-----Original Message-----
From: Randy Dunlap [mailto:rdunlap@infradead.org]
Sent: Saturday, August 22, 2020 4:08 AM
To: Song Bao Hua (Barry Song) <redacted>; hch@lst.de;
m.szyprowski@samsung.com; robin.murphy@arm.com; will@kernel.org;
ganapatrao.kulkarni@cavium.com; catalin.marinas@arm.com;
akpm@linux-foundation.org
Cc: iommu@lists.linux-foundation.org; linux-arm-kernel@lists.infradead.org;
linux-kernel@vger.kernel.org; Zengtao (B) [off-list ref];
huangdaode [off-list ref]; Linuxarm [off-list ref];
Jonathan Cameron [off-list ref]; Nicolas Saenz Julienne
[off-list ref]; Steve Capper [off-list ref]; Mike
Rapoport [off-list ref]
Subject: Re: [PATCH v7 1/3] dma-contiguous: provide the ability to reserve
per-numa CMA

On 8/21/20 4:33 AM, Barry Song wrote:

quoted

---
 -v7: with respect to Will's comments
 * move to use for_each_online_node
 * add description if users don't specify pernuma_cma
 * provide default value for CONFIG_DMA_PERNUMA_CMA

 .../admin-guide/kernel-parameters.txt         |  11 ++
 include/linux/dma-contiguous.h                |   6 ++
 kernel/dma/Kconfig                            |  11 ++
 kernel/dma/contiguous.c                       | 100

++++++++++++++++--

quoted

 4 files changed, 118 insertions(+), 10 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt

b/Documentation/admin-guide/kernel-parameters.txt

quoted

index bdc1f33fd3d1..c609527fc35a 100644

--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt

@@ -599,6 +599,17 @@
 			altogether. For more information, see
 			include/linux/dma-contiguous.h

+	pernuma_cma=nn[MG]
+			[ARM64,KNL]
+			Sets the size of kernel per-numa memory area for
+			contiguous memory allocations. A value of 0 disables
+			per-numa CMA altogether. And If this option is not
+			specificed, the default value is 0.
+			With per-numa CMA enabled, DMA users on node nid will
+			first try to allocate buffer from the pernuma area
+			which is located in node nid, if the allocation fails,
+			they will fallback to the global default memory area.
+

Entries in kernel-parameters.txt are supposed to be in alphabetical order
but this one is not.  If you want to keep it near the cma= entry, you can
rename it like Mike suggested.  Otherwise it needs to be moved.

As I've replied in Mike's comment, I'd like to rename it to cma_per...

quoted

 	cmo_free_hint=	[PPC] Format: { yes | no }
 			Specify whether pages are marked as being inactive
 			when they are freed.  This is used in CMO environments

--
~Randy

Thanks
Barry

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