[RFC v2 03/11] vb2: Move cache synchronisation from buffer done to dqbuf handler

Laurent Pinchart
2016-12-16T01:23:58Z

From: Sakari Ailus <sakari.ailus@linux.intel.com>

The cache synchronisation may be a time consuming operation and thus not
best performed in an interrupt which is a typical context for
vb2_buffer_done() calls. This may consume up to tens of ms on some
machines, depending on the buffer size.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
Changes since v1:

- Don't rename the 'i' loop counter to 'plane'
---
drivers/media/v4l2-core/videobuf2-core.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index 8ba48703b189..15a83f338072 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -889,7 +889,6 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
{
struct vb2_queue *q = vb->vb2_queue;
unsigned long flags;
- unsigned int plane;

if (WARN_ON(vb->state != VB2_BUF_STATE_ACTIVE))
return;
@@ -910,10 +909,6 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
dprintk(4, "done processing on buffer %d, state: %d\n",
vb->index, state);

- /* sync buffers */
- for (plane = 0; plane < vb->num_planes; ++plane)
- call_void_memop(vb, finish, vb->planes[plane].mem_priv);
-
spin_lock_irqsave(&q->done_lock, flags);
if (state == VB2_BUF_STATE_QUEUED ||
state == VB2_BUF_STATE_REQUEUEING) {
@@ -1571,6 +1566,10 @@ static void __vb2_dqbuf(struct vb2_buffer *vb)

vb->state = VB2_BUF_STATE_DEQUEUED;

+ /* sync buffers */
+ for (i = 0; i < vb->num_planes; ++i)
+ call_void_memop(vb, finish, vb->planes[i].mem_priv);
+
/* unmap DMABUF buffer */
if (q->memory == VB2_MEMORY_DMABUF)
for (i = 0; i < vb->num_planes; ++i) {