From 604ba48220357b9e3f3607c0e19f5790f5074e2b Mon Sep 17 00:00:00 2001 From: Andy Hung Date: Tue, 23 Aug 2016 18:15:32 -0700 Subject: [PATCH] Fix Mutex::timedLock to properly handle relative time Bug: 31008450 Change-Id: Ie6c17e17b7a8c3d8a087c47be535e9d04f285380 --- include/utils/Mutex.h | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/include/utils/Mutex.h b/include/utils/Mutex.h index 9b0b734d6..848a600b3 100644 --- a/include/utils/Mutex.h +++ b/include/utils/Mutex.h @@ -64,13 +64,18 @@ public: status_t tryLock(); #if defined(__ANDROID__) - // lock the mutex, but don't wait longer than timeoutMilliseconds. + // Lock the mutex, but don't wait longer than timeoutNs (relative time). // Returns 0 on success, TIMED_OUT for failure due to timeout expiration. // // OSX doesn't have pthread_mutex_timedlock() or equivalent. To keep // capabilities consistent across host OSes, this method is only available // when building Android binaries. - status_t timedLock(nsecs_t timeoutMilliseconds); + // + // FIXME?: pthread_mutex_timedlock is based on CLOCK_REALTIME, + // which is subject to NTP adjustments, and includes time during suspend, + // so a timeout may occur even though no processes could run. + // Not holding a partial wakelock may lead to a system suspend. + status_t timedLock(nsecs_t timeoutNs); #endif // Manages the mutex automatically. It'll be locked when Autolock is @@ -134,6 +139,7 @@ inline status_t Mutex::tryLock() { } #if defined(__ANDROID__) inline status_t Mutex::timedLock(nsecs_t timeoutNs) { + timeoutNs += systemTime(SYSTEM_TIME_REALTIME); const struct timespec ts = { /* .tv_sec = */ static_cast(timeoutNs / 1000000000), /* .tv_nsec = */ static_cast(timeoutNs % 1000000000),