lavu/buffer: drop USE_ATOMICS

USE_ATOMICS is only set if there is no thread implementation enabled, in
which case you can't expect any lock mechanism from FFmpeg.

This is also conflicting with the incoming use of stdatomic.

diff --git a/libavutil/buffer.c b/libavutil/buffer.c
index 478e4880e5c604ad0686fac9444218d3e5951d6d..33cb513cc9bb6b1402a1dbc27aa31aa3ba8971d7 100644 (file)
--- a/libavutil/buffer.c
+++ b/libavutil/buffer.c
@@ -284,44 +284,6 @@ void av_buffer_pool_uninit(AVBufferPool **ppool)
         buffer_pool_free(pool);
 }
 
-#if USE_ATOMICS
-/* remove the whole buffer list from the pool and return it */
-static BufferPoolEntry *get_pool(AVBufferPool *pool)
-{
-    BufferPoolEntry *cur = *(void * volatile *)&pool->pool, *last = NULL;
-
-    while (cur != last) {
-        last = cur;
-        cur = avpriv_atomic_ptr_cas((void * volatile *)&pool->pool, last, NULL);
-        if (!cur)
-            return NULL;
-    }
-
-    return cur;
-}
-
-static void add_to_pool(BufferPoolEntry *buf)
-{
-    AVBufferPool *pool;
-    BufferPoolEntry *cur, *end = buf;
-
-    if (!buf)
-        return;
-    pool = buf->pool;
-
-    while (end->next)
-        end = end->next;
-
-    while (avpriv_atomic_ptr_cas((void * volatile *)&pool->pool, NULL, buf)) {
-        /* pool is not empty, retrieve it and append it to our list */
-        cur = get_pool(pool);
-        end->next = cur;
-        while (end->next)
-            end = end->next;
-    }
-}
-#endif
-
 static void pool_release_buffer(void *opaque, uint8_t *data)
 {
     BufferPoolEntry *buf = opaque;
@@ -330,14 +292,10 @@ static void pool_release_buffer(void *opaque, uint8_t *data)
     if(CONFIG_MEMORY_POISONING)
         memset(buf->data, FF_MEMORY_POISON, pool->size);
 
-#if USE_ATOMICS
-    add_to_pool(buf);
-#else
     ff_mutex_lock(&pool->mutex);
     buf->next = pool->pool;
     pool->pool = buf;
     ff_mutex_unlock(&pool->mutex);
-#endif
 
     if (!avpriv_atomic_int_add_and_fetch(&pool->refcount, -1))
         buffer_pool_free(pool);
@@ -369,11 +327,6 @@ static AVBufferRef *pool_alloc_buffer(AVBufferPool *pool)
     ret->buffer->opaque = buf;
     ret->buffer->free   = pool_release_buffer;
 
-#if USE_ATOMICS
-    avpriv_atomic_int_add_and_fetch(&pool->refcount, 1);
-    avpriv_atomic_int_add_and_fetch(&pool->nb_allocated, 1);
-#endif
-
     return ret;
 }
 
@@ -382,29 +335,6 @@ AVBufferRef *av_buffer_pool_get(AVBufferPool *pool)
     AVBufferRef *ret;
     BufferPoolEntry *buf;
 
-#if USE_ATOMICS
-    /* check whether the pool is empty */
-    buf = get_pool(pool);
-    if (!buf && pool->refcount <= pool->nb_allocated) {
-        av_log(NULL, AV_LOG_DEBUG, "Pool race dectected, spining to avoid overallocation and eventual OOM\n");
-        while (!buf && avpriv_atomic_int_get(&pool->refcount) <= avpriv_atomic_int_get(&pool->nb_allocated))
-            buf = get_pool(pool);
-    }
-
-    if (!buf)
-        return pool_alloc_buffer(pool);
-
-    /* keep the first entry, return the rest of the list to the pool */
-    add_to_pool(buf->next);
-    buf->next = NULL;
-
-    ret = av_buffer_create(buf->data, pool->size, pool_release_buffer,
-                           buf, 0);
-    if (!ret) {
-        add_to_pool(buf);
-        return NULL;
-    }
-#else
     ff_mutex_lock(&pool->mutex);
     buf = pool->pool;
     if (buf) {
@@ -418,7 +348,6 @@ AVBufferRef *av_buffer_pool_get(AVBufferPool *pool)
         ret = pool_alloc_buffer(pool);
     }
     ff_mutex_unlock(&pool->mutex);
-#endif
 
     if (ret)
         avpriv_atomic_int_add_and_fetch(&pool->refcount, 1);

diff --git a/libavutil/buffer_internal.h b/libavutil/buffer_internal.h
index 29ce8a643c0a4234c58f0cab77092661b12cf16e..bbd40a04e47a7a4b4c1381b6ce0750fcad66b370 100644 (file)
--- a/libavutil/buffer_internal.h
+++ b/libavutil/buffer_internal.h
@@ -87,8 +87,6 @@ struct AVBufferPool {
      */
     volatile int refcount;
 
-    volatile int nb_allocated;
-
     int size;
     void *opaque;
     AVBufferRef* (*alloc)(int size);

diff --git a/libavutil/thread.h b/libavutil/thread.h
index 32ddf40365afe289936caf22e967a7e91efeaff5..6e5744736becb5956faba3de47b2152bb13f5182 100644 (file)
--- a/libavutil/thread.h
+++ b/libavutil/thread.h
@@ -26,8 +26,6 @@
 
 #if HAVE_PTHREADS || HAVE_W32THREADS || HAVE_OS2THREADS
 
-#define USE_ATOMICS 0
-
 #if HAVE_PTHREADS
 #include <pthread.h>
 
@@ -146,8 +144,6 @@ static inline int strict_pthread_once(pthread_once_t *once_control, void (*init_
 
 #else
 
-#define USE_ATOMICS 1
-
 #define AVMutex char
 
 #define ff_mutex_init(mutex, attr) (0)