diff options
| author | Vinayak Menon | 2013-04-29 15:08:55 -0700 |
|---|---|---|
| committer | Linus Torvalds | 2013-04-29 15:54:40 -0700 |
| commit | 9ca24e2e19325edc3ed0b437657d26219b7a768a (patch) | |
| tree | f77c807f879d8a23ababae31a9006a204d0a204a | |
| parent | b476e2951fcf7a25574b7b193944b041687f3ed4 (diff) | |
mmKconfig: add an option to disable bounce
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>
Cc: David Rientjes <rientjes@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/Kconfig | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/mm/Kconfig b/mm/Kconfig index 3bea74f1ccfe..e742d06285b7 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -263,8 +263,14 @@ config ZONE_DMA_FLAG default "1" config BOUNCE - def_bool y + bool "Enable bounce buffers" + default 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 HIGHMEM is selected, but you + 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 |