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linux-2.6/drivers/staging/android/Kconfig
Robert Love 11980c2ac4 ashmem: Anonymous shared memory subsystem
The anonymous shared memory (ashmem) subsystem provides a
Unix-y,file-based shared memory interface to user-space. It
works like anonymous memory (e.g. mmapping fd=0) except if
you share the file descriptor via the usual means, you will
share the mapping. The shared memory can be accessed via both
mmap or file I/O. The backing store is a simple shmem file.

Additionally, ashmem introduces the concept of page pinning.
Pinned pages (the default) behave like any anonymous memory.
Unpinned pages are available to the kernel for eviction during
VM pressure. When repinning the pages, the return value
instructs user-space as to any eviction. In this manner,
user-space processes may implement caching and similar
resource management that efficiently integrates with kernel
memory management.

Signed-off-by: Robert Love <rlove@google.com>

ashmem: Don't install fault handler for private mmaps.

Ashmem is used to create named private heaps. If this heap is backed
by a tmpfs file it will allocate two pages for every page touched.
In 2.6.27, the extra page would later be freed, but 2.6.29 does not
scan anonymous pages when running without swap so the memory is not
freed while the file is referenced. This change changes the behavior
of private ashmem mmaps to match /dev/zero instead tmpfs.

Signed-off-by: Arve Hjønnevåg <arve@android.com>

ashmem: Add common prefix to name reported in /proc/pid/maps

Signed-off-by: Arve Hjønnevåg <arve@android.com>

ashmem: don't require a page aligned size

This makes ashmem more similar to shmem and mmap, by
not requiring the specified size to be page aligned,
instead rounding it internally as needed.

Signed-off-by: Marco Nelissen <marcone@android.com>
[jstultz: Improved commit subject and included patch description
from rlove. Also moved ashmem files to staging dir, and reworked
code to avoid touching mm/shmem.c while we're in staging.]
CC: Brian Swetland <swetland@google.com>
CC: Colin Cross <ccross@android.com>
CC: Arve Hjønnevåg <arve@android.com>
CC: Dima Zavin <dima@android.com>
CC: Robert Love <rlove@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-12-21 13:38:28 -08:00

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menu "Android"
config ANDROID
bool "Android Drivers"
default N
---help---
Enable support for various drivers needed on the Android platform
if ANDROID
config ANDROID_BINDER_IPC
bool "Android Binder IPC Driver"
default n
config ASHMEM
bool "Enable the Anonymous Shared Memory Subsystem"
default n
depends on SHMEM || TINY_SHMEM
help
The ashmem subsystem is a new shared memory allocator, similar to
POSIX SHM but with different behavior and sporting a simpler
file-based API.
config ANDROID_LOGGER
tristate "Android log driver"
default n
config ANDROID_RAM_CONSOLE
bool "Android RAM buffer console"
default n
config ANDROID_RAM_CONSOLE_ENABLE_VERBOSE
bool "Enable verbose console messages on Android RAM console"
default y
depends on ANDROID_RAM_CONSOLE
menuconfig ANDROID_RAM_CONSOLE_ERROR_CORRECTION
bool "Android RAM Console Enable error correction"
default n
depends on ANDROID_RAM_CONSOLE
depends on !ANDROID_RAM_CONSOLE_EARLY_INIT
select REED_SOLOMON
select REED_SOLOMON_ENC8
select REED_SOLOMON_DEC8
if ANDROID_RAM_CONSOLE_ERROR_CORRECTION
config ANDROID_RAM_CONSOLE_ERROR_CORRECTION_DATA_SIZE
int "Android RAM Console Data data size"
default 128
help
Must be a power of 2.
config ANDROID_RAM_CONSOLE_ERROR_CORRECTION_ECC_SIZE
int "Android RAM Console ECC size"
default 16
config ANDROID_RAM_CONSOLE_ERROR_CORRECTION_SYMBOL_SIZE
int "Android RAM Console Symbol size"
default 8
config ANDROID_RAM_CONSOLE_ERROR_CORRECTION_POLYNOMIAL
hex "Android RAM Console Polynomial"
default 0x19 if (ANDROID_RAM_CONSOLE_ERROR_CORRECTION_SYMBOL_SIZE = 4)
default 0x29 if (ANDROID_RAM_CONSOLE_ERROR_CORRECTION_SYMBOL_SIZE = 5)
default 0x61 if (ANDROID_RAM_CONSOLE_ERROR_CORRECTION_SYMBOL_SIZE = 6)
default 0x89 if (ANDROID_RAM_CONSOLE_ERROR_CORRECTION_SYMBOL_SIZE = 7)
default 0x11d if (ANDROID_RAM_CONSOLE_ERROR_CORRECTION_SYMBOL_SIZE = 8)
endif # ANDROID_RAM_CONSOLE_ERROR_CORRECTION
config ANDROID_RAM_CONSOLE_EARLY_INIT
bool "Start Android RAM console early"
default n
depends on ANDROID_RAM_CONSOLE
config ANDROID_RAM_CONSOLE_EARLY_ADDR
hex "Android RAM console virtual address"
default 0
depends on ANDROID_RAM_CONSOLE_EARLY_INIT
config ANDROID_RAM_CONSOLE_EARLY_SIZE
hex "Android RAM console buffer size"
default 0
depends on ANDROID_RAM_CONSOLE_EARLY_INIT
config ANDROID_TIMED_OUTPUT
bool "Timed output class driver"
default y
config ANDROID_TIMED_GPIO
tristate "Android timed gpio driver"
depends on GENERIC_GPIO && ANDROID_TIMED_OUTPUT
default n
config ANDROID_LOW_MEMORY_KILLER
bool "Android Low Memory Killer"
default N
---help---
Register processes to be killed when memory is low
config ANDROID_PMEM
bool "Android pmem allocator"
depends on ARM
source "drivers/staging/android/switch/Kconfig"
endif # if ANDROID
endmenu