Commit a2ab6cd5 authored by Rémi Denis-Courmont's avatar Rémi Denis-Courmont

block_FifoPace: proper waiting for overflowing queue

parent a2f64f8a
...@@ -300,6 +300,8 @@ static inline block_t *block_ChainGather( block_t *p_list ) ...@@ -300,6 +300,8 @@ static inline block_t *block_ChainGather( block_t *p_list )
VLC_EXPORT( block_fifo_t *, block_FifoNew, ( void ) LIBVLC_USED ); VLC_EXPORT( block_fifo_t *, block_FifoNew, ( void ) LIBVLC_USED );
VLC_EXPORT( void, block_FifoRelease, ( block_fifo_t * ) ); VLC_EXPORT( void, block_FifoRelease, ( block_fifo_t * ) );
/* TODO: do we need to export this? */
void block_FifoPace (block_fifo_t *fifo, size_t max_depth, size_t max_size);
VLC_EXPORT( void, block_FifoEmpty, ( block_fifo_t * ) ); VLC_EXPORT( void, block_FifoEmpty, ( block_fifo_t * ) );
VLC_EXPORT( size_t, block_FifoPut, ( block_fifo_t *, block_t * ) ); VLC_EXPORT( size_t, block_FifoPut, ( block_fifo_t *, block_t * ) );
VLC_EXPORT( void, block_FifoWake, ( block_fifo_t * ) ); VLC_EXPORT( void, block_FifoWake, ( block_fifo_t * ) );
......
...@@ -32,10 +32,13 @@ ...@@ -32,10 +32,13 @@
#include <sys/stat.h> #include <sys/stat.h>
#include "vlc_block.h" #include "vlc_block.h"
/***************************************************************************** /**
* Block functions. * @section Block handling functions.
*****************************************************************************/ */
/* private */
/**
* Internal state for heap block.
*/
struct block_sys_t struct block_sys_t
{ {
block_t self; block_t self;
...@@ -342,13 +345,18 @@ block_t *block_File (int fd) ...@@ -342,13 +345,18 @@ block_t *block_File (int fd)
return block; return block;
} }
/***************************************************************************** /**
* block_fifo_t management * @section Thread-safe block queue functions
*****************************************************************************/ */
/**
* Internal state for block queues
*/
struct block_fifo_t struct block_fifo_t
{ {
vlc_mutex_t lock; /* fifo data lock */ vlc_mutex_t lock; /* fifo data lock */
vlc_cond_t wait; /* fifo data conditional variable */ vlc_cond_t wait; /**< Wait for data */
vlc_cond_t wait_room; /**< Wait for queue depth to shrink */
block_t *p_first; block_t *p_first;
block_t **pp_last; block_t **pp_last;
...@@ -365,6 +373,7 @@ block_fifo_t *block_FifoNew( void ) ...@@ -365,6 +373,7 @@ block_fifo_t *block_FifoNew( void )
vlc_mutex_init( &p_fifo->lock ); vlc_mutex_init( &p_fifo->lock );
vlc_cond_init( &p_fifo->wait ); vlc_cond_init( &p_fifo->wait );
vlc_cond_init( &p_fifo->wait_room );
p_fifo->p_first = NULL; p_fifo->p_first = NULL;
p_fifo->pp_last = &p_fifo->p_first; p_fifo->pp_last = &p_fifo->p_first;
p_fifo->i_depth = p_fifo->i_size = 0; p_fifo->i_depth = p_fifo->i_size = 0;
...@@ -376,6 +385,7 @@ block_fifo_t *block_FifoNew( void ) ...@@ -376,6 +385,7 @@ block_fifo_t *block_FifoNew( void )
void block_FifoRelease( block_fifo_t *p_fifo ) void block_FifoRelease( block_fifo_t *p_fifo )
{ {
block_FifoEmpty( p_fifo ); block_FifoEmpty( p_fifo );
vlc_cond_destroy( &p_fifo->wait_room );
vlc_cond_destroy( &p_fifo->wait ); vlc_cond_destroy( &p_fifo->wait );
vlc_mutex_destroy( &p_fifo->lock ); vlc_mutex_destroy( &p_fifo->lock );
free( p_fifo ); free( p_fifo );
...@@ -398,9 +408,39 @@ void block_FifoEmpty( block_fifo_t *p_fifo ) ...@@ -398,9 +408,39 @@ void block_FifoEmpty( block_fifo_t *p_fifo )
p_fifo->i_depth = p_fifo->i_size = 0; p_fifo->i_depth = p_fifo->i_size = 0;
p_fifo->p_first = NULL; p_fifo->p_first = NULL;
p_fifo->pp_last = &p_fifo->p_first; p_fifo->pp_last = &p_fifo->p_first;
vlc_cond_broadcast( &p_fifo->wait_room );
vlc_mutex_unlock( &p_fifo->lock ); vlc_mutex_unlock( &p_fifo->lock );
} }
/**
* Wait until the FIFO gets below a certain size (if needed).
*
* Note that if more than one thread writes to the FIFO, you cannot assume that
* the FIFO is actually below the requested size upon return (since another
* thread could have refilled it already). This is typically not an issue, as
* this function is meant for (relaxed) congestion control.
*
* This function may be a cancellation point and it is cancel-safe.
*
* @param fifo queue to wait on
* @param max_depth wait until the queue has no more than this many blocks
* (use SIZE_MAX to ignore this constraint)
* @param max_size wait until the queue has no more than this many bytes
* (use SIZE_MAX to ignore this constraint)
* @return nothing.
*/
void block_FifoPace (block_fifo_t *fifo, size_t max_depth, size_t max_size)
{
vlc_mutex_lock (&fifo->lock);
while ((fifo->i_depth > max_depth) || (fifo->i_size > max_size))
{
mutex_cleanup_push (&fifo->lock);
vlc_cond_wait (&fifo->wait_room, &fifo->lock);
vlc_cleanup_pop ();
}
vlc_mutex_unlock (&fifo->lock);
}
/** /**
* Immediately queue one block at the end of a FIFO. * Immediately queue one block at the end of a FIFO.
* @param fifo queue * @param fifo queue
...@@ -471,6 +511,8 @@ block_t *block_FifoGet( block_fifo_t *p_fifo ) ...@@ -471,6 +511,8 @@ block_t *block_FifoGet( block_fifo_t *p_fifo )
p_fifo->pp_last = &p_fifo->p_first; p_fifo->pp_last = &p_fifo->p_first;
} }
/* We don't know how many threads can queue new packets now. */
vlc_cond_broadcast( &p_fifo->wait_room );
vlc_mutex_unlock( &p_fifo->lock ); vlc_mutex_unlock( &p_fifo->lock );
b->p_next = NULL; b->p_next = NULL;
......
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