diff options
| -rw-r--r-- | replay/replay-internal.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/replay/replay-internal.c b/replay/replay-internal.c index eba8246aae..2e8a3e947a 100644 --- a/replay/replay-internal.c +++ b/replay/replay-internal.c @@ -22,6 +22,9 @@ It also protects replay events queue which stores events to be written or read to the log. */ static QemuMutex lock; +/* Condition and queue for fair ordering of mutex lock requests. */ +static QemuCond mutex_cond; +static unsigned long mutex_head, mutex_tail; /* File for replay writing */ static bool write_error; @@ -197,9 +200,10 @@ static __thread bool replay_locked; void replay_mutex_init(void) { qemu_mutex_init(&lock); + qemu_cond_init(&mutex_cond); /* Hold the mutex while we start-up */ - qemu_mutex_lock(&lock); replay_locked = true; + ++mutex_tail; } bool replay_mutex_locked(void) @@ -211,10 +215,16 @@ bool replay_mutex_locked(void) void replay_mutex_lock(void) { if (replay_mode != REPLAY_MODE_NONE) { + unsigned long id; g_assert(!qemu_mutex_iothread_locked()); g_assert(!replay_mutex_locked()); qemu_mutex_lock(&lock); + id = mutex_tail++; + while (id != mutex_head) { + qemu_cond_wait(&mutex_cond, &lock); + } replay_locked = true; + qemu_mutex_unlock(&lock); } } @@ -222,7 +232,10 @@ void replay_mutex_unlock(void) { if (replay_mode != REPLAY_MODE_NONE) { g_assert(replay_mutex_locked()); + qemu_mutex_lock(&lock); + ++mutex_head; replay_locked = false; + qemu_cond_broadcast(&mutex_cond); qemu_mutex_unlock(&lock); } } |