linux-kernel - [PATCH v6 5/5] s5p-mfc: Set DMA_ATTR_ALLOC_SINGLE

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Message-Id: <1452533428-12762-6-git-send-email-dianders@chromium.org>
Date:	Mon, 11 Jan 2016 09:30:27 -0800
From:	Douglas Anderson <dianders@...omium.org>
To:	linux@....linux.org.uk, mchehab@....samsung.com,
	robin.murphy@....com, tfiga@...omium.org, m.szyprowski@...sung.com
Cc:	pawel@...iak.com, Dmitry Torokhov <dmitry.torokhov@...il.com>,
	hch@...radead.org, Douglas Anderson <dianders@...omium.org>,
	kyungmin.park@...sung.com, k.debski@...sung.com,
	jtp.park@...sung.com, linux-arm-kernel@...ts.infradead.org,
	linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v6 5/5] s5p-mfc: Set DMA_ATTR_ALLOC_SINGLE_PAGES

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 ("ARM: dma-mapping: Use
DMA_ATTR_ALLOC_SINGLE_PAGES hint to optimize allocation").

Signed-off-by: Douglas Anderson <dianders@...omium.org>
---
Changes in v6:
- renamed DMA_ATTR_NO_HUGE_PAGE to DMA_ATTR_ALLOC_SINGLE_PAGES

Changes in v5:
- s5p-mfc patch new for v5

Changes in v4: None
Changes in v3: None
Changes in v2: None

 drivers/media/platform/s5p-mfc/s5p_mfc.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc.c b/drivers/media/platform/s5p-mfc/s5p_mfc.c
index 927ab4928779..421d25a1aec1 100644
--- a/drivers/media/platform/s5p-mfc/s5p_mfc.c
+++ b/drivers/media/platform/s5p-mfc/s5p_mfc.c
@@ -1095,6 +1095,7 @@ static int s5p_mfc_alloc_memdevs(struct s5p_mfc_dev *dev)
 /* MFC probe function */
 static int s5p_mfc_probe(struct platform_device *pdev)
 {
+	DEFINE_DMA_ATTRS(attrs);
 	struct s5p_mfc_dev *dev;
 	struct video_device *vfd;
 	struct resource *res;
@@ -1164,12 +1165,20 @@ static int s5p_mfc_probe(struct platform_device *pdev)
 		}
 	}
 
-	dev->alloc_ctx[0] = vb2_dma_contig_init_ctx(dev->mem_dev_l);
+	/*
+	 * We'll do mostly sequential access, so sacrifice TLB efficiency for
+	 * faster allocation.
+	 */
+	dma_set_attr(DMA_ATTR_ALLOC_SINGLE_PAGES, &attrs);
+
+	dev->alloc_ctx[0] = vb2_dma_contig_init_ctx_attrs(dev->mem_dev_l,
+							  &attrs);
 	if (IS_ERR(dev->alloc_ctx[0])) {
 		ret = PTR_ERR(dev->alloc_ctx[0]);
 		goto err_res;
 	}
-	dev->alloc_ctx[1] = vb2_dma_contig_init_ctx(dev->mem_dev_r);
+	dev->alloc_ctx[1] = vb2_dma_contig_init_ctx_attrs(dev->mem_dev_r,
+							  &attrs);
 	if (IS_ERR(dev->alloc_ctx[1])) {
 		ret = PTR_ERR(dev->alloc_ctx[1]);
 		goto err_mem_init_ctx_1;
-- 
2.6.0.rc2.230.g3dd15c0