default "$ARCH_DEFCONFIG"
default "arch/$ARCH/defconfig"
+config CONSTRUCTORS
+ bool
+ depends on !UML
+ default y
+
menu "General setup"
config EXPERIMENTAL
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 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.
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
- 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
+ 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"
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,
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
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
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"
+ default y if PROFILING
+ 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 profiling sources"
+ depends on PERF_COUNTERS && EVENT_TRACING
+ default y
+ help
+ Allow the use of tracepoints as software performance counters.
+
+ When this is enabled, you can create perf counters based on
+ tracepoints using PERF_TYPE_TRACEPOINT and the tracepoint ID
+ found in debugfs://tracing/events/*/*/id. (The -e/--events
+ option to the perf tool can parse and interpret symbolic
+ tracepoints, in the subsystem:tracepoint_name format.)
+
+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
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
+ 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.
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.
config SLOW_WORK
default n
- bool "Enable slow work thread pool"
+ 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
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
Code Review / linux-2.6.git / blobdiff