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Improve handling of source state reads

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This avoids using seq_cst for loading the source state when either inside the
mixer, or otherwise protected from inconsistencies with async updates. It also
fixes potential race conditions with getting the source offset just as a source
stops.
This commit is contained in:
Chris Robinson
2017-02-24 01:47:34 -08:00
parent 652ef2b7fd
commit eceeabaf2f
2 changed files with 91 additions and 74 deletions
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OpenAL32/Include/alSource.h
+1 -1
View File
@@ -226,7 +226,7 @@ ALboolean ApplyOffset(ALsource *Source);
inline ALboolean IsPlayingOrPaused(const ALsource *source)
{
ALenum state = ATOMIC_LOAD_SEQ(&source->state);
ALenum state = ATOMIC_LOAD(&source->state, almemory_order_relaxed);
return state == AL_PLAYING || state == AL_PAUSED;
}
OpenAL32/alSource.c
+90 -73
View File
@@ -139,9 +139,15 @@ static inline ALvoice *GetSourceVoice(const ALsource *source, const ALCcontext *
return NULL;
}
static inline bool IsPlayingOrPausedSeq(const ALsource *source)
{
ALenum state = ATOMIC_LOAD_SEQ(&source->state);
return state == AL_PLAYING || state == AL_PAUSED;
}
static inline bool SourceShouldUpdate(const ALsource *source, const ALCcontext *context)
{
return IsPlayingOrPaused(source) &&
return IsPlayingOrPausedSeq(source) &&
!ATOMIC_LOAD(&context->DeferUpdates, almemory_order_acquire);
}
@@ -525,18 +531,24 @@ static ALboolean SetSourcefv(ALsource *Source, ALCcontext *Context, SourceProp p
Source->OffsetType = prop;
Source->Offset = *values;
if(IsPlayingOrPaused(Source) &&
if(IsPlayingOrPausedSeq(Source) &&
!ATOMIC_LOAD(&Context->DeferUpdates, almemory_order_acquire))
{
ALCdevice_Lock(Context->Device);
WriteLock(&Source->queue_lock);
if(ApplyOffset(Source) == AL_FALSE)
/* Double-check that the source is still playing while we have
* the lock.
*/
if(IsPlayingOrPaused(Source))
{
WriteLock(&Source->queue_lock);
if(ApplyOffset(Source) == AL_FALSE)
{
WriteUnlock(&Source->queue_lock);
ALCdevice_Unlock(Context->Device);
SET_ERROR_AND_RETURN_VALUE(Context, AL_INVALID_VALUE, AL_FALSE);
}
WriteUnlock(&Source->queue_lock);
ALCdevice_Unlock(Context->Device);
SET_ERROR_AND_RETURN_VALUE(Context, AL_INVALID_VALUE, AL_FALSE);
}
WriteUnlock(&Source->queue_lock);
ALCdevice_Unlock(Context->Device);
}
return AL_TRUE;
@@ -672,7 +684,7 @@ static ALboolean SetSourceiv(ALsource *Source, ALCcontext *Context, SourceProp p
}
WriteLock(&Source->queue_lock);
if(IsPlayingOrPaused(Source))
if(IsPlayingOrPausedSeq(Source))
{
WriteUnlock(&Source->queue_lock);
UnlockBuffersRead(device);
@@ -726,18 +738,21 @@ static ALboolean SetSourceiv(ALsource *Source, ALCcontext *Context, SourceProp p
Source->OffsetType = prop;
Source->Offset = *values;
if(IsPlayingOrPaused(Source) &&
if(IsPlayingOrPausedSeq(Source) &&
!ATOMIC_LOAD(&Context->DeferUpdates, almemory_order_acquire))
{
ALCdevice_Lock(Context->Device);
WriteLock(&Source->queue_lock);
if(ApplyOffset(Source) == AL_FALSE)
if(IsPlayingOrPaused(Source))
{
WriteLock(&Source->queue_lock);
if(ApplyOffset(Source) == AL_FALSE)
{
WriteUnlock(&Source->queue_lock);
ALCdevice_Unlock(Context->Device);
SET_ERROR_AND_RETURN_VALUE(Context, AL_INVALID_VALUE, AL_FALSE);
}
WriteUnlock(&Source->queue_lock);
ALCdevice_Unlock(Context->Device);
SET_ERROR_AND_RETURN_VALUE(Context, AL_INVALID_VALUE, AL_FALSE);
}
WriteUnlock(&Source->queue_lock);
ALCdevice_Unlock(Context->Device);
}
return AL_TRUE;
@@ -844,7 +859,7 @@ static ALboolean SetSourceiv(ALsource *Source, ALCcontext *Context, SourceProp p
}
UnlockFiltersRead(device);
if(slot != Source->Send[values[1]].Slot && IsPlayingOrPaused(Source))
if(slot != Source->Send[values[1]].Slot && IsPlayingOrPausedSeq(Source))
{
/* Add refcount on the new slot, and release the previous slot */
if(slot) IncrementRef(&slot->ref);
@@ -2927,7 +2942,7 @@ void UpdateAllSourceProps(ALCcontext *context)
{
ALvoice *voice = context->Voices[pos];
ALsource *source = voice->Source;
if(source != NULL && source->NeedsUpdate && IsPlayingOrPaused(source))
if(source != NULL && source->NeedsUpdate && IsPlayingOrPausedSeq(source))
{
source->NeedsUpdate = AL_FALSE;
UpdateSourceProps(source, num_sends);
@@ -3080,31 +3095,25 @@ static ALint64 GetSourceSampleOffset(ALsource *Source, ALCdevice *device, ALuint
ALuint refcount;
ReadLock(&Source->queue_lock);
if(!IsPlayingOrPaused(Source))
{
ReadUnlock(&Source->queue_lock);
do {
while(((refcount=ATOMIC_LOAD(&device->MixCount, almemory_order_acquire))&1))
althrd_yield();
*clocktime = GetDeviceClockTime(device);
ATOMIC_THREAD_FENCE(almemory_order_acquire);
} while(refcount != ATOMIC_LOAD(&device->MixCount, almemory_order_relaxed));
return 0;
}
do {
BufferList = Current = NULL;
readPos = 0;
while(((refcount=ATOMIC_LOAD(&device->MixCount, almemory_order_acquire))&1))
althrd_yield();
*clocktime = GetDeviceClockTime(device);
BufferList = ATOMIC_LOAD(&Source->queue, almemory_order_relaxed);
Current = ATOMIC_LOAD(&Source->current_buffer, almemory_order_relaxed);
if(IsPlayingOrPaused(Source))
{
BufferList = ATOMIC_LOAD(&Source->queue, almemory_order_relaxed);
Current = ATOMIC_LOAD(&Source->current_buffer, almemory_order_relaxed);
readPos = (ALuint64)ATOMIC_LOAD(&Source->position, almemory_order_relaxed) << 32;
readPos |= (ALuint64)ATOMIC_LOAD(&Source->position_fraction, almemory_order_relaxed) <<
(32-FRACTIONBITS);
readPos = (ALuint64)ATOMIC_LOAD(&Source->position, almemory_order_relaxed) << 32;
readPos |= ATOMIC_LOAD(&Source->position_fraction, almemory_order_relaxed) <<
(32-FRACTIONBITS);
}
ATOMIC_THREAD_FENCE(almemory_order_acquire);
} while(refcount != ATOMIC_LOAD(&device->MixCount, almemory_order_relaxed));
while(BufferList && BufferList != Current)
{
if(BufferList->buffer)
@@ -3125,55 +3134,59 @@ static ALdouble GetSourceSecOffset(ALsource *Source, ALCdevice *device, ALuint64
{
const ALbufferlistitem *BufferList;
const ALbufferlistitem *Current;
const ALbuffer *Buffer = NULL;
ALuint64 readPos;
ALuint refcount;
ALdouble offset;
ReadLock(&Source->queue_lock);
if(!IsPlayingOrPaused(Source))
{
ReadUnlock(&Source->queue_lock);
do {
while(((refcount=ATOMIC_LOAD(&device->MixCount, almemory_order_acquire))&1))
althrd_yield();
*clocktime = GetDeviceClockTime(device);
ATOMIC_THREAD_FENCE(almemory_order_acquire);
} while(refcount != ATOMIC_LOAD(&device->MixCount, almemory_order_relaxed));
return 0.0;
}
do {
BufferList = Current = NULL;
readPos = 0;
while(((refcount=ATOMIC_LOAD(&device->MixCount, almemory_order_acquire))&1))
althrd_yield();
*clocktime = GetDeviceClockTime(device);
BufferList = ATOMIC_LOAD(&Source->queue, almemory_order_relaxed);
Current = ATOMIC_LOAD(&Source->current_buffer, almemory_order_relaxed);
if(IsPlayingOrPaused(Source))
{
BufferList = ATOMIC_LOAD(&Source->queue, almemory_order_relaxed);
Current = ATOMIC_LOAD(&Source->current_buffer, almemory_order_relaxed);
readPos = (ALuint64)ATOMIC_LOAD(&Source->position, almemory_order_relaxed)<<FRACTIONBITS;
readPos |= (ALuint64)ATOMIC_LOAD(&Source->position_fraction, almemory_order_relaxed);
readPos = (ALuint64)ATOMIC_LOAD(&Source->position, almemory_order_relaxed) <<
FRACTIONBITS;
readPos |= ATOMIC_LOAD(&Source->position_fraction, almemory_order_relaxed);
}
ATOMIC_THREAD_FENCE(almemory_order_acquire);
} while(refcount != ATOMIC_LOAD(&device->MixCount, almemory_order_relaxed));
while(BufferList && BufferList != Current)
{
const ALbuffer *buffer = BufferList->buffer;
if(buffer != NULL)
{
if(!Buffer) Buffer = buffer;
readPos += (ALuint64)buffer->SampleLen << FRACTIONBITS;
}
BufferList = BufferList->next;
}
while(BufferList && !Buffer)
if(!Current)
offset = 0.0;
else
{
Buffer = BufferList->buffer;
BufferList = BufferList->next;
const ALbuffer *Buffer = NULL;
while(BufferList && BufferList != Current)
{
const ALbuffer *buffer = BufferList->buffer;
if(buffer != NULL)
{
if(!Buffer) Buffer = buffer;
readPos += (ALuint64)buffer->SampleLen << FRACTIONBITS;
}
BufferList = BufferList->next;
}
while(BufferList && !Buffer)
{
Buffer = BufferList->buffer;
BufferList = BufferList->next;
}
assert(Buffer != NULL);
offset = (ALdouble)readPos / (ALdouble)FRACTIONONE /
(ALdouble)Buffer->Frequency;
}
assert(Buffer != NULL);
ReadUnlock(&Source->queue_lock);
return (ALdouble)readPos / (ALdouble)FRACTIONONE / (ALdouble)Buffer->Frequency;
return offset;
}
/* GetSourceOffset
@@ -3190,21 +3203,17 @@ static ALdouble GetSourceOffset(ALsource *Source, ALenum name, ALCdevice *device
ALboolean readFin = AL_FALSE;
ALuint readPos, readPosFrac;
ALuint totalBufferLen;
ALdouble offset = 0.0;
ALboolean looping;
ALuint refcount;
ALdouble offset;
ALenum state;
ReadLock(&Source->queue_lock);
if(!IsPlayingOrPaused(Source))
{
ReadUnlock(&Source->queue_lock);
return 0.0;
}
totalBufferLen = 0;
do {
while(((refcount=ATOMIC_LOAD(&device->MixCount, almemory_order_acquire))&1))
althrd_yield();
state = ATOMIC_LOAD(&Source->state, almemory_order_relaxed);
BufferList = ATOMIC_LOAD(&Source->queue, almemory_order_relaxed);
Current = ATOMIC_LOAD(&Source->current_buffer, almemory_order_relaxed);
@@ -3215,6 +3224,13 @@ static ALdouble GetSourceOffset(ALsource *Source, ALenum name, ALCdevice *device
ATOMIC_THREAD_FENCE(almemory_order_acquire);
} while(refcount != ATOMIC_LOAD(&device->MixCount, almemory_order_relaxed));
if(state != AL_PLAYING && state != AL_PAUSED)
{
ReadUnlock(&Source->queue_lock);
return 0.0;
}
totalBufferLen = 0;
while(BufferList != NULL)
{
const ALbuffer *buffer;
@@ -3238,6 +3254,7 @@ static ALdouble GetSourceOffset(ALsource *Source, ALenum name, ALCdevice *device
readPos = readPosFrac = 0;
}
offset = 0.0;
switch(name)
{
case AL_SEC_OFFSET: