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
+
+choice
+ prompt "Kernel compression mode"
+ default KERNEL_GZIP
+ depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA
+ 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. Its compression ratio is
+ the poorest among the 3 choices; however its speed (both
+ compression and decompression) is the fastest.
+
+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.
+
+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 AUDIT_TREE
def_bool y
- depends on AUDITSYSCALL && INOTIFY
+ depends on AUDITSYSCALL
+ select INOTIFY
+
+menu "RCU Subsystem"
+
+choice
+ prompt "RCU Implementation"
+ default TREE_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.
+
+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.
+
+config PREEMPT_RCU
+ bool "Preemptible 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.
+
+endchoice
+
+config RCU_TRACE
+ bool "Enable tracing for RCU"
+ depends on TREE_RCU || PREEMPT_RCU
+ help
+ This option provides tracing in RCU which presents stats
+ in debugfs for debugging RCU implementation.
+
+ Say Y here if you want to enable RCU tracing
+ Say N if you are unsure.
+
+config RCU_FANOUT
+ int "Tree-based hierarchical RCU fanout value"
+ range 2 64 if 64BIT
+ range 2 32 if !64BIT
+ depends on TREE_RCU
+ default 64 if 64BIT
+ default 32 if !64BIT
+ help
+ This option controls the fanout of hierarchical implementations
+ of RCU, allowing RCU to work efficiently on machines with
+ large numbers of CPUs. This value must be at least the cube
+ root of NR_CPUS, which allows NR_CPUS up to 32,768 for 32-bit
+ systems and up to 262,144 for 64-bit systems.
+
+ Select a specific number if testing RCU itself.
+ Take the default if unsure.
+
+config RCU_FANOUT_EXACT
+ bool "Disable tree-based hierarchical RCU auto-balancing"
+ depends on TREE_RCU
+ default n
+ help
+ This option forces use of the exact RCU_FANOUT value specified,
+ regardless of imbalances in the hierarchy. This is useful for
+ testing RCU itself, and might one day be useful on systems with
+ strong NUMA behavior.
+
+ Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
+
+ Say N if unsure.
+
+config TREE_RCU_TRACE
+ def_bool RCU_TRACE && TREE_RCU
+ select DEBUG_FS
+ help
+ This option provides tracing for the TREE_RCU implementation,
+ permitting Makefile to trivially select kernel/rcutree_trace.c.
+
+config PREEMPT_RCU_TRACE
+ def_bool RCU_TRACE && PREEMPT_RCU
+ select DEBUG_FS
+ help
+ This option provides tracing for the PREEMPT_RCU implementation,
+ permitting Makefile to trivially select kernel/rcupreempt_trace.c.
+
+endmenu # "RCU Subsystem"
config IKCONFIG
tristate "Kernel .config support"
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.
+ Refer to Documentation/cgroups/cgroups.txt for more
+ information on "cgroup" pseudo filesystem.
endchoice
-menu "Control Group support"
-config CGROUPS
- bool "Control Group support"
+menuconfig CGROUPS
+ boolean "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.
+endif # CGROUPS
-endmenu
+config MM_OWNER
+ bool
config SYSFS_DEPRECATED
bool
config SYSFS_DEPRECATED_V2
- bool "Create deprecated sysfs layout for older userspace tools"
+ bool "remove sysfs features which may confuse 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
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_COUNTERS
+ bool
+ help
+ See tools/perf/design.txt for details.
+
+menu "Performance Counters"
+
+config PERF_COUNTERS
+ bool "Kernel Performance Counters"
+ depends on HAVE_PERF_COUNTERS
+ select ANON_INODES
+ help
+ Enable kernel support for performance counter hardware.
+
+ Performance counters are special hardware registers available
+ on most modern CPUs. 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 Counter subsystem provides an abstraction of
+ these hardware capabilities, available via a system call. It
+ provides per task and per CPU counters, and it provides event
+ capabilities on top of those.
+
+ Say Y if unsure.
+
+config EVENT_PROFILE
+ bool "Tracepoint profile sources"
+ depends on PERF_COUNTERS && EVENT_TRACER
+ default y
+
+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 STRIP_ASM_SYMS
+ bool "Strip assembler-generated symbols during link"
+ default n
+ help
+ Strip internal assembler-generated symbols during a link (symbols
+ that look like '.Lxxx') so they don't pollute the output of
+ get_wchan() and suchlike.
+
+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
config MARKERS
bool "Activate markers"
- depends on TRACEPOINTS
+ select TRACEPOINTS
help
Place an empty function call at each marker site. Can be
dynamically changed for a probe function.
source "arch/Kconfig"
+config SLOW_WORK
+ default n
+ bool
+ help
+ 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.
+
+ 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.
+
endmenu # General setup
config HAVE_GENERIC_DMA_COHERENT
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
-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.
-
-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.
-
-config PREEMPT_RCU
- bool "Preemptible 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.
-
-endchoice
-
-config RCU_TRACE
- bool "Enable tracing for RCU"
- depends on TREE_RCU || PREEMPT_RCU
- help
- This option provides tracing in RCU which presents stats
- in debugfs for debugging RCU implementation.
-
- Say Y here if you want to enable RCU tracing
- Say N if you are unsure.
-
-config RCU_FANOUT
- int "Tree-based hierarchical RCU fanout value"
- range 2 64 if 64BIT
- range 2 32 if !64BIT
- depends on TREE_RCU
- default 64 if 64BIT
- default 32 if !64BIT
- help
- This option controls the fanout of hierarchical implementations
- of RCU, allowing RCU to work efficiently on machines with
- large numbers of CPUs. This value must be at least the cube
- root of NR_CPUS, which allows NR_CPUS up to 32,768 for 32-bit
- systems and up to 262,144 for 64-bit systems.
-
- Select a specific number if testing RCU itself.
- Take the default if unsure.
-
-config RCU_FANOUT_EXACT
- bool "Disable tree-based hierarchical RCU auto-balancing"
- depends on TREE_RCU
- default n
- help
- This option forces use of the exact RCU_FANOUT value specified,
- regardless of imbalances in the hierarchy. This is useful for
- testing RCU itself, and might one day be useful on systems with
- strong NUMA behavior.
-
- Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
-
- Say N if unsure.
-
-config TREE_RCU_TRACE
- def_bool RCU_TRACE && TREE_RCU
- select DEBUG_FS
- help
- This option provides tracing for the TREE_RCU implementation,
- permitting Makefile to trivially select kernel/rcutree_trace.c.
-
-config PREEMPT_RCU_TRACE
- def_bool RCU_TRACE && PREEMPT_RCU
- select DEBUG_FS
- help
- This option provides tracing for the PREEMPT_RCU implementation,
- permitting Makefile to trivially select kernel/rcupreempt_trace.c.