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authorAlex Bligh <alex@alex.org.uk>2013-08-21 16:02:46 +0100
committerStefan Hajnoczi <stefanha@redhat.com>2013-08-22 19:10:27 +0200
commitff83c66eccf5b5f6b6530d504e3be41559250dcb (patch)
tree85fbeb62b89962d992b6ad94827687313b1ec335 /qemu-timer.c
parentf9a976b7408f061fc7fc48b14d16797ed6f8fd97 (diff)
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 <alex@alex.org.uk> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'qemu-timer.c')
-rw-r--r--qemu-timer.c207
1 files changed, 151 insertions, 56 deletions
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) {