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author | Stefan Hajnoczi <stefanha@redhat.com> | 2013-09-12 11:02:19 +0200 |
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committer | Stefan Hajnoczi <stefanha@redhat.com> | 2013-09-18 15:48:33 +0200 |
commit | 978f2205c791de0e02c8802a645bea657408abfd (patch) | |
tree | 891dad80378641797daa324f4bce9fb2a709fb79 /include/qemu/timer.h | |
parent | da718ceb1730bfe6fea0178df979639b14a0646e (diff) | |
download | hqemu-978f2205c791de0e02c8802a645bea657408abfd.zip hqemu-978f2205c791de0e02c8802a645bea657408abfd.tar.gz |
qemu-timer: make qemu_timer_mod_ns() and qemu_timer_del() thread-safe
Introduce QEMUTimerList->active_timers_lock to protect the linked list
of active timers. This allows qemu_timer_mod_ns() to be called from any
thread.
Note that vm_clock is not thread-safe and its use of
qemu_clock_has_timers() works fine today but is also not thread-safe.
The purpose of this patch is to eventually let device models set or
cancel timers from a vcpu thread without holding the global mutex.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'include/qemu/timer.h')
-rw-r--r-- | include/qemu/timer.h | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/include/qemu/timer.h b/include/qemu/timer.h index e4934dd..b58903b 100644 --- a/include/qemu/timer.h +++ b/include/qemu/timer.h @@ -115,6 +115,10 @@ static inline int64_t qemu_clock_get_us(QEMUClockType type) * Determines whether a clock's default timer list * has timers attached * + * Note that this function should not be used when other threads also access + * the timer list. The return value may be outdated by the time it is acted + * upon. + * * Returns: true if the clock's default timer list * has timers attached */ @@ -271,6 +275,10 @@ void timerlist_free(QEMUTimerList *timer_list); * * Determine whether a timer list has active timers * + * Note that this function should not be used when other threads also access + * the timer list. The return value may be outdated by the time it is acted + * upon. + * * Returns: true if the timer list has timers. */ bool timerlist_has_timers(QEMUTimerList *timer_list); @@ -512,6 +520,9 @@ void timer_free(QEMUTimer *ts); * @ts: the timer * * Delete a timer from the active list. + * + * This function is thread-safe but the timer and its timer list must not be + * freed while this function is running. */ void timer_del(QEMUTimer *ts); @@ -521,6 +532,9 @@ void timer_del(QEMUTimer *ts); * @expire_time: the expiry time in nanoseconds * * Modify a timer to expire at @expire_time + * + * This function is thread-safe but the timer and its timer list must not be + * freed while this function is running. */ void timer_mod_ns(QEMUTimer *ts, int64_t expire_time); @@ -531,6 +545,9 @@ void timer_mod_ns(QEMUTimer *ts, int64_t expire_time); * * Modify a timer to expiry at @expire_time, taking into * account the scale associated with the timer. + * + * This function is thread-safe but the timer and its timer list must not be + * freed while this function is running. */ void timer_mod(QEMUTimer *ts, int64_t expire_timer); |