Thread (35 messages) 35 messages, 8 authors, 2020-10-16

Re: [PATCH v3 8/8] mm: Update DMA zones description

From: Christoph Hellwig <hch@lst.de>
Date: 2020-10-15 05:40:30
Also in: linux-arm-kernel, linux-iommu, linux-mm, lkml

On Wed, Oct 14, 2020 at 09:12:10PM +0200, Nicolas Saenz Julienne wrote:
quoted hunk ↗ jump to hunk
The default behavior for arm64 changed, so reflect that.

Signed-off-by: Nicolas Saenz Julienne <redacted>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
---
 include/linux/mmzone.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index fb3bf696c05e..4ee2306351b9 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -363,8 +363,9 @@ enum zone_type {
 	 *  - arm only uses ZONE_DMA, the size, up to 4G, may vary depending on
 	 *    the specific device.
 	 *
-	 *  - arm64 has a fixed 1G ZONE_DMA and ZONE_DMA32 for the rest of the
-	 *    lower 4G.
+	 *  - arm64 uses a single 4GB ZONE_DMA, except on the Raspberry Pi 4,
+	 *    in which ZONE_DMA covers the first GB and ZONE_DMA32 the rest of
+	 *    the lower 4GB.
Honestly I think this comment just needs to go away.  We can't really list
every setup in a comment in common code.
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