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 $some_pid > /containers/0/tasks to get status of the freezer subsystem : # cat /containers/0/freezer.state RUNNING to freeze all tasks in the container : # echo FROZEN > /containers/0/freezer.state # cat /containers/0/freezer.state FREEZING # cat /containers/0/freezer.state FROZEN to unfreeze all tasks in the container : # echo RUNNING > /containers/0/freezer.state # cat /containers/0/freezer.state RUNNING This is the basic mechanism which should do the right thing for user space task in a simple scenario. It's important to note that freezing can be incomplete. In that case we return EBUSY. This means that some tasks in the cgroup are busy doing something that prevents us from completely freezing the cgroup at this time. After EBUSY, the cgroup will remain partially frozen -- reflected by freezer.state reporting "FREEZING" when read. The state will remain "FREEZING" until one of these things happens: 1) Userspace cancels the freezing operation by writing "RUNNING" to the freezer.state file 2) Userspace retries the freezing operation by writing "FROZEN" to the freezer.state file (writing "FREEZING" is not legal and returns EIO) 3) The tasks that blocked the cgroup from entering the "FROZEN" state disappear from the cgroup's set of tasks. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: export thaw_process] Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Acked-by: Serge E. Hallyn <serue@us.ibm.com> Tested-by: Matt Helsley <matthltc@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
272 lines
6.6 KiB
Plaintext
272 lines
6.6 KiB
Plaintext
config DEFCONFIG_LIST
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string
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option defconfig_list
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default "arch/$ARCH/defconfig"
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# UML uses the generic IRQ subsystem
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config GENERIC_HARDIRQS
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bool
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default y
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config UML
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bool
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default y
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config MMU
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bool
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default y
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config NO_IOMEM
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def_bool y
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mainmenu "Linux/Usermode Kernel Configuration"
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config ISA
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bool
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config SBUS
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bool
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config PCI
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bool
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config PCMCIA
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bool
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# Yet to do!
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config TRACE_IRQFLAGS_SUPPORT
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bool
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default n
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config LOCKDEP_SUPPORT
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bool
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default y
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config STACKTRACE_SUPPORT
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bool
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default n
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config GENERIC_CALIBRATE_DELAY
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bool
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default y
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config GENERIC_BUG
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bool
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default y
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depends on BUG
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config GENERIC_TIME
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bool
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default y
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config GENERIC_CLOCKEVENTS
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bool
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default y
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# Used in kernel/irq/manage.c and include/linux/irq.h
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config IRQ_RELEASE_METHOD
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bool
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default y
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config HZ
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int
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default 100
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menu "UML-specific options"
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config STATIC_LINK
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bool "Force a static link"
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default n
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help
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This option gives you the ability to force a static link of UML.
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Normally, UML is linked as a shared binary. This is inconvenient for
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use in a chroot jail. So, if you intend to run UML inside a chroot,
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you probably want to say Y here.
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Additionally, this option enables using higher memory spaces (up to
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2.75G) for UML.
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source "arch/um/Kconfig.arch"
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source "mm/Kconfig"
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source "kernel/time/Kconfig"
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config LD_SCRIPT_STATIC
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bool
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default y
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depends on STATIC_LINK
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config LD_SCRIPT_DYN
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bool
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default y
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depends on !LD_SCRIPT_STATIC
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source "fs/Kconfig.binfmt"
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config HOSTFS
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tristate "Host filesystem"
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help
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While the User-Mode Linux port uses its own root file system for
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booting and normal file access, this module lets the UML user
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access files stored on the host. It does not require any
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network connection between the Host and UML. An example use of
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this might be:
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mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
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where /tmp/fromhost is an empty directory inside UML and
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/tmp/umlshare is a directory on the host with files the UML user
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wishes to access.
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For more information, see
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<http://user-mode-linux.sourceforge.net/hostfs.html>.
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If you'd like to be able to work with files stored on the host,
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say Y or M here; otherwise say N.
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config HPPFS
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tristate "HoneyPot ProcFS (EXPERIMENTAL)"
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depends on EXPERIMENTAL
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help
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hppfs (HoneyPot ProcFS) is a filesystem which allows UML /proc
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entries to be overridden, removed, or fabricated from the host.
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Its purpose is to allow a UML to appear to be a physical machine
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by removing or changing anything in /proc which gives away the
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identity of a UML.
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See <http://user-mode-linux.sf.net/old/hppfs.html> for more information.
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You only need this if you are setting up a UML honeypot. Otherwise,
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it is safe to say 'N' here.
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config MCONSOLE
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bool "Management console"
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default y
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help
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The user mode linux management console is a low-level interface to
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the kernel, somewhat like the i386 SysRq interface. Since there is
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a full-blown operating system running under every user mode linux
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instance, there is much greater flexibility possible than with the
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SysRq mechanism.
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If you answer 'Y' to this option, to use this feature, you need the
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mconsole client (called uml_mconsole) which is present in CVS in
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2.4.5-9um and later (path /tools/mconsole), and is also in the
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distribution RPM package in 2.4.6 and later.
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It is safe to say 'Y' here.
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config MAGIC_SYSRQ
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bool "Magic SysRq key"
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depends on MCONSOLE
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help
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If you say Y here, you will have some control over the system even
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if the system crashes for example during kernel debugging (e.g., you
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will be able to flush the buffer cache to disk, reboot the system
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immediately or dump some status information). A key for each of the
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possible requests is provided.
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This is the feature normally accomplished by pressing a key
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while holding SysRq (Alt+PrintScreen).
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On UML, this is accomplished by sending a "sysrq" command with
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mconsole, followed by the letter for the requested command.
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The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
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unless you really know what this hack does.
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config SMP
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bool "Symmetric multi-processing support (EXPERIMENTAL)"
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default n
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depends on BROKEN
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help
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This option enables UML SMP support.
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It is NOT related to having a real SMP box. Not directly, at least.
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UML implements virtual SMP by allowing as many processes to run
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simultaneously on the host as there are virtual processors configured.
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Obviously, if the host is a uniprocessor, those processes will
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timeshare, but, inside UML, will appear to be running simultaneously.
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If the host is a multiprocessor, then UML processes may run
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simultaneously, depending on the host scheduler.
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This, however, is supported only in TT mode. So, if you use the SKAS
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patch on your host, switching to TT mode and enabling SMP usually
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gives you worse performances.
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Also, since the support for SMP has been under-developed, there could
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be some bugs being exposed by enabling SMP.
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If you don't know what to do, say N.
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config NR_CPUS
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int "Maximum number of CPUs (2-32)"
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range 2 32
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depends on SMP
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default "32"
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config HIGHMEM
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bool "Highmem support (EXPERIMENTAL)"
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depends on !64BIT && EXPERIMENTAL
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default n
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help
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This was used to allow UML to run with big amounts of memory.
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Currently it is unstable, so if unsure say N.
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To use big amounts of memory, it is recommended enable static
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linking (i.e. CONFIG_STATIC_LINK) - this should allow the
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guest to use up to 2.75G of memory.
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config KERNEL_STACK_ORDER
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int "Kernel stack size order"
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default 1 if 64BIT
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range 1 10 if 64BIT
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default 0 if !64BIT
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help
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This option determines the size of UML kernel stacks. They will
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be 1 << order pages. The default is OK unless you're running Valgrind
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on UML, in which case, set this to 3.
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endmenu
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source "init/Kconfig"
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source "kernel/Kconfig.freezer"
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source "drivers/block/Kconfig"
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source "arch/um/Kconfig.char"
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source "drivers/base/Kconfig"
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source "net/Kconfig"
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source "arch/um/Kconfig.net"
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source "drivers/net/Kconfig"
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source "drivers/connector/Kconfig"
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source "fs/Kconfig"
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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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source "drivers/scsi/Kconfig"
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source "drivers/md/Kconfig"
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if BROKEN
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source "drivers/mtd/Kconfig"
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endif
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source "drivers/leds/Kconfig"
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#This is just to shut up some Kconfig warnings, so no prompt.
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config INPUT
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bool
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default n
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source "arch/um/Kconfig.debug"
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