diff mbox

[1/9] s5p-mfc: Set DMA_ATTR_ALLOC_SINGLE_PAGES

Message ID 1479287098-30493-2-git-send-email-m.szyprowski@samsung.com
State New
Headers show

Commit Message

Marek Szyprowski Nov. 16, 2016, 9:04 a.m. UTC 
From: Douglas Anderson <dianders@chromium.org>


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@chromium.org>

[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@samsung.com>

---
 drivers/media/platform/s5p-mfc/s5p_mfc.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

-- 
1.9.1

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diff mbox

Patch

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);