Commit 053a96ca authored by Nicolas Pitre's avatar Nicolas Pitre

[ARM] add CONFIG_HIGHMEM option

Here it is... HIGHMEM for the ARM architecture.  :-)

If you don't have enough ram for highmem pages to be allocated and still
want to test this, then the cmdline option "vmalloc=" can be used with
a value large enough to force the highmem threshold down.

Successfully tested on a Marvell DB-78x00-BP Development Board with
2 GB of RAM.
Signed-off-by: default avatarNicolas Pitre <nico@marvell.com>
parent 3f973e22
......@@ -915,6 +915,23 @@ config NODES_SHIFT
default "2"
depends on NEED_MULTIPLE_NODES
config HIGHMEM
bool "High Memory Support (EXPERIMENTAL)"
depends on MMU && EXPERIMENTAL
help
The address space of ARM processors is only 4 Gigabytes large
and it has to accommodate user address space, kernel address
space as well as some memory mapped IO. That means that, if you
have a large amount of physical memory and/or IO, not all of the
memory can be "permanently mapped" by the kernel. The physical
memory that is not permanently mapped is called "high memory".
Depending on the selected kernel/user memory split, minimum
vmalloc space and actual amount of RAM, you may not need this
option which should result in a slightly faster kernel.
If unsure, say n.
source "mm/Kconfig"
config LEDS
......
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