[PATCH 1/9] s5p-mfc: Set DMA_ATTR_ALLOC_SINGLE_PAGES

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Douglas Anderson <dianders@xxxxxxxxxxxx>

We do video allocation all the time and we need it to be fast.  Plus TLB
efficiency isn't terribly important for video.

That means we want to set DMA_ATTR_ALLOC_SINGLE_PAGES.

See also the previous change (commit 14d3ae2efeed "ARM: dma-mapping: Use
DMA_ATTR_ALLOC_SINGLE_PAGES hint to optimize allocation").

Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
[mszyprow: rebased patch onto v4.9-rc1 and adapted changes to latest videbuf2
 changes, this simplifies code changes to only set proper dma attribute flag
 and comment the reason for it, added commit id of arch/arm/mm patch]
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
 drivers/media/platform/s5p-mfc/s5p_mfc.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc.c b/drivers/media/platform/s5p-mfc/s5p_mfc.c
index 27b375e75555..a0a29194ccd1 100644
--- a/drivers/media/platform/s5p-mfc/s5p_mfc.c
+++ b/drivers/media/platform/s5p-mfc/s5p_mfc.c
@@ -851,6 +851,11 @@ static int s5p_mfc_open(struct file *file)
 		ret = -ENOENT;
 		goto err_queue_init;
 	}
+	/*
+	 * We'll do mostly sequential access, so sacrifice TLB efficiency for
+	 * faster allocation.
+	 */
+	q->dma_attrs = DMA_ATTR_ALLOC_SINGLE_PAGES;
 	q->mem_ops = &vb2_dma_contig_memops;
 	q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
 	ret = vb2_queue_init(q);
@@ -881,6 +886,12 @@ static int s5p_mfc_open(struct file *file)
 	 * will keep the value of bytesused intact.
 	 */
 	q->allow_zero_bytesused = 1;
+
+	/*
+	 * We'll do mostly sequential access, so sacrifice TLB efficiency for
+	 * faster allocation.
+	 */
+	q->dma_attrs = DMA_ATTR_ALLOC_SINGLE_PAGES;
 	q->mem_ops = &vb2_dma_contig_memops;
 	q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
 	ret = vb2_queue_init(q);
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Linux SoC Development]     [Linux Rockchip Development]     [Linux USB Development]     [Video for Linux]     [Linux Audio Users]     [Linux SCSI]     [Yosemite News]

  Powered by Linux