mirrors/gstreamer
mirrors/gstreamer
1
1
Fork 0
mirror of https://gitlab.freedesktop.org/gstreamer/gstreamer.git synced 2024-12-18 22:36:33 +00:00
Code Issues 1 Projects Releases Wiki Activity

dmabuf: share the mapping with shared copies of the memory

Browse source 
With lots of shared memory instances (e.g. created by a RTP payloader) the
overhead of duplicating the file descriptor and creating extra mappings is
significant. To avoid this, the parent memory maps the whole region and the
shared copies just reuse the same mapping.

https://bugzilla.gnome.org/show_bug.cgi?id=730441
This commit is contained in:
Michael Olbrich 2014-05-20 11:18:56 +02:00 committed by Nicolas Dufresne
parent d8a1dc5ea8
commit b60888fd4b
1 changed files with 14 additions and 9 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

23
gst-libs/gst/allocators/gstdmabuf.c
View file

@ -53,7 +53,6 @@ typedef struct
gpointer data;
gint mmapping_flags;
gint mmap_count;
gsize mmap_size;
GMutex lock;
} GstDmaBufMemory;
@ -68,9 +67,10 @@ gst_dmabuf_allocator_free (GstAllocator * allocator, GstMemory * gmem)
if (mem->data) {
g_warning (G_STRLOC ":%s: Freeing memory %p still mapped", G_STRFUNC, mem);
munmap ((void *) mem->data, mem->mmap_size);
munmap ((void *) mem->data, gmem->maxsize);
}
close (mem->fd);
if (mem->fd >= 0)
close (mem->fd);
g_mutex_clear (&mem->lock);
g_slice_free (GstDmaBufMemory, mem);
GST_DEBUG ("%p: freed", mem);
@ -85,6 +85,9 @@ gst_dmabuf_mem_map (GstMemory * gmem, gsize maxsize, GstMapFlags flags)
gint prot;
gpointer ret = NULL;
if (gmem->parent)
return gst_dmabuf_mem_map (gmem->parent, maxsize, flags);
g_mutex_lock (&mem->lock);
prot = flags & GST_MAP_READ ? PROT_READ : 0;
@ -94,7 +97,7 @@ gst_dmabuf_mem_map (GstMemory * gmem, gsize maxsize, GstMapFlags flags)
if (mem->data) {
/* only return address if mapping flags are a subset
* of the previous flags */
if ((mem->mmapping_flags & prot) && (mem->mmap_size >= maxsize)) {
if (mem->mmapping_flags & prot) {
ret = mem->data;
mem->mmap_count++;
}
@ -103,7 +106,7 @@ gst_dmabuf_mem_map (GstMemory * gmem, gsize maxsize, GstMapFlags flags)
}
if (mem->fd != -1) {
mem->data = mmap (0, maxsize, prot, MAP_SHARED, mem->fd, 0);
mem->data = mmap (0, gmem->maxsize, prot, MAP_SHARED, mem->fd, 0);
if (mem->data == MAP_FAILED) {
mem->data = NULL;
GST_ERROR ("%p: fd %d: mmap failed: %s", mem, mem->fd,
@ -116,7 +119,6 @@ gst_dmabuf_mem_map (GstMemory * gmem, gsize maxsize, GstMapFlags flags)
if (mem->data) {
mem->mmapping_flags = prot;
mem->mmap_size = maxsize;
mem->mmap_count++;
ret = mem->data;
}
@ -134,12 +136,15 @@ gst_dmabuf_mem_unmap (GstMemory * gmem)
{
#ifdef HAVE_MMAP
GstDmaBufMemory *mem = (GstDmaBufMemory *) gmem;
if (gmem->parent)
return gst_dmabuf_mem_unmap (gmem->parent);
g_mutex_lock (&mem->lock);
if (mem->data && !(--mem->mmap_count)) {
munmap ((void *) mem->data, mem->mmap_size);
munmap ((void *) mem->data, gmem->maxsize);
mem->data = NULL;
mem->mmap_size = 0;
mem->mmapping_flags = 0;
GST_DEBUG ("%p: fd %d unmapped", mem, mem->fd);
}
@ -171,7 +176,7 @@ gst_dmabuf_mem_share (GstMemory * gmem, gssize offset, gssize size)
GST_MINI_OBJECT_FLAG_LOCK_READONLY, mem->mem.allocator, parent,
mem->mem.maxsize, mem->mem.align, mem->mem.offset + offset, size);
sub->fd = dup (mem->fd);
sub->fd = -1;
g_mutex_init (&sub->lock);
return GST_MEMORY_CAST (sub);