From ff83c66eccf5b5f6b6530d504e3be41559250dcb Mon Sep 17 00:00:00 2001 From: Alex Bligh Date: Wed, 21 Aug 2013 16:02:46 +0100 Subject: aio / timers: Split QEMUClock into QEMUClock and QEMUTimerList Split QEMUClock into QEMUClock and QEMUTimerList so that we can have more than one QEMUTimerList associated with the same clock. Introduce a main_loop_timerlist concept and make existing qemu_clock_* calls that actually should operate on a QEMUTimerList call the relevant QEMUTimerList implementations, using the clock's default timerlist. This vastly reduces the invasiveness of this change and means the API stays constant for existing users. Introduce a list of QEMUTimerLists associated with each clock so that reenabling the clock can cause all the notifiers to be called. Note the code to do the notifications is added in a later patch. Switch QEMUClockType to an enum. Remove global variables vm_clock, host_clock and rt_clock and add compatibility defines. Do not fix qemu_next_alarm_deadline as it's going to be deleted. Add qemu_clock_use_for_deadline to indicate whether a particular clock should be used for deadline calculations. When use_icount is true, vm_clock should not be used for deadline calculations as it does not contain a nanosecond count. Instead, icount timeouts come from the execution thread doing aio_notify or qemu_notify as appropriate. This function is used in the next patch. Signed-off-by: Alex Bligh Signed-off-by: Stefan Hajnoczi --- qemu-timer.c | 207 +++++++++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 151 insertions(+), 56 deletions(-) (limited to 'qemu-timer.c') diff --git a/qemu-timer.c b/qemu-timer.c index 52a1947800..b045184c04 100644 --- a/qemu-timer.c +++ b/qemu-timer.c @@ -49,22 +49,29 @@ /* timers */ struct QEMUClock { - QEMUTimer *active_timers; + QEMUTimerList *main_loop_timerlist; + QLIST_HEAD(, QEMUTimerList) timerlists; NotifierList reset_notifiers; int64_t last; - int type; + QEMUClockType type; bool enabled; }; -struct QEMUTimer { - int64_t expire_time; /* in nanoseconds */ +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 + * used by different AioContexts / threads. Each clock also has + * a list of the QEMUTimerLists associated with it, in order that + * reenabling the clock can call all the notifiers. + */ + +struct QEMUTimerList { QEMUClock *clock; - QEMUTimerCB *cb; - void *opaque; - QEMUTimer *next; - int scale; + QEMUTimer *active_timers; + QLIST_ENTRY(QEMUTimerList) list; }; struct qemu_alarm_timer { @@ -93,21 +100,25 @@ static int64_t qemu_next_alarm_deadline(void) { int64_t delta = INT64_MAX; int64_t rtdelta; + int64_t hdelta; - if (!use_icount && vm_clock->enabled && vm_clock->active_timers) { - delta = vm_clock->active_timers->expire_time - - qemu_get_clock_ns(vm_clock); + if (!use_icount && vm_clock->enabled && + vm_clock->main_loop_timerlist->active_timers) { + delta = vm_clock->main_loop_timerlist->active_timers->expire_time - + qemu_get_clock_ns(vm_clock); } - if (host_clock->enabled && host_clock->active_timers) { - int64_t hdelta = host_clock->active_timers->expire_time - - qemu_get_clock_ns(host_clock); + if (host_clock->enabled && + host_clock->main_loop_timerlist->active_timers) { + hdelta = host_clock->main_loop_timerlist->active_timers->expire_time - + qemu_get_clock_ns(host_clock); if (hdelta < delta) { delta = hdelta; } } - if (rt_clock->enabled && rt_clock->active_timers) { - rtdelta = (rt_clock->active_timers->expire_time - - qemu_get_clock_ns(rt_clock)); + if (rt_clock->enabled && + rt_clock->main_loop_timerlist->active_timers) { + rtdelta = (rt_clock->main_loop_timerlist->active_timers->expire_time - + qemu_get_clock_ns(rt_clock)); if (rtdelta < delta) { delta = rtdelta; } @@ -231,11 +242,42 @@ next: } } -QEMUClock *rt_clock; -QEMUClock *vm_clock; -QEMUClock *host_clock; +static QEMUTimerList *timerlist_new_from_clock(QEMUClock *clock) +{ + 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); + + timer_list = g_malloc0(sizeof(QEMUTimerList)); + timer_list->clock = clock; + QLIST_INSERT_HEAD(&clock->timerlists, timer_list, list); + return timer_list; +} + +QEMUTimerList *timerlist_new(QEMUClockType type) +{ + return timerlist_new_from_clock(qemu_clock_ptr(type)); +} -static QEMUClock *qemu_clock_new(int type) +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; + } + } + g_free(timer_list); +} + +static QEMUClock *qemu_clock_new(QEMUClockType type) { QEMUClock *clock; @@ -243,10 +285,17 @@ static QEMUClock *qemu_clock_new(int type) 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); return clock; } +bool qemu_clock_use_for_deadline(QEMUClock *clock) +{ + return !(use_icount && (clock->type == QEMU_CLOCK_VIRTUAL)); +} + void qemu_clock_enable(QEMUClock *clock, bool enabled) { bool old = clock->enabled; @@ -256,24 +305,36 @@ void qemu_clock_enable(QEMUClock *clock, bool enabled) } } -int64_t qemu_clock_has_timers(QEMUClock *clock) +bool timerlist_has_timers(QEMUTimerList *timer_list) { - return !!clock->active_timers; + return !!timer_list->active_timers; } -int64_t qemu_clock_expired(QEMUClock *clock) +bool qemu_clock_has_timers(QEMUClock *clock) { - return (clock->active_timers && - clock->active_timers->expire_time < qemu_get_clock_ns(clock)); + return timerlist_has_timers(clock->main_loop_timerlist); } -int64_t qemu_clock_deadline(QEMUClock *clock) +bool timerlist_expired(QEMUTimerList *timer_list) +{ + return (timer_list->active_timers && + timer_list->active_timers->expire_time < + qemu_get_clock_ns(timer_list->clock)); +} + +bool qemu_clock_expired(QEMUClock *clock) +{ + return timerlist_expired(clock->main_loop_timerlist); +} + +int64_t timerlist_deadline(QEMUTimerList *timer_list) { /* To avoid problems with overflow limit this to 2^32. */ int64_t delta = INT32_MAX; - if (clock->enabled && clock->active_timers) { - delta = clock->active_timers->expire_time - qemu_get_clock_ns(clock); + if (timer_list->clock->enabled && timer_list->active_timers) { + delta = timer_list->active_timers->expire_time - + qemu_get_clock_ns(timer_list->clock); } if (delta < 0) { delta = 0; @@ -281,20 +342,26 @@ int64_t qemu_clock_deadline(QEMUClock *clock) return delta; } +int64_t qemu_clock_deadline(QEMUClock *clock) +{ + return timerlist_deadline(clock->main_loop_timerlist); +} + /* * As above, but return -1 for no deadline, and do not cap to 2^32 * as we know the result is always positive. */ -int64_t qemu_clock_deadline_ns(QEMUClock *clock) +int64_t timerlist_deadline_ns(QEMUTimerList *timer_list) { int64_t delta; - if (!clock->enabled || !clock->active_timers) { + if (!timer_list->clock->enabled || !timer_list->active_timers) { return -1; } - delta = clock->active_timers->expire_time - qemu_get_clock_ns(clock); + delta = timer_list->active_timers->expire_time - + qemu_get_clock_ns(timer_list->clock); if (delta <= 0) { return 0; @@ -303,6 +370,21 @@ int64_t qemu_clock_deadline_ns(QEMUClock *clock) return delta; } +int64_t qemu_clock_deadline_ns(QEMUClock *clock) +{ + return timerlist_deadline_ns(clock->main_loop_timerlist); +} + +QEMUClock *timerlist_get_clock(QEMUTimerList *timer_list) +{ + return timer_list->clock; +} + +QEMUTimerList *qemu_clock_get_main_loop_timerlist(QEMUClock *clock) +{ + return clock->main_loop_timerlist; +} + /* Transition function to convert a nanosecond timeout to ms * This is used where a system does not support ppoll */ @@ -351,17 +433,21 @@ int qemu_poll_ns(GPollFD *fds, guint nfds, int64_t timeout) } -QEMUTimer *qemu_new_timer(QEMUClock *clock, int scale, - QEMUTimerCB *cb, void *opaque) +void timer_init(QEMUTimer *ts, + QEMUTimerList *timer_list, int scale, + QEMUTimerCB *cb, void *opaque) { - QEMUTimer *ts; - - ts = g_malloc0(sizeof(QEMUTimer)); - ts->clock = clock; + ts->timer_list = timer_list; ts->cb = cb; ts->opaque = opaque; ts->scale = scale; - return ts; +} + +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) @@ -376,7 +462,7 @@ void qemu_del_timer(QEMUTimer *ts) /* NOTE: this code must be signal safe because timer_expired() can be called from a signal. */ - pt = &ts->clock->active_timers; + pt = &ts->timer_list->active_timers; for(;;) { t = *pt; if (!t) @@ -400,7 +486,7 @@ void qemu_mod_timer_ns(QEMUTimer *ts, int64_t expire_time) /* 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->clock->active_timers; + pt = &ts->timer_list->active_timers; for(;;) { t = *pt; if (!timer_expired_ns(t, expire_time)) { @@ -413,12 +499,12 @@ void qemu_mod_timer_ns(QEMUTimer *ts, int64_t expire_time) *pt = ts; /* Rearm if necessary */ - if (pt == &ts->clock->active_timers) { + if (pt == &ts->timer_list->active_timers) { if (!alarm_timer->pending) { qemu_rearm_alarm_timer(alarm_timer); } /* Interrupt execution to force deadline recalculation. */ - qemu_clock_warp(ts->clock); + qemu_clock_warp(ts->timer_list->clock); if (use_icount) { qemu_notify_event(); } @@ -433,7 +519,7 @@ void qemu_mod_timer(QEMUTimer *ts, int64_t expire_time) bool timer_pending(QEMUTimer *ts) { QEMUTimer *t; - for (t = ts->clock->active_timers; t != NULL; t = t->next) { + for (t = ts->timer_list->active_timers; t != NULL; t = t->next) { if (t == ts) { return true; } @@ -446,23 +532,24 @@ bool timer_expired(QEMUTimer *timer_head, int64_t current_time) return timer_expired_ns(timer_head, current_time * timer_head->scale); } -bool qemu_run_timers(QEMUClock *clock) +bool timerlist_run_timers(QEMUTimerList *timer_list) { QEMUTimer *ts; int64_t current_time; bool progress = false; - if (!clock->enabled) + if (!timer_list->clock->enabled) { return progress; + } - current_time = qemu_get_clock_ns(clock); + current_time = qemu_get_clock_ns(timer_list->clock); for(;;) { - ts = clock->active_timers; + ts = timer_list->active_timers; if (!timer_expired_ns(ts, current_time)) { break; } /* remove timer from the list before calling the callback */ - clock->active_timers = ts->next; + timer_list->active_timers = ts->next; ts->next = NULL; /* run the callback (the timer list can be modified) */ @@ -472,6 +559,11 @@ bool qemu_run_timers(QEMUClock *clock) return progress; } +bool qemu_run_timers(QEMUClock *clock) +{ + return timerlist_run_timers(clock->main_loop_timerlist); +} + int64_t qemu_get_clock_ns(QEMUClock *clock) { int64_t now, last; @@ -509,11 +601,13 @@ void qemu_unregister_clock_reset_notifier(QEMUClock *clock, Notifier *notifier) void init_clocks(void) { - if (!rt_clock) { - rt_clock = qemu_clock_new(QEMU_CLOCK_REALTIME); - vm_clock = qemu_clock_new(QEMU_CLOCK_VIRTUAL); - host_clock = qemu_clock_new(QEMU_CLOCK_HOST); + QEMUClockType type; + for (type = 0; type < QEMU_CLOCK_MAX; type++) { + if (!qemu_clocks[type]) { + qemu_clocks[type] = qemu_clock_new(type); + } } + #ifdef CONFIG_PRCTL_PR_SET_TIMERSLACK prctl(PR_SET_TIMERSLACK, 1, 0, 0, 0); #endif @@ -530,9 +624,10 @@ bool qemu_run_all_timers(void) alarm_timer->pending = false; /* vm time timers */ - progress |= qemu_run_timers(vm_clock); - progress |= qemu_run_timers(rt_clock); - progress |= qemu_run_timers(host_clock); + QEMUClockType type; + for (type = 0; type < QEMU_CLOCK_MAX; type++) { + progress |= qemu_run_timers(qemu_clock_ptr(type)); + } /* rearm timer, if not periodic */ if (alarm_timer->expired) { -- cgit v1.2.1