queues every message has a priority which decides about succession
of receiving it by a process. If you want to compile and run
programs written e.g. for Solaris with use of its POSIX message
- queues (functions mq_*) say Y here. To use this feature you will
- also need mqueue library, available from
- <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
+ queues (functions mq_*) say Y here.
POSIX message queues are visible as a filesystem called 'mqueue'
and can be mounted somewhere if you want to do filesystem
This option enables access to the kernel configuration file
through /proc/config.gz.
+config LOG_BUF_SHIFT
+ int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
+ range 12 21
+ default 17 if S390 || LOCKDEP
+ default 16 if X86_NUMAQ || IA64
+ default 15 if SMP
+ default 14
+ help
+ Select kernel log buffer size as a power of 2.
+ Defaults and Examples:
+ 17 => 128 KB for S/390
+ 16 => 64 KB for x86 NUMAQ or IA-64
+ 15 => 32 KB for SMP
+ 14 => 16 KB for uniprocessor
+ 13 => 8 KB
+ 12 => 4 KB
+
config CPUSETS
bool "Cpuset support"
depends on SMP
releases.
If enabled, this option will also move any device structures
- that belong to a class, back into the /sys/class heirachy, in
+ that belong to a class, back into the /sys/class hierarchy, in
order to support older versions of udev.
If you are using a distro that was released in 2006 or later,
support for "fast userspace mutexes". The resulting kernel may not
run glibc-based applications correctly.
+config ANON_INODES
+ bool "Enable anonymous inode source" if EMBEDDED
+ default y
+ help
+ Anonymous inode source for pseudo-files like epoll, signalfd,
+ timerfd and eventfd.
+
+ If unsure, say Y.
+
config EPOLL
bool "Enable eventpoll support" if EMBEDDED
default y
+ depends on ANON_INODES
help
Disabling this option will cause the kernel to be built without
support for epoll family of system calls.
+config SIGNALFD
+ bool "Enable signalfd() system call" if EMBEDDED
+ depends on ANON_INODES
+ default y
+ help
+ Enable the signalfd() system call that allows to receive signals
+ on a file descriptor.
+
+ If unsure, say Y.
+
config SHMEM
bool "Use full shmem filesystem" if EMBEDDED
default y
on EMBEDDED systems. /proc/vmstat will only show page counts
if VM event counters are disabled.
+config SLUB_DEBUG
+ default y
+ bool "Enable SLUB debugging support" if EMBEDDED
+ depends on SLUB
+ help
+ SLUB has extensive debug support features. Disabling these can
+ result in significant savings in code size. This also disables
+ SLUB sysfs support. /sys/slab will not exist and there will be
+ no support for cache validation etc.
+
choice
prompt "Choose SLAB allocator"
default SLAB
bool "SLAB"
help
The regular slab allocator that is established and known to work
- well in all environments. It organizes chache hot objects in
+ well in all environments. It organizes cache hot objects in
per cpu and per node queues. SLAB is the default choice for
- slab allocator.
+ a slab allocator.
config SLUB
depends on EXPERIMENTAL && !ARCH_USES_SLAB_PAGE_STRUCT
instead of managing queues of cached objects (SLAB approach).
Per cpu caching is realized using slabs of objects instead
of queues of objects. SLUB can use memory efficiently
- way and has enhanced diagnostics.
+ and has enhanced diagnostics.
config SLOB
#
-# SLOB cannot support SMP because SLAB_DESTROY_BY_RCU does not work
-# properly.
+# SLOB does not support SMP because SLAB_DESTROY_BY_RCU is unsupported
#
depends on EMBEDDED && !SMP && !SPARSEMEM
bool "SLOB (Simple Allocator)"
help
SLOB replaces the SLAB allocator with a drastically simpler
allocator. SLOB is more space efficient that SLAB but does not
- scale well (single lock for all operations) and is more susceptible
- to fragmentation. SLOB it is a great choice to reduce
- memory usage and code size for embedded systems.
+ scale well (single lock for all operations) and is also highly
+ susceptible to fragmentation. SLUB can accomplish a higher object
+ density. It is usually better to use SLUB instead of SLOB.
endchoice