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config ARCH
string
option env="ARCH"
config KERNELVERSION
string
option env="KERNELVERSION"
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config DEFCONFIG_LIST
string
[PATCH] uml: use DEFCONFIG_LIST to avoid reading host's config
This should make sure that, for UML, host's configuration files are not
considered, which avoids various pains to the user. Our dependency are such
that the obtained Kconfig will be valid and will lead to successful
compilation - however they cannot prevent an user from disabling any boot
device, and if an option is not set in the read .config (say
/boot/config-XXX), with make menuconfig ARCH=um, it is not set. This always
disables UBD and all console I/O channels, which leads to non-working UML
kernels, so this bothers users - especially now, since it will happen on
almost every machine (/boot/config-`uname -r` exists almost on every machine).
It can be workarounded with make defconfig ARCH=um, but it is non-obvious and
can be avoided, so please _do_ merge this patch.
Given the existence of options, it could be interesting to implement
(additionally) "option required" - with it, Kconfig will refuse reading a
.config file (from wherever it comes) if the given option is not set. With
this, one could mark with it the option characteristic of the given
architecture (it was an old proposal of Roman Zippel, when I pointed out our
problem):
config UML
option required
default y
However this should be further discussed:
*) for x86, it must support constructs like:
==arch/i386/Kconfig==
config 64BIT
option required
default n
where Kconfig must require that CONFIG_64BIT is disabled or not present in the
read .config.
*) do we want to do such checks only for the starting defconfig or also for
.config? Which leads to:
*) I may want to port a x86_64 .config to x86 and viceversa, or even among more
different archs. Should that be allowed, and in which measure (the user may
force skipping the check for a .config or it is only given a warning by
default)?
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: <kbuild-devel@lists.sourceforge.net>
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-20 10:28:23 +04:00
depends on !UML
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option defconfig_list
default "/lib/modules/$UNAME_RELEASE/.config"
default "/etc/kernel-config"
default "/boot/config-$UNAME_RELEASE"
default "arch/$ARCH/defconfig"
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menu "General setup"
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config EXPERIMENTAL
bool "Prompt for development and/or incomplete code/drivers"
---help---
Some of the various things that Linux supports (such as network
drivers, file systems, network protocols, etc.) can be in a state
of development where the functionality, stability, or the level of
testing is not yet high enough for general use. This is usually
known as the "alpha-test" phase among developers. If a feature is
currently in alpha-test, then the developers usually discourage
uninformed widespread use of this feature by the general public to
avoid "Why doesn't this work?" type mail messages. However, active
testing and use of these systems is welcomed. Just be aware that it
may not meet the normal level of reliability or it may fail to work
in some special cases. Detailed bug reports from people familiar
with the kernel internals are usually welcomed by the developers
(before submitting bug reports, please read the documents
<file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
<file:Documentation/BUG-HUNTING>, and
<file:Documentation/oops-tracing.txt> in the kernel source).
This option will also make obsoleted drivers available. These are
drivers that have been replaced by something else, and/or are
scheduled to be removed in a future kernel release.
Unless you intend to help test and develop a feature or driver that
falls into this category, or you have a situation that requires
using these features, you should probably say N here, which will
cause the configurator to present you with fewer choices. If
you say Y here, you will be offered the choice of using features or
drivers that are currently considered to be in the alpha-test phase.
config BROKEN
bool
config BROKEN_ON_SMP
bool
depends on BROKEN || !SMP
default y
config LOCK_KERNEL
bool
depends on SMP || PREEMPT
default y
config INIT_ENV_ARG_LIMIT
int
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default 32 if !UML
default 128 if UML
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help
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Maximum of each of the number of arguments and environment
variables passed to init from the kernel command line.
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config LOCALVERSION
string "Local version - append to kernel release"
help
Append an extra string to the end of your kernel version.
This will show up when you type uname, for example.
The string you set here will be appended after the contents of
any files with a filename matching localversion* in your
object and source tree, in that order. Your total string can
be a maximum of 64 characters.
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config LOCALVERSION_AUTO
bool "Automatically append version information to the version string"
default y
help
This will try to automatically determine if the current tree is a
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release tree by looking for git tags that belong to the current
top of tree revision.
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A string of the format -gxxxxxxxx will be added to the localversion
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if a git-based tree is found. The string generated by this will be
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appended after any matching localversion* files, and after the value
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set in CONFIG_LOCALVERSION.
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(The actual string used here is the first eight characters produced
by running the command:
$ git rev-parse --verify HEAD
which is done within the script "scripts/setlocalversion".)
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config SWAP
bool "Support for paging of anonymous memory (swap)"
[PATCH] BLOCK: Make it possible to disable the block layer [try #6]
Make it possible to disable the block layer. Not all embedded devices require
it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require
the block layer to be present.
This patch does the following:
(*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev
support.
(*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls
an item that uses the block layer. This includes:
(*) Block I/O tracing.
(*) Disk partition code.
(*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS.
(*) The SCSI layer. As far as I can tell, even SCSI chardevs use the
block layer to do scheduling. Some drivers that use SCSI facilities -
such as USB storage - end up disabled indirectly from this.
(*) Various block-based device drivers, such as IDE and the old CDROM
drivers.
(*) MTD blockdev handling and FTL.
(*) JFFS - which uses set_bdev_super(), something it could avoid doing by
taking a leaf out of JFFS2's book.
(*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and
linux/elevator.h contingent on CONFIG_BLOCK being set. sector_div() is,
however, still used in places, and so is still available.
(*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and
parts of linux/fs.h.
(*) Makes a number of files in fs/ contingent on CONFIG_BLOCK.
(*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK.
(*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK
is not enabled.
(*) fs/no-block.c is created to hold out-of-line stubs and things that are
required when CONFIG_BLOCK is not set:
(*) Default blockdev file operations (to give error ENODEV on opening).
(*) Makes some /proc changes:
(*) /proc/devices does not list any blockdevs.
(*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK.
(*) Makes some compat ioctl handling contingent on CONFIG_BLOCK.
(*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if
given command other than Q_SYNC or if a special device is specified.
(*) In init/do_mounts.c, no reference is made to the blockdev routines if
CONFIG_BLOCK is not defined. This does not prohibit NFS roots or JFFS2.
(*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return
error ENOSYS by way of cond_syscall if so).
(*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if
CONFIG_BLOCK is not set, since they can't then happen.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 22:45:40 +04:00
depends on MMU && BLOCK
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default y
help
This option allows you to choose whether you want to have support
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for so called swap devices or swap files in your kernel that are
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used to provide more virtual memory than the actual RAM present
in your computer. If unsure say Y.
config SYSVIPC
bool "System V IPC"
---help---
Inter Process Communication is a suite of library functions and
system calls which let processes (running programs) synchronize and
exchange information. It is generally considered to be a good thing,
and some programs won't run unless you say Y here. In particular, if
you want to run the DOS emulator dosemu under Linux (read the
DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
you'll need to say Y here.
You can find documentation about IPC with "info ipc" and also in
section 6.4 of the Linux Programmer's Guide, available from
<http://www.tldp.org/guides.html>.
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config SYSVIPC_SYSCTL
bool
depends on SYSVIPC
depends on SYSCTL
default y
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config POSIX_MQUEUE
bool "POSIX Message Queues"
depends on NET && EXPERIMENTAL
---help---
POSIX variant of message queues is a part of IPC. In POSIX message
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
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queues (functions mq_*) say Y here.
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POSIX message queues are visible as a filesystem called 'mqueue'
and can be mounted somewhere if you want to do filesystem
operations on message queues.
If unsure, say Y.
config BSD_PROCESS_ACCT
bool "BSD Process Accounting"
help
If you say Y here, a user level program will be able to instruct the
kernel (via a special system call) to write process accounting
information to a file: whenever a process exits, information about
that process will be appended to the file by the kernel. The
information includes things such as creation time, owning user,
command name, memory usage, controlling terminal etc. (the complete
list is in the struct acct in <file:include/linux/acct.h>). It is
up to the user level program to do useful things with this
information. This is generally a good idea, so say Y.
config BSD_PROCESS_ACCT_V3
bool "BSD Process Accounting version 3 file format"
depends on BSD_PROCESS_ACCT
default n
help
If you say Y here, the process accounting information is written
in a new file format that also logs the process IDs of each
process and it's parent. Note that this file format is incompatible
with previous v0/v1/v2 file formats, so you will need updated tools
for processing it. A preliminary version of these tools is available
at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
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config TASKSTATS
bool "Export task/process statistics through netlink (EXPERIMENTAL)"
depends on NET
default n
help
Export selected statistics for tasks/processes through the
generic netlink interface. Unlike BSD process accounting, the
statistics are available during the lifetime of tasks/processes as
responses to commands. Like BSD accounting, they are sent to user
space on task exit.
Say N if unsure.
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config TASK_DELAY_ACCT
bool "Enable per-task delay accounting (EXPERIMENTAL)"
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depends on TASKSTATS
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help
Collect information on time spent by a task waiting for system
resources like cpu, synchronous block I/O completion and swapping
in pages. Such statistics can help in setting a task's priorities
relative to other tasks for cpu, io, rss limits etc.
Say N if unsure.
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config TASK_XACCT
bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
depends on TASKSTATS
help
Collect extended task accounting data and send the data
to userland for processing over the taskstats interface.
Say N if unsure.
config TASK_IO_ACCOUNTING
bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
depends on TASK_XACCT
help
Collect information on the number of bytes of storage I/O which this
task has caused.
Say N if unsure.
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config AUDIT
bool "Auditing support"
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depends on NET
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help
Enable auditing infrastructure that can be used with another
kernel subsystem, such as SELinux (which requires this for
logging of avc messages output). Does not do system-call
auditing without CONFIG_AUDITSYSCALL.
config AUDITSYSCALL
bool "Enable system-call auditing support"
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depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64|| SUPERH)
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default y if SECURITY_SELINUX
help
Enable low-overhead system-call auditing infrastructure that
can be used independently or with another kernel subsystem,
[PATCH] audit: path-based rules
In this implementation, audit registers inotify watches on the parent
directories of paths specified in audit rules. When audit's inotify
event handler is called, it updates any affected rules based on the
filesystem event. If the parent directory is renamed, removed, or its
filesystem is unmounted, audit removes all rules referencing that
inotify watch.
To keep things simple, this implementation limits location-based
auditing to the directory entries in an existing directory. Given
a path-based rule for /foo/bar/passwd, the following table applies:
passwd modified -- audit event logged
passwd replaced -- audit event logged, rules list updated
bar renamed -- rule removed
foo renamed -- untracked, meaning that the rule now applies to
the new location
Audit users typically want to have many rules referencing filesystem
objects, which can significantly impact filtering performance. This
patch also adds an inode-number-based rule hash to mitigate this
situation.
The patch is relative to the audit git tree:
http://kernel.org/git/?p=linux/kernel/git/viro/audit-current.git;a=summary
and uses the inotify kernel API:
http://lkml.org/lkml/2006/6/1/145
Signed-off-by: Amy Griffis <amy.griffis@hp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-04-08 00:55:56 +04:00
such as SELinux. To use audit's filesystem watch feature, please
ensure that INOTIFY is configured.
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[PATCH] audit: watching subtrees
New kind of audit rule predicates: "object is visible in given subtree".
The part that can be sanely implemented, that is. Limitations:
* if you have hardlink from outside of tree, you'd better watch
it too (or just watch the object itself, obviously)
* if you mount something under a watched tree, tell audit
that new chunk should be added to watched subtrees
* if you umount something in a watched tree and it's still mounted
elsewhere, you will get matches on events happening there. New command
tells audit to recalculate the trees, trimming such sources of false
positives.
Note that it's _not_ about path - if something mounted in several places
(multiple mount, bindings, different namespaces, etc.), the match does
_not_ depend on which one we are using for access.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2007-07-22 16:04:18 +04:00
config AUDIT_TREE
def_bool y
depends on AUDITSYSCALL && INOTIFY
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config IKCONFIG
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tristate "Kernel .config support"
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---help---
This option enables the complete Linux kernel ".config" file
contents to be saved in the kernel. It provides documentation
of which kernel options are used in a running kernel or in an
on-disk kernel. This information can be extracted from the kernel
image file with the script scripts/extract-ikconfig and used as
input to rebuild the current kernel or to build another kernel.
It can also be extracted from a running kernel by reading
/proc/config.gz if enabled (below).
config IKCONFIG_PROC
bool "Enable access to .config through /proc/config.gz"
depends on IKCONFIG && PROC_FS
---help---
This option enables access to the kernel configuration file
through /proc/config.gz.
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config LOG_BUF_SHIFT
int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
range 12 21
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default 17
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help
Select kernel log buffer size as a power of 2.
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Examples:
17 => 128 KB
16 => 64 KB
15 => 32 KB
14 => 16 KB
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13 => 8 KB
12 => 4 KB
Task Control Groups: basic task cgroup framework
Generic Process Control Groups
--------------------------
There have recently been various proposals floating around for
resource management/accounting and other task grouping subsystems in
the kernel, including ResGroups, User BeanCounters, NSProxy
cgroups, and others. These all need the basic abstraction of being
able to group together multiple processes in an aggregate, in order to
track/limit the resources permitted to those processes, or control
other behaviour of the processes, and all implement this grouping in
different ways.
This patchset provides a framework for tracking and grouping processes
into arbitrary "cgroups" and assigning arbitrary state to those
groupings, in order to control the behaviour of the cgroup as an
aggregate.
The intention is that the various resource management and
virtualization/cgroup efforts can also become task cgroup
clients, with the result that:
- the userspace APIs are (somewhat) normalised
- it's easier to test e.g. the ResGroups CPU controller in
conjunction with the BeanCounters memory controller, or use either of
them as the resource-control portion of a virtual server system.
- the additional kernel footprint of any of the competing resource
management systems is substantially reduced, since it doesn't need
to provide process grouping/containment, hence improving their
chances of getting into the kernel
This patch:
Add the main task cgroups framework - the cgroup filesystem, and the
basic structures for tracking membership and associating subsystem state
objects to tasks.
Signed-off-by: Paul Menage <menage@google.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 10:39:30 +04:00
config CGROUPS
bool "Control Group support"
help
This option will let you use process cgroup subsystems
such as Cpusets
Say N if unsure.
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config CGROUP_DEBUG
bool "Example debug cgroup subsystem"
depends on CGROUPS
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default n
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help
This option enables a simple cgroup subsystem that
exports useful debugging information about the cgroups
framework
Say N if unsure
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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.
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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.
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config CPUSETS
bool "Cpuset support"
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depends on SMP && CGROUPS
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help
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This option will let you create and manage CPUSETs which
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allow dynamically partitioning a system into sets of CPUs and
Memory Nodes and assigning tasks to run only within those sets.
This is primarily useful on large SMP or NUMA systems.
Say N if unsure.
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config GROUP_SCHED
bool "Group CPU scheduler"
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default y
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help
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This feature lets CPU scheduler recognize task groups and control CPU
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bandwidth allocation to such task groups.
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config FAIR_GROUP_SCHED
bool "Group scheduling for SCHED_OTHER"
depends on GROUP_SCHED
default y
config RT_GROUP_SCHED
bool "Group scheduling for SCHED_RR/FIFO"
depends on EXPERIMENTAL
depends on GROUP_SCHED
default n
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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/sched-rt-group.txt for more information.
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2007-10-15 19:00:09 +04:00
choice
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depends on GROUP_SCHED
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prompt "Basis for grouping tasks"
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default USER_SCHED
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config USER_SCHED
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bool "user id"
help
This option will choose userid as the basis for grouping
tasks, thus providing equal CPU bandwidth to each user.
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config CGROUP_SCHED
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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.
2007-10-15 19:00:09 +04:00
endchoice
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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
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config RESOURCE_COUNTERS
bool "Resource counters"
help
This option enables controller independent resource accounting
infrastructure that works with cgroups
depends on CGROUPS
cgroups: add an owner to the mm_struct
Remove the mem_cgroup member from mm_struct and instead adds an owner.
This approach was suggested by Paul Menage. The advantage of this approach
is that, once the mm->owner is known, using the subsystem id, the cgroup
can be determined. It also allows several control groups that are
virtually grouped by mm_struct, to exist independent of the memory
controller i.e., without adding mem_cgroup's for each controller, to
mm_struct.
A new config option CONFIG_MM_OWNER is added and the memory resource
controller selects this config option.
This patch also adds cgroup callbacks to notify subsystems when mm->owner
changes. The mm_cgroup_changed callback is called with the task_lock() of
the new task held and is called just prior to changing the mm->owner.
I am indebted to Paul Menage for the several reviews of this patchset and
helping me make it lighter and simpler.
This patch was tested on a powerpc box, it was compiled with both the
MM_OWNER config turned on and off.
After the thread group leader exits, it's moved to init_css_state by
cgroup_exit(), thus all future charges from runnings threads would be
redirected to the init_css_set's subsystem.
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Hirokazu Takahashi <taka@valinux.co.jp>
Cc: David Rientjes <rientjes@google.com>,
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 12:00:16 +04:00
config MM_OWNER
bool
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config CGROUP_MEM_RES_CTLR
bool "Memory Resource Controller for Control Groups"
depends on CGROUPS && RESOURCE_COUNTERS
cgroups: add an owner to the mm_struct
Remove the mem_cgroup member from mm_struct and instead adds an owner.
This approach was suggested by Paul Menage. The advantage of this approach
is that, once the mm->owner is known, using the subsystem id, the cgroup
can be determined. It also allows several control groups that are
virtually grouped by mm_struct, to exist independent of the memory
controller i.e., without adding mem_cgroup's for each controller, to
mm_struct.
A new config option CONFIG_MM_OWNER is added and the memory resource
controller selects this config option.
This patch also adds cgroup callbacks to notify subsystems when mm->owner
changes. The mm_cgroup_changed callback is called with the task_lock() of
the new task held and is called just prior to changing the mm->owner.
I am indebted to Paul Menage for the several reviews of this patchset and
helping me make it lighter and simpler.
This patch was tested on a powerpc box, it was compiled with both the
MM_OWNER config turned on and off.
After the thread group leader exits, it's moved to init_css_state by
cgroup_exit(), thus all future charges from runnings threads would be
redirected to the init_css_set's subsystem.
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Hirokazu Takahashi <taka@valinux.co.jp>
Cc: David Rientjes <rientjes@google.com>,
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 12:00:16 +04:00
select MM_OWNER
2008-03-05 01:28:39 +03:00
help
Provides a memory resource controller that manages both page cache and
RSS memory.
Note that setting this option increases fixed memory overhead
associated with each page of memory in the system by 4/8 bytes
and also increases cache misses because struct page on many 64bit
systems will not fit into a single cache line anymore.
Only enable when you're ok with these trade offs and really
sure you need the memory resource controller.
cgroups: add an owner to the mm_struct
Remove the mem_cgroup member from mm_struct and instead adds an owner.
This approach was suggested by Paul Menage. The advantage of this approach
is that, once the mm->owner is known, using the subsystem id, the cgroup
can be determined. It also allows several control groups that are
virtually grouped by mm_struct, to exist independent of the memory
controller i.e., without adding mem_cgroup's for each controller, to
mm_struct.
A new config option CONFIG_MM_OWNER is added and the memory resource
controller selects this config option.
This patch also adds cgroup callbacks to notify subsystems when mm->owner
changes. The mm_cgroup_changed callback is called with the task_lock() of
the new task held and is called just prior to changing the mm->owner.
I am indebted to Paul Menage for the several reviews of this patchset and
helping me make it lighter and simpler.
This patch was tested on a powerpc box, it was compiled with both the
MM_OWNER config turned on and off.
After the thread group leader exits, it's moved to init_css_state by
cgroup_exit(), thus all future charges from runnings threads would be
redirected to the init_css_set's subsystem.
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Hirokazu Takahashi <taka@valinux.co.jp>
Cc: David Rientjes <rientjes@google.com>,
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 12:00:16 +04:00
This config option also selects MM_OWNER config option, which
could in turn add some fork/exit overhead.
2006-09-14 13:23:28 +04:00
config SYSFS_DEPRECATED
2008-03-04 16:54:47 +03:00
bool
config SYSFS_DEPRECATED_V2
2006-09-14 13:23:28 +04:00
bool "Create deprecated sysfs files"
2007-12-31 21:05:34 +03:00
depends on SYSFS
2006-09-14 13:23:28 +04:00
default y
2008-03-04 16:54:47 +03:00
select SYSFS_DEPRECATED
2006-09-14 13:23:28 +04:00
help
This option creates deprecated symlinks such as the
"device"-link, the <subsystem>:<name>-link, and the
"bus"-link. It may also add deprecated key in the
uevent environment.
None of these features or values should be used today, as
they export driver core implementation details to userspace
or export properties which can't be kept stable across kernel
releases.
If enabled, this option will also move any device structures
2007-05-09 09:12:20 +04:00
that belong to a class, back into the /sys/class hierarchy, in
2008-03-04 01:47:13 +03:00
order to support older versions of udev and some userspace
programs.
2006-09-14 13:23:28 +04:00
2008-03-04 01:47:13 +03:00
If you are using a distro with the most recent userspace
packages, it should be safe to say N here.
2006-09-14 13:23:28 +04:00
2007-10-19 10:39:39 +04:00
config PROC_PID_CPUSET
bool "Include legacy /proc/<pid>/cpuset file"
depends on CPUSETS
default y
2006-03-23 21:56:55 +03:00
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.
2008-02-08 15:18:19 +03:00
config NAMESPACES
bool "Namespaces support" if EMBEDDED
default !EMBEDDED
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.
2008-02-08 15:18:21 +03:00
config UTS_NS
bool "UTS namespace"
depends on NAMESPACES
help
In this namespace tasks see different info provided with the
uname() system call
2008-02-08 15:18:22 +03:00
config IPC_NS
bool "IPC namespace"
depends on NAMESPACES && SYSVIPC
help
In this namespace tasks work with IPC ids which correspond to
different IPC objects in different namespaces
2008-02-08 15:18:23 +03:00
config USER_NS
bool "User namespace (EXPERIMENTAL)"
depends on NAMESPACES && EXPERIMENTAL
help
This allows containers, i.e. vservers, to use user namespaces
to provide different user info for different servers.
If unsure, say N.
2008-02-08 15:18:24 +03:00
config PID_NS
bool "PID Namespaces (EXPERIMENTAL)"
default n
depends on NAMESPACES && EXPERIMENTAL
help
Suport process id namespaces. This allows having multiple
process 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.
2007-03-06 12:42:17 +03:00
config BLK_DEV_INITRD
bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
depends on BROKEN || !FRV
help
The initial RAM filesystem is a ramfs which is loaded by the
boot loader (loadlin or lilo) and that is mounted as root
before the normal boot procedure. It is typically used to
load modules needed to mount the "real" root file system,
etc. See <file:Documentation/initrd.txt> for details.
If RAM disk support (BLK_DEV_RAM) is also included, this
also enables initial RAM disk (initrd) support and adds
15 Kbytes (more on some other architectures) to the kernel size.
If unsure say Y.
2007-02-10 12:44:43 +03:00
if BLK_DEV_INITRD
2005-08-10 22:44:50 +04:00
source "usr/Kconfig"
2007-02-10 12:44:43 +03:00
endif
Move size optimization option outside of EMBEDDED menu, mark it EXPERIMENTAL
Also, disable on sparc64 - a number of people report breakage. Probably
a compiler bug, but it's quite possible that it tickles some latent
kernel problem too.
It still defaults to 'y' everywhere else (when enabled through
EXPERIMENTAL), and Dave Jones points out that Fedora (and RHEL4) has
been building with size optimizations for a long time on x86, x86-64,
ia64, s390, s390x, ppc32 and ppc64. So it is really only moderately
experimental, but the sparc64 breakage certainly shows that it can
trigger "issues".
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-12-15 05:52:21 +03:00
config CC_OPTIMIZE_FOR_SIZE
2008-04-28 03:39:43 +04:00
bool "Optimize for size"
Move size optimization option outside of EMBEDDED menu, mark it EXPERIMENTAL
Also, disable on sparc64 - a number of people report breakage. Probably
a compiler bug, but it's quite possible that it tickles some latent
kernel problem too.
It still defaults to 'y' everywhere else (when enabled through
EXPERIMENTAL), and Dave Jones points out that Fedora (and RHEL4) has
been building with size optimizations for a long time on x86, x86-64,
ia64, s390, s390x, ppc32 and ppc64. So it is really only moderately
experimental, but the sparc64 breakage certainly shows that it can
trigger "issues".
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-12-15 05:52:21 +03:00
default y
help
Enabling this option will pass "-Os" instead of "-O2" to gcc
resulting in a smaller kernel.
If unsure, say N.
2006-10-01 10:28:13 +04:00
config SYSCTL
bool
2005-04-17 02:20:36 +04:00
menuconfig EMBEDDED
bool "Configure standard kernel features (for small systems)"
help
This option allows certain base kernel options and settings
to be disabled or tweaked. This is for specialized
environments which can tolerate a "non-standard" kernel.
Only use this if you really know what you are doing.
2006-09-16 23:15:53 +04:00
config UID16
bool "Enable 16-bit UID system calls" if EMBEDDED
2008-04-26 14:17:12 +04:00
depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
2006-09-16 23:15:53 +04:00
default y
help
This enables the legacy 16-bit UID syscall wrappers.
2006-09-27 12:51:04 +04:00
config SYSCTL_SYSCALL
2006-10-01 10:28:13 +04:00
bool "Sysctl syscall support" if EMBEDDED
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default y
2006-09-27 12:51:04 +04:00
select SYSCTL
2006-09-16 23:15:53 +04:00
---help---
2006-11-09 04:44:51 +03:00
sys_sysctl uses binary paths that have been found challenging
to properly maintain and use. The interface in /proc/sys
using paths with ascii names is now the primary path to this
information.
2006-09-27 12:51:04 +04:00
2006-11-09 04:44:51 +03:00
Almost nothing using the binary sysctl interface so if you are
trying to save some space it is probably safe to disable this,
making your kernel marginally smaller.
2006-09-27 12:51:04 +04:00
2006-11-09 04:44:51 +03:00
If unsure say Y here.
2006-09-16 23:15:53 +04:00
2008-04-29 12:02:36 +04:00
config SYSCTL_SYSCALL_CHECK
bool "Sysctl checks" if EMBEDDED
depends on SYSCTL_SYSCALL
default y
---help---
sys_sysctl uses binary paths that have been found challenging
to properly maintain and use. This enables checks that help
you to keep things correct.
If unsure say Y here.
2005-04-17 02:20:36 +04:00
config KALLSYMS
2006-12-12 21:25:11 +03:00
bool "Load all symbols for debugging/ksymoops" if EMBEDDED
2005-04-17 02:20:36 +04:00
default y
help
Say Y here to let the kernel print out symbolic crash information and
symbolic stack backtraces. This increases the size of the kernel
somewhat, as all symbols have to be loaded into the kernel image.
config KALLSYMS_ALL
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
2005-07-20 07:43:05 +04:00
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.
2005-04-17 02:20:36 +04:00
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.
2005-05-01 19:59:02 +04:00
2005-11-16 22:27:07 +03:00
config HOTPLUG
bool "Support for hot-pluggable devices" if EMBEDDED
default y
help
This option is provided for the case where no hotplug or uevent
capabilities is wanted by the kernel. You should only consider
disabling this option for embedded systems that do not use modules, a
dynamic /dev tree, or dynamic device discovery. Just say Y.
2005-05-01 19:59:02 +04:00
config PRINTK
default y
bool "Enable support for printk" if EMBEDDED
help
This option enables normal printk support. Removing it
eliminates most of the message strings from the kernel image
and makes the kernel more or less silent. As this makes it
very difficult to diagnose system problems, saying N here is
strongly discouraged.
2005-05-01 19:59:01 +04:00
config BUG
bool "BUG() support" if EMBEDDED
default y
help
Disabling this option eliminates support for BUG and WARN, reducing
the size of your kernel image and potentially quietly ignoring
numerous fatal conditions. You should only consider disabling this
option for embedded systems with no facilities for reporting errors.
Just say Y.
2006-01-08 12:05:25 +03:00
config ELF_CORE
default y
bool "Enable ELF core dumps" if EMBEDDED
help
Enable support for generating core dumps. Disabling saves about 4k.
2008-02-07 00:39:44 +03:00
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.
2008-02-10 01:24:09 +03:00
On non-ancient distros (post-2000 ones) N is usually a safe choice.
2008-02-07 00:39:44 +03:00
2005-04-17 02:20:36 +04:00
config BASE_FULL
default y
bool "Enable full-sized data structures for core" if EMBEDDED
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
default y
2006-06-27 13:54:53 +04:00
select RT_MUTEXES
2005-04-17 02:20:36 +04:00
help
Disabling this option will cause the kernel to be built without
support for "fast userspace mutexes". The resulting kernel may not
run glibc-based applications correctly.
2007-05-11 09:23:11 +04:00
config ANON_INODES
2007-07-31 11:39:10 +04:00
bool
2007-05-11 09:23:11 +04:00
2005-04-17 02:20:36 +04:00
config EPOLL
bool "Enable eventpoll support" if EMBEDDED
default y
2007-07-31 11:39:10 +04:00
select ANON_INODES
2005-04-17 02:20:36 +04:00
help
Disabling this option will cause the kernel to be built without
support for epoll family of system calls.
signal/timer/event: signalfd core
This patch series implements the new signalfd() system call.
I took part of the original Linus code (and you know how badly it can be
broken :), and I added even more breakage ;) Signals are fetched from the same
signal queue used by the process, so signalfd will compete with standard
kernel delivery in dequeue_signal(). If you want to reliably fetch signals on
the signalfd file, you need to block them with sigprocmask(SIG_BLOCK). This
seems to be working fine on my Dual Opteron machine. I made a quick test
program for it:
http://www.xmailserver.org/signafd-test.c
The signalfd() system call implements signal delivery into a file descriptor
receiver. The signalfd file descriptor if created with the following API:
int signalfd(int ufd, const sigset_t *mask, size_t masksize);
The "ufd" parameter allows to change an existing signalfd sigmask, w/out going
to close/create cycle (Linus idea). Use "ufd" == -1 if you want a brand new
signalfd file.
The "mask" allows to specify the signal mask of signals that we are interested
in. The "masksize" parameter is the size of "mask".
The signalfd fd supports the poll(2) and read(2) system calls. The poll(2)
will return POLLIN when signals are available to be dequeued. As a direct
consequence of supporting the Linux poll subsystem, the signalfd fd can use
used together with epoll(2) too.
The read(2) system call will return a "struct signalfd_siginfo" structure in
the userspace supplied buffer. The return value is the number of bytes copied
in the supplied buffer, or -1 in case of error. The read(2) call can also
return 0, in case the sighand structure to which the signalfd was attached,
has been orphaned. The O_NONBLOCK flag is also supported, and read(2) will
return -EAGAIN in case no signal is available.
If the size of the buffer passed to read(2) is lower than sizeof(struct
signalfd_siginfo), -EINVAL is returned. A read from the signalfd can also
return -ERESTARTSYS in case a signal hits the process. The format of the
struct signalfd_siginfo is, and the valid fields depends of the (->code &
__SI_MASK) value, in the same way a struct siginfo would:
struct signalfd_siginfo {
__u32 signo; /* si_signo */
__s32 err; /* si_errno */
__s32 code; /* si_code */
__u32 pid; /* si_pid */
__u32 uid; /* si_uid */
__s32 fd; /* si_fd */
__u32 tid; /* si_fd */
__u32 band; /* si_band */
__u32 overrun; /* si_overrun */
__u32 trapno; /* si_trapno */
__s32 status; /* si_status */
__s32 svint; /* si_int */
__u64 svptr; /* si_ptr */
__u64 utime; /* si_utime */
__u64 stime; /* si_stime */
__u64 addr; /* si_addr */
};
[akpm@linux-foundation.org: fix signalfd_copyinfo() on i386]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 09:23:13 +04:00
config SIGNALFD
bool "Enable signalfd() system call" if EMBEDDED
2007-07-31 11:39:10 +04:00
select ANON_INODES
signal/timer/event: signalfd core
This patch series implements the new signalfd() system call.
I took part of the original Linus code (and you know how badly it can be
broken :), and I added even more breakage ;) Signals are fetched from the same
signal queue used by the process, so signalfd will compete with standard
kernel delivery in dequeue_signal(). If you want to reliably fetch signals on
the signalfd file, you need to block them with sigprocmask(SIG_BLOCK). This
seems to be working fine on my Dual Opteron machine. I made a quick test
program for it:
http://www.xmailserver.org/signafd-test.c
The signalfd() system call implements signal delivery into a file descriptor
receiver. The signalfd file descriptor if created with the following API:
int signalfd(int ufd, const sigset_t *mask, size_t masksize);
The "ufd" parameter allows to change an existing signalfd sigmask, w/out going
to close/create cycle (Linus idea). Use "ufd" == -1 if you want a brand new
signalfd file.
The "mask" allows to specify the signal mask of signals that we are interested
in. The "masksize" parameter is the size of "mask".
The signalfd fd supports the poll(2) and read(2) system calls. The poll(2)
will return POLLIN when signals are available to be dequeued. As a direct
consequence of supporting the Linux poll subsystem, the signalfd fd can use
used together with epoll(2) too.
The read(2) system call will return a "struct signalfd_siginfo" structure in
the userspace supplied buffer. The return value is the number of bytes copied
in the supplied buffer, or -1 in case of error. The read(2) call can also
return 0, in case the sighand structure to which the signalfd was attached,
has been orphaned. The O_NONBLOCK flag is also supported, and read(2) will
return -EAGAIN in case no signal is available.
If the size of the buffer passed to read(2) is lower than sizeof(struct
signalfd_siginfo), -EINVAL is returned. A read from the signalfd can also
return -ERESTARTSYS in case a signal hits the process. The format of the
struct signalfd_siginfo is, and the valid fields depends of the (->code &
__SI_MASK) value, in the same way a struct siginfo would:
struct signalfd_siginfo {
__u32 signo; /* si_signo */
__s32 err; /* si_errno */
__s32 code; /* si_code */
__u32 pid; /* si_pid */
__u32 uid; /* si_uid */
__s32 fd; /* si_fd */
__u32 tid; /* si_fd */
__u32 band; /* si_band */
__u32 overrun; /* si_overrun */
__u32 trapno; /* si_trapno */
__s32 status; /* si_status */
__s32 svint; /* si_int */
__u64 svptr; /* si_ptr */
__u64 utime; /* si_utime */
__u64 stime; /* si_stime */
__u64 addr; /* si_addr */
};
[akpm@linux-foundation.org: fix signalfd_copyinfo() on i386]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 09:23:13 +04:00
default y
help
Enable the signalfd() system call that allows to receive signals
on a file descriptor.
If unsure, say Y.
signal/timer/event: timerfd core
This patch introduces a new system call for timers events delivered though
file descriptors. This allows timer event to be used with standard POSIX
poll(2), select(2) and read(2). As a consequence of supporting the Linux
f_op->poll subsystem, they can be used with epoll(2) too.
The system call is defined as:
int timerfd(int ufd, int clockid, int flags, const struct itimerspec *utmr);
The "ufd" parameter allows for re-use (re-programming) of an existing timerfd
w/out going through the close/open cycle (same as signalfd). If "ufd" is -1,
s new file descriptor will be created, otherwise the existing "ufd" will be
re-programmed.
The "clockid" parameter is either CLOCK_MONOTONIC or CLOCK_REALTIME. The time
specified in the "utmr->it_value" parameter is the expiry time for the timer.
If the TFD_TIMER_ABSTIME flag is set in "flags", this is an absolute time,
otherwise it's a relative time.
If the time specified in the "utmr->it_interval" is not zero (.tv_sec == 0,
tv_nsec == 0), this is the period at which the following ticks should be
generated.
The "utmr->it_interval" should be set to zero if only one tick is requested.
Setting the "utmr->it_value" to zero will disable the timer, or will create a
timerfd without the timer enabled.
The function returns the new (or same, in case "ufd" is a valid timerfd
descriptor) file, or -1 in case of error.
As stated before, the timerfd file descriptor supports poll(2), select(2) and
epoll(2). When a timer event happened on the timerfd, a POLLIN mask will be
returned.
The read(2) call can be used, and it will return a u32 variable holding the
number of "ticks" that happened on the interface since the last call to
read(2). The read(2) call supportes the O_NONBLOCK flag too, and EAGAIN will
be returned if no ticks happened.
A quick test program, shows timerfd working correctly on my amd64 box:
http://www.xmailserver.org/timerfd-test.c
[akpm@linux-foundation.org: add sys_timerfd to sys_ni.c]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 09:23:16 +04:00
config TIMERFD
bool "Enable timerfd() system call" if EMBEDDED
2007-07-31 11:39:10 +04:00
select ANON_INODES
signal/timer/event: timerfd core
This patch introduces a new system call for timers events delivered though
file descriptors. This allows timer event to be used with standard POSIX
poll(2), select(2) and read(2). As a consequence of supporting the Linux
f_op->poll subsystem, they can be used with epoll(2) too.
The system call is defined as:
int timerfd(int ufd, int clockid, int flags, const struct itimerspec *utmr);
The "ufd" parameter allows for re-use (re-programming) of an existing timerfd
w/out going through the close/open cycle (same as signalfd). If "ufd" is -1,
s new file descriptor will be created, otherwise the existing "ufd" will be
re-programmed.
The "clockid" parameter is either CLOCK_MONOTONIC or CLOCK_REALTIME. The time
specified in the "utmr->it_value" parameter is the expiry time for the timer.
If the TFD_TIMER_ABSTIME flag is set in "flags", this is an absolute time,
otherwise it's a relative time.
If the time specified in the "utmr->it_interval" is not zero (.tv_sec == 0,
tv_nsec == 0), this is the period at which the following ticks should be
generated.
The "utmr->it_interval" should be set to zero if only one tick is requested.
Setting the "utmr->it_value" to zero will disable the timer, or will create a
timerfd without the timer enabled.
The function returns the new (or same, in case "ufd" is a valid timerfd
descriptor) file, or -1 in case of error.
As stated before, the timerfd file descriptor supports poll(2), select(2) and
epoll(2). When a timer event happened on the timerfd, a POLLIN mask will be
returned.
The read(2) call can be used, and it will return a u32 variable holding the
number of "ticks" that happened on the interface since the last call to
read(2). The read(2) call supportes the O_NONBLOCK flag too, and EAGAIN will
be returned if no ticks happened.
A quick test program, shows timerfd working correctly on my amd64 box:
http://www.xmailserver.org/timerfd-test.c
[akpm@linux-foundation.org: add sys_timerfd to sys_ni.c]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 09:23:16 +04:00
default y
help
Enable the timerfd() system call that allows to receive timer
events on a file descriptor.
If unsure, say Y.
signal/timer/event: eventfd core
This is a very simple and light file descriptor, that can be used as event
wait/dispatch by userspace (both wait and dispatch) and by the kernel
(dispatch only). It can be used instead of pipe(2) in all cases where those
would simply be used to signal events. Their kernel overhead is much lower
than pipes, and they do not consume two fds. When used in the kernel, it can
offer an fd-bridge to enable, for example, functionalities like KAIO or
syslets/threadlets to signal to an fd the completion of certain operations.
But more in general, an eventfd can be used by the kernel to signal readiness,
in a POSIX poll/select way, of interfaces that would otherwise be incompatible
with it. The API is:
int eventfd(unsigned int count);
The eventfd API accepts an initial "count" parameter, and returns an eventfd
fd. It supports poll(2) (POLLIN, POLLOUT, POLLERR), read(2) and write(2).
The POLLIN flag is raised when the internal counter is greater than zero.
The POLLOUT flag is raised when at least a value of "1" can be written to the
internal counter.
The POLLERR flag is raised when an overflow in the counter value is detected.
The write(2) operation can never overflow the counter, since it blocks (unless
O_NONBLOCK is set, in which case -EAGAIN is returned).
But the eventfd_signal() function can do it, since it's supposed to not sleep
during its operation.
The read(2) function reads the __u64 counter value, and reset the internal
value to zero. If the value read is equal to (__u64) -1, an overflow happened
on the internal counter (due to 2^64 eventfd_signal() posts that has never
been retired - unlickely, but possible).
The write(2) call writes an __u64 count value, and adds it to the current
counter. The eventfd fd supports O_NONBLOCK also.
On the kernel side, we have:
struct file *eventfd_fget(int fd);
int eventfd_signal(struct file *file, unsigned int n);
The eventfd_fget() should be called to get a struct file* from an eventfd fd
(this is an fget() + check of f_op being an eventfd fops pointer).
The kernel can then call eventfd_signal() every time it wants to post an event
to userspace. The eventfd_signal() function can be called from any context.
An eventfd() simple test and bench is available here:
http://www.xmailserver.org/eventfd-bench.c
This is the eventfd-based version of pipetest-4 (pipe(2) based):
http://www.xmailserver.org/pipetest-4.c
Not that performance matters much in the eventfd case, but eventfd-bench
shows almost as double as performance than pipetest-4.
[akpm@linux-foundation.org: fix i386 build]
[akpm@linux-foundation.org: add sys_eventfd to sys_ni.c]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 09:23:19 +04:00
config EVENTFD
bool "Enable eventfd() system call" if EMBEDDED
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select ANON_INODES
signal/timer/event: eventfd core
This is a very simple and light file descriptor, that can be used as event
wait/dispatch by userspace (both wait and dispatch) and by the kernel
(dispatch only). It can be used instead of pipe(2) in all cases where those
would simply be used to signal events. Their kernel overhead is much lower
than pipes, and they do not consume two fds. When used in the kernel, it can
offer an fd-bridge to enable, for example, functionalities like KAIO or
syslets/threadlets to signal to an fd the completion of certain operations.
But more in general, an eventfd can be used by the kernel to signal readiness,
in a POSIX poll/select way, of interfaces that would otherwise be incompatible
with it. The API is:
int eventfd(unsigned int count);
The eventfd API accepts an initial "count" parameter, and returns an eventfd
fd. It supports poll(2) (POLLIN, POLLOUT, POLLERR), read(2) and write(2).
The POLLIN flag is raised when the internal counter is greater than zero.
The POLLOUT flag is raised when at least a value of "1" can be written to the
internal counter.
The POLLERR flag is raised when an overflow in the counter value is detected.
The write(2) operation can never overflow the counter, since it blocks (unless
O_NONBLOCK is set, in which case -EAGAIN is returned).
But the eventfd_signal() function can do it, since it's supposed to not sleep
during its operation.
The read(2) function reads the __u64 counter value, and reset the internal
value to zero. If the value read is equal to (__u64) -1, an overflow happened
on the internal counter (due to 2^64 eventfd_signal() posts that has never
been retired - unlickely, but possible).
The write(2) call writes an __u64 count value, and adds it to the current
counter. The eventfd fd supports O_NONBLOCK also.
On the kernel side, we have:
struct file *eventfd_fget(int fd);
int eventfd_signal(struct file *file, unsigned int n);
The eventfd_fget() should be called to get a struct file* from an eventfd fd
(this is an fget() + check of f_op being an eventfd fops pointer).
The kernel can then call eventfd_signal() every time it wants to post an event
to userspace. The eventfd_signal() function can be called from any context.
An eventfd() simple test and bench is available here:
http://www.xmailserver.org/eventfd-bench.c
This is the eventfd-based version of pipetest-4 (pipe(2) based):
http://www.xmailserver.org/pipetest-4.c
Not that performance matters much in the eventfd case, but eventfd-bench
shows almost as double as performance than pipetest-4.
[akpm@linux-foundation.org: fix i386 build]
[akpm@linux-foundation.org: add sys_eventfd to sys_ni.c]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 09:23:19 +04:00
default y
help
Enable the eventfd() system call that allows to receive both
kernel notification (ie. KAIO) or userspace notifications.
If unsure, say Y.
2005-04-17 02:20:36 +04:00
config SHMEM
bool "Use full shmem filesystem" if EMBEDDED
default y
depends on MMU
help
The shmem is an internal filesystem used to manage shared memory.
It is backed by swap and manages resource limits. It is also exported
to userspace as tmpfs if TMPFS is enabled. Disabling this
option replaces shmem and tmpfs with the much simpler ramfs code,
which may be appropriate on small systems without swap.
2006-06-30 12:55:45 +04:00
config VM_EVENT_COUNTERS
default y
bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
help
2006-12-22 12:06:10 +03:00
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
if VM event counters are disabled.
2006-06-30 12:55:45 +04:00
2007-05-09 13:32:44 +04:00
config SLUB_DEBUG
default y
bool "Enable SLUB debugging support" if EMBEDDED
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depends on SLUB
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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.
2007-05-07 01:49:36 +04:00
choice
prompt "Choose SLAB allocator"
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default SLUB
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help
This option allows to select a slab allocator.
config SLAB
bool "SLAB"
help
The regular slab allocator that is established and known to work
2007-05-09 13:32:47 +04:00
well in all environments. It organizes cache hot objects in
2007-05-07 01:49:36 +04:00
per cpu and per node queues. SLAB is the default choice for
2007-05-09 13:32:47 +04:00
a slab allocator.
2007-05-07 01:49:36 +04:00
config SLUB
bool "SLUB (Unqueued Allocator)"
help
SLUB is a slab allocator that minimizes cache line usage
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
2007-05-09 13:32:47 +04:00
and has enhanced diagnostics.
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config SLOB
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depends on EMBEDDED
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bool "SLOB (Simple Allocator)"
help
2008-02-05 09:29:38 +03:00
SLOB replaces the stock allocator with a drastically simpler
allocator. SLOB is generally more space efficient but
does not perform as well on large systems.
2007-05-07 01:49:36 +04:00
endchoice
2008-02-02 23:10:36 +03:00
config PROFILING
bool "Profiling support (EXPERIMENTAL)"
help
Say Y here to enable the extended profiling support mechanisms used
by profilers such as OProfile.
config MARKERS
bool "Activate markers"
help
Place an empty function call at each marker site. Can be
dynamically changed for a probe function.
2008-02-02 23:10:33 +03:00
source "arch/Kconfig"
2008-02-05 09:29:07 +03:00
config PROC_PAGE_MONITOR
default y
depends on PROC_FS && MMU
bool "Enable /proc page monitoring" if EMBEDDED
help
Various /proc files exist to monitor process memory utilization:
/proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
/proc/kpagecount, and /proc/kpageflags. Disabling these
interfaces will reduce the size of the kernel by approximately 4kb.
2005-04-17 02:20:36 +04:00
endmenu # General setup
2008-01-03 00:04:48 +03:00
config SLABINFO
bool
depends on PROC_FS
2008-04-14 19:53:02 +04:00
depends on SLAB || SLUB_DEBUG
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default y
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config RT_MUTEXES
boolean
select PLIST
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config TINY_SHMEM
default !SHMEM
bool
config BASE_SMALL
int
default 0 if BASE_FULL
default 1 if !BASE_FULL
2007-07-16 10:39:29 +04:00
menuconfig MODULES
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bool "Enable loadable module support"
help
Kernel modules are small pieces of compiled code which can
be inserted in the running kernel, rather than being
permanently built into the kernel. You use the "modprobe"
tool to add (and sometimes remove) them. If you say Y here,
many parts of the kernel can be built as modules (by
answering M instead of Y where indicated): this is most
useful for infrequently used options which are not required
for booting. For more information, see the man pages for
modprobe, lsmod, modinfo, insmod and rmmod.
If you say Y here, you will need to run "make
modules_install" to put the modules under /lib/modules/
where modprobe can find them (you may need to be root to do
this).
If unsure, say Y.
config MODULE_UNLOAD
bool "Module unloading"
depends on MODULES
help
Without this option you will not be able to unload any
modules (note that some modules may not be unloadable
anyway), which makes your kernel slightly smaller and
simpler. If unsure, say Y.
config MODULE_FORCE_UNLOAD
bool "Forced module unloading"
depends on MODULE_UNLOAD && EXPERIMENTAL
help
This option allows you to force a module to unload, even if the
kernel believes it is unsafe: the kernel will remove the module
without waiting for anyone to stop using it (using the -f option to
rmmod). This is mainly for kernel developers and desperate users.
If unsure, say N.
config MODVERSIONS
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bool "Module versioning support"
depends on MODULES
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help
Usually, you have to use modules compiled with your kernel.
Saying Y here makes it sometimes possible to use modules
compiled for different kernels, by adding enough information
to the modules to (hopefully) spot any changes which would
make them incompatible with the kernel you are running. If
unsure, say N.
config MODULE_SRCVERSION_ALL
bool "Source checksum for all modules"
depends on MODULES
help
Modules which contain a MODULE_VERSION get an extra "srcversion"
field inserted into their modinfo section, which contains a
sum of the source files which made it. This helps maintainers
see exactly which source was used to build a module (since
others sometimes change the module source without updating
the version). With this option, such a "srcversion" field
will be created for all modules. If unsure, say N.
config KMOD
bool "Automatic kernel module loading"
depends on MODULES
help
Normally when you have selected some parts of the kernel to
be created as kernel modules, you must load them (using the
"modprobe" command) before you can use them. If you say Y
here, some parts of the kernel will be able to load modules
automatically: when a part of the kernel needs a module, it
runs modprobe with the appropriate arguments, thereby
loading the module if it is available. If unsure, say Y.
config STOP_MACHINE
bool
default y
depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
help
Need stop_machine() primitive.
2005-11-04 10:43:35 +03:00
source "block/Kconfig"
2007-10-17 10:27:31 +04:00
config PREEMPT_NOTIFIERS
bool
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config CLASSIC_RCU
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def_bool !PREEMPT_RCU
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help
This option selects the classic RCU implementation that is
designed for best read-side performance on non-realtime
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systems. Classic RCU is the default. Note that the
PREEMPT_RCU symbol is used to select/deselect this option.