default "$ARCH_DEFCONFIG"
default "arch/$ARCH/defconfig"
+config CONSTRUCTORS
+ bool
+ depends on !UML
+ default y
+
menu "General setup"
config EXPERIMENTAL
which is done within the script "scripts/setlocalversion".)
+config HAVE_KERNEL_GZIP
+ bool
+
+config HAVE_KERNEL_BZIP2
+ bool
+
+config HAVE_KERNEL_LZMA
+ bool
+
+config HAVE_KERNEL_LZO
+ bool
+
+choice
+ prompt "Kernel compression mode"
+ default KERNEL_GZIP
+ depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_LZO
+ help
+ The linux kernel is a kind of self-extracting executable.
+ Several compression algorithms are available, which differ
+ in efficiency, compression and decompression speed.
+ Compression speed is only relevant when building a kernel.
+ Decompression speed is relevant at each boot.
+
+ If you have any problems with bzip2 or lzma compressed
+ kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
+ version of this functionality (bzip2 only), for 2.4, was
+ supplied by Christian Ludwig)
+
+ High compression options are mostly useful for users, who
+ are low on disk space (embedded systems), but for whom ram
+ size matters less.
+
+ If in doubt, select 'gzip'
+
+config KERNEL_GZIP
+ bool "Gzip"
+ depends on HAVE_KERNEL_GZIP
+ help
+ The old and tried gzip compression. It provides a good balance
+ between compression ratio and decompression speed.
+
+config KERNEL_BZIP2
+ bool "Bzip2"
+ depends on HAVE_KERNEL_BZIP2
+ help
+ Its compression ratio and speed is intermediate.
+ Decompression speed is slowest among the three. The kernel
+ size is about 10% smaller with bzip2, in comparison to gzip.
+ Bzip2 uses a large amount of memory. For modern kernels you
+ will need at least 8MB RAM or more for booting.
+
+config KERNEL_LZMA
+ bool "LZMA"
+ depends on HAVE_KERNEL_LZMA
+ help
+ The most recent compression algorithm.
+ Its ratio is best, decompression speed is between the other
+ two. Compression is slowest. The kernel size is about 33%
+ smaller with LZMA in comparison to gzip.
+
+config KERNEL_LZO
+ bool "LZO"
+ depends on HAVE_KERNEL_LZO
+ help
+ Its compression ratio is the poorest among the 4. The kernel
+ size is about about 10% bigger than gzip; however its speed
+ (both compression and decompression) is the fastest.
+
+endchoice
+
config SWAP
bool "Support for paging of anonymous memory (swap)"
depends on MMU && BLOCK
If unsure, say Y.
+config POSIX_MQUEUE_SYSCTL
+ bool
+ depends on POSIX_MQUEUE
+ depends on SYSCTL
+ default y
+
config BSD_PROCESS_ACCT
bool "BSD Process Accounting"
help
config AUDITSYSCALL
bool "Enable system-call auditing support"
- depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64|| SUPERH)
+ depends on AUDIT && (X86 || PPC || S390 || IA64 || UML || SPARC64 || SUPERH)
default y if SECURITY_SELINUX
help
Enable low-overhead system-call auditing infrastructure that
config AUDIT_TREE
def_bool y
- depends on AUDITSYSCALL && INOTIFY
+ depends on AUDITSYSCALL
+ select INOTIFY
menu "RCU Subsystem"
choice
prompt "RCU Implementation"
- default CLASSIC_RCU
-
-config CLASSIC_RCU
- bool "Classic RCU"
- help
- This option selects the classic RCU implementation that is
- designed for best read-side performance on non-realtime
- systems.
-
- Select this option if you are unsure.
+ default TREE_RCU
config TREE_RCU
bool "Tree-based hierarchical RCU"
help
This option selects the RCU implementation that is
designed for very large SMP system with hundreds or
- thousands of CPUs.
+ thousands of CPUs. It also scales down nicely to
+ smaller systems.
-config PREEMPT_RCU
- bool "Preemptible RCU"
+config TREE_PREEMPT_RCU
+ bool "Preemptable tree-based hierarchical RCU"
depends on PREEMPT
help
- This option reduces the latency of the kernel by making certain
- RCU sections preemptible. Normally RCU code is non-preemptible, if
- this option is selected then read-only RCU sections become
- preemptible. This helps latency, but may expose bugs due to
- now-naive assumptions about each RCU read-side critical section
- remaining on a given CPU through its execution.
+ This option selects the RCU implementation that is
+ designed for very large SMP systems with hundreds or
+ thousands of CPUs, but for which real-time response
+ is also required. It also scales down nicely to
+ smaller systems.
+
+config TINY_RCU
+ bool "UP-only small-memory-footprint RCU"
+ depends on !SMP
+ help
+ This option selects the RCU implementation that is
+ designed for UP systems from which real-time response
+ is not required. This option greatly reduces the
+ memory footprint of RCU.
endchoice
config RCU_TRACE
bool "Enable tracing for RCU"
- depends on TREE_RCU || PREEMPT_RCU
+ depends on TREE_RCU || TREE_PREEMPT_RCU
help
This option provides tracing in RCU which presents stats
in debugfs for debugging RCU implementation.
int "Tree-based hierarchical RCU fanout value"
range 2 64 if 64BIT
range 2 32 if !64BIT
- depends on TREE_RCU
+ depends on TREE_RCU || TREE_PREEMPT_RCU
default 64 if 64BIT
default 32 if !64BIT
help
config RCU_FANOUT_EXACT
bool "Disable tree-based hierarchical RCU auto-balancing"
- depends on TREE_RCU
+ depends on TREE_RCU || TREE_PREEMPT_RCU
default n
help
This option forces use of the exact RCU_FANOUT value specified,
Say N if unsure.
-config TREE_RCU_TRACE
- def_bool RCU_TRACE && TREE_RCU
- select DEBUG_FS
+config RCU_FAST_NO_HZ
+ bool "Accelerate last non-dyntick-idle CPU's grace periods"
+ depends on TREE_RCU && NO_HZ && SMP
+ default n
help
- This option provides tracing for the TREE_RCU implementation,
- permitting Makefile to trivially select kernel/rcutree_trace.c.
+ This option causes RCU to attempt to accelerate grace periods
+ in order to allow the final CPU to enter dynticks-idle state
+ more quickly. On the other hand, this option increases the
+ overhead of the dynticks-idle checking, particularly on systems
+ with large numbers of CPUs.
+
+ Say Y if energy efficiency is critically important, particularly
+ if you have relatively few CPUs.
-config PREEMPT_RCU_TRACE
- def_bool RCU_TRACE && PREEMPT_RCU
+ Say N if you are unsure.
+
+config TREE_RCU_TRACE
+ def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
select DEBUG_FS
help
- This option provides tracing for the PREEMPT_RCU implementation,
- permitting Makefile to trivially select kernel/rcupreempt_trace.c.
+ This option provides tracing for the TREE_RCU and
+ TREE_PREEMPT_RCU implementations, permitting Makefile to
+ trivially select kernel/rcutree_trace.c.
endmenu # "RCU Subsystem"
config HAVE_UNSTABLE_SCHED_CLOCK
bool
-config GROUP_SCHED
- bool "Group CPU scheduler"
- depends on EXPERIMENTAL
- default n
- help
- This feature lets CPU scheduler recognize task groups and control CPU
- bandwidth allocation to such task groups.
- In order to create a group from arbitrary set of processes, use
- CONFIG_CGROUPS. (See Control Group support.)
-
-config FAIR_GROUP_SCHED
- bool "Group scheduling for SCHED_OTHER"
- depends on GROUP_SCHED
- default GROUP_SCHED
-
-config RT_GROUP_SCHED
- bool "Group scheduling for SCHED_RR/FIFO"
- depends on EXPERIMENTAL
- depends on GROUP_SCHED
- default n
+menuconfig CGROUPS
+ boolean "Control Group support"
+ depends on EVENTFD
help
- This feature lets you explicitly allocate real CPU bandwidth
- to users or control groups (depending on the "Basis for grouping tasks"
- setting below. If enabled, it will also make it impossible to
- schedule realtime tasks for non-root users until you allocate
- realtime bandwidth for them.
- See Documentation/scheduler/sched-rt-group.txt for more information.
-
-choice
- depends on GROUP_SCHED
- prompt "Basis for grouping tasks"
- default USER_SCHED
-
-config USER_SCHED
- bool "user id"
- help
- This option will choose userid as the basis for grouping
- tasks, thus providing equal CPU bandwidth to each user.
-
-config CGROUP_SCHED
- bool "Control groups"
- depends on CGROUPS
- help
- This option allows you to create arbitrary task groups
- using the "cgroup" pseudo filesystem and control
- the cpu bandwidth allocated to each such task group.
- Refer to Documentation/cgroups.txt for more information
- on "cgroup" pseudo filesystem.
-
-endchoice
-
-menu "Control Group support"
-config CGROUPS
- bool "Control Group support"
- help
- This option add support for grouping sets of processes together, for
+ This option adds support for grouping sets of processes together, for
use with process control subsystems such as Cpusets, CFS, memory
controls or device isolation.
See
- - Documentation/cpusets.txt (Cpusets)
- Documentation/scheduler/sched-design-CFS.txt (CFS)
- - Documentation/cgroups/ (features for grouping, isolation)
- - Documentation/controllers/ (features for resource control)
+ - Documentation/cgroups/ (features for grouping, isolation
+ and resource control)
Say N if unsure.
+if CGROUPS
+
config CGROUP_DEBUG
bool "Example debug cgroup subsystem"
depends on CGROUPS
help
This option enables a simple cgroup subsystem that
exports useful debugging information about the cgroups
- framework
+ framework.
- Say N if unsure
+ Say N if unsure.
config CGROUP_NS
- bool "Namespace cgroup subsystem"
- depends on CGROUPS
- help
- Provides a simple namespace cgroup subsystem to
- provide hierarchical naming of sets of namespaces,
- for instance virtual servers and checkpoint/restart
- jobs.
+ bool "Namespace cgroup subsystem"
+ depends on CGROUPS
+ help
+ Provides a simple namespace cgroup subsystem to
+ provide hierarchical naming of sets of namespaces,
+ for instance virtual servers and checkpoint/restart
+ jobs.
config CGROUP_FREEZER
- bool "control group freezer subsystem"
- depends on CGROUPS
- help
- Provides a way to freeze and unfreeze all tasks in a
+ bool "Freezer cgroup subsystem"
+ depends on CGROUPS
+ help
+ Provides a way to freeze and unfreeze all tasks in a
cgroup.
config CGROUP_DEVICE
config CPUSETS
bool "Cpuset support"
- depends on SMP && CGROUPS
+ depends on CGROUPS
help
This option will let you create and manage CPUSETs which
allow dynamically partitioning a system into sets of CPUs and
Say N if unsure.
+config PROC_PID_CPUSET
+ bool "Include legacy /proc/<pid>/cpuset file"
+ depends on CPUSETS
+ default y
+
config CGROUP_CPUACCT
bool "Simple CPU accounting cgroup subsystem"
depends on CGROUPS
help
Provides a simple Resource Controller for monitoring the
- total CPU consumed by the tasks in a cgroup
+ total CPU consumed by the tasks in a cgroup.
config RESOURCE_COUNTERS
bool "Resource counters"
help
This option enables controller independent resource accounting
- infrastructure that works with cgroups
+ infrastructure that works with cgroups.
depends on CGROUPS
config CGROUP_MEM_RES_CTLR
select MM_OWNER
help
Provides a memory resource controller that manages both anonymous
- memory and page cache. (See Documentation/controllers/memory.txt)
+ memory and page cache. (See Documentation/cgroups/memory.txt)
Note that setting this option increases fixed memory overhead
associated with each page of memory in the system. By this,
This config option also selects MM_OWNER config option, which
could in turn add some fork/exit overhead.
-config MM_OWNER
- bool
-
config CGROUP_MEM_RES_CTLR_SWAP
bool "Memory Resource Controller Swap Extension(EXPERIMENTAL)"
depends on CGROUP_MEM_RES_CTLR && SWAP && EXPERIMENTAL
is disabled by boot option, this will be automatically disabled and
there will be no overhead from this. Even when you set this config=y,
if boot option "noswapaccount" is set, swap will not be accounted.
+ Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
+ size is 4096bytes, 512k per 1Gbytes of swap.
+menuconfig CGROUP_SCHED
+ bool "Group CPU scheduler"
+ depends on EXPERIMENTAL && CGROUPS
+ default n
+ help
+ This feature lets CPU scheduler recognize task groups and control CPU
+ bandwidth allocation to such task groups. It uses cgroups to group
+ tasks.
-endmenu
+if CGROUP_SCHED
+config FAIR_GROUP_SCHED
+ bool "Group scheduling for SCHED_OTHER"
+ depends on CGROUP_SCHED
+ default CGROUP_SCHED
+
+config RT_GROUP_SCHED
+ bool "Group scheduling for SCHED_RR/FIFO"
+ depends on EXPERIMENTAL
+ depends on CGROUP_SCHED
+ default n
+ help
+ This feature lets you explicitly allocate real CPU bandwidth
+ to users or control groups (depending on the "Basis for grouping tasks"
+ setting below. If enabled, it will also make it impossible to
+ schedule realtime tasks for non-root users until you allocate
+ realtime bandwidth for them.
+ See Documentation/scheduler/sched-rt-group.txt for more information.
+
+endif #CGROUP_SCHED
+
+endif # CGROUPS
+
+config MM_OWNER
+ bool
config SYSFS_DEPRECATED
bool
config SYSFS_DEPRECATED_V2
- bool "Create deprecated sysfs layout for older userspace tools"
+ bool "enable deprecated sysfs features to support old userspace tools"
depends on SYSFS
- default y
+ default n
select SYSFS_DEPRECATED
help
This option switches the layout of sysfs to the deprecated
- version.
+ version. Do not use it on recent distributions.
The current sysfs layout features a unified device tree at
/sys/devices/, which is able to express a hierarchy between
if the original kernel, that came with your distribution, has
this option set to N.
-config PROC_PID_CPUSET
- bool "Include legacy /proc/<pid>/cpuset file"
- depends on CPUSETS
- default y
-
config RELAY
bool "Kernel->user space relay support (formerly relayfs)"
help
config IPC_NS
bool "IPC namespace"
- depends on NAMESPACES && SYSVIPC
+ depends on NAMESPACES && (SYSVIPC || POSIX_MQUEUE)
help
In this namespace tasks work with IPC ids which correspond to
- different IPC objects in different namespaces
+ different IPC objects in different namespaces.
config USER_NS
bool "User namespace (EXPERIMENTAL)"
depends on NAMESPACES && EXPERIMENTAL
help
Support process id namespaces. This allows having multiple
- process with the same pid as long as they are in different
+ processes with the same pid as long as they are in different
pid namespaces. This is a building block of containers.
Unless you want to work with an experimental feature
say N here.
+config NET_NS
+ bool "Network namespace"
+ default n
+ depends on NAMESPACES && EXPERIMENTAL && NET
+ help
+ Allow user space to create what appear to be multiple instances
+ of the network stack.
+
config BLK_DEV_INITRD
bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
depends on BROKEN || !FRV
config SYSCTL
bool
+config ANON_INODES
+ bool
+
menuconfig EMBEDDED
bool "Configure standard kernel features (for small systems)"
help
config SYSCTL_SYSCALL
bool "Sysctl syscall support" if EMBEDDED
+ depends on PROC_SYSCTL
default y
select SYSCTL
---help---
Say N.
-config KALLSYMS_STRIP_GENERATED
- bool "Strip machine generated symbols from kallsyms"
- depends on KALLSYMS_ALL
- default y
- help
- Say N if you want kallsyms to retain even machine generated symbols.
-
config KALLSYMS_EXTRA_PASS
bool "Do an extra kallsyms pass"
depends on KALLSYMS
This option allows to disable the internal PC-Speaker
support, saving some memory.
-config COMPAT_BRK
- bool "Disable heap randomization"
- default y
- help
- Randomizing heap placement makes heap exploits harder, but it
- also breaks ancient binaries (including anything libc5 based).
- This option changes the bootup default to heap randomization
- disabled, and can be overriden runtime by setting
- /proc/sys/kernel/randomize_va_space to 2.
-
- On non-ancient distros (post-2000 ones) N is usually a safe choice.
-
config BASE_FULL
default y
bool "Enable full-sized data structures for core" if EMBEDDED
support for "fast userspace mutexes". The resulting kernel may not
run glibc-based applications correctly.
-config ANON_INODES
- bool
-
config EPOLL
bool "Enable eventpoll support" if EMBEDDED
default y
by some high performance threaded applications. Disabling
this option saves about 7k.
+config HAVE_PERF_EVENTS
+ bool
+ help
+ See tools/perf/design.txt for details.
+
+config PERF_USE_VMALLOC
+ bool
+ help
+ See tools/perf/design.txt for details
+
+menu "Kernel Performance Events And Counters"
+
+config PERF_EVENTS
+ bool "Kernel performance events and counters"
+ default y if (PROFILING || PERF_COUNTERS)
+ depends on HAVE_PERF_EVENTS
+ select ANON_INODES
+ help
+ Enable kernel support for various performance events provided
+ by software and hardware.
+
+ Software events are supported either built-in or via the
+ use of generic tracepoints.
+
+ Most modern CPUs support performance events via performance
+ counter registers. These registers count the number of certain
+ types of hw events: such as instructions executed, cachemisses
+ suffered, or branches mis-predicted - without slowing down the
+ kernel or applications. These registers can also trigger interrupts
+ when a threshold number of events have passed - and can thus be
+ used to profile the code that runs on that CPU.
+
+ The Linux Performance Event subsystem provides an abstraction of
+ these software and hardware event capabilities, available via a
+ system call and used by the "perf" utility in tools/perf/. It
+ provides per task and per CPU counters, and it provides event
+ capabilities on top of those.
+
+ Say Y if unsure.
+
+config PERF_COUNTERS
+ bool "Kernel performance counters (old config option)"
+ depends on HAVE_PERF_EVENTS
+ help
+ This config has been obsoleted by the PERF_EVENTS
+ config option - please see that one for details.
+
+ It has no effect on the kernel whether you enable
+ it or not, it is a compatibility placeholder.
+
+ Say N if unsure.
+
+config DEBUG_PERF_USE_VMALLOC
+ default n
+ bool "Debug: use vmalloc to back perf mmap() buffers"
+ depends on PERF_EVENTS && DEBUG_KERNEL
+ select PERF_USE_VMALLOC
+ help
+ Use vmalloc memory to back perf mmap() buffers.
+
+ Mostly useful for debugging the vmalloc code on platforms
+ that don't require it.
+
+ Say N if unsure.
+
+endmenu
+
config VM_EVENT_COUNTERS
default y
bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
SLUB sysfs support. /sys/slab will not exist and there will be
no support for cache validation etc.
+config COMPAT_BRK
+ bool "Disable heap randomization"
+ default y
+ help
+ Randomizing heap placement makes heap exploits harder, but it
+ also breaks ancient binaries (including anything libc5 based).
+ This option changes the bootup default to heap randomization
+ disabled, and can be overridden at runtime by setting
+ /proc/sys/kernel/randomize_va_space to 2.
+
+ On non-ancient distros (post-2000 ones) N is usually a safe choice.
+
choice
prompt "Choose SLAB allocator"
default SLUB
endchoice
+config MMAP_ALLOW_UNINITIALIZED
+ bool "Allow mmapped anonymous memory to be uninitialized"
+ depends on EMBEDDED && !MMU
+ default n
+ help
+ Normally, and according to the Linux spec, anonymous memory obtained
+ from mmap() has it's contents cleared before it is passed to
+ userspace. Enabling this config option allows you to request that
+ mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
+ providing a huge performance boost. If this option is not enabled,
+ then the flag will be ignored.
+
+ This is taken advantage of by uClibc's malloc(), and also by
+ ELF-FDPIC binfmt's brk and stack allocator.
+
+ Because of the obvious security issues, this option should only be
+ enabled on embedded devices where you control what is run in
+ userspace. Since that isn't generally a problem on no-MMU systems,
+ it is normally safe to say Y here.
+
+ See Documentation/nommu-mmap.txt for more information.
+
config PROFILING
- bool "Profiling support (EXPERIMENTAL)"
+ bool "Profiling support"
help
Say Y here to enable the extended profiling support mechanisms used
by profilers such as OProfile.
config TRACEPOINTS
bool
-config MARKERS
- bool "Activate markers"
- depends on TRACEPOINTS
+source "arch/Kconfig"
+
+config SLOW_WORK
+ default n
+ bool
help
- Place an empty function call at each marker site. Can be
- dynamically changed for a probe function.
+ The slow work thread pool provides a number of dynamically allocated
+ threads that can be used by the kernel to perform operations that
+ take a relatively long time.
-source "arch/Kconfig"
+ An example of this would be CacheFiles doing a path lookup followed
+ by a series of mkdirs and a create call, all of which have to touch
+ disk.
+
+ See Documentation/slow-work.txt.
+
+config SLOW_WORK_DEBUG
+ bool "Slow work debugging through debugfs"
+ default n
+ depends on SLOW_WORK && DEBUG_FS
+ help
+ Display the contents of the slow work run queue through debugfs,
+ including items currently executing.
+
+ See Documentation/slow-work.txt.
endmenu # General setup
config RT_MUTEXES
boolean
- select PLIST
config BASE_SMALL
int
cpu_possible_map, some of them chose to initialize cpu_possible_map
with all 1s, and others with all 0s. When they were centralised,
it was better to provide this option than to break all the archs
- and have several arch maintainers persuing me down dark alleys.
+ and have several arch maintainers pursuing me down dark alleys.
config STOP_MACHINE
bool
config PREEMPT_NOTIFIERS
bool
+config PADATA
+ depends on SMP
+ bool
+
+source "kernel/Kconfig.locks"