On Monday 22 April 2013 11:17 PM, Russell King - ARM Linux wrote: > On Mon, Apr 22, 2013 at 08:53:00PM +0530, vinayakm.list@xxxxxxxxx wrote: >> From: Vinayak Menon <vinayakm.list@xxxxxxxxx> >> >> There are times when HIGHMEM is enabled, but >> we don't prefer CONFIG_BOUNCE to be enabled. >> CONFIG_BOUNCE can reduce the block device >> throughput, and this is not ideal for machines >> where we don't gain much by enabling it. So >> provide an option to deselect CONFIG_BOUNCE. The >> observation was made while measuring eMMC throughput >> using iozone on an ARM device with 1GB RAM. >> >> Signed-off-by: Vinayak Menon <vinayakm.list@xxxxxxxxx> >> --- >> mm/Kconfig | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git a/mm/Kconfig b/mm/Kconfig >> index 3bea74f..29f9736 100644 >> --- a/mm/Kconfig >> +++ b/mm/Kconfig >> @@ -263,8 +263,14 @@ config ZONE_DMA_FLAG >> default "1" >> >> config BOUNCE >> + bool "Enable bounce buffers" >> def_bool y >> depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM) > > I don't think this is correct. You shouldn't use "bool" with "def_bool". > Sure, add the "bool", but also change "def_bool" to "default". Yes. I will change it to "default" and this looks to be correct even from the definition in kconfig-language.txt. But I see other instances in mm/Kconfig, where bool and def_bool are used together. When I had tested this patch with def_bool, it worked as expected. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>