = {.res = CLOCK_REALTIME_RES }; + struct k_clock clock_realtime = {.res = CLOCK_REALTIME_RES, + .abs_struct = &abs_list + }; struct k_clock clock_monotonic = {.res = CLOCK_REALTIME_RES, + .abs_struct = NULL, .clock_get = do_posix_clock_monotonic_gettime, .clock_set = do_posix_clock_monotonic_settime }; @@ -212,7 +225,6 @@ posix_timers_cache = kmem_cache_create("posix_timers_cache", sizeof (struct k_itimer), 0, 0, 0, 0); idr_init(&posix_timers_id); - return 0; } @@ -239,19 +251,92 @@ (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC; } +/* + * This function adjusts the timer as needed as a result of the clock + * being set. It should only be called for absolute timers, and then + * under the abs_list lock. It computes the time difference and sets + * the new jiffies value in the timer. It also updates the timers + * reference wall_to_monotonic value. It is complicated by the fact + * that tstojiffies() only handles positive times and it needs to work + * with both positive and negative times. Also, for negative offsets, + * we need to defeat the res round up. + * + * Return is true if there is a new time, else false. + */ +static long add_clockset_delta(struct k_itimer *timr, + struct timespec *new_wall_to) +{ + struct timespec delta; + int sign = 0; + u64 exp; + + set_normalized_timespec(&delta, + new_wall_to->tv_sec - + timr->wall_to_prev.tv_sec, + new_wall_to->tv_nsec - + timr->wall_to_prev.tv_nsec); + if (likely(!(delta.tv_sec | delta.tv_nsec))) + return 0; + if (delta.tv_sec < 0) { + set_normalized_timespec(&delta, + -delta.tv_sec, + 1 - delta.tv_nsec - + posix_clocks[timr->it_clock].res); + sign++; + } + tstojiffie(&delta, posix_clocks[timr->it_clock].res, &exp); + timr->wall_to_prev = *new_wall_to; + timr->it_timer.expires += (sign ? -exp : exp); + return 1; +} + +static void remove_from_abslist(struct k_itimer *timr) +{ + if (!list_empty(&timr->abs_timer_entry)) { + spin_lock(&abs_list.lock); + list_del_init(&timr->abs_timer_entry); + spin_unlock(&abs_list.lock); + } +} + static void schedule_next_timer(struct k_itimer *timr) { + struct timespec new_wall_to; struct now_struct now; + unsigned long seq; - /* Set up the timer for the next interval (if there is one) */ + /* + * Set up the timer for the next interval (if there is one). + * Note: this code uses the abs_timer_lock to protect + * wall_to_prev and must hold it until exp is set, not exactly + * obvious... + + * This function is used for CLOCK_REALTIME* and + * CLOCK_MONOTONIC* timers. If we ever want to handle other + * CLOCKs, the calling code (do_schedule_next_timer) would need + * to pull the "clock" info from the timer and dispatch the + * "other" CLOCKs "next timer" code (which, I suppose should + * also be added to the k_clock structure). + */ if (!timr->it_incr) return; - posix_get_now(&now); do { - posix_bump_timer(timr); - }while (posix_time_before(&timr->it_timer, &now)); + seq = read_seqbegin(&xtime_lock); + new_wall_to = wall_to_monotonic; + posix_get_now(&now); + } while (read_seqretry(&xtime_lock, seq)); + + if (!list_empty(&timr->abs_timer_entry)) { + spin_lock(&abs_list.lock); + add_clockset_delta(timr, &new_wall_to); + + posix_bump_timer(timr, now); + spin_unlock(&abs_list.lock); + } else { + posix_bump_timer(timr, now); + } timr->it_overrun_last = timr->it_overrun; timr->it_overrun = -1; ++timr->it_requeue_pending; @@ -312,7 +397,15 @@ memset(&timr->sigq->info, 0, sizeof(siginfo_t)); - /* Send signal to the process that owns this timer. */ + /* + * Send signal to the process that owns this timer. + + * This code assumes that all the possible abs_lists share the + * same lock (there is only one list at this time). If this is + * not the case, the CLOCK info would need to be used to find + * the proper abs list lock. + */ + timr->sigq->info.si_signo = timr->it_sigev_signo; timr->sigq->info.si_errno = 0; timr->sigq->info.si_code = SI_TIMER; @@ -320,6 +413,9 @@ timr->sigq->info.si_value = timr->it_sigev_value; if (timr->it_incr) timr->sigq->info.si_sys_private = ++timr->it_requeue_pending; + else { + remove_from_abslist(timr); + } if (timr->it_sigev_notify & SIGEV_THREAD_ID) { if (unlikely(timr->it_process->flags & PF_EXITING)) { @@ -350,16 +446,51 @@ * This function gets called when a POSIX.1b interval timer expires. It * is used as a callback from the kernel internal timer. The * run_timer_list code ALWAYS calls with interrutps on. + + * This code is for CLOCK_REALTIME* and CLOCK_MONOTONIC* timers. */ static void posix_timer_fn(unsigned long __data) { struct k_itimer *timr = (struct k_itimer *) __data; unsigned long flags; + unsigned long seq; + struct timespec delta, new_wall_to; + u64 exp = 0; + int do_notify = 1; spin_lock_irqsave(&timr->it_lock, flags); set_timer_inactive(timr); - timer_notify_task(timr); - unlock_timer(timr, flags); + if (!list_empty(&timr->abs_timer_entry)) { + spin_lock(&abs_list.lock); + do { + seq = read_seqbegin(&xtime_lock); + new_wall_to = wall_to_monotonic; + } while (read_seqretry(&xtime_lock, seq)); + set_normalized_timespec(&delta, + new_wall_to.tv_sec - + timr->wall_to_prev.tv_sec, + new_wall_to.tv_nsec - + timr->wall_to_prev.tv_nsec); + if (likely((delta.tv_sec | delta.tv_nsec ) == 0)) { + /* do nothing, timer is on time */ + } else if (delta.tv_sec < 0) { + /* do nothing, timer is already late */ + } else { + /* timer is early due to a clock set */ + tstojiffie(&delta, + posix_clocks[timr->it_clock].res, + &exp); + timr->wall_to_prev = new_wall_to; + timr->it_timer.expires += exp; + add_timer(&timr->it_timer); + do_notify = 0; + } + spin_unlock(&abs_list.lock); + + } + if (do_notify) + timer_notify_task(timr); + unlock_timer(timr, flags); /* hold thru abs lock to keep irq off */ } @@ -398,6 +529,7 @@ return tmr; memset(tmr, 0, sizeof (struct k_itimer)); tmr->it_id = (timer_t)-1; + INIT_LIST_HEAD(&tmr->abs_timer_entry); if (unlikely(!(tmr->sigq = sigqueue_alloc()))) { kmem_cache_free(posix_timers_cache, tmr); tmr = 0; @@ -626,8 +758,7 @@ if (expires) { if (timr->it_requeue_pending & REQUEUE_PENDING || (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) { - while (posix_time_before(&timr->it_timer, &now)) - posix_bump_timer(timr); + posix_bump_timer(timr, now); expires = timr->it_timer.expires; } else @@ -703,11 +834,10 @@ * time to it to get the proper time for the timer. */ static int adjust_abs_time(struct k_clock *clock, struct timespec *tp, - int abs, u64 *exp) + int abs, u64 *exp, struct timespec *wall_to) { struct timespec now; struct timespec oc = *tp; - struct timespec wall_to_mono; u64 jiffies_64_f; int rtn =0; @@ -715,15 +845,15 @@ /* * The mask pick up the 4 basic clocks */ - if (!(clock - &posix_clocks[0]) & ~CLOCKS_MASK) { + if (!((clock - &posix_clocks[0]) & ~CLOCKS_MASK)) { jiffies_64_f = do_posix_clock_monotonic_gettime_parts( - &now, &wall_to_mono); + &now, wall_to); /* * If we are doing a MONOTONIC clock */ if((clock - &posix_clocks[0]) & CLOCKS_MONO){ - now.tv_sec += wall_to_mono.tv_sec; - now.tv_nsec += wall_to_mono.tv_nsec; + now.tv_sec += wall_to->tv_sec; + now.tv_nsec += wall_to->tv_nsec; } } else { /* @@ -813,6 +943,8 @@ #else del_timer(&timr->it_timer); #endif + remove_from_abslist(timr); + timr->it_requeue_pending = (timr->it_requeue_pending + 2) & ~REQUEUE_PENDING; timr->it_overrun_last = 0; @@ -827,24 +959,25 @@ if (adjust_abs_time(clock, &new_setting->it_value, flags & TIMER_ABSTIME, - &expire_64)) { + &expire_64, &(timr->wall_to_prev))) { return -EINVAL; } timr->it_timer.expires = (unsigned long)expire_64; tstojiffie(&new_setting->it_interval, clock->res, &expire_64); timr->it_incr = (unsigned long)expire_64; - /* - * For some reason the timer does not fire immediately if expires is - * equal to jiffies, so the timer notify function is called directly. - * We do not even queue SIGEV_NONE timers! + * We do not even queue SIGEV_NONE timers! But we do put them + * in the abs list so we can do that right. */ - if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE)) { - if (timr->it_timer.expires == jiffies) - timer_notify_task(timr); - else - add_timer(&timr->it_timer); + if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE)) + add_timer(&timr->it_timer); + + if (flags & TIMER_ABSTIME && clock->abs_struct) { + spin_lock(&clock->abs_struct->lock); + list_add_tail(&(timr->abs_timer_entry), + &(clock->abs_struct->list)); + spin_unlock(&clock->abs_struct->lock); } return 0; } @@ -878,7 +1011,7 @@ if (!posix_clocks[timr->it_clock].timer_set) error = do_timer_settime(timr, flags, &new_spec, rtn); else - error = posix_clocks[timr->it_clock].timer_set(timr, + error = posix_clocks[timr->it_clock].timer_set(timr, flags, &new_spec, rtn); unlock_timer(timr, flag); @@ -911,6 +1044,8 @@ #else del_timer(&timer->it_timer); #endif + remove_from_abslist(timer); + return 0; } @@ -1153,13 +1288,93 @@ * On locking, clock_was_set() is called from update_wall_clock which * holds (or has held for it) a write_lock_irq( xtime_lock) and is * called from the timer bh code. Thus we need the irq save locks. + * + * Also, on the call from update_wall_clock, that is done as part of a + * softirq thing. We don't want to delay the system that much (possibly + * long list of timers to fix), so we defer that work to keventd. */ static DECLARE_WAIT_QUEUE_HEAD(nanosleep_abs_wqueue); +static DECLARE_WORK(clock_was_set_work, (void(*)(void*))clock_was_set, NULL); + +static DECLARE_MUTEX(clock_was_set_lock); void clock_was_set(void) { + struct k_itimer *timr; + struct timespec new_wall_to; + LIST_HEAD(cws_list); + unsigned long seq; + + + if (unlikely(in_interrupt())) { + schedule_work(&clock_was_set_work); + return; + } wake_up_all(&nanosleep_abs_wqueue); + + /* + * Check if there exist TIMER_ABSTIME timers to correct. + * + * Notes on locking: This code is run in task context with irq + * on. We CAN be interrupted! All other usage of the abs list + * lock is under the timer lock which holds the irq lock as + * well. We REALLY don't want to scan the whole list with the + * interrupt system off, AND we would like a sequence lock on + * this code as well. Since we assume that the clock will not + * be set often, it seems ok to take and release the irq lock + * for each timer. In fact add_timer will do this, so this is + * not an issue. So we know when we are done, we will move the + * whole list to a new location. Then as we process each entry, + * we will move it to the actual list again. This way, when our + * copy is empty, we are done. We are not all that concerned + * about preemption so we will use a semaphore lock to protect + * aginst reentry. This way we will not stall another + * processor. It is possible that this may delay some timers + * that should have expired, given the new clock, but even this + * will be minimal as we will always update to the current time, + * even if it was set by a task that is waiting for entry to + * this code. Timers that expire too early will be caught by + * the expire code and restarted. + + * Absolute timers that repeat are left in the abs list while + * waiting for the task to pick up the signal. This means we + * may find timers that are not in the "add_timer" list, but are + * in the abs list. We do the same thing for these, save + * putting them back in the "add_timer" list. (Note, these are + * left in the abs list mainly to indicate that they are + * ABSOLUTE timers, a fact that is used by the re-arm code, and + * for which we have no other flag.) + + */ + + down(&clock_was_set_lock); + spin_lock_irq(&abs_list.lock); + list_splice_init(&abs_list.list, &cws_list); + spin_unlock_irq(&abs_list.lock); + do { + do { + seq = read_seqbegin(&xtime_lock); + new_wall_to = wall_to_monotonic; + } while (read_seqretry(&xtime_lock, seq)); + + spin_lock_irq(&abs_list.lock); + if (list_empty(&cws_list)) { + spin_unlock_irq(&abs_list.lock); + break; + } + timr = list_entry(cws_list.next, struct k_itimer, + abs_timer_entry); + + list_del_init(&timr->abs_timer_entry); + if (add_clockset_delta(timr, &new_wall_to) && + del_timer(&timr->it_timer)) /* timer run yet? */ + add_timer(&timr->it_timer); + list_add(&timr->abs_timer_entry, &abs_list.list); + spin_unlock_irq(&abs_list.lock); + } while (1); + + up(&clock_was_set_lock); } long clock_nanosleep_restart(struct restart_block *restart_block); @@ -1202,7 +1417,7 @@ long do_clock_nanosleep(clockid_t which_clock, int flags, struct timespec *tsave) { - struct timespec t; + struct timespec t, dum; struct timer_list new_timer; DECLARE_WAITQUEUE(abs_wqueue, current); u64 rq_time = (u64)0; @@ -1242,7 +1457,7 @@ t = *tsave; if (abs || !rq_time) { adjust_abs_time(&posix_clocks[which_clock], &t, abs, - &rq_time); + &rq_time, &dum); rq_time += (t.tv_sec || t.tv_nsec); } Binary files linux-2.6.6-kbdw/scripts/bin2c and linux/scripts/bin2c differ