config CONSTRUCTORS
bool
depends on !UML
- default y
+
+config HAVE_IRQ_WORK
+ bool
+
+config IRQ_WORK
+ bool
+ depends on HAVE_IRQ_WORK
menu "General setup"
depends on BROKEN || !SMP
default y
-config LOCK_KERNEL
- bool
- depends on SMP || PREEMPT
- default y
-
config INIT_ENV_ARG_LIMIT
int
default 32 if !UML
config HAVE_KERNEL_LZMA
bool
+config HAVE_KERNEL_XZ
+ bool
+
config HAVE_KERNEL_LZO
bool
prompt "Kernel compression mode"
default KERNEL_LZO if ARCH_RK29
default KERNEL_GZIP
- depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_LZO
+ depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO
help
The linux kernel is a kind of self-extracting executable.
Several compression algorithms are available, which differ
two. Compression is slowest. The kernel size is about 33%
smaller with LZMA in comparison to gzip.
+config KERNEL_XZ
+ bool "XZ"
+ depends on HAVE_KERNEL_XZ
+ help
+ XZ uses the LZMA2 algorithm and instruction set specific
+ BCJ filters which can improve compression ratio of executable
+ code. The size of the kernel is about 30% smaller with XZ in
+ comparison to gzip. On architectures for which there is a BCJ
+ filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
+ will create a few percent smaller kernel than plain LZMA.
+
+ The speed is about the same as with LZMA: The decompression
+ speed of XZ is better than that of bzip2 but worse than gzip
+ and LZO. Compression is slow.
+
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
+ size is about 10% bigger than gzip; however its speed
(both compression and decompression) is the fastest.
endchoice
+config DEFAULT_HOSTNAME
+ string "Default hostname"
+ default "(none)"
+ help
+ This option determines the default system hostname before userspace
+ calls sethostname(2). The kernel traditionally uses "(none)" here,
+ but you may wish to use a different default here to make a minimal
+ system more usable with less configuration.
+
config SWAP
bool "Support for paging of anonymous memory (swap)"
depends on MMU && BLOCK
for processing it. A preliminary version of these tools is available
at <http://www.gnu.org/software/acct/>.
+config FHANDLE
+ bool "open by fhandle syscalls"
+ select EXPORTFS
+ help
+ If you say Y here, a user level program will be able to map
+ file names to handle and then later use the handle for
+ different file system operations. This is useful in implementing
+ userspace file servers, which now track files using handles instead
+ of names. The handle would remain the same even if file names
+ get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
+ syscalls.
+
config TASKSTATS
bool "Export task/process statistics through netlink (EXPERIMENTAL)"
depends on NET
depends on AUDITSYSCALL
select FSNOTIFY
+source "kernel/irq/Kconfig"
+
menu "RCU Subsystem"
choice
config TREE_RCU
bool "Tree-based hierarchical RCU"
+ depends on !PREEMPT && SMP
help
This option selects the RCU implementation that is
designed for very large SMP system with hundreds or
smaller systems.
config TREE_PREEMPT_RCU
- bool "Preemptable tree-based hierarchical RCU"
+ bool "Preemptible tree-based hierarchical RCU"
depends on PREEMPT
help
This option selects the RCU implementation that is
is not required. This option greatly reduces the
memory footprint of RCU.
+config TINY_PREEMPT_RCU
+ bool "Preemptible UP-only small-memory-footprint RCU"
+ depends on !SMP && PREEMPT
+ help
+ This option selects the RCU implementation that is designed
+ for real-time UP systems. This option greatly reduces the
+ memory footprint of RCU.
+
endchoice
+config PREEMPT_RCU
+ def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
+ help
+ This option enables preemptible-RCU code that is common between
+ the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
+
config RCU_TRACE
bool "Enable tracing for RCU"
- depends on TREE_RCU || TREE_PREEMPT_RCU
help
This option provides tracing in RCU which presents stats
in debugfs for debugging RCU implementation.
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.
+ large numbers of CPUs. This value must be at least the fourth
+ root of NR_CPUS, which allows NR_CPUS to be insanely large.
+ The default value of RCU_FANOUT should be used for production
+ systems, but if you are stress-testing the RCU implementation
+ itself, small RCU_FANOUT values allow you to test large-system
+ code paths on small(er) systems.
Select a specific number if testing RCU itself.
Take the default if unsure.
TREE_PREEMPT_RCU implementations, permitting Makefile to
trivially select kernel/rcutree_trace.c.
+config RCU_BOOST
+ bool "Enable RCU priority boosting"
+ depends on RT_MUTEXES && PREEMPT_RCU
+ default n
+ help
+ This option boosts the priority of preempted RCU readers that
+ block the current preemptible RCU grace period for too long.
+ This option also prevents heavy loads from blocking RCU
+ callback invocation for all flavors of RCU.
+
+ Say Y here if you are working with real-time apps or heavy loads
+ Say N here if you are unsure.
+
+config RCU_BOOST_PRIO
+ int "Real-time priority to boost RCU readers to"
+ range 1 99
+ depends on RCU_BOOST
+ default 1
+ help
+ This option specifies the real-time priority to which preempted
+ RCU readers are to be boosted. If you are working with CPU-bound
+ real-time applications, you should specify a priority higher then
+ the highest-priority CPU-bound application.
+
+ Specify the real-time priority, or take the default if unsure.
+
+config RCU_BOOST_DELAY
+ int "Milliseconds to delay boosting after RCU grace-period start"
+ range 0 3000
+ depends on RCU_BOOST
+ default 500
+ help
+ This option specifies the time to wait after the beginning of
+ a given grace period before priority-boosting preempted RCU
+ readers blocking that grace period. Note that any RCU reader
+ blocking an expedited RCU grace period is boosted immediately.
+
+ Accept the default if unsure.
+
endmenu # "RCU Subsystem"
config IKCONFIG
config CGROUP_DEBUG
bool "Example debug cgroup subsystem"
- depends on CGROUPS
default n
help
This option enables a simple cgroup subsystem that
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.
-
config CGROUP_FREEZER
bool "Freezer cgroup subsystem"
- depends on CGROUPS
help
Provides a way to freeze and unfreeze all tasks in a
cgroup.
config CGROUP_DEVICE
bool "Device controller for cgroups"
- depends on CGROUPS && EXPERIMENTAL
help
Provides a cgroup implementing whitelists for devices which
a process in the cgroup can mknod or open.
config CPUSETS
bool "Cpuset support"
- depends on CGROUPS
help
This option will let you create and manage CPUSETs which
allow dynamically partitioning a system into sets of CPUs and
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.
help
This option enables controller independent resource accounting
infrastructure that works with cgroups.
- depends on CGROUPS
config CGROUP_MEM_RES_CTLR
bool "Memory Resource Controller for Control Groups"
- depends on CGROUPS && RESOURCE_COUNTERS
+ depends on RESOURCE_COUNTERS
select MM_OWNER
help
Provides a memory resource controller that manages both anonymous
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.
+config CGROUP_MEM_RES_CTLR_SWAP_ENABLED
+ bool "Memory Resource Controller Swap Extension enabled by default"
+ depends on CGROUP_MEM_RES_CTLR_SWAP
+ default y
+ help
+ Memory Resource Controller Swap Extension comes with its price in
+ a bigger memory consumption. General purpose distribution kernels
+ which want to enable the feature but keep it disabled by default
+ and let the user enable it by swapaccount boot command line
+ parameter should have this option unselected.
+ For those who want to have the feature enabled by default should
+ select this option (if, for some reason, they need to disable it
+ then noswapaccount does the trick).
+
+config CGROUP_PERF
+ bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
+ depends on PERF_EVENTS && CGROUPS
+ help
+ This option extends the per-cpu mode to restrict monitoring to
+ threads which belong to the cgroup specified and run on the
+ designated cpu.
+
+ Say N if unsure.
menuconfig CGROUP_SCHED
bool "Group CPU scheduler"
- depends on EXPERIMENTAL && CGROUPS
+ depends on EXPERIMENTAL
default n
help
This feature lets CPU scheduler recognize task groups and control CPU
config BLK_CGROUP
tristate "Block IO controller"
- depends on CGROUPS && BLOCK
+ depends on BLOCK
default n
---help---
Generic block IO controller cgroup interface. This is the common
Currently, CFQ IO scheduler uses it to recognize task groups and
control disk bandwidth allocation (proportional time slice allocation)
- to such task groups.
+ to such task groups. It is also used by bio throttling logic in
+ block layer to implement upper limit in IO rates on a device.
This option only enables generic Block IO controller infrastructure.
- One needs to also enable actual IO controlling logic in CFQ for it
- to take effect. (CONFIG_CFQ_GROUP_IOSCHED=y).
+ One needs to also enable actual IO controlling logic/policy. For
+ enabling proportional weight division of disk bandwidth in CFQ, set
+ CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
+ CONFIG_BLK_DEV_THROTTLING=y.
See Documentation/cgroups/blkio-controller.txt for more information.
endif # CGROUPS
-config MM_OWNER
- bool
-
-config SYSFS_DEPRECATED
- bool
-
-config SYSFS_DEPRECATED_V2
- bool "enable deprecated sysfs features to support old userspace tools"
- depends on SYSFS
- default n
- select SYSFS_DEPRECATED
- help
- This option switches the layout of sysfs to the deprecated
- 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
- class devices. If the deprecated option is set to Y, the
- unified device tree is split into a bus device tree at
- /sys/devices/ and several individual class device trees at
- /sys/class/. The class and bus devices will be connected by
- "<subsystem>:<name>" and the "device" links. The "block"
- class devices, will not show up in /sys/class/block/. Some
- subsystems will suppress the creation of some devices which
- depend on the unified device tree.
-
- This option is not a pure compatibility option that can
- be safely enabled on newer distributions. It will change the
- layout of sysfs to the non-extensible deprecated version,
- and disable some features, which can not be exported without
- confusing older userspace tools. Since 2007/2008 all major
- distributions do not enable this option, and ship no tools which
- depend on the deprecated layout or this option.
-
- If you are using a new kernel on an older distribution, or use
- older userspace tools, you might need to say Y here. Do not say Y,
- if the original kernel, that came with your distribution, has
- this option set to N.
-
-config RELAY
- bool "Kernel->user space relay support (formerly relayfs)"
- help
- This option enables support for relay interface support in
- certain file systems (such as debugfs).
- It is designed to provide an efficient mechanism for tools and
- facilities to relay large amounts of data from kernel space to
- user space.
-
- If unsure, say N.
-
-config NAMESPACES
- bool "Namespaces support" if EMBEDDED
- default !EMBEDDED
+menuconfig NAMESPACES
+ bool "Namespaces support" if EXPERT
+ default !EXPERT
help
Provides the way to make tasks work with different objects using
the same id. For example same IPC id may refer to different objects
or same user id or pid may refer to different tasks when used in
different namespaces.
+if NAMESPACES
+
config UTS_NS
bool "UTS namespace"
- depends on NAMESPACES
+ default y
help
In this namespace tasks see different info provided with the
uname() system call
config IPC_NS
bool "IPC namespace"
- depends on NAMESPACES && (SYSVIPC || POSIX_MQUEUE)
+ depends on (SYSVIPC || POSIX_MQUEUE)
+ default y
help
In this namespace tasks work with IPC ids which correspond to
different IPC objects in different namespaces.
config USER_NS
bool "User namespace (EXPERIMENTAL)"
- depends on NAMESPACES && EXPERIMENTAL
+ depends on EXPERIMENTAL
+ default y
help
This allows containers, i.e. vservers, to use user namespaces
to provide different user info for different servers.
If unsure, say N.
config PID_NS
- bool "PID Namespaces (EXPERIMENTAL)"
- default n
- depends on NAMESPACES && EXPERIMENTAL
+ bool "PID Namespaces"
+ default y
help
Support process id namespaces. This allows having multiple
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
+ depends on NET
+ default y
help
Allow user space to create what appear to be multiple instances
of the network stack.
+endif # NAMESPACES
+
+config SCHED_AUTOGROUP
+ bool "Automatic process group scheduling"
+ select EVENTFD
+ select CGROUPS
+ select CGROUP_SCHED
+ select FAIR_GROUP_SCHED
+ help
+ This option optimizes the scheduler for common desktop workloads by
+ automatically creating and populating task groups. This separation
+ of workloads isolates aggressive CPU burners (like build jobs) from
+ desktop applications. Task group autogeneration is currently based
+ upon task session.
+
+config MM_OWNER
+ bool
+
+config SYSFS_DEPRECATED
+ bool "Enable deprecated sysfs features to support old userspace tools"
+ depends on SYSFS
+ default n
+ help
+ This option adds code that switches the layout of the "block" class
+ devices, to not show up in /sys/class/block/, but only in
+ /sys/block/.
+
+ This switch is only active when the sysfs.deprecated=1 boot option is
+ passed or the SYSFS_DEPRECATED_V2 option is set.
+
+ This option allows new kernels to run on old distributions and tools,
+ which might get confused by /sys/class/block/. Since 2007/2008 all
+ major distributions and tools handle this just fine.
+
+ Recent distributions and userspace tools after 2009/2010 depend on
+ the existence of /sys/class/block/, and will not work with this
+ option enabled.
+
+ Only if you are using a new kernel on an old distribution, you might
+ need to say Y here.
+
+config SYSFS_DEPRECATED_V2
+ bool "Enable deprecated sysfs features by default"
+ default n
+ depends on SYSFS
+ depends on SYSFS_DEPRECATED
+ help
+ Enable deprecated sysfs by default.
+
+ See the CONFIG_SYSFS_DEPRECATED option for more details about this
+ option.
+
+ Only if you are using a new kernel on an old distribution, you might
+ need to say Y here. Even then, odds are you would not need it
+ enabled, you can always pass the boot option if absolutely necessary.
+
+config RELAY
+ bool "Kernel->user space relay support (formerly relayfs)"
+ help
+ This option enables support for relay interface support in
+ certain file systems (such as debugfs).
+ It is designed to provide an efficient mechanism for tools and
+ facilities to relay large amounts of data from kernel space to
+ user space.
+
+ If unsure, say N.
+
config BLK_DEV_INITRD
bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
depends on BROKEN || !FRV
config CC_OPTIMIZE_FOR_SIZE
bool "Optimize for size"
- default y
help
Enabling this option will pass "-Os" instead of "-O2" to gcc
resulting in a smaller kernel.
help
Set default panic timeout.
-menuconfig EMBEDDED
- bool "Configure standard kernel features (for small systems)"
+menuconfig EXPERT
+ bool "Configure standard kernel features (expert users)"
help
This option allows certain base kernel options and settings
to be disabled or tweaked. This is for specialized
Only use this if you really know what you are doing.
config UID16
- bool "Enable 16-bit UID system calls" if EMBEDDED
+ bool "Enable 16-bit UID system calls" if EXPERT
depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
default y
help
This enables the legacy 16-bit UID syscall wrappers.
config SYSCTL_SYSCALL
- bool "Sysctl syscall support" if EMBEDDED
+ bool "Sysctl syscall support" if EXPERT
depends on PROC_SYSCTL
default y
select SYSCTL
If unsure say Y here.
config KALLSYMS
- bool "Load all symbols for debugging/ksymoops" if EMBEDDED
+ bool "Load all symbols for debugging/ksymoops" if EXPERT
default y
help
Say Y here to let the kernel print out symbolic crash information and
bool "Include all symbols in kallsyms"
depends on DEBUG_KERNEL && KALLSYMS
help
- Normally kallsyms only contains the symbols of functions, for nicer
- OOPS messages. Some debuggers can use kallsyms for other
- symbols too: say Y here to include all symbols, if you need them
- and you don't care about adding 300k to the size of your kernel.
+ Normally kallsyms only contains the symbols of functions for nicer
+ OOPS messages and backtraces (i.e., symbols from the text and inittext
+ sections). This is sufficient for most cases. And only in very rare
+ cases (e.g., when a debugger is used) all symbols are required (e.g.,
+ names of variables from the data sections, etc).
- Say N.
-
-config KALLSYMS_EXTRA_PASS
- bool "Do an extra kallsyms pass"
- depends on KALLSYMS
- help
- If kallsyms is not working correctly, the build will fail with
- inconsistent kallsyms data. If that occurs, log a bug report and
- turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
- Always say N here unless you find a bug in kallsyms, which must be
- reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
- you wait for kallsyms to be fixed.
+ This option makes sure that all symbols are loaded into the kernel
+ image (i.e., symbols from all sections) in cost of increased kernel
+ size (depending on the kernel configuration, it may be 300KiB or
+ something like this).
+ Say N unless you really need all symbols.
config HOTPLUG
- bool "Support for hot-pluggable devices" if EMBEDDED
+ bool "Support for hot-pluggable devices" if EXPERT
default y
help
This option is provided for the case where no hotplug or uevent
config PRINTK
default y
- bool "Enable support for printk" if EMBEDDED
+ bool "Enable support for printk" if EXPERT
help
This option enables normal printk support. Removing it
eliminates most of the message strings from the kernel image
strongly discouraged.
config BUG
- bool "BUG() support" if EMBEDDED
+ bool "BUG() support" if EXPERT
default y
help
Disabling this option eliminates support for BUG and WARN, reducing
config ELF_CORE
default y
- bool "Enable ELF core dumps" if EMBEDDED
+ bool "Enable ELF core dumps" if EXPERT
help
Enable support for generating core dumps. Disabling saves about 4k.
config PCSPKR_PLATFORM
- bool "Enable PC-Speaker support" if EMBEDDED
+ bool "Enable PC-Speaker support" if EXPERT
depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES
default y
help
config BASE_FULL
default y
- bool "Enable full-sized data structures for core" if EMBEDDED
+ bool "Enable full-sized data structures for core" if EXPERT
help
Disabling this option reduces the size of miscellaneous core
kernel data structures. This saves memory on small machines,
but may reduce performance.
config FUTEX
- bool "Enable futex support" if EMBEDDED
+ bool "Enable futex support" if EXPERT
default y
select RT_MUTEXES
help
run glibc-based applications correctly.
config EPOLL
- bool "Enable eventpoll support" if EMBEDDED
+ bool "Enable eventpoll support" if EXPERT
default y
select ANON_INODES
help
support for epoll family of system calls.
config SIGNALFD
- bool "Enable signalfd() system call" if EMBEDDED
+ bool "Enable signalfd() system call" if EXPERT
select ANON_INODES
default y
help
If unsure, say Y.
config TIMERFD
- bool "Enable timerfd() system call" if EMBEDDED
+ bool "Enable timerfd() system call" if EXPERT
select ANON_INODES
default y
help
If unsure, say Y.
config EVENTFD
- bool "Enable eventfd() system call" if EMBEDDED
+ bool "Enable eventfd() system call" if EXPERT
select ANON_INODES
default y
help
If unsure, say Y.
config SHMEM
- bool "Use full shmem filesystem" if EMBEDDED
+ bool "Use full shmem filesystem" if EXPERT
default y
depends on MMU
help
file-based API.
config AIO
- bool "Enable AIO support" if EMBEDDED
+ bool "Enable AIO support" if EXPERT
default y
help
This option enables POSIX asynchronous I/O which may by used
by some high performance threaded applications. Disabling
this option saves about 7k.
+config EMBEDDED
+ bool "Embedded system"
+ select EXPERT
+ help
+ This option should be enabled if compiling the kernel for
+ an embedded system so certain expert options are available
+ for configuration.
+
config HAVE_PERF_EVENTS
bool
help
default y if (PROFILING || PERF_COUNTERS)
depends on HAVE_PERF_EVENTS
select ANON_INODES
+ select IRQ_WORK
help
Enable kernel support for various performance events provided
by software and hardware.
config VM_EVENT_COUNTERS
default y
- bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
+ bool "Enable VM event counters for /proc/vmstat" if EXPERT
help
VM event counters are needed for event counts to be shown.
This option allows the disabling of the VM event counters
- on EMBEDDED systems. /proc/vmstat will only show page counts
+ on EXPERT systems. /proc/vmstat will only show page counts
if VM event counters are disabled.
config PCI_QUIRKS
default y
- bool "Enable PCI quirk workarounds" if EMBEDDED
+ bool "Enable PCI quirk workarounds" if EXPERT
depends on PCI
help
This enables workarounds for various PCI chipset
config SLUB_DEBUG
default y
- bool "Enable SLUB debugging support" if EMBEDDED
+ bool "Enable SLUB debugging support" if EXPERT
depends on SLUB && SYSFS
help
SLUB has extensive debug support features. Disabling these can
a slab allocator.
config SLOB
- depends on EMBEDDED
+ depends on EXPERT
bool "SLOB (Simple Allocator)"
help
SLOB replaces the stock allocator with a drastically simpler
config MMAP_ALLOW_UNINITIALIZED
bool "Allow mmapped anonymous memory to be uninitialized"
- depends on EMBEDDED && !MMU
+ depends on EXPERT && !MMU
default n
help
Normally, and according to the Linux spec, anonymous memory obtained
projects / firefly-linux-kernel-4.4.55.git / blobdiff