Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

cma: make default CMA area size zero for x86

Browse source 
This makes CMA memory area size zero for x86 in default configuration
(doesn't change on the other architectures).  If default CMA size is
zero, DMA_CMA is disabled.  It can be enabled by passing cma= to the
kernel.

This makes less impact on x86.  Because there is no mainline driver that
requires it for x86, and Peter Hurley reported the performance
regression, as this is trying to drive _all_ dma mapping allocations
through a _very_ small window.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Reported-by: Peter Hurley <peter@hurleysoftware.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Chuck Ebbert <cebbert.lkml@gmail.com>
Cc: Jean Delvare <jdelvare@suse.de>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Akinobu Mita 2014-12-10 15:43:14 -08:00 committed by Linus Torvalds
parent c05543293e
commit d7be003a9d
1 changed files with 7 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

8
drivers/base/Kconfig
View file

@ -267,18 +267,24 @@ comment "Default contiguous memory area size:"
config CMA_SIZE_MBYTES config CMA_SIZE_MBYTES
int "Size in Mega Bytes" int "Size in Mega Bytes"
depends on !CMA_SIZE_SEL_PERCENTAGE depends on !CMA_SIZE_SEL_PERCENTAGE
default 0 if X86
default 16 default 16
help help
Defines the size (in MiB) of the default memory area for Contiguous Defines the size (in MiB) of the default memory area for Contiguous
Memory Allocator. Memory Allocator. If the size of 0 is selected, CMA is disabled by
default, but it can be enabled by passing cma=size[MG] to the kernel.
config CMA_SIZE_PERCENTAGE config CMA_SIZE_PERCENTAGE
int "Percentage of total memory" int "Percentage of total memory"
depends on !CMA_SIZE_SEL_MBYTES depends on !CMA_SIZE_SEL_MBYTES
default 0 if X86
default 10 default 10
help help
Defines the size of the default memory area for Contiguous Memory Defines the size of the default memory area for Contiguous Memory
Allocator as a percentage of the total memory in the system. Allocator as a percentage of the total memory in the system.
If 0 percent is selected, CMA is disabled by default, but it can be
enabled by passing cma=size[MG] to the kernel.
choice choice
prompt "Selected region size" prompt "Selected region size"