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authorMarek Szyprowski <m.szyprowski@samsung.com>2011-12-29 13:09:51 +0100
committerMarek Szyprowski <m.szyprowski@samsung.com>2012-05-21 15:09:37 +0200
commitc64be2bb1c6eb43c838b2c6d57b074078be208dd (patch)
treed0720eda4a440ff91f3296b0f90cc53ac514d4b9 /Documentation/kernel-parameters.txt
parent49f223a9cd96c7293d7258ff88c2bdf83065f69c (diff)
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drivers: add Contiguous Memory Allocator
The Contiguous Memory Allocator is a set of helper functions for DMA mapping framework that improves allocations of contiguous memory chunks. CMA grabs memory on system boot, marks it with MIGRATE_CMA migrate type and gives back to the system. Kernel is allowed to allocate only movable pages within CMA's managed memory so that it can be used for example for page cache when DMA mapping do not use it. On dma_alloc_from_contiguous() request such pages are migrated out of CMA area to free required contiguous block and fulfill the request. This allows to allocate large contiguous chunks of memory at any time assuming that there is enough free memory available in the system. This code is heavily based on earlier works by Michal Nazarewicz. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Tested-by: Rob Clark <rob.clark@linaro.org> Tested-by: Ohad Ben-Cohen <ohad@wizery.com> Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> Tested-by: Robert Nelson <robertcnelson@gmail.com> Tested-by: Barry Song <Baohua.Song@csr.com>
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diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index c1601e5..669e8bb 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -508,6 +508,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
Also note the kernel might malfunction if you disable
some critical bits.
+ cma=nn[MG] [ARM,KNL]
+ Sets the size of kernel global memory area for contiguous
+ memory allocations. For more information, see
+ include/linux/dma-contiguous.h
+
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
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