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author | Paolo Bonzini <pbonzini@redhat.com> | 2013-09-12 11:02:20 +0200 |
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committer | Stefan Hajnoczi <stefanha@redhat.com> | 2013-09-18 15:48:33 +0200 |
commit | 3db1ee7c2af2fbbfe259712e3ce74158bc667ad3 (patch) | |
tree | e251ed3d3324e051c0ff37aa929f3b33dd5f9e3a /qemu-timer.c | |
parent | 978f2205c791de0e02c8802a645bea657408abfd (diff) | |
download | qemu-3db1ee7c2af2fbbfe259712e3ce74158bc667ad3.zip qemu-3db1ee7c2af2fbbfe259712e3ce74158bc667ad3.tar.gz qemu-3db1ee7c2af2fbbfe259712e3ce74158bc667ad3.tar.bz2 |
qemu-timer: do not take the lock in timer_pending
We can deduce the result from expire_time, by making it always -1 if
the timer is not in the active_timers list. We need to check against
negative times passed to timer_mod_ns; clamping them to zero is not
a problem because the only clock that has a zero value at VM startup
is QEMU_CLOCK_VIRTUAL, and it is monotonic so it cannot be non-zero.
QEMU_CLOCK_HOST, instead, is not monotonic but it cannot go to negative
values unless the host time is seriously screwed up and points to
the 1960s.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'qemu-timer.c')
-rw-r--r-- | qemu-timer.c | 19 |
1 files changed, 5 insertions, 14 deletions
diff --git a/qemu-timer.c b/qemu-timer.c index e504747..6b62e88 100644 --- a/qemu-timer.c +++ b/qemu-timer.c @@ -312,6 +312,7 @@ void timer_init(QEMUTimer *ts, ts->cb = cb; ts->opaque = opaque; ts->scale = scale; + ts->expire_time = -1; } void timer_free(QEMUTimer *ts) @@ -323,6 +324,7 @@ static void timer_del_locked(QEMUTimerList *timer_list, QEMUTimer *ts) { QEMUTimer **pt, *t; + ts->expire_time = -1; pt = &timer_list->active_timers; for(;;) { t = *pt; @@ -365,7 +367,7 @@ void timer_mod_ns(QEMUTimer *ts, int64_t expire_time) } pt = &t->next; } - ts->expire_time = expire_time; + ts->expire_time = MAX(expire_time, 0); ts->next = *pt; *pt = ts; qemu_mutex_unlock(&timer_list->active_timers_lock); @@ -385,19 +387,7 @@ void timer_mod(QEMUTimer *ts, int64_t expire_time) bool timer_pending(QEMUTimer *ts) { - QEMUTimerList *timer_list = ts->timer_list; - QEMUTimer *t; - bool found = false; - - qemu_mutex_lock(&timer_list->active_timers_lock); - for (t = timer_list->active_timers; t != NULL; t = t->next) { - if (t == ts) { - found = true; - break; - } - } - qemu_mutex_unlock(&timer_list->active_timers_lock); - return found; + return ts->expire_time >= 0; } bool timer_expired(QEMUTimer *timer_head, int64_t current_time) @@ -429,6 +419,7 @@ bool timerlist_run_timers(QEMUTimerList *timer_list) /* 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); |