Messages in this thread | | | Date | Mon, 22 Apr 2013 09:58:12 -0700 | From | Randy Dunlap <> | Subject | Re: [PATCH] mm: add an option to disable bounce |
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On 04/22/13 08:23, vinayakm.list@gmail.com wrote: > From: Vinayak Menon <vinayakm.list@gmail.com> > > 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@gmail.com> > --- > 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) > + help > + Enable bounce buffers for devices that cannot access > + the full range of memory available to the CPU. Enabled > + by default when ZONE_DMA or HIGMEM is selected, but you
HIGHMEM
> + may say n to override this. > > # On the 'tile' arch, USB OHCI needs the bounce pool since tilegx will often > # have more than 4GB of memory, but we don't currently use the IOTLB to present >
-- ~Randy
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