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ALSA: pcm_core: Fix wake_up() optimization
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This change fixes the "ALSA: pcm_lib - optimize wake_up() calls for PCM I/O"
commit. New sleeping queue is introduced to separate user space and kernel
space wake_ups. runtime->nowake is renamed to twake (transfer wake).

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
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Jaroslav Kysela committed Jan 21, 2010
1 parent d1db38c commit c91a988
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Showing 4 changed files with 17 additions and 12 deletions.
5 changes: 3 additions & 2 deletions include/sound/pcm.h
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Original file line number Diff line number Diff line change
Expand Up @@ -311,8 +311,9 @@ struct snd_pcm_runtime {
struct snd_pcm_mmap_control *control;

/* -- locking / scheduling -- */
unsigned int nowake: 1; /* no wakeup (data-copy in progress) */
wait_queue_head_t sleep;
unsigned int twake: 1; /* do transfer (!poll) wakeup */
wait_queue_head_t sleep; /* poll sleep */
wait_queue_head_t tsleep; /* transfer sleep */
struct fasync_struct *fasync;

/* -- private section -- */
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1 change: 1 addition & 0 deletions sound/core/pcm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -894,6 +894,7 @@ int snd_pcm_attach_substream(struct snd_pcm *pcm, int stream,
memset((void*)runtime->control, 0, size);

init_waitqueue_head(&runtime->sleep);
init_waitqueue_head(&runtime->tsleep);

runtime->status->state = SNDRV_PCM_STATE_OPEN;

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20 changes: 10 additions & 10 deletions sound/core/pcm_lib.c
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Original file line number Diff line number Diff line change
Expand Up @@ -285,8 +285,8 @@ int snd_pcm_update_state(struct snd_pcm_substream *substream,
return -EPIPE;
}
}
if (!runtime->nowake && avail >= runtime->control->avail_min)
wake_up(&runtime->sleep);
if (avail >= runtime->control->avail_min)
wake_up(runtime->twake ? &runtime->tsleep : &runtime->sleep);
return 0;
}

Expand Down Expand Up @@ -1692,7 +1692,7 @@ static int wait_for_avail_min(struct snd_pcm_substream *substream,
long tout;

init_waitqueue_entry(&wait, current);
add_wait_queue(&runtime->sleep, &wait);
add_wait_queue(&runtime->tsleep, &wait);
for (;;) {
if (signal_pending(current)) {
err = -ERESTARTSYS;
Expand Down Expand Up @@ -1735,7 +1735,7 @@ static int wait_for_avail_min(struct snd_pcm_substream *substream,
break;
}
_endloop:
remove_wait_queue(&runtime->sleep, &wait);
remove_wait_queue(&runtime->tsleep, &wait);
*availp = avail;
return err;
}
Expand Down Expand Up @@ -1794,7 +1794,7 @@ static snd_pcm_sframes_t snd_pcm_lib_write1(struct snd_pcm_substream *substream,
goto _end_unlock;
}

runtime->nowake = 1;
runtime->twake = 1;
while (size > 0) {
snd_pcm_uframes_t frames, appl_ptr, appl_ofs;
snd_pcm_uframes_t avail;
Expand All @@ -1816,7 +1816,7 @@ static snd_pcm_sframes_t snd_pcm_lib_write1(struct snd_pcm_substream *substream,
if (frames > cont)
frames = cont;
if (snd_BUG_ON(!frames)) {
runtime->nowake = 0;
runtime->twake = 0;
snd_pcm_stream_unlock_irq(substream);
return -EINVAL;
}
Expand Down Expand Up @@ -1855,7 +1855,7 @@ static snd_pcm_sframes_t snd_pcm_lib_write1(struct snd_pcm_substream *substream,
}
}
_end_unlock:
runtime->nowake = 0;
runtime->twake = 0;
if (xfer > 0 && err >= 0)
snd_pcm_update_state(substream, runtime);
snd_pcm_stream_unlock_irq(substream);
Expand Down Expand Up @@ -2016,7 +2016,7 @@ static snd_pcm_sframes_t snd_pcm_lib_read1(struct snd_pcm_substream *substream,
goto _end_unlock;
}

runtime->nowake = 1;
runtime->twake = 1;
while (size > 0) {
snd_pcm_uframes_t frames, appl_ptr, appl_ofs;
snd_pcm_uframes_t avail;
Expand Down Expand Up @@ -2045,7 +2045,7 @@ static snd_pcm_sframes_t snd_pcm_lib_read1(struct snd_pcm_substream *substream,
if (frames > cont)
frames = cont;
if (snd_BUG_ON(!frames)) {
runtime->nowake = 0;
runtime->twake = 0;
snd_pcm_stream_unlock_irq(substream);
return -EINVAL;
}
Expand Down Expand Up @@ -2078,7 +2078,7 @@ static snd_pcm_sframes_t snd_pcm_lib_read1(struct snd_pcm_substream *substream,
xfer += frames;
}
_end_unlock:
runtime->nowake = 0;
runtime->twake = 0;
if (xfer > 0 && err >= 0)
snd_pcm_update_state(substream, runtime);
snd_pcm_stream_unlock_irq(substream);
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3 changes: 3 additions & 0 deletions sound/core/pcm_native.c
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Original file line number Diff line number Diff line change
Expand Up @@ -919,6 +919,7 @@ static void snd_pcm_post_stop(struct snd_pcm_substream *substream, int state)
runtime->status->state = state;
}
wake_up(&runtime->sleep);
wake_up(&runtime->tsleep);
}

static struct action_ops snd_pcm_action_stop = {
Expand Down Expand Up @@ -1004,6 +1005,7 @@ static void snd_pcm_post_pause(struct snd_pcm_substream *substream, int push)
SNDRV_TIMER_EVENT_MPAUSE,
&runtime->trigger_tstamp);
wake_up(&runtime->sleep);
wake_up(&runtime->tsleep);
} else {
runtime->status->state = SNDRV_PCM_STATE_RUNNING;
if (substream->timer)
Expand Down Expand Up @@ -1061,6 +1063,7 @@ static void snd_pcm_post_suspend(struct snd_pcm_substream *substream, int state)
runtime->status->suspended_state = runtime->status->state;
runtime->status->state = SNDRV_PCM_STATE_SUSPENDED;
wake_up(&runtime->sleep);
wake_up(&runtime->tsleep);
}

static struct action_ops snd_pcm_action_suspend = {
Expand Down

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