Loading system/osi/src/alarm.c +90 −22 Original line number Diff line number Diff line Loading @@ -62,6 +62,7 @@ extern bt_os_callouts_t *bt_os_callouts; // unit tests to run faster. It should not be modified by production code. int64_t TIMER_INTERVAL_FOR_WAKELOCK_IN_MS = 3000; static const clockid_t CLOCK_ID = CLOCK_BOOTTIME; static const clockid_t CLOCK_ID_ALARM = CLOCK_BOOTTIME_ALARM; static const char *WAKE_LOCK_ID = "bluedroid_timer"; // This mutex ensures that the |alarm_set|, |alarm_cancel|, and alarm callback Loading @@ -70,6 +71,7 @@ static const char *WAKE_LOCK_ID = "bluedroid_timer"; static pthread_mutex_t monitor; static list_t *alarms; static timer_t timer; static timer_t wakeup_timer; static bool timer_set; // All alarm callbacks are dispatched from |callback_thread| Loading @@ -84,6 +86,7 @@ static void schedule_next_instance(alarm_t *alarm, bool force_reschedule); static void reschedule_root_alarm(void); static void timer_callback(void *data); static void callback_dispatch(void *context); static bool timer_create_internal(const clockid_t clock_id, timer_t *timer); alarm_t *alarm_new(void) { // Make sure we have a list we can insert alarms into. Loading Loading @@ -215,38 +218,64 @@ void alarm_cleanup(void) { static bool lazy_initialize(void) { assert(alarms == NULL); // timer_t doesn't have an invalid value so we must track whether // the |timer| variable is valid ourselves. bool timer_initialized = false; bool wakeup_timer_initialized = false; pthread_mutex_init(&monitor, NULL); alarms = list_new(NULL); if (!alarms) { LOG_ERROR(LOG_TAG, "%s unable to allocate alarm list.", __func__); return false; goto error; } struct sigevent sigevent; memset(&sigevent, 0, sizeof(sigevent)); sigevent.sigev_notify = SIGEV_THREAD; sigevent.sigev_notify_function = (void (*)(union sigval))timer_callback; if (timer_create(CLOCK_ID, &sigevent, &timer) == -1) { LOG_ERROR(LOG_TAG, "%s unable to create timer: %s", __func__, strerror(errno)); return false; } if (!timer_create_internal(CLOCK_ID, &timer)) goto error; timer_initialized = true; if (!timer_create_internal(CLOCK_ID_ALARM, &wakeup_timer)) goto error; wakeup_timer_initialized = true; alarm_expired = semaphore_new(0); if (!alarm_expired) { LOG_ERROR(LOG_TAG, "%s unable to create alarm expired semaphore", __func__); return false; goto error; } callback_thread_active = true; callback_thread = thread_new("alarm_callbacks"); if (!callback_thread) { LOG_ERROR(LOG_TAG, "%s unable to create alarm callback thread.", __func__); return false; goto error; } thread_post(callback_thread, callback_dispatch, NULL); return true; error: thread_free(callback_thread); callback_thread = NULL; callback_thread_active = false; semaphore_free(alarm_expired); alarm_expired = NULL; if (wakeup_timer_initialized) timer_delete(wakeup_timer); if (timer_initialized) timer_delete(timer); list_free(alarms); alarms = NULL; pthread_mutex_destroy(&monitor); return false; } static period_ms_t now(void) { Loading Loading @@ -293,18 +322,19 @@ static void schedule_next_instance(alarm_t *alarm, bool force_reschedule) { // NOTE: must be called with monitor lock. static void reschedule_root_alarm(void) { bool timer_was_set = timer_set; assert(alarms != NULL); // If used in a zeroed state, disarms the timer struct itimerspec wakeup_time; memset(&wakeup_time, 0, sizeof(wakeup_time)); const bool timer_was_set = timer_set; // If used in a zeroed state, disarms the timer. struct itimerspec timer_time; memset(&timer_time, 0, sizeof(timer_time)); if (list_is_empty(alarms)) goto done; alarm_t *next = list_front(alarms); int64_t next_expiration = next->deadline - now(); const alarm_t *next = list_front(alarms); const int64_t next_expiration = next->deadline - now(); if (next_expiration < TIMER_INTERVAL_FOR_WAKELOCK_IN_MS) { if (!timer_set) { int status = acquire_wake_lock(PARTIAL_WAKE_LOCK, WAKE_LOCK_ID); Loading @@ -314,20 +344,43 @@ static void reschedule_root_alarm(void) { } } timer_time.it_value.tv_sec = (next->deadline / 1000); timer_time.it_value.tv_nsec = (next->deadline % 1000) * 1000000LL; // It is entirely unsafe to call timer_settime(2) with a zeroed timerspec for // timers with *_ALARM clock IDs. Although the man page states that the timer // would be canceled, the current behavior (as of Linux kernel 3.17) is that // the callback is issued immediately. The only way to cancel an *_ALARM timer // is to delete the timer. But unfortunately, deleting and re-creating a timer // is rather expensive; every timer_create(2) spawns a new thread. So we simply // set the timer to fire at the largest possible time. // // If we've reached this code path, we're going to grab a wake lock and wait for // the next timer to fire. In that case, there's no reason to have a pending wakeup // timer so we simply cancel it. struct itimerspec end_of_time; memset(&end_of_time, 0, sizeof(end_of_time)); end_of_time.it_value.tv_sec = (time_t)((1LL << (sizeof(time_t) * 8 - 1)) - 1); timer_settime(wakeup_timer, TIMER_ABSTIME, &end_of_time, NULL); } else { // WARNING: do not attempt to use relative timers with *_ALARM clock IDs // in kernels before 3.17 unless you have the following patch: // https://lkml.org/lkml/2014/7/7/576 struct itimerspec wakeup_time; memset(&wakeup_time, 0, sizeof(wakeup_time)); wakeup_time.it_value.tv_sec = (next->deadline / 1000); wakeup_time.it_value.tv_nsec = (next->deadline % 1000) * 1000000LL; } else { if (!bt_os_callouts->set_wake_alarm(next_expiration, true, timer_callback, NULL)) LOG_ERROR(LOG_TAG, "%s unable to set wake alarm for %" PRId64 "ms.", __func__, next_expiration); if (timer_settime(wakeup_timer, TIMER_ABSTIME, &wakeup_time, NULL) == -1) LOG_ERROR(LOG_TAG, "%s unable to set wakeup timer: %s", __func__, strerror(errno)); } done: timer_set = wakeup_time.it_value.tv_sec != 0 || wakeup_time.it_value.tv_nsec != 0; timer_set = timer_time.it_value.tv_sec != 0 || timer_time.it_value.tv_nsec != 0; if (timer_was_set && !timer_set) { release_wake_lock(WAKE_LOCK_ID); } if (timer_settime(timer, TIMER_ABSTIME, &wakeup_time, NULL) == -1) if (timer_settime(timer, TIMER_ABSTIME, &timer_time, NULL) == -1) LOG_ERROR(LOG_TAG, "%s unable to set timer: %s", __func__, strerror(errno)); // If next expiration was in the past (e.g. short timer that got context switched) Loading Loading @@ -401,3 +454,18 @@ static void callback_dispatch(UNUSED_ATTR void *context) { LOG_DEBUG(LOG_TAG, "%s Callback thread exited", __func__); } static bool timer_create_internal(const clockid_t clock_id, timer_t *timer) { assert(timer != NULL); struct sigevent sigevent; memset(&sigevent, 0, sizeof(sigevent)); sigevent.sigev_notify = SIGEV_THREAD; sigevent.sigev_notify_function = (void (*)(union sigval))timer_callback; if (timer_create(clock_id, &sigevent, timer) == -1) { LOG_ERROR("%s unable to create timer with clock %d: %s", __func__, clock_id, strerror(errno)); return false; } return true; } Loading
system/osi/src/alarm.c +90 −22 Original line number Diff line number Diff line Loading @@ -62,6 +62,7 @@ extern bt_os_callouts_t *bt_os_callouts; // unit tests to run faster. It should not be modified by production code. int64_t TIMER_INTERVAL_FOR_WAKELOCK_IN_MS = 3000; static const clockid_t CLOCK_ID = CLOCK_BOOTTIME; static const clockid_t CLOCK_ID_ALARM = CLOCK_BOOTTIME_ALARM; static const char *WAKE_LOCK_ID = "bluedroid_timer"; // This mutex ensures that the |alarm_set|, |alarm_cancel|, and alarm callback Loading @@ -70,6 +71,7 @@ static const char *WAKE_LOCK_ID = "bluedroid_timer"; static pthread_mutex_t monitor; static list_t *alarms; static timer_t timer; static timer_t wakeup_timer; static bool timer_set; // All alarm callbacks are dispatched from |callback_thread| Loading @@ -84,6 +86,7 @@ static void schedule_next_instance(alarm_t *alarm, bool force_reschedule); static void reschedule_root_alarm(void); static void timer_callback(void *data); static void callback_dispatch(void *context); static bool timer_create_internal(const clockid_t clock_id, timer_t *timer); alarm_t *alarm_new(void) { // Make sure we have a list we can insert alarms into. Loading Loading @@ -215,38 +218,64 @@ void alarm_cleanup(void) { static bool lazy_initialize(void) { assert(alarms == NULL); // timer_t doesn't have an invalid value so we must track whether // the |timer| variable is valid ourselves. bool timer_initialized = false; bool wakeup_timer_initialized = false; pthread_mutex_init(&monitor, NULL); alarms = list_new(NULL); if (!alarms) { LOG_ERROR(LOG_TAG, "%s unable to allocate alarm list.", __func__); return false; goto error; } struct sigevent sigevent; memset(&sigevent, 0, sizeof(sigevent)); sigevent.sigev_notify = SIGEV_THREAD; sigevent.sigev_notify_function = (void (*)(union sigval))timer_callback; if (timer_create(CLOCK_ID, &sigevent, &timer) == -1) { LOG_ERROR(LOG_TAG, "%s unable to create timer: %s", __func__, strerror(errno)); return false; } if (!timer_create_internal(CLOCK_ID, &timer)) goto error; timer_initialized = true; if (!timer_create_internal(CLOCK_ID_ALARM, &wakeup_timer)) goto error; wakeup_timer_initialized = true; alarm_expired = semaphore_new(0); if (!alarm_expired) { LOG_ERROR(LOG_TAG, "%s unable to create alarm expired semaphore", __func__); return false; goto error; } callback_thread_active = true; callback_thread = thread_new("alarm_callbacks"); if (!callback_thread) { LOG_ERROR(LOG_TAG, "%s unable to create alarm callback thread.", __func__); return false; goto error; } thread_post(callback_thread, callback_dispatch, NULL); return true; error: thread_free(callback_thread); callback_thread = NULL; callback_thread_active = false; semaphore_free(alarm_expired); alarm_expired = NULL; if (wakeup_timer_initialized) timer_delete(wakeup_timer); if (timer_initialized) timer_delete(timer); list_free(alarms); alarms = NULL; pthread_mutex_destroy(&monitor); return false; } static period_ms_t now(void) { Loading Loading @@ -293,18 +322,19 @@ static void schedule_next_instance(alarm_t *alarm, bool force_reschedule) { // NOTE: must be called with monitor lock. static void reschedule_root_alarm(void) { bool timer_was_set = timer_set; assert(alarms != NULL); // If used in a zeroed state, disarms the timer struct itimerspec wakeup_time; memset(&wakeup_time, 0, sizeof(wakeup_time)); const bool timer_was_set = timer_set; // If used in a zeroed state, disarms the timer. struct itimerspec timer_time; memset(&timer_time, 0, sizeof(timer_time)); if (list_is_empty(alarms)) goto done; alarm_t *next = list_front(alarms); int64_t next_expiration = next->deadline - now(); const alarm_t *next = list_front(alarms); const int64_t next_expiration = next->deadline - now(); if (next_expiration < TIMER_INTERVAL_FOR_WAKELOCK_IN_MS) { if (!timer_set) { int status = acquire_wake_lock(PARTIAL_WAKE_LOCK, WAKE_LOCK_ID); Loading @@ -314,20 +344,43 @@ static void reschedule_root_alarm(void) { } } timer_time.it_value.tv_sec = (next->deadline / 1000); timer_time.it_value.tv_nsec = (next->deadline % 1000) * 1000000LL; // It is entirely unsafe to call timer_settime(2) with a zeroed timerspec for // timers with *_ALARM clock IDs. Although the man page states that the timer // would be canceled, the current behavior (as of Linux kernel 3.17) is that // the callback is issued immediately. The only way to cancel an *_ALARM timer // is to delete the timer. But unfortunately, deleting and re-creating a timer // is rather expensive; every timer_create(2) spawns a new thread. So we simply // set the timer to fire at the largest possible time. // // If we've reached this code path, we're going to grab a wake lock and wait for // the next timer to fire. In that case, there's no reason to have a pending wakeup // timer so we simply cancel it. struct itimerspec end_of_time; memset(&end_of_time, 0, sizeof(end_of_time)); end_of_time.it_value.tv_sec = (time_t)((1LL << (sizeof(time_t) * 8 - 1)) - 1); timer_settime(wakeup_timer, TIMER_ABSTIME, &end_of_time, NULL); } else { // WARNING: do not attempt to use relative timers with *_ALARM clock IDs // in kernels before 3.17 unless you have the following patch: // https://lkml.org/lkml/2014/7/7/576 struct itimerspec wakeup_time; memset(&wakeup_time, 0, sizeof(wakeup_time)); wakeup_time.it_value.tv_sec = (next->deadline / 1000); wakeup_time.it_value.tv_nsec = (next->deadline % 1000) * 1000000LL; } else { if (!bt_os_callouts->set_wake_alarm(next_expiration, true, timer_callback, NULL)) LOG_ERROR(LOG_TAG, "%s unable to set wake alarm for %" PRId64 "ms.", __func__, next_expiration); if (timer_settime(wakeup_timer, TIMER_ABSTIME, &wakeup_time, NULL) == -1) LOG_ERROR(LOG_TAG, "%s unable to set wakeup timer: %s", __func__, strerror(errno)); } done: timer_set = wakeup_time.it_value.tv_sec != 0 || wakeup_time.it_value.tv_nsec != 0; timer_set = timer_time.it_value.tv_sec != 0 || timer_time.it_value.tv_nsec != 0; if (timer_was_set && !timer_set) { release_wake_lock(WAKE_LOCK_ID); } if (timer_settime(timer, TIMER_ABSTIME, &wakeup_time, NULL) == -1) if (timer_settime(timer, TIMER_ABSTIME, &timer_time, NULL) == -1) LOG_ERROR(LOG_TAG, "%s unable to set timer: %s", __func__, strerror(errno)); // If next expiration was in the past (e.g. short timer that got context switched) Loading Loading @@ -401,3 +454,18 @@ static void callback_dispatch(UNUSED_ATTR void *context) { LOG_DEBUG(LOG_TAG, "%s Callback thread exited", __func__); } static bool timer_create_internal(const clockid_t clock_id, timer_t *timer) { assert(timer != NULL); struct sigevent sigevent; memset(&sigevent, 0, sizeof(sigevent)); sigevent.sigev_notify = SIGEV_THREAD; sigevent.sigev_notify_function = (void (*)(union sigval))timer_callback; if (timer_create(clock_id, &sigevent, timer) == -1) { LOG_ERROR("%s unable to create timer with clock %d: %s", __func__, clock_id, strerror(errno)); return false; } return true; }