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Commit c91a988d authored by Jaroslav Kysela's avatar Jaroslav Kysela
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ALSA: pcm_core: Fix wake_up() optimization 



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: default avatarJaroslav Kysela <perex@perex.cz>
parent d1db38c0

include/sound/pcm.h

+3 −2
Original line number Diff line number Diff line
@@ -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 -- */

sound/core/pcm.c

+1 −0
Original line number Diff line number Diff line
@@ -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;

sound/core/pcm_lib.c

+10 −10
Original line number Diff line number Diff line
@@ -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;

}
@@ -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;
@@ -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;

}
@@ -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;
@@ -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;

		}
@@ -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);
@@ -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;
@@ -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;

		}
@@ -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);

sound/core/pcm_native.c

+3 −0
Original line number Diff line number Diff line
@@ -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 = {
@@ -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)
@@ -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 = {