X-Git-Url: https://git.proxmox.com/?a=blobdiff_plain;f=qemu-timer.c;h=e15ce477ccd55c44f518d348f5a2e4c0e68bf8a6;hb=455df3f32341a3dff00f1726ff0749b3dd783bdf;hp=b6f93049f9263430e268575b78c69ad1827d0348;hpb=63111b69cce420886ba7bfb8e367bd6c6969c1b6;p=qemu.git diff --git a/qemu-timer.c b/qemu-timer.c index b6f93049f..e15ce477c 100644 --- a/qemu-timer.c +++ b/qemu-timer.c @@ -44,8 +44,8 @@ /***********************************************************/ /* timers */ -struct QEMUClock { - QEMUTimerList *main_loop_timerlist; +typedef struct QEMUClock { + /* We rely on BQL to protect the timerlists */ QLIST_HEAD(, QEMUTimerList) timerlists; NotifierList reset_notifiers; @@ -53,10 +53,10 @@ struct QEMUClock { QEMUClockType type; bool enabled; -}; +} QEMUClock; QEMUTimerListGroup main_loop_tlg; -QEMUClock *qemu_clocks[QEMU_CLOCK_MAX]; +QEMUClock qemu_clocks[QEMU_CLOCK_MAX]; /* A QEMUTimerList is a list of timers attached to a clock. More * than one QEMUTimerList can be attached to each clock, for instance @@ -67,90 +67,106 @@ QEMUClock *qemu_clocks[QEMU_CLOCK_MAX]; struct QEMUTimerList { QEMUClock *clock; + QemuMutex active_timers_lock; QEMUTimer *active_timers; QLIST_ENTRY(QEMUTimerList) list; QEMUTimerListNotifyCB *notify_cb; void *notify_opaque; + + /* lightweight method to mark the end of timerlist's running */ + QemuEvent timers_done_ev; }; +/** + * qemu_clock_ptr: + * @type: type of clock + * + * Translate a clock type into a pointer to QEMUClock object. + * + * Returns: a pointer to the QEMUClock object + */ +static inline QEMUClock *qemu_clock_ptr(QEMUClockType type) +{ + return &qemu_clocks[type]; +} + static bool timer_expired_ns(QEMUTimer *timer_head, int64_t current_time) { return timer_head && (timer_head->expire_time <= current_time); } -static QEMUTimerList *timerlist_new_from_clock(QEMUClock *clock, - QEMUTimerListNotifyCB *cb, - void *opaque) +QEMUTimerList *timerlist_new(QEMUClockType type, + QEMUTimerListNotifyCB *cb, + void *opaque) { QEMUTimerList *timer_list; - - /* Assert if we do not have a clock. If you see this - * assertion in means that the clocks have not been - * initialised before a timerlist is needed. This - * normally happens if an AioContext is used before - * init_clocks() is called within main(). - */ - assert(clock); + QEMUClock *clock = qemu_clock_ptr(type); timer_list = g_malloc0(sizeof(QEMUTimerList)); + qemu_event_init(&timer_list->timers_done_ev, false); timer_list->clock = clock; timer_list->notify_cb = cb; timer_list->notify_opaque = opaque; + qemu_mutex_init(&timer_list->active_timers_lock); QLIST_INSERT_HEAD(&clock->timerlists, timer_list, list); return timer_list; } -QEMUTimerList *timerlist_new(QEMUClockType type, - QEMUTimerListNotifyCB *cb, void *opaque) -{ - return timerlist_new_from_clock(qemu_clock_ptr(type), cb, opaque); -} - void timerlist_free(QEMUTimerList *timer_list) { assert(!timerlist_has_timers(timer_list)); if (timer_list->clock) { QLIST_REMOVE(timer_list, list); - if (timer_list->clock->main_loop_timerlist == timer_list) { - timer_list->clock->main_loop_timerlist = NULL; - } } + qemu_mutex_destroy(&timer_list->active_timers_lock); g_free(timer_list); } -static QEMUClock *qemu_clock_new(QEMUClockType type) +static void qemu_clock_init(QEMUClockType type) { - QEMUClock *clock; + QEMUClock *clock = qemu_clock_ptr(type); - clock = g_malloc0(sizeof(QEMUClock)); clock->type = type; clock->enabled = true; clock->last = INT64_MIN; QLIST_INIT(&clock->timerlists); notifier_list_init(&clock->reset_notifiers); - clock->main_loop_timerlist = timerlist_new_from_clock(clock, NULL, NULL); - return clock; + main_loop_tlg.tl[type] = timerlist_new(type, NULL, NULL); } -bool qemu_clock_use_for_deadline(QEMUClock *clock) +bool qemu_clock_use_for_deadline(QEMUClockType type) { - return !(use_icount && (clock->type == QEMU_CLOCK_VIRTUAL)); + return !(use_icount && (type == QEMU_CLOCK_VIRTUAL)); } -void qemu_clock_notify(QEMUClock *clock) +void qemu_clock_notify(QEMUClockType type) { QEMUTimerList *timer_list; + QEMUClock *clock = qemu_clock_ptr(type); QLIST_FOREACH(timer_list, &clock->timerlists, list) { timerlist_notify(timer_list); } } -void qemu_clock_enable(QEMUClock *clock, bool enabled) +/* Disabling the clock will wait for related timerlists to stop + * executing qemu_run_timers. Thus, this functions should not + * be used from the callback of a timer that is based on @clock. + * Doing so would cause a deadlock. + * + * Caller should hold BQL. + */ +void qemu_clock_enable(QEMUClockType type, bool enabled) { + QEMUClock *clock = qemu_clock_ptr(type); + QEMUTimerList *tl; bool old = clock->enabled; clock->enabled = enabled; if (enabled && !old) { - qemu_clock_notify(clock); + qemu_clock_notify(type); + } else if (!enabled && old) { + QLIST_FOREACH(tl, &clock->timerlists, list) { + qemu_event_wait(&tl->timers_done_ev); + } } } @@ -159,21 +175,31 @@ bool timerlist_has_timers(QEMUTimerList *timer_list) return !!timer_list->active_timers; } -bool qemu_clock_has_timers(QEMUClock *clock) +bool qemu_clock_has_timers(QEMUClockType type) { - return timerlist_has_timers(clock->main_loop_timerlist); + return timerlist_has_timers( + main_loop_tlg.tl[type]); } bool timerlist_expired(QEMUTimerList *timer_list) { - return (timer_list->active_timers && - timer_list->active_timers->expire_time < - qemu_get_clock_ns(timer_list->clock)); + int64_t expire_time; + + qemu_mutex_lock(&timer_list->active_timers_lock); + if (!timer_list->active_timers) { + qemu_mutex_unlock(&timer_list->active_timers_lock); + return false; + } + expire_time = timer_list->active_timers->expire_time; + qemu_mutex_unlock(&timer_list->active_timers_lock); + + return expire_time < qemu_clock_get_ns(timer_list->clock->type); } -bool qemu_clock_expired(QEMUClock *clock) +bool qemu_clock_expired(QEMUClockType type) { - return timerlist_expired(clock->main_loop_timerlist); + return timerlist_expired( + main_loop_tlg.tl[type]); } /* @@ -184,13 +210,25 @@ bool qemu_clock_expired(QEMUClock *clock) int64_t timerlist_deadline_ns(QEMUTimerList *timer_list) { int64_t delta; + int64_t expire_time; - if (!timer_list->clock->enabled || !timer_list->active_timers) { + if (!timer_list->clock->enabled) { + return -1; + } + + /* The active timers list may be modified before the caller uses our return + * value but ->notify_cb() is called when the deadline changes. Therefore + * the caller should notice the change and there is no race condition. + */ + qemu_mutex_lock(&timer_list->active_timers_lock); + if (!timer_list->active_timers) { + qemu_mutex_unlock(&timer_list->active_timers_lock); return -1; } + expire_time = timer_list->active_timers->expire_time; + qemu_mutex_unlock(&timer_list->active_timers_lock); - delta = timer_list->active_timers->expire_time - - qemu_get_clock_ns(timer_list->clock); + delta = expire_time - qemu_clock_get_ns(timer_list->clock->type); if (delta <= 0) { return 0; @@ -199,20 +237,16 @@ int64_t timerlist_deadline_ns(QEMUTimerList *timer_list) return delta; } -int64_t qemu_clock_deadline_ns(QEMUClock *clock) -{ - return timerlist_deadline_ns(clock->main_loop_timerlist); -} - /* Calculate the soonest deadline across all timerlists attached * to the clock. This is used for the icount timeout so we * ignore whether or not the clock should be used in deadline * calculations. */ -int64_t qemu_clock_deadline_ns_all(QEMUClock *clock) +int64_t qemu_clock_deadline_ns_all(QEMUClockType type) { int64_t deadline = -1; QEMUTimerList *timer_list; + QEMUClock *clock = qemu_clock_ptr(type); QLIST_FOREACH(timer_list, &clock->timerlists, list) { deadline = qemu_soonest_timeout(deadline, timerlist_deadline_ns(timer_list)); @@ -220,14 +254,14 @@ int64_t qemu_clock_deadline_ns_all(QEMUClock *clock) return deadline; } -QEMUClock *timerlist_get_clock(QEMUTimerList *timer_list) +QEMUClockType timerlist_get_clock(QEMUTimerList *timer_list) { - return timer_list->clock; + return timer_list->clock->type; } -QEMUTimerList *qemu_clock_get_main_loop_timerlist(QEMUClock *clock) +QEMUTimerList *qemu_clock_get_main_loop_timerlist(QEMUClockType type) { - return clock->main_loop_timerlist; + return main_loop_tlg.tl[type]; } void timerlist_notify(QEMUTimerList *timer_list) @@ -295,28 +329,20 @@ void timer_init(QEMUTimer *ts, ts->cb = cb; ts->opaque = opaque; ts->scale = scale; + ts->expire_time = -1; } -QEMUTimer *qemu_new_timer(QEMUClock *clock, int scale, - QEMUTimerCB *cb, void *opaque) -{ - return timer_new_tl(clock->main_loop_timerlist, - scale, cb, opaque); -} - -void qemu_free_timer(QEMUTimer *ts) +void timer_free(QEMUTimer *ts) { g_free(ts); } -/* stop a timer, but do not dealloc it */ -void qemu_del_timer(QEMUTimer *ts) +static void timer_del_locked(QEMUTimerList *timer_list, QEMUTimer *ts) { QEMUTimer **pt, *t; - /* NOTE: this code must be signal safe because - timer_expired() can be called from a signal. */ - pt = &ts->timer_list->active_timers; + ts->expire_time = -1; + pt = &timer_list->active_timers; for(;;) { t = *pt; if (!t) @@ -329,51 +355,98 @@ void qemu_del_timer(QEMUTimer *ts) } } -/* modify the current timer so that it will be fired when current_time - >= expire_time. The corresponding callback will be called. */ -void qemu_mod_timer_ns(QEMUTimer *ts, int64_t expire_time) +static bool timer_mod_ns_locked(QEMUTimerList *timer_list, + QEMUTimer *ts, int64_t expire_time) { QEMUTimer **pt, *t; - qemu_del_timer(ts); - /* add the timer in the sorted list */ - /* NOTE: this code must be signal safe because - timer_expired() can be called from a signal. */ - pt = &ts->timer_list->active_timers; - for(;;) { + pt = &timer_list->active_timers; + for (;;) { t = *pt; if (!timer_expired_ns(t, expire_time)) { break; } pt = &t->next; } - ts->expire_time = expire_time; + ts->expire_time = MAX(expire_time, 0); ts->next = *pt; *pt = ts; - /* Rearm if necessary */ - if (pt == &ts->timer_list->active_timers) { - /* Interrupt execution to force deadline recalculation. */ - qemu_clock_warp(ts->timer_list->clock); - timerlist_notify(ts->timer_list); - } + return pt == &timer_list->active_timers; } -void qemu_mod_timer(QEMUTimer *ts, int64_t expire_time) +static void timerlist_rearm(QEMUTimerList *timer_list) { - qemu_mod_timer_ns(ts, expire_time * ts->scale); + /* Interrupt execution to force deadline recalculation. */ + qemu_clock_warp(timer_list->clock->type); + timerlist_notify(timer_list); } -bool timer_pending(QEMUTimer *ts) +/* stop a timer, but do not dealloc it */ +void timer_del(QEMUTimer *ts) { - QEMUTimer *t; - for (t = ts->timer_list->active_timers; t != NULL; t = t->next) { - if (t == ts) { - return true; + QEMUTimerList *timer_list = ts->timer_list; + + qemu_mutex_lock(&timer_list->active_timers_lock); + timer_del_locked(timer_list, ts); + qemu_mutex_unlock(&timer_list->active_timers_lock); +} + +/* modify the current timer so that it will be fired when current_time + >= expire_time. The corresponding callback will be called. */ +void timer_mod_ns(QEMUTimer *ts, int64_t expire_time) +{ + QEMUTimerList *timer_list = ts->timer_list; + bool rearm; + + qemu_mutex_lock(&timer_list->active_timers_lock); + timer_del_locked(timer_list, ts); + rearm = timer_mod_ns_locked(timer_list, ts, expire_time); + qemu_mutex_unlock(&timer_list->active_timers_lock); + + if (rearm) { + timerlist_rearm(timer_list); + } +} + +/* modify the current timer so that it will be fired when current_time + >= expire_time or the current deadline, whichever comes earlier. + The corresponding callback will be called. */ +void timer_mod_anticipate_ns(QEMUTimer *ts, int64_t expire_time) +{ + QEMUTimerList *timer_list = ts->timer_list; + bool rearm; + + qemu_mutex_lock(&timer_list->active_timers_lock); + if (ts->expire_time == -1 || ts->expire_time > expire_time) { + if (ts->expire_time != -1) { + timer_del_locked(timer_list, ts); } + rearm = timer_mod_ns_locked(timer_list, ts, expire_time); + } else { + rearm = false; } - return false; + qemu_mutex_unlock(&timer_list->active_timers_lock); + + if (rearm) { + timerlist_rearm(timer_list); + } +} + +void timer_mod(QEMUTimer *ts, int64_t expire_time) +{ + timer_mod_ns(ts, expire_time * ts->scale); +} + +void timer_mod_anticipate(QEMUTimer *ts, int64_t expire_time) +{ + timer_mod_anticipate_ns(ts, expire_time * ts->scale); +} + +bool timer_pending(QEMUTimer *ts) +{ + return ts->expire_time >= 0; } bool timer_expired(QEMUTimer *timer_head, int64_t current_time) @@ -386,31 +459,44 @@ bool timerlist_run_timers(QEMUTimerList *timer_list) QEMUTimer *ts; int64_t current_time; bool progress = false; - + QEMUTimerCB *cb; + void *opaque; + + qemu_event_reset(&timer_list->timers_done_ev); if (!timer_list->clock->enabled) { - return progress; + goto out; } - current_time = qemu_get_clock_ns(timer_list->clock); + current_time = qemu_clock_get_ns(timer_list->clock->type); for(;;) { + qemu_mutex_lock(&timer_list->active_timers_lock); ts = timer_list->active_timers; if (!timer_expired_ns(ts, current_time)) { + qemu_mutex_unlock(&timer_list->active_timers_lock); break; } + /* remove timer from the list before calling the callback */ timer_list->active_timers = ts->next; ts->next = NULL; + ts->expire_time = -1; + cb = ts->cb; + opaque = ts->opaque; + qemu_mutex_unlock(&timer_list->active_timers_lock); /* run the callback (the timer list can be modified) */ - ts->cb(ts->opaque); + cb(opaque); progress = true; } + +out: + qemu_event_set(&timer_list->timers_done_ev); return progress; } -bool qemu_run_timers(QEMUClock *clock) +bool qemu_clock_run_timers(QEMUClockType type) { - return timerlist_run_timers(clock->main_loop_timerlist); + return timerlist_run_timers(main_loop_tlg.tl[type]); } void timerlistgroup_init(QEMUTimerListGroup *tlg, @@ -445,7 +531,7 @@ int64_t timerlistgroup_deadline_ns(QEMUTimerListGroup *tlg) int64_t deadline = -1; QEMUClockType type; for (type = 0; type < QEMU_CLOCK_MAX; type++) { - if (qemu_clock_use_for_deadline(tlg->tl[type]->clock)) { + if (qemu_clock_use_for_deadline(tlg->tl[type]->clock->type)) { deadline = qemu_soonest_timeout(deadline, timerlist_deadline_ns( tlg->tl[type])); @@ -454,11 +540,12 @@ int64_t timerlistgroup_deadline_ns(QEMUTimerListGroup *tlg) return deadline; } -int64_t qemu_get_clock_ns(QEMUClock *clock) +int64_t qemu_clock_get_ns(QEMUClockType type) { int64_t now, last; + QEMUClock *clock = qemu_clock_ptr(type); - switch(clock->type) { + switch (type) { case QEMU_CLOCK_REALTIME: return get_clock(); default: @@ -479,12 +566,15 @@ int64_t qemu_get_clock_ns(QEMUClock *clock) } } -void qemu_register_clock_reset_notifier(QEMUClock *clock, Notifier *notifier) +void qemu_clock_register_reset_notifier(QEMUClockType type, + Notifier *notifier) { + QEMUClock *clock = qemu_clock_ptr(type); notifier_list_add(&clock->reset_notifiers, notifier); } -void qemu_unregister_clock_reset_notifier(QEMUClock *clock, Notifier *notifier) +void qemu_clock_unregister_reset_notifier(QEMUClockType type, + Notifier *notifier) { notifier_remove(notifier); } @@ -493,10 +583,7 @@ void init_clocks(void) { QEMUClockType type; for (type = 0; type < QEMU_CLOCK_MAX; type++) { - if (!qemu_clocks[type]) { - qemu_clocks[type] = qemu_clock_new(type); - main_loop_tlg.tl[type] = qemu_clocks[type]->main_loop_timerlist; - } + qemu_clock_init(type); } #ifdef CONFIG_PRCTL_PR_SET_TIMERSLACK @@ -509,13 +596,13 @@ uint64_t timer_expire_time_ns(QEMUTimer *ts) return timer_pending(ts) ? ts->expire_time : -1; } -bool qemu_run_all_timers(void) +bool qemu_clock_run_all_timers(void) { bool progress = false; QEMUClockType type; for (type = 0; type < QEMU_CLOCK_MAX; type++) { - progress |= qemu_run_timers(qemu_clock_ptr(type)); + progress |= qemu_clock_run_timers(type); } return progress;