Thread (12 messages) 12 messages, 4 authors, 2020-08-21

Re: [PATCH v7 1/3] dma-contiguous: provide the ability to reserve per-numa CMA

From: Randy Dunlap <hidden>
Date: 2020-08-21 16:09:00
Also in: linux-iommu, lkml

On 8/21/20 4:33 AM, Barry Song wrote:
quoted hunk ↗ jump to hunk
---
 -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 ++++++++++++++++--
 4 files changed, 118 insertions(+), 10 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
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.

 	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


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