| Message ID | 20240605074035.2620140-5-yunkec@chromium.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | media: videobuf2-core: attach once if multiple planes share the same dbuf | expand |
On Wed, Jun 05, 2024 at 04:40:35PM +0900, Yunke Cao wrote: > When multiple planes use the same dma buf, each plane will have its own dma > buf attachment and mapping. It is a waste of IOVA space. > > This patch adds a dbuf_duplicated boolean in vb2_plane. If a plane's dbuf > is the same as an existing plane, do not create another attachment and > mapping. > > Signed-off-by: Yunke Cao <yunkec@chromium.org> > --- > v3 > - Adjust the patch according to the previous patches to resolve conflicts. > - Add comment to explain the purpose of the change. > > v2 > - Separate out the refactor changes out to previous patches. > - Fix mem_priv check. > --- > .../media/common/videobuf2/videobuf2-core.c | 29 ++++++++++++++++--- > include/media/videobuf2-core.h | 3 ++ > 2 files changed, 28 insertions(+), 4 deletions(-) > > diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c > index cbc8928f0418..90b65bf6c463 100644 > --- a/drivers/media/common/videobuf2/videobuf2-core.c > +++ b/drivers/media/common/videobuf2/videobuf2-core.c > @@ -304,10 +304,13 @@ static void __vb2_plane_dmabuf_put(struct vb2_buffer *vb, struct vb2_plane *p) > if (!p->mem_priv) > return; > > - if (p->dbuf_mapped) > - call_void_memop(vb, unmap_dmabuf, p->mem_priv); > + if (!p->dbuf_duplicated) { > + if (p->dbuf_mapped) > + call_void_memop(vb, unmap_dmabuf, p->mem_priv); > + > + call_void_memop(vb, detach_dmabuf, p->mem_priv); > + } > > - call_void_memop(vb, detach_dmabuf, p->mem_priv); > dma_buf_put(p->dbuf); > p->mem_priv = NULL; > p->dbuf = NULL; > @@ -316,6 +319,7 @@ static void __vb2_plane_dmabuf_put(struct vb2_buffer *vb, struct vb2_plane *p) > p->length = 0; > p->m.fd = 0; > p->data_offset = 0; > + p->dbuf_duplicated = false; > } > > /* > @@ -1374,7 +1378,7 @@ static int __prepare_dmabuf(struct vb2_buffer *vb) > struct vb2_plane planes[VB2_MAX_PLANES]; > struct vb2_queue *q = vb->vb2_queue; > void *mem_priv; > - unsigned int plane; > + unsigned int plane, i; > int ret = 0; > bool reacquired = vb->planes[0].mem_priv == NULL; > > @@ -1427,6 +1431,23 @@ static int __prepare_dmabuf(struct vb2_buffer *vb) > } > > for (plane = 0; plane < vb->num_planes; ++plane) { > + /* > + * This is an optimization to reduce dma_buf attachment/mapping. > + * When the same dma_buf is used for multiple planes, there is no need > + * to create duplicated attachments. > + */ > + for (i = 0; i < plane; ++i) { > + if (planes[plane].dbuf == vb->planes[i].dbuf) { Oops, I just realized that we forgot about one thing. vb_queue has alloc_devs[] array with per-plane struct device used for DMA mapping API. If those are different, we can't reuse the attachment, so we need to check them here too... Best regards, Tomasz > + vb->planes[plane].dbuf_duplicated = true; > + vb->planes[plane].dbuf = vb->planes[i].dbuf; > + vb->planes[plane].mem_priv = vb->planes[i].mem_priv; > + break; > + } > + } > + > + if (vb->planes[plane].dbuf_duplicated) > + continue; > + > /* Acquire each plane's memory */ > mem_priv = call_ptr_memop(attach_dmabuf, > vb, > diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h > index 955237ac503d..053ced60595f 100644 > --- a/include/media/videobuf2-core.h > +++ b/include/media/videobuf2-core.h > @@ -154,6 +154,8 @@ struct vb2_mem_ops { > * @mem_priv: private data with this plane. > * @dbuf: dma_buf - shared buffer object. > * @dbuf_mapped: flag to show whether dbuf is mapped or not > + * @duplicated_dbuf: boolean to show whether dbuf is duplicated with a > + * previous plane of the buffer. > * @bytesused: number of bytes occupied by data in the plane (payload). > * @length: size of this plane (NOT the payload) in bytes. The maximum > * valid size is MAX_UINT - PAGE_SIZE. > @@ -179,6 +181,7 @@ struct vb2_plane { > void *mem_priv; > struct dma_buf *dbuf; > unsigned int dbuf_mapped; > + bool dbuf_duplicated; > unsigned int bytesused; > unsigned int length; > unsigned int min_length; > -- > 2.45.1.288.g0e0cd299f1-goog >
Thanks! I didn't know alloc_devs can be different within a vb2 buffer. Updated in v4. Best, Yunke On Wed, Jun 12, 2024 at 3:36 PM Tomasz Figa <tfiga@chromium.org> wrote: > > On Wed, Jun 05, 2024 at 04:40:35PM +0900, Yunke Cao wrote: > > When multiple planes use the same dma buf, each plane will have its own dma > > buf attachment and mapping. It is a waste of IOVA space. > > > > This patch adds a dbuf_duplicated boolean in vb2_plane. If a plane's dbuf > > is the same as an existing plane, do not create another attachment and > > mapping. > > > > Signed-off-by: Yunke Cao <yunkec@chromium.org> > > --- > > v3 > > - Adjust the patch according to the previous patches to resolve conflicts. > > - Add comment to explain the purpose of the change. > > > > v2 > > - Separate out the refactor changes out to previous patches. > > - Fix mem_priv check. > > --- > > .../media/common/videobuf2/videobuf2-core.c | 29 ++++++++++++++++--- > > include/media/videobuf2-core.h | 3 ++ > > 2 files changed, 28 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c > > index cbc8928f0418..90b65bf6c463 100644 > > --- a/drivers/media/common/videobuf2/videobuf2-core.c > > +++ b/drivers/media/common/videobuf2/videobuf2-core.c > > @@ -304,10 +304,13 @@ static void __vb2_plane_dmabuf_put(struct vb2_buffer *vb, struct vb2_plane *p) > > if (!p->mem_priv) > > return; > > > > - if (p->dbuf_mapped) > > - call_void_memop(vb, unmap_dmabuf, p->mem_priv); > > + if (!p->dbuf_duplicated) { > > + if (p->dbuf_mapped) > > + call_void_memop(vb, unmap_dmabuf, p->mem_priv); > > + > > + call_void_memop(vb, detach_dmabuf, p->mem_priv); > > + } > > > > - call_void_memop(vb, detach_dmabuf, p->mem_priv); > > dma_buf_put(p->dbuf); > > p->mem_priv = NULL; > > p->dbuf = NULL; > > @@ -316,6 +319,7 @@ static void __vb2_plane_dmabuf_put(struct vb2_buffer *vb, struct vb2_plane *p) > > p->length = 0; > > p->m.fd = 0; > > p->data_offset = 0; > > + p->dbuf_duplicated = false; > > } > > > > /* > > @@ -1374,7 +1378,7 @@ static int __prepare_dmabuf(struct vb2_buffer *vb) > > struct vb2_plane planes[VB2_MAX_PLANES]; > > struct vb2_queue *q = vb->vb2_queue; > > void *mem_priv; > > - unsigned int plane; > > + unsigned int plane, i; > > int ret = 0; > > bool reacquired = vb->planes[0].mem_priv == NULL; > > > > @@ -1427,6 +1431,23 @@ static int __prepare_dmabuf(struct vb2_buffer *vb) > > } > > > > for (plane = 0; plane < vb->num_planes; ++plane) { > > + /* > > + * This is an optimization to reduce dma_buf attachment/mapping. > > + * When the same dma_buf is used for multiple planes, there is no need > > + * to create duplicated attachments. > > + */ > > + for (i = 0; i < plane; ++i) { > > + if (planes[plane].dbuf == vb->planes[i].dbuf) { > > Oops, I just realized that we forgot about one thing. vb_queue has > alloc_devs[] array with per-plane struct device used for DMA mapping > API. If those are different, we can't reuse the attachment, so we need > to check them here too... > > Best regards, > Tomasz > > > + vb->planes[plane].dbuf_duplicated = true; > > + vb->planes[plane].dbuf = vb->planes[i].dbuf; > > + vb->planes[plane].mem_priv = vb->planes[i].mem_priv; > > + break; > > + } > > + } > > + > > + if (vb->planes[plane].dbuf_duplicated) > > + continue; > > + > > /* Acquire each plane's memory */ > > mem_priv = call_ptr_memop(attach_dmabuf, > > vb, > > diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h > > index 955237ac503d..053ced60595f 100644 > > --- a/include/media/videobuf2-core.h > > +++ b/include/media/videobuf2-core.h > > @@ -154,6 +154,8 @@ struct vb2_mem_ops { > > * @mem_priv: private data with this plane. > > * @dbuf: dma_buf - shared buffer object. > > * @dbuf_mapped: flag to show whether dbuf is mapped or not > > + * @duplicated_dbuf: boolean to show whether dbuf is duplicated with a > > + * previous plane of the buffer. > > * @bytesused: number of bytes occupied by data in the plane (payload). > > * @length: size of this plane (NOT the payload) in bytes. The maximum > > * valid size is MAX_UINT - PAGE_SIZE. > > @@ -179,6 +181,7 @@ struct vb2_plane { > > void *mem_priv; > > struct dma_buf *dbuf; > > unsigned int dbuf_mapped; > > + bool dbuf_duplicated; > > unsigned int bytesused; > > unsigned int length; > > unsigned int min_length; > > -- > > 2.45.1.288.g0e0cd299f1-goog > >
diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c index cbc8928f0418..90b65bf6c463 100644 --- a/drivers/media/common/videobuf2/videobuf2-core.c +++ b/drivers/media/common/videobuf2/videobuf2-core.c @@ -304,10 +304,13 @@ static void __vb2_plane_dmabuf_put(struct vb2_buffer *vb, struct vb2_plane *p) if (!p->mem_priv) return; - if (p->dbuf_mapped) - call_void_memop(vb, unmap_dmabuf, p->mem_priv); + if (!p->dbuf_duplicated) { + if (p->dbuf_mapped) + call_void_memop(vb, unmap_dmabuf, p->mem_priv); + + call_void_memop(vb, detach_dmabuf, p->mem_priv); + } - call_void_memop(vb, detach_dmabuf, p->mem_priv); dma_buf_put(p->dbuf); p->mem_priv = NULL; p->dbuf = NULL; @@ -316,6 +319,7 @@ static void __vb2_plane_dmabuf_put(struct vb2_buffer *vb, struct vb2_plane *p) p->length = 0; p->m.fd = 0; p->data_offset = 0; + p->dbuf_duplicated = false; } /* @@ -1374,7 +1378,7 @@ static int __prepare_dmabuf(struct vb2_buffer *vb) struct vb2_plane planes[VB2_MAX_PLANES]; struct vb2_queue *q = vb->vb2_queue; void *mem_priv; - unsigned int plane; + unsigned int plane, i; int ret = 0; bool reacquired = vb->planes[0].mem_priv == NULL; @@ -1427,6 +1431,23 @@ static int __prepare_dmabuf(struct vb2_buffer *vb) } for (plane = 0; plane < vb->num_planes; ++plane) { + /* + * This is an optimization to reduce dma_buf attachment/mapping. + * When the same dma_buf is used for multiple planes, there is no need + * to create duplicated attachments. + */ + for (i = 0; i < plane; ++i) { + if (planes[plane].dbuf == vb->planes[i].dbuf) { + vb->planes[plane].dbuf_duplicated = true; + vb->planes[plane].dbuf = vb->planes[i].dbuf; + vb->planes[plane].mem_priv = vb->planes[i].mem_priv; + break; + } + } + + if (vb->planes[plane].dbuf_duplicated) + continue; + /* Acquire each plane's memory */ mem_priv = call_ptr_memop(attach_dmabuf, vb, diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index 955237ac503d..053ced60595f 100644 --- a/include/media/videobuf2-core.h +++ b/include/media/videobuf2-core.h @@ -154,6 +154,8 @@ struct vb2_mem_ops { * @mem_priv: private data with this plane. * @dbuf: dma_buf - shared buffer object. * @dbuf_mapped: flag to show whether dbuf is mapped or not + * @duplicated_dbuf: boolean to show whether dbuf is duplicated with a + * previous plane of the buffer. * @bytesused: number of bytes occupied by data in the plane (payload). * @length: size of this plane (NOT the payload) in bytes. The maximum * valid size is MAX_UINT - PAGE_SIZE. @@ -179,6 +181,7 @@ struct vb2_plane { void *mem_priv; struct dma_buf *dbuf; unsigned int dbuf_mapped; + bool dbuf_duplicated; unsigned int bytesused; unsigned int length; unsigned int min_length;
When multiple planes use the same dma buf, each plane will have its own dma buf attachment and mapping. It is a waste of IOVA space. This patch adds a dbuf_duplicated boolean in vb2_plane. If a plane's dbuf is the same as an existing plane, do not create another attachment and mapping. Signed-off-by: Yunke Cao <yunkec@chromium.org> --- v3 - Adjust the patch according to the previous patches to resolve conflicts. - Add comment to explain the purpose of the change. v2 - Separate out the refactor changes out to previous patches. - Fix mem_priv check. --- .../media/common/videobuf2/videobuf2-core.c | 29 ++++++++++++++++--- include/media/videobuf2-core.h | 3 ++ 2 files changed, 28 insertions(+), 4 deletions(-)