* [PATCH] cma: decrease CMA_ALIGNMENT lower limit to 2
@ 2020-09-30 10:28 Paul Cercueil
2020-10-05 13:04 ` Christoph Hellwig
0 siblings, 1 reply; 2+ messages in thread
From: Paul Cercueil @ 2020-09-30 10:28 UTC (permalink / raw)
To: Christoph Hellwig, Marek Szyprowski, Robin Murphy
Cc: Paul Cercueil, iommu, od, linux-kernel
On an embedded system with a tiny (1 MiB) CMA area for video memory, and
a simple enough video pipeline, we can decrease the CMA_ALIGNMENT by a
factor of 2 to avoid wasting memory, as all the allocations for video
buffers will be of the exact same size (dictated by the size of the
screen).
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---
kernel/dma/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig
index 847a9d1fa634..f15e782e19ca 100644
--- a/kernel/dma/Kconfig
+++ b/kernel/dma/Kconfig
@@ -162,7 +162,7 @@ endchoice
config CMA_ALIGNMENT
int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
- range 4 12
+ range 2 12
default 8
help
DMA mapping framework by default aligns all buffers to the smallest
--
2.28.0
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* Re: [PATCH] cma: decrease CMA_ALIGNMENT lower limit to 2
2020-09-30 10:28 [PATCH] cma: decrease CMA_ALIGNMENT lower limit to 2 Paul Cercueil
@ 2020-10-05 13:04 ` Christoph Hellwig
0 siblings, 0 replies; 2+ messages in thread
From: Christoph Hellwig @ 2020-10-05 13:04 UTC (permalink / raw)
To: Paul Cercueil; +Cc: linux-kernel, iommu, od, Robin Murphy, Christoph Hellwig
Thanks,
applied to dma-mapping for-next.
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