[FFmpeg-devel] [PATCH] avutil/buffer: add a dynamic size buffer pool API
wm4
nfxjfg at googlemail.com
Wed Mar 28 12:59:56 EEST 2018
On Tue, 27 Mar 2018 23:11:27 -0300
James Almer <jamrial at gmail.com> wrote:
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
> Implemented as a completely separate API as suggested. Missing
> Changelog, APIChanges and version bump as usual.
>
> libavutil/buffer.c | 159 ++++++++++++++++++++++++++++++++++++++++++++
> libavutil/buffer.h | 53 +++++++++++++++
> libavutil/buffer_internal.h | 14 ++++
> 3 files changed, 226 insertions(+)
>
> diff --git a/libavutil/buffer.c b/libavutil/buffer.c
> index 8d1aa5fa84..c39a14c3c7 100644
> --- a/libavutil/buffer.c
> +++ b/libavutil/buffer.c
> @@ -24,6 +24,7 @@
> #include "common.h"
> #include "mem.h"
> #include "thread.h"
> +#include "tree.h"
>
> AVBufferRef *av_buffer_create(uint8_t *data, int size,
> void (*free)(void *opaque, uint8_t *data),
> @@ -355,3 +356,161 @@ AVBufferRef *av_buffer_pool_get(AVBufferPool *pool)
>
> return ret;
> }
> +
> +AVBufferDynPool *av_buffer_dyn_pool_init(AVBufferRef* (*alloc)(int size))
> +{
> + AVBufferDynPool *pool = av_mallocz(sizeof(*pool));
> + if (!pool)
> + return NULL;
> +
> + ff_mutex_init(&pool->mutex, NULL);
> +
> + pool->alloc = alloc ? alloc : av_buffer_alloc;
> +
> + atomic_init(&pool->refcount, 1);
> +
> + return pool;
> +}
> +
> +static int free_node(void *opaque, void *elem)
> +{
> + BufferPoolEntry *buf = elem;
> +
> + buf->free(buf->opaque, buf->data);
> + av_free(buf);
> +
> + return 0;
> +}
> +
> +static void buffer_dyn_pool_free(AVBufferDynPool *pool)
> +{
> + av_tree_enumerate(pool->root, NULL, NULL, free_node);
> + av_tree_destroy(pool->root);
> +
> + ff_mutex_destroy(&pool->mutex);
> +
> + av_freep(&pool);
> +}
> +
> +void av_buffer_dyn_pool_uninit(AVBufferDynPool **ppool)
> +{
> + AVBufferDynPool *pool;
> +
> + if (!ppool || !*ppool)
> + return;
> + pool = *ppool;
> + *ppool = NULL;
> +
> + if (atomic_fetch_add_explicit(&pool->refcount, -1, memory_order_acq_rel) == 1)
> + buffer_dyn_pool_free(pool);
> +}
> +
> +static int cmp_insert(const void *key, const void *node)
> +{
> + int ret = ((const BufferPoolEntry *) key)->size - ((const BufferPoolEntry *) node)->size;
> +
> + if (!ret)
> + ret = ((const BufferPoolEntry *) key)->data - ((const BufferPoolEntry *) node)->data;
> + return ret;
> +}
> +
> +static void pool_release_dyn_buffer(void *opaque, uint8_t *data)
> +{
> + BufferPoolEntry *buf = opaque;
> + AVBufferDynPool *pool = buf->dynpool;
> +
> + if(CONFIG_MEMORY_POISONING)
> + memset(buf->data, FF_MEMORY_POISON, buf->size);
> +
> + ff_mutex_lock(&pool->mutex);
> + /* Add the buffer into the pool, using the preallocated
> + * AVTreeNode stored in buf->node */
> + av_tree_insert(&pool->root, buf, cmp_insert, &buf->node);
> + ff_mutex_unlock(&pool->mutex);
> +
> + if (atomic_fetch_add_explicit(&pool->refcount, -1, memory_order_acq_rel) == 1)
> + buffer_dyn_pool_free(pool);
> +}
> +
> +static AVBufferRef *pool_alloc_dyn_buffer(AVBufferDynPool *pool, int size)
> +{
> + BufferPoolEntry *buf;
> + AVBufferRef *ret;
> +
> + ret = pool->alloc(size);
> + if (!ret)
> + return NULL;
> +
> + buf = av_mallocz(sizeof(*buf));
> + if (!buf) {
> + av_buffer_unref(&ret);
> + return NULL;
> + }
> +
> + buf->node = av_tree_node_alloc();
> + if (!buf->node) {
> + av_free(buf);
> + av_buffer_unref(&ret);
> + return NULL;
> + }
> +
> + buf->data = ret->buffer->data;
> + buf->opaque = ret->buffer->opaque;
> + buf->free = ret->buffer->free;
> + buf->size = size;
> + buf->dynpool = pool;
> +
> + ret->buffer->opaque = buf;
> + ret->buffer->free = pool_release_dyn_buffer;
> +
> + return ret;
> +}
> +
> +static int cmp_find(const void *key, const void *node)
> +{
> + return *(const int *)key - ((const BufferPoolEntry *) node)->size;
> +}
> +
> +AVBufferRef *av_buffer_dyn_pool_get(AVBufferDynPool *pool, int size)
> +{
> + AVBufferRef *ret;
> + BufferPoolEntry *buf, *next[2] = { NULL, NULL };
> +
> + ff_mutex_lock(&pool->mutex);
> + /* Find a big enough buffer in the pool. */
> + buf = av_tree_find(pool->root, &size, cmp_find, (void **)next);
> +
> + if (!buf)
> + /* If none of the requested size exists, use a bigger one. */
> + buf = next[1];
> + if (!buf && (buf = next[0])) {
> + /* If the pool also doesn't have a bigger buffer, but does
> + * have a smaller one, then replace it with a new buffer of
> + * the requested size. */
> + av_tree_insert(&pool->root, buf, cmp_insert, &buf->node);
> + buf->free(buf->opaque, buf->data);
> + av_free(buf->node);
> + av_freep(&buf);
> + }
> +
> + if (buf) {
> + ret = av_buffer_create(buf->data, buf->size, pool_release_dyn_buffer,
> + buf, 0);
> + if (ret) {
> + /* Remove the buffer from the pool. Zero and store the
> + * AVTreeNode used for it in buf->node so we can use it
> + * again once the buffer is put back in the pool. */
> + av_tree_insert(&pool->root, buf, cmp_insert, &buf->node);
> + memset(buf->node, 0, av_tree_node_size);
> + ret->size = size;
> + }
> + } else {
> + ret = pool_alloc_dyn_buffer(pool, size);
> + }
> + ff_mutex_unlock(&pool->mutex);
> +
> + if (ret)
> + atomic_fetch_add_explicit(&pool->refcount, 1, memory_order_relaxed);
> +
> + return ret;
> +}
> diff --git a/libavutil/buffer.h b/libavutil/buffer.h
> index 73b6bd0b14..d06b301fe5 100644
> --- a/libavutil/buffer.h
> +++ b/libavutil/buffer.h
> @@ -284,6 +284,59 @@ void av_buffer_pool_uninit(AVBufferPool **pool);
> */
> AVBufferRef *av_buffer_pool_get(AVBufferPool *pool);
>
> +/**
> + * @}
> + */
> +
> +/**
> + * @defgroup lavu_bufferdynpool AVBufferDynPool
> + * @ingroup lavu_data
> + *
> + * @{
> + * AVBufferDynPool is an API for a lock-free thread-safe pool of AVBuffers.
> + *
> + * Unlike AVBufferPool, AVBufferDynPool allows the user to request buffers
> + * of any arbitrary size. It is functionally the same otherwise.
> + */
> +
> +/**
> + * The buffer pool. This structure is opaque and not meant to be accessed
> + * directly. It is allocated with av_buffer_dyn_pool_init() and freed with
> + * av_buffer_dyn_pool_uninit().
> + */
> +typedef struct AVBufferDynPool AVBufferDynPool;
> +
> +/**
> + * Allocate and initialize a buffer pool.
> + *
> + * @param alloc a function that will be used to allocate new buffers when the
> + * pool is empty. May be NULL, then the default allocator will be used
> + * (av_buffer_alloc()).
> + * @return newly created buffer pool on success, NULL on error.
> + */
> +AVBufferDynPool *av_buffer_dyn_pool_init(AVBufferRef* (*alloc)(int size));
No custom free pool free function like the fixed buffer API? (Not sure if neded.)
> +
> +/**
> + * Mark the pool as being available for freeing. It will actually be freed only
> + * once all the allocated buffers associated with the pool are released. Thus it
> + * is safe to call this function while some of the allocated buffers are still
> + * in use.
> + *
> + * @param pool pointer to the pool to be freed. It will be set to NULL.
> + */
> +void av_buffer_dyn_pool_uninit(AVBufferDynPool **pool);
> +
> +/**
> + * Allocate a new AVBuffer, reusing an old buffer from the pool when available.
> + * This function may be called simultaneously from multiple threads.
> + *
> + * @param pool pointer to an initialized pool.
> + * @param size Required buffer size in bytes.
> + *
> + * @return a reference to the new buffer on success, NULL on error.
> + */
> +AVBufferRef *av_buffer_dyn_pool_get(AVBufferDynPool *pool, int size);
> +
> /**
> * @}
> */
> diff --git a/libavutil/buffer_internal.h b/libavutil/buffer_internal.h
> index 54b67047e5..2c0e9ea063 100644
> --- a/libavutil/buffer_internal.h
> +++ b/libavutil/buffer_internal.h
> @@ -61,6 +61,7 @@ struct AVBuffer {
>
> typedef struct BufferPoolEntry {
> uint8_t *data;
> + size_t size;
>
> /*
> * Backups of the original opaque/free of the AVBuffer corresponding to
> @@ -71,6 +72,9 @@ typedef struct BufferPoolEntry {
>
> AVBufferPool *pool;
> struct BufferPoolEntry *next;
> +
> + AVBufferDynPool *dynpool;
> + struct AVTreeNode *node;
> } BufferPoolEntry;
>
> struct AVBufferPool {
> @@ -95,4 +99,14 @@ struct AVBufferPool {
> void (*pool_free)(void *opaque);
> };
>
> +struct AVBufferDynPool {
> + AVMutex mutex;
> + struct AVTreeNode *root;
> +
> + atomic_uint refcount;
> +
> + int size;
> + AVBufferRef* (*alloc)(int size);
> +};
> +
> #endif /* AVUTIL_BUFFER_INTERNAL_H */
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