dc52ddc0e6
This patch implements a new freezer subsystem in the control groups framework. It provides a way to stop and resume execution of all tasks in a cgroup by writing in the cgroup filesystem. The freezer subsystem in the container filesystem defines a file named freezer.state. Writing "FROZEN" to the state file will freeze all tasks in the cgroup. Subsequently writing "RUNNING" will unfreeze the tasks in the cgroup. Reading will return the current state. * Examples of usage : # mkdir /containers/freezer # mount -t cgroup -ofreezer freezer /containers # mkdir /containers/0 # echo $some_pid > /containers/0/tasks to get status of the freezer subsystem : # cat /containers/0/freezer.state RUNNING to freeze all tasks in the container : # echo FROZEN > /containers/0/freezer.state # cat /containers/0/freezer.state FREEZING # cat /containers/0/freezer.state FROZEN to unfreeze all tasks in the container : # echo RUNNING > /containers/0/freezer.state # cat /containers/0/freezer.state RUNNING This is the basic mechanism which should do the right thing for user space task in a simple scenario. It's important to note that freezing can be incomplete. In that case we return EBUSY. This means that some tasks in the cgroup are busy doing something that prevents us from completely freezing the cgroup at this time. After EBUSY, the cgroup will remain partially frozen -- reflected by freezer.state reporting "FREEZING" when read. The state will remain "FREEZING" until one of these things happens: 1) Userspace cancels the freezing operation by writing "RUNNING" to the freezer.state file 2) Userspace retries the freezing operation by writing "FROZEN" to the freezer.state file (writing "FREEZING" is not legal and returns EIO) 3) The tasks that blocked the cgroup from entering the "FROZEN" state disappear from the cgroup's set of tasks. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: export thaw_process] Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Acked-by: Serge E. Hallyn <serue@us.ibm.com> Tested-by: Matt Helsley <matthltc@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
264 lines
6.5 KiB
Plaintext
264 lines
6.5 KiB
Plaintext
# For a description of the syntax of this configuration file,
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# see Documentation/kbuild/kconfig-language.txt.
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mainmenu "Linux/Xtensa Kernel Configuration"
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config FRAME_POINTER
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bool
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default n
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config ZONE_DMA
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bool
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default y
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config XTENSA
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bool
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default y
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select HAVE_IDE
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help
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Xtensa processors are 32-bit RISC machines designed by Tensilica
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primarily for embedded systems. These processors are both
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configurable and extensible. The Linux port to the Xtensa
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architecture supports all processor configurations and extensions,
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with reasonable minimum requirements. The Xtensa Linux project has
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a home page at <http://xtensa.sourceforge.net/>.
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config RWSEM_XCHGADD_ALGORITHM
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bool
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default y
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config GENERIC_FIND_NEXT_BIT
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bool
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default y
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config GENERIC_HWEIGHT
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bool
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default y
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config GENERIC_HARDIRQS
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bool
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default y
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config ARCH_HAS_ILOG2_U32
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bool
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default n
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config ARCH_HAS_ILOG2_U64
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bool
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default n
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config NO_IOPORT
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def_bool y
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config HZ
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int
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default 100
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source "init/Kconfig"
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source "kernel/Kconfig.freezer"
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menu "Processor type and features"
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choice
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prompt "Xtensa Processor Configuration"
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default XTENSA_VARIANT_FSF
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config XTENSA_VARIANT_FSF
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bool "fsf"
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endchoice
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config MMU
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bool
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default y
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config XTENSA_UNALIGNED_USER
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bool "Unaligned memory access in use space"
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---help---
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The Xtensa architecture currently does not handle unaligned
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memory accesses in hardware but through an exception handler.
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Per default, unaligned memory accesses are disabled in user space.
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Say Y here to enable unaligned memory access in user space.
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config PREEMPT
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bool "Preemptible Kernel"
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---help---
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This option reduces the latency of the kernel when reacting to
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real-time or interactive events by allowing a low priority process to
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be preempted even if it is in kernel mode executing a system call.
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Unfortunately the kernel code has some race conditions if both
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CONFIG_SMP and CONFIG_PREEMPT are enabled, so this option is
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currently disabled if you are building an SMP kernel.
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Say Y here if you are building a kernel for a desktop, embedded
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or real-time system. Say N if you are unsure.
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config MATH_EMULATION
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bool "Math emulation"
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help
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Can we use information of configuration file?
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config HIGHMEM
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bool "High memory support"
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endmenu
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menu "Platform options"
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choice
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prompt "Xtensa System Type"
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default XTENSA_PLATFORM_ISS
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config XTENSA_PLATFORM_ISS
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bool "ISS"
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help
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ISS is an acronym for Tensilica's Instruction Set Simulator.
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config XTENSA_PLATFORM_XT2000
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bool "XT2000"
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help
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XT2000 is the name of Tensilica's feature-rich emulation platform.
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This hardware is capable of running a full Linux distribution.
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endchoice
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config XTENSA_CALIBRATE_CCOUNT
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bool "Auto calibration of the CPU clock rate"
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---help---
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On some platforms (XT2000, for example), the CPU clock rate can
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vary. The frequency can be determined, however, by measuring
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against a well known, fixed frequency, such as an UART oscillator.
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config XTENSA_CPU_CLOCK
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int "CPU clock rate [MHz]"
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depends on !XTENSA_CALIBRATE_CCOUNT
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default "16"
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config GENERIC_CALIBRATE_DELAY
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bool "Auto calibration of the BogoMIPS value"
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---help---
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The BogoMIPS value can easily be derived from the CPU frequency.
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config CMDLINE_BOOL
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bool "Default bootloader kernel arguments"
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config CMDLINE
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string "Initial kernel command string"
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depends on CMDLINE_BOOL
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default "console=ttyS0,38400 root=/dev/ram"
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help
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On some architectures (EBSA110 and CATS), there is currently no way
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for the boot loader to pass arguments to the kernel. For these
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architectures, you should supply some command-line options at build
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time by entering them here. As a minimum, you should specify the
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memory size and the root device (e.g., mem=64M root=/dev/nfs).
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config SERIAL_CONSOLE
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bool
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depends on XTENSA_PLATFORM_ISS
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default y
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config XTENSA_ISS_NETWORK
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bool
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depends on XTENSA_PLATFORM_ISS
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default y
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source "mm/Kconfig"
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endmenu
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menu "Bus options"
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config PCI
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bool "PCI support" if !XTENSA_PLATFORM_ISS
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depends on !XTENSA_PLATFORM_ISS
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default y
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help
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Find out whether you have a PCI motherboard. PCI is the name of a
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bus system, i.e. the way the CPU talks to the other stuff inside
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your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
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VESA. If you have PCI, say Y, otherwise N.
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source "drivers/pci/Kconfig"
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config HOTPLUG
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bool "Support for hot-pluggable devices"
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---help---
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Say Y here if you want to plug devices into your computer while
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the system is running, and be able to use them quickly. In many
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cases, the devices can likewise be unplugged at any time too.
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One well known example of this is PCMCIA- or PC-cards, credit-card
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size devices such as network cards, modems or hard drives which are
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plugged into slots found on all modern laptop computers. Another
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example, used on modern desktops as well as laptops, is USB.
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Enable HOTPLUG and build a modular kernel. Get agent software
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(from <http://linux-hotplug.sourceforge.net/>) and install it.
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Then your kernel will automatically call out to a user mode "policy
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agent" (/sbin/hotplug) to load modules and set up software needed
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to use devices as you hotplug them.
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source "drivers/pcmcia/Kconfig"
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source "drivers/pci/hotplug/Kconfig"
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endmenu
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menu "Executable file formats"
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# only elf supported
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config KCORE_ELF
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bool
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depends on PROC_FS
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default y
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help
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If you enabled support for /proc file system then the file
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/proc/kcore will contain the kernel core image in ELF format. This
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can be used in gdb:
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$ cd /usr/src/linux ; gdb vmlinux /proc/kcore
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This is especially useful if you have compiled the kernel with the
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"-g" option to preserve debugging information. It is mainly used
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for examining kernel data structures on the live kernel.
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source "fs/Kconfig.binfmt"
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endmenu
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source "net/Kconfig"
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source "drivers/Kconfig"
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source "fs/Kconfig"
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menu "Xtensa initrd options"
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depends on BLK_DEV_INITRD
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config EMBEDDED_RAMDISK
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bool "Embed root filesystem ramdisk into the kernel"
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config EMBEDDED_RAMDISK_IMAGE
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string "Filename of gzipped ramdisk image"
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depends on EMBEDDED_RAMDISK
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default "ramdisk.gz"
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help
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This is the filename of the ramdisk image to be built into the
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kernel. Relative pathnames are relative to arch/xtensa/boot/ramdisk/.
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The ramdisk image is not part of the kernel distribution; you must
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provide one yourself.
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endmenu
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source "arch/xtensa/Kconfig.debug"
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source "security/Kconfig"
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source "crypto/Kconfig"
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source "lib/Kconfig"
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