audioserver: Use timed lock instead of bouncing for dumps
The technique of bouncing lock attempts does not work well
in the case when another lock has higher priority and acquires
the lock frequently. Timed lock works better in this case
because the acquiring thread is then put in a queue and gets
the lock as soon as another thread releases it. The wait time
in the worst case (deadlock) is the same.
Bug: 118842894
Test: Run VOICE_COMMUNICATION capture + AEC effect, dump audioflinger
Change-Id: Idc4fc2b6f5faf6988979f9354dd92441af33e600
diff --git a/services/soundtrigger/Android.bp b/services/soundtrigger/Android.bp
index 1f2283a..3f02f48 100644
--- a/services/soundtrigger/Android.bp
+++ b/services/soundtrigger/Android.bp
@@ -28,6 +28,7 @@
"libhardware",
"libsoundtrigger",
"libaudioclient",
+ "libaudioutils",
"libmediautils",
"libhwbinder",
diff --git a/services/soundtrigger/SoundTriggerHwService.cpp b/services/soundtrigger/SoundTriggerHwService.cpp
index fe2ccf2..f89683a 100644
--- a/services/soundtrigger/SoundTriggerHwService.cpp
+++ b/services/soundtrigger/SoundTriggerHwService.cpp
@@ -22,6 +22,7 @@
#include <sys/types.h>
#include <pthread.h>
+#include <audio_utils/clock.h>
#include <system/sound_trigger.h>
#include <cutils/atomic.h>
#include <cutils/properties.h>
@@ -146,20 +147,12 @@
}
-static const int kDumpLockRetries = 50;
-static const int kDumpLockSleep = 60000;
+static const int kDumpLockTimeoutNs = 1 * NANOS_PER_SECOND;
-static bool tryLock(Mutex& mutex)
+static bool dumpTryLock(Mutex& mutex)
{
- bool locked = false;
- for (int i = 0; i < kDumpLockRetries; ++i) {
- if (mutex.tryLock() == NO_ERROR) {
- locked = true;
- break;
- }
- usleep(kDumpLockSleep);
- }
- return locked;
+ status_t err = mutex.timedLock(kDumpLockTimeoutNs);
+ return err == NO_ERROR;
}
status_t SoundTriggerHwService::dump(int fd, const Vector<String16>& args __unused) {
@@ -168,7 +161,7 @@
result.appendFormat("Permission Denial: can't dump SoundTriggerHwService");
write(fd, result.string(), result.size());
} else {
- bool locked = tryLock(mServiceLock);
+ bool locked = dumpTryLock(mServiceLock);
// failed to lock - SoundTriggerHwService is probably deadlocked
if (!locked) {
result.append("SoundTriggerHwService may be deadlocked\n");