audio HAL: fix thread starvation
Fix thread starvation issue where the capture or playback threads
running in FIFO priority would constantly acquire the stream mutex preventing
other threads to complete routing commands.
Bug: 21880828.
Change-Id: I99fcbb94da8f918f63b31e5bf713f3456a735869
diff --git a/hal/audio_hw.c b/hal/audio_hw.c
index 5c46c1e..5f9ffdc 100644
--- a/hal/audio_hw.c
+++ b/hal/audio_hw.c
@@ -792,6 +792,20 @@
return ret;
}
+void lock_input_stream(struct stream_in *in)
+{
+ pthread_mutex_lock(&in->pre_lock);
+ pthread_mutex_lock(&in->lock);
+ pthread_mutex_unlock(&in->pre_lock);
+}
+
+void lock_output_stream(struct stream_out *out)
+{
+ pthread_mutex_lock(&out->pre_lock);
+ pthread_mutex_lock(&out->lock);
+ pthread_mutex_unlock(&out->pre_lock);
+}
+
/* must be called with out->lock locked */
static int send_offload_cmd_l(struct stream_out* out, int command)
{
@@ -832,7 +846,7 @@
prctl(PR_SET_NAME, (unsigned long)"Offload Callback", 0, 0, 0);
ALOGV("%s", __func__);
- pthread_mutex_lock(&out->lock);
+ lock_output_stream(out);
for (;;) {
struct offload_cmd *cmd = NULL;
stream_callback_event_t event;
@@ -891,7 +905,7 @@
ALOGE("%s unknown command received: %d", __func__, cmd->cmd);
break;
}
- pthread_mutex_lock(&out->lock);
+ lock_output_stream(out);
out->offload_thread_blocked = false;
pthread_cond_signal(&out->cond);
if (send_callback) {
@@ -923,7 +937,7 @@
static int destroy_offload_callback_thread(struct stream_out *out)
{
- pthread_mutex_lock(&out->lock);
+ lock_output_stream(out);
stop_compressed_output_l(out);
send_offload_cmd_l(out, OFFLOAD_CMD_EXIT);
@@ -1246,7 +1260,7 @@
ALOGV("%s: enter: usecase(%d: %s)", __func__,
out->usecase, use_case_table[out->usecase]);
- pthread_mutex_lock(&out->lock);
+ lock_output_stream(out);
if (!out->standby) {
pthread_mutex_lock(&adev->lock);
out->standby = true;
@@ -1332,7 +1346,7 @@
ret = str_parms_get_str(parms, AUDIO_PARAMETER_STREAM_ROUTING, value, sizeof(value));
if (ret >= 0) {
val = atoi(value);
- pthread_mutex_lock(&out->lock);
+ lock_output_stream(out);
pthread_mutex_lock(&adev->lock);
/*
@@ -1496,7 +1510,7 @@
/* No Output device supported other than BT for playback.
* Sleep for the amount of buffer duration
*/
- pthread_mutex_lock(&out->lock);
+ lock_output_stream(out);
usleep(bytes * 1000000 / audio_stream_frame_size(&out->stream.common) /
out_get_sample_rate(&out->stream.common));
pthread_mutex_unlock(&out->lock);
@@ -1511,7 +1525,7 @@
struct audio_device *adev = out->dev;
ssize_t ret = 0;
- pthread_mutex_lock(&out->lock);
+ lock_output_stream(out);
if (out->standby) {
out->standby = false;
pthread_mutex_lock(&adev->lock);
@@ -1578,7 +1592,7 @@
struct stream_out *out = (struct stream_out *)stream;
*dsp_frames = 0;
if ((out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD) && (dsp_frames != NULL)) {
- pthread_mutex_lock(&out->lock);
+ lock_output_stream(out);
if (out->compr != NULL) {
compress_get_tstamp(out->compr, (unsigned long *)dsp_frames,
&out->sample_rate);
@@ -1616,7 +1630,7 @@
int ret = -1;
unsigned long dsp_frames;
- pthread_mutex_lock(&out->lock);
+ lock_output_stream(out);
if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD) {
if (out->compr != NULL) {
@@ -1660,7 +1674,7 @@
struct stream_out *out = (struct stream_out *)stream;
ALOGV("%s", __func__);
- pthread_mutex_lock(&out->lock);
+ lock_output_stream(out);
out->offload_callback = callback;
out->offload_cookie = cookie;
pthread_mutex_unlock(&out->lock);
@@ -1673,7 +1687,7 @@
int status = -ENOSYS;
ALOGV("%s", __func__);
if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD) {
- pthread_mutex_lock(&out->lock);
+ lock_output_stream(out);
if (out->compr != NULL && out->offload_state == OFFLOAD_STATE_PLAYING) {
status = compress_pause(out->compr);
out->offload_state = OFFLOAD_STATE_PAUSED;
@@ -1690,7 +1704,7 @@
ALOGV("%s", __func__);
if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD) {
status = 0;
- pthread_mutex_lock(&out->lock);
+ lock_output_stream(out);
if (out->compr != NULL && out->offload_state == OFFLOAD_STATE_PAUSED) {
status = compress_resume(out->compr);
out->offload_state = OFFLOAD_STATE_PLAYING;
@@ -1706,7 +1720,7 @@
int status = -ENOSYS;
ALOGV("%s", __func__);
if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD) {
- pthread_mutex_lock(&out->lock);
+ lock_output_stream(out);
if (type == AUDIO_DRAIN_EARLY_NOTIFY)
status = send_offload_cmd_l(out, OFFLOAD_CMD_PARTIAL_DRAIN);
else
@@ -1721,7 +1735,7 @@
struct stream_out *out = (struct stream_out *)stream;
ALOGV("%s", __func__);
if (out->usecase == USECASE_AUDIO_PLAYBACK_OFFLOAD) {
- pthread_mutex_lock(&out->lock);
+ lock_output_stream(out);
stop_compressed_output_l(out);
pthread_mutex_unlock(&out->lock);
return 0;
@@ -1773,7 +1787,8 @@
struct audio_device *adev = in->dev;
int status = 0;
ALOGV("%s: enter", __func__);
- pthread_mutex_lock(&in->lock);
+
+ lock_input_stream(in);
if (!in->standby && in->is_st_session) {
ALOGD("%s: sound trigger pcm stop lab", __func__);
@@ -1818,7 +1833,8 @@
ret = str_parms_get_str(parms, AUDIO_PARAMETER_STREAM_INPUT_SOURCE, value, sizeof(value));
- pthread_mutex_lock(&in->lock);
+ lock_input_stream(in);
+
pthread_mutex_lock(&adev->lock);
if (ret >= 0) {
val = atoi(value);
@@ -1866,7 +1882,8 @@
struct audio_device *adev = in->dev;
int i, ret = -1;
- pthread_mutex_lock(&in->lock);
+ lock_input_stream(in);
+
if (in->is_st_session) {
ALOGVV(" %s: reading on st session bytes=%d", __func__, bytes);
/* Read from sound trigger HAL */
@@ -1930,7 +1947,7 @@
if (status != 0)
return status;
- pthread_mutex_lock(&in->lock);
+ lock_input_stream(in);
pthread_mutex_lock(&in->dev->lock);
if ((in->source == AUDIO_SOURCE_VOICE_COMMUNICATION) &&
in->enable_aec != enable &&
@@ -2178,6 +2195,7 @@
/* out->written = 0; by calloc() */
pthread_mutex_init(&out->lock, (const pthread_mutexattr_t *) NULL);
+ pthread_mutex_init(&out->pre_lock, (const pthread_mutexattr_t *) NULL);
pthread_cond_init(&out->cond, (const pthread_condattr_t *) NULL);
config->format = out->stream.common.get_format(&out->stream.common);
@@ -2427,6 +2445,7 @@
in = (struct stream_in *)calloc(1, sizeof(struct stream_in));
pthread_mutex_init(&in->lock, (const pthread_mutexattr_t *) NULL);
+ pthread_mutex_init(&in->pre_lock, (const pthread_mutexattr_t *) NULL);
in->stream.common.get_sample_rate = in_get_sample_rate;
in->stream.common.set_sample_rate = in_set_sample_rate;
diff --git a/hal/audio_hw.h b/hal/audio_hw.h
index b4b2583..2dfbda0 100644
--- a/hal/audio_hw.h
+++ b/hal/audio_hw.h
@@ -123,6 +123,7 @@
struct stream_out {
struct audio_stream_out stream;
pthread_mutex_t lock; /* see note below on mutex acquisition order */
+ pthread_mutex_t pre_lock; /* acquire before lock to avoid DOS by playback thread */
pthread_cond_t cond;
struct pcm_config config;
struct compr_config compr_config;
@@ -161,6 +162,7 @@
struct stream_in {
struct audio_stream_in stream;
pthread_mutex_t lock; /* see note below on mutex acquisition order */
+ pthread_mutex_t pre_lock; /* acquire before lock to avoid DOS by capture thread */
struct pcm_config config;
struct pcm *pcm;
int standby;