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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"
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default "$ARCH_DEFCONFIG"
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default "arch/$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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2007-05-02 01:08:11 +04:00
(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".)
2005-07-31 12:57:49 +04:00
2009-01-05 02:41:25 +03:00
config HAVE_KERNEL_GZIP
bool
config HAVE_KERNEL_BZIP2
bool
config HAVE_KERNEL_LZMA
bool
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choice
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prompt "Kernel compression mode"
default KERNEL_GZIP
depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA
help
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The linux kernel is a kind of self-extracting executable.
Several compression algorithms are available, which differ
in efficiency, compression and decompression speed.
Compression speed is only relevant when building a kernel.
Decompression speed is relevant at each boot.
If you have any problems with bzip2 or lzma compressed
kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
version of this functionality (bzip2 only), for 2.4, was
supplied by Christian Ludwig)
High compression options are mostly useful for users, who
are low on disk space (embedded systems), but for whom ram
size matters less.
If in doubt, select 'gzip'
config KERNEL_GZIP
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bool "Gzip"
depends on HAVE_KERNEL_GZIP
help
The old and tried gzip compression. Its compression ratio is
the poorest among the 3 choices; however its speed (both
compression and decompression) is the fastest.
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config KERNEL_BZIP2
bool "Bzip2"
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depends on HAVE_KERNEL_BZIP2
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help
Its compression ratio and speed is intermediate.
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Decompression speed is slowest among the three. The kernel
size is about 10% smaller with bzip2, in comparison to gzip.
Bzip2 uses a large amount of memory. For modern kernels you
will need at least 8MB RAM or more for booting.
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config KERNEL_LZMA
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bool "LZMA"
depends on HAVE_KERNEL_LZMA
help
The most recent compression algorithm.
Its ratio is best, decompression speed is between the other
two. Compression is slowest. The kernel size is about 33%
smaller with LZMA in comparison to gzip.
2009-01-05 00:46:17 +03:00
endchoice
2005-04-17 02:20:36 +04:00
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.
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config POSIX_MQUEUE_SYSCTL
bool
depends on POSIX_MQUEUE
depends on SYSCTL
default y
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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
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at <http://www.gnu.org/software/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
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depends on AUDITSYSCALL
select INOTIFY
[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
2009-01-15 23:28:29 +03:00
menu "RCU Subsystem"
choice
prompt "RCU Implementation"
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default TREE_RCU
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config CLASSIC_RCU
bool "Classic RCU"
help
This option selects the classic RCU implementation that is
designed for best read-side performance on non-realtime
systems.
Select this option if you are unsure.
config TREE_RCU
bool "Tree-based hierarchical RCU"
help
This option selects the RCU implementation that is
designed for very large SMP system with hundreds or
thousands of CPUs.
config PREEMPT_RCU
bool "Preemptible RCU"
depends on PREEMPT
help
This option reduces the latency of the kernel by making certain
RCU sections preemptible. Normally RCU code is non-preemptible, if
this option is selected then read-only RCU sections become
preemptible. This helps latency, but may expose bugs due to
now-naive assumptions about each RCU read-side critical section
remaining on a given CPU through its execution.
endchoice
config RCU_TRACE
bool "Enable tracing for RCU"
depends on TREE_RCU || PREEMPT_RCU
help
This option provides tracing in RCU which presents stats
in debugfs for debugging RCU implementation.
Say Y here if you want to enable RCU tracing
Say N if you are unsure.
config RCU_FANOUT
int "Tree-based hierarchical RCU fanout value"
range 2 64 if 64BIT
range 2 32 if !64BIT
depends on TREE_RCU
default 64 if 64BIT
default 32 if !64BIT
help
This option controls the fanout of hierarchical implementations
of RCU, allowing RCU to work efficiently on machines with
large numbers of CPUs. This value must be at least the cube
root of NR_CPUS, which allows NR_CPUS up to 32,768 for 32-bit
systems and up to 262,144 for 64-bit systems.
Select a specific number if testing RCU itself.
Take the default if unsure.
config RCU_FANOUT_EXACT
bool "Disable tree-based hierarchical RCU auto-balancing"
depends on TREE_RCU
default n
help
This option forces use of the exact RCU_FANOUT value specified,
regardless of imbalances in the hierarchy. This is useful for
testing RCU itself, and might one day be useful on systems with
strong NUMA behavior.
Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
Say N if unsure.
config TREE_RCU_TRACE
def_bool RCU_TRACE && TREE_RCU
select DEBUG_FS
help
This option provides tracing for the TREE_RCU implementation,
permitting Makefile to trivially select kernel/rcutree_trace.c.
config PREEMPT_RCU_TRACE
def_bool RCU_TRACE && PREEMPT_RCU
select DEBUG_FS
help
This option provides tracing for the PREEMPT_RCU implementation,
permitting Makefile to trivially select kernel/rcupreempt_trace.c.
endmenu # "RCU Subsystem"
2005-04-17 02:20:36 +04:00
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
2008-05-06 01:19:50 +04:00
#
# Architectures with an unreliable sched_clock() should select this:
#
config HAVE_UNSTABLE_SCHED_CLOCK
bool
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config GROUP_SCHED
bool "Group CPU scheduler"
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depends on EXPERIMENTAL
default n
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help
2007-10-15 19:00:12 +04:00
This feature lets CPU scheduler recognize task groups and control CPU
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bandwidth allocation to such task groups.
2009-01-08 05:07:30 +03:00
In order to create a group from arbitrary set of processes, use
CONFIG_CGROUPS. (See Control Group support.)
2007-10-15 19:00:07 +04:00
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config FAIR_GROUP_SCHED
bool "Group scheduling for SCHED_OTHER"
depends on GROUP_SCHED
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default GROUP_SCHED
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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.
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See Documentation/scheduler/sched-rt-group.txt for more information.
2008-02-13 17:45:40 +03:00
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.
2007-10-15 19:00:09 +04:00
2008-02-13 17:45:40 +03:00
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.
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Refer to Documentation/cgroups/cgroups.txt for more
information on "cgroup" pseudo filesystem.
2007-10-19 10:41:03 +04:00
2007-10-15 19:00:09 +04:00
endchoice
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menuconfig CGROUPS
boolean "Control Group support"
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help
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This option adds support for grouping sets of processes together, for
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use with process control subsystems such as Cpusets, CFS, memory
controls or device isolation.
See
- Documentation/scheduler/sched-design-CFS.txt (CFS)
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- Documentation/cgroups/ (features for grouping, isolation
and resource control)
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Say N if unsure.
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if CGROUPS
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config CGROUP_DEBUG
bool "Example debug cgroup subsystem"
depends on CGROUPS
default n
help
This option enables a simple cgroup subsystem that
exports useful debugging information about the cgroups
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framework.
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2009-01-16 00:50:58 +03:00
Say N if unsure.
2009-01-08 05:07:30 +03:00
config CGROUP_NS
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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.
2009-01-08 05:07:30 +03:00
config CGROUP_FREEZER
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bool "Freezer cgroup subsystem"
depends on CGROUPS
help
Provides a way to freeze and unfreeze all tasks in a
2009-01-08 05:07:30 +03:00
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"
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depends on CGROUPS
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help
This option will let you create and manage CPUSETs which
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 PROC_PID_CPUSET
bool "Include legacy /proc/<pid>/cpuset file"
depends on CPUSETS
default y
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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
2009-01-16 00:50:58 +03:00
total CPU consumed by the tasks in a cgroup.
2007-12-02 22:04:49 +03:00
2008-02-07 11:13:49 +03:00
config RESOURCE_COUNTERS
bool "Resource counters"
help
This option enables controller independent resource accounting
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infrastructure that works with cgroups.
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depends on CGROUPS
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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
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help
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Provides a memory resource controller that manages both anonymous
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memory and page cache. (See Documentation/cgroups/memory.txt)
2008-03-05 01:28:39 +03:00
Note that setting this option increases fixed memory overhead
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associated with each page of memory in the system. By this,
20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
usage tracking struct at boot. Total amount of this is printed out
at boot.
2008-03-05 01:28:39 +03:00
Only enable when you're ok with these trade offs and really
2008-10-30 00:01:06 +03:00
sure you need the memory resource controller. Even when you enable
this, you can set "cgroup_disable=memory" at your boot option to
disable memory resource controller and you can avoid overheads.
2009-01-08 05:07:35 +03:00
(and lose benefits of memory resource controller)
2008-03-05 01:28:39 +03:00
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.
2009-01-08 05:07:57 +03:00
config CGROUP_MEM_RES_CTLR_SWAP
bool "Memory Resource Controller Swap Extension(EXPERIMENTAL)"
depends on CGROUP_MEM_RES_CTLR && SWAP && EXPERIMENTAL
help
Add swap management feature to memory resource controller. When you
enable this, you can limit mem+swap usage per cgroup. In other words,
when you disable this, memory resource controller has no cares to
usage of swap...a process can exhaust all of the swap. This extension
is useful when you want to avoid exhaustion swap but this itself
adds more overheads and consumes memory for remembering information.
Especially if you use 32bit system or small memory system, please
be careful about enabling this. When memory resource controller
is disabled by boot option, this will be automatically disabled and
there will be no overhead from this. Even when you set this config=y,
if boot option "noswapaccount" is set, swap will not be accounted.
2009-04-03 03:57:47 +04:00
Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
size is 4096bytes, 512k per 1Gbytes of swap.
2009-01-08 05:07:57 +03:00
2009-01-16 00:50:58 +03:00
endif # CGROUPS
2009-01-08 05:07:57 +03:00
2009-01-16 00:50:58 +03:00
config MM_OWNER
bool
2009-01-08 05:07:30 +03:00
2006-09-14 13:23:28 +04:00
config SYSFS_DEPRECATED
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bool
config SYSFS_DEPRECATED_V2
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bool "Create deprecated sysfs layout for older userspace tools"
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depends on SYSFS
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default y
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select SYSFS_DEPRECATED
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help
2008-11-01 16:03:00 +03:00
This option switches the layout of sysfs to the deprecated
version.
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.
2006-09-14 13:23:28 +04:00
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"
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depends on NAMESPACES && (SYSVIPC || POSIX_MQUEUE)
2008-02-08 15:18:22 +03:00
help
In this namespace tasks work with IPC ids which correspond to
2009-04-07 06:01:08 +04:00
different IPC objects in different namespaces.
2008-02-08 15:18:22 +03:00
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
2008-07-06 16:48:02 +04:00
Support process id namespaces. This allows having multiple
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processes with the same pid as long as they are in different
2008-02-08 15:18:24 +03:00
pid namespaces. This is a building block of containers.
Unless you want to work with an experimental feature
say N here.
2009-01-26 23:25:55 +03:00
config NET_NS
bool "Network namespace"
default n
depends on NAMESPACES && EXPERIMENTAL && NET
help
Allow user space to create what appear to be multiple instances
of the network stack.
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
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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.
2008-07-16 02:31:16 +04:00
If unsure, say Y.
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
2006-10-01 10:28:13 +04:00
config SYSCTL
bool
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config ANON_INODES
bool
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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
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bool "Sysctl syscall support" if EMBEDDED
2006-11-09 04:44:51 +03:00
default y
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select SYSCTL
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---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
2005-04-17 02:20:36 +04:00
config KALLSYMS
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bool "Load all symbols for debugging/ksymoops" if EMBEDDED
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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.
2008-05-07 14:39:56 +04:00
config PCSPKR_PLATFORM
bool "Enable PC-Speaker support" if EMBEDDED
depends on ALPHA || X86 || MIPS || PPC_PREP || PPC_CHRP || PPC_PSERIES
default y
help
This option allows to disable the internal PC-Speaker
support, saving some memory.
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.
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
2007-07-31 11:39:10 +04:00
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.
2008-10-16 09:05:12 +04:00
config AIO
bool "Enable AIO support" if EMBEDDED
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.
2008-12-04 22:12:29 +03:00
config HAVE_PERF_COUNTERS
bool
2009-06-12 21:17:43 +04:00
help
See tools/perf/design.txt for details.
2008-12-04 22:12:29 +03:00
menu "Performance Counters"
config PERF_COUNTERS
bool "Kernel Performance Counters"
depends on HAVE_PERF_COUNTERS
2008-12-08 21:38:33 +03:00
select ANON_INODES
2008-12-04 22:12:29 +03:00
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.
2009-03-19 22:26:17 +03:00
config EVENT_PROFILE
bool "Tracepoint profile sources"
depends on PERF_COUNTERS && EVENT_TRACER
default y
2008-12-04 22:12:29 +03:00
endmenu
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
2008-08-19 12:28:24 +04:00
config PCI_QUIRKS
default y
2008-10-22 10:53:25 +04:00
bool "Enable PCI quirk workarounds" if EMBEDDED
depends on PCI
2008-08-19 12:28:24 +04:00
help
This enables workarounds for various PCI chipset
bugs/quirks. Disable this only if your target machine is
unaffected by PCI quirks.
2007-05-09 13:32:44 +04:00
config SLUB_DEBUG
default y
bool "Enable SLUB debugging support" if EMBEDDED
2008-04-30 03:16:06 +04:00
depends on SLUB && SYSFS
2007-05-09 13:32:44 +04:00
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.
2009-06-06 02:02:47 +04:00
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.
2009-03-10 22:55:46 +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
2009-01-26 13:12:25 +03:00
disabled, and can be overridden at runtime by setting
2009-03-10 22:55:46 +03:00
/proc/sys/kernel/randomize_va_space to 2.
On non-ancient distros (post-2000 ones) N is usually a safe choice.
2007-05-07 01:49:36 +04:00
choice
prompt "Choose SLAB allocator"
2007-07-17 15:03:32 +04:00
default SLUB
2007-05-07 01:49:36 +04:00
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
2008-11-06 01:18:19 +03:00
per cpu and per node queues.
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
2008-11-06 01:18:19 +03:00
and has enhanced diagnostics. SLUB is the default choice for
a slab allocator.
2007-05-07 01:49:36 +04:00
config SLOB
2007-07-16 10:38:24 +04:00
depends on EMBEDDED
2007-05-07 01:49:36 +04:00
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.
2008-07-23 16:15:22 +04:00
#
# Place an empty function call at each tracepoint site. Can be
# dynamically changed for a probe function.
#
tracing: Kernel Tracepoints
Implementation of kernel tracepoints. Inspired from the Linux Kernel
Markers. Allows complete typing verification by declaring both tracing
statement inline functions and probe registration/unregistration static
inline functions within the same macro "DEFINE_TRACE". No format string
is required. See the tracepoint Documentation and Samples patches for
usage examples.
Taken from the documentation patch :
"A tracepoint placed in code provides a hook to call a function (probe)
that you can provide at runtime. A tracepoint can be "on" (a probe is
connected to it) or "off" (no probe is attached). When a tracepoint is
"off" it has no effect, except for adding a tiny time penalty (checking
a condition for a branch) and space penalty (adding a few bytes for the
function call at the end of the instrumented function and adds a data
structure in a separate section). When a tracepoint is "on", the
function you provide is called each time the tracepoint is executed, in
the execution context of the caller. When the function provided ends its
execution, it returns to the caller (continuing from the tracepoint
site).
You can put tracepoints at important locations in the code. They are
lightweight hooks that can pass an arbitrary number of parameters, which
prototypes are described in a tracepoint declaration placed in a header
file."
Addition and removal of tracepoints is synchronized by RCU using the
scheduler (and preempt_disable) as guarantees to find a quiescent state
(this is really RCU "classic"). The update side uses rcu_barrier_sched()
with call_rcu_sched() and the read/execute side uses
"preempt_disable()/preempt_enable()".
We make sure the previous array containing probes, which has been
scheduled for deletion by the rcu callback, is indeed freed before we
proceed to the next update. It therefore limits the rate of modification
of a single tracepoint to one update per RCU period. The objective here
is to permit fast batch add/removal of probes on _different_
tracepoints.
Changelog :
- Use #name ":" #proto as string to identify the tracepoint in the
tracepoint table. This will make sure not type mismatch happens due to
connexion of a probe with the wrong type to a tracepoint declared with
the same name in a different header.
- Add tracepoint_entry_free_old.
- Change __TO_TRACE to get rid of the 'i' iterator.
Masami Hiramatsu <mhiramat@redhat.com> :
Tested on x86-64.
Performance impact of a tracepoint : same as markers, except that it
adds about 70 bytes of instructions in an unlikely branch of each
instrumented function (the for loop, the stack setup and the function
call). It currently adds a memory read, a test and a conditional branch
at the instrumentation site (in the hot path). Immediate values will
eventually change this into a load immediate, test and branch, which
removes the memory read which will make the i-cache impact smaller
(changing the memory read for a load immediate removes 3-4 bytes per
site on x86_32 (depending on mov prefixes), or 7-8 bytes on x86_64, it
also saves the d-cache hit).
About the performance impact of tracepoints (which is comparable to
markers), even without immediate values optimizations, tests done by
Hideo Aoki on ia64 show no regression. His test case was using hackbench
on a kernel where scheduler instrumentation (about 5 events in code
scheduler code) was added.
Quoting Hideo Aoki about Markers :
I evaluated overhead of kernel marker using linux-2.6-sched-fixes git
tree, which includes several markers for LTTng, using an ia64 server.
While the immediate trace mark feature isn't implemented on ia64, there
is no major performance regression. So, I think that we don't have any
issues to propose merging marker point patches into Linus's tree from
the viewpoint of performance impact.
I prepared two kernels to evaluate. The first one was compiled without
CONFIG_MARKERS. The second one was enabled CONFIG_MARKERS.
I downloaded the original hackbench from the following URL:
http://devresources.linux-foundation.org/craiger/hackbench/src/hackbench.c
I ran hackbench 5 times in each condition and calculated the average and
difference between the kernels.
The parameter of hackbench: every 50 from 50 to 800
The number of CPUs of the server: 2, 4, and 8
Below is the results. As you can see, major performance regression
wasn't found in any case. Even if number of processes increases,
differences between marker-enabled kernel and marker- disabled kernel
doesn't increase. Moreover, if number of CPUs increases, the differences
doesn't increase either.
Curiously, marker-enabled kernel is better than marker-disabled kernel
in more than half cases, although I guess it comes from the difference
of memory access pattern.
* 2 CPUs
Number of | without | with | diff | diff |
processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] |
--------------------------------------------------------------
50 | 4.811 | 4.872 | +0.061 | +1.27 |
100 | 9.854 | 10.309 | +0.454 | +4.61 |
150 | 15.602 | 15.040 | -0.562 | -3.6 |
200 | 20.489 | 20.380 | -0.109 | -0.53 |
250 | 25.798 | 25.652 | -0.146 | -0.56 |
300 | 31.260 | 30.797 | -0.463 | -1.48 |
350 | 36.121 | 35.770 | -0.351 | -0.97 |
400 | 42.288 | 42.102 | -0.186 | -0.44 |
450 | 47.778 | 47.253 | -0.526 | -1.1 |
500 | 51.953 | 52.278 | +0.325 | +0.63 |
550 | 58.401 | 57.700 | -0.701 | -1.2 |
600 | 63.334 | 63.222 | -0.112 | -0.18 |
650 | 68.816 | 68.511 | -0.306 | -0.44 |
700 | 74.667 | 74.088 | -0.579 | -0.78 |
750 | 78.612 | 79.582 | +0.970 | +1.23 |
800 | 85.431 | 85.263 | -0.168 | -0.2 |
--------------------------------------------------------------
* 4 CPUs
Number of | without | with | diff | diff |
processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] |
--------------------------------------------------------------
50 | 2.586 | 2.584 | -0.003 | -0.1 |
100 | 5.254 | 5.283 | +0.030 | +0.56 |
150 | 8.012 | 8.074 | +0.061 | +0.76 |
200 | 11.172 | 11.000 | -0.172 | -1.54 |
250 | 13.917 | 14.036 | +0.119 | +0.86 |
300 | 16.905 | 16.543 | -0.362 | -2.14 |
350 | 19.901 | 20.036 | +0.135 | +0.68 |
400 | 22.908 | 23.094 | +0.186 | +0.81 |
450 | 26.273 | 26.101 | -0.172 | -0.66 |
500 | 29.554 | 29.092 | -0.461 | -1.56 |
550 | 32.377 | 32.274 | -0.103 | -0.32 |
600 | 35.855 | 35.322 | -0.533 | -1.49 |
650 | 39.192 | 38.388 | -0.804 | -2.05 |
700 | 41.744 | 41.719 | -0.025 | -0.06 |
750 | 45.016 | 44.496 | -0.520 | -1.16 |
800 | 48.212 | 47.603 | -0.609 | -1.26 |
--------------------------------------------------------------
* 8 CPUs
Number of | without | with | diff | diff |
processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] |
--------------------------------------------------------------
50 | 2.094 | 2.072 | -0.022 | -1.07 |
100 | 4.162 | 4.273 | +0.111 | +2.66 |
150 | 6.485 | 6.540 | +0.055 | +0.84 |
200 | 8.556 | 8.478 | -0.078 | -0.91 |
250 | 10.458 | 10.258 | -0.200 | -1.91 |
300 | 12.425 | 12.750 | +0.325 | +2.62 |
350 | 14.807 | 14.839 | +0.032 | +0.22 |
400 | 16.801 | 16.959 | +0.158 | +0.94 |
450 | 19.478 | 19.009 | -0.470 | -2.41 |
500 | 21.296 | 21.504 | +0.208 | +0.98 |
550 | 23.842 | 23.979 | +0.137 | +0.57 |
600 | 26.309 | 26.111 | -0.198 | -0.75 |
650 | 28.705 | 28.446 | -0.259 | -0.9 |
700 | 31.233 | 31.394 | +0.161 | +0.52 |
750 | 34.064 | 33.720 | -0.344 | -1.01 |
800 | 36.320 | 36.114 | -0.206 | -0.57 |
--------------------------------------------------------------
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: 'Peter Zijlstra' <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-18 20:16:16 +04:00
config TRACEPOINTS
2008-07-23 16:15:22 +04:00
bool
tracing: Kernel Tracepoints
Implementation of kernel tracepoints. Inspired from the Linux Kernel
Markers. Allows complete typing verification by declaring both tracing
statement inline functions and probe registration/unregistration static
inline functions within the same macro "DEFINE_TRACE". No format string
is required. See the tracepoint Documentation and Samples patches for
usage examples.
Taken from the documentation patch :
"A tracepoint placed in code provides a hook to call a function (probe)
that you can provide at runtime. A tracepoint can be "on" (a probe is
connected to it) or "off" (no probe is attached). When a tracepoint is
"off" it has no effect, except for adding a tiny time penalty (checking
a condition for a branch) and space penalty (adding a few bytes for the
function call at the end of the instrumented function and adds a data
structure in a separate section). When a tracepoint is "on", the
function you provide is called each time the tracepoint is executed, in
the execution context of the caller. When the function provided ends its
execution, it returns to the caller (continuing from the tracepoint
site).
You can put tracepoints at important locations in the code. They are
lightweight hooks that can pass an arbitrary number of parameters, which
prototypes are described in a tracepoint declaration placed in a header
file."
Addition and removal of tracepoints is synchronized by RCU using the
scheduler (and preempt_disable) as guarantees to find a quiescent state
(this is really RCU "classic"). The update side uses rcu_barrier_sched()
with call_rcu_sched() and the read/execute side uses
"preempt_disable()/preempt_enable()".
We make sure the previous array containing probes, which has been
scheduled for deletion by the rcu callback, is indeed freed before we
proceed to the next update. It therefore limits the rate of modification
of a single tracepoint to one update per RCU period. The objective here
is to permit fast batch add/removal of probes on _different_
tracepoints.
Changelog :
- Use #name ":" #proto as string to identify the tracepoint in the
tracepoint table. This will make sure not type mismatch happens due to
connexion of a probe with the wrong type to a tracepoint declared with
the same name in a different header.
- Add tracepoint_entry_free_old.
- Change __TO_TRACE to get rid of the 'i' iterator.
Masami Hiramatsu <mhiramat@redhat.com> :
Tested on x86-64.
Performance impact of a tracepoint : same as markers, except that it
adds about 70 bytes of instructions in an unlikely branch of each
instrumented function (the for loop, the stack setup and the function
call). It currently adds a memory read, a test and a conditional branch
at the instrumentation site (in the hot path). Immediate values will
eventually change this into a load immediate, test and branch, which
removes the memory read which will make the i-cache impact smaller
(changing the memory read for a load immediate removes 3-4 bytes per
site on x86_32 (depending on mov prefixes), or 7-8 bytes on x86_64, it
also saves the d-cache hit).
About the performance impact of tracepoints (which is comparable to
markers), even without immediate values optimizations, tests done by
Hideo Aoki on ia64 show no regression. His test case was using hackbench
on a kernel where scheduler instrumentation (about 5 events in code
scheduler code) was added.
Quoting Hideo Aoki about Markers :
I evaluated overhead of kernel marker using linux-2.6-sched-fixes git
tree, which includes several markers for LTTng, using an ia64 server.
While the immediate trace mark feature isn't implemented on ia64, there
is no major performance regression. So, I think that we don't have any
issues to propose merging marker point patches into Linus's tree from
the viewpoint of performance impact.
I prepared two kernels to evaluate. The first one was compiled without
CONFIG_MARKERS. The second one was enabled CONFIG_MARKERS.
I downloaded the original hackbench from the following URL:
http://devresources.linux-foundation.org/craiger/hackbench/src/hackbench.c
I ran hackbench 5 times in each condition and calculated the average and
difference between the kernels.
The parameter of hackbench: every 50 from 50 to 800
The number of CPUs of the server: 2, 4, and 8
Below is the results. As you can see, major performance regression
wasn't found in any case. Even if number of processes increases,
differences between marker-enabled kernel and marker- disabled kernel
doesn't increase. Moreover, if number of CPUs increases, the differences
doesn't increase either.
Curiously, marker-enabled kernel is better than marker-disabled kernel
in more than half cases, although I guess it comes from the difference
of memory access pattern.
* 2 CPUs
Number of | without | with | diff | diff |
processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] |
--------------------------------------------------------------
50 | 4.811 | 4.872 | +0.061 | +1.27 |
100 | 9.854 | 10.309 | +0.454 | +4.61 |
150 | 15.602 | 15.040 | -0.562 | -3.6 |
200 | 20.489 | 20.380 | -0.109 | -0.53 |
250 | 25.798 | 25.652 | -0.146 | -0.56 |
300 | 31.260 | 30.797 | -0.463 | -1.48 |
350 | 36.121 | 35.770 | -0.351 | -0.97 |
400 | 42.288 | 42.102 | -0.186 | -0.44 |
450 | 47.778 | 47.253 | -0.526 | -1.1 |
500 | 51.953 | 52.278 | +0.325 | +0.63 |
550 | 58.401 | 57.700 | -0.701 | -1.2 |
600 | 63.334 | 63.222 | -0.112 | -0.18 |
650 | 68.816 | 68.511 | -0.306 | -0.44 |
700 | 74.667 | 74.088 | -0.579 | -0.78 |
750 | 78.612 | 79.582 | +0.970 | +1.23 |
800 | 85.431 | 85.263 | -0.168 | -0.2 |
--------------------------------------------------------------
* 4 CPUs
Number of | without | with | diff | diff |
processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] |
--------------------------------------------------------------
50 | 2.586 | 2.584 | -0.003 | -0.1 |
100 | 5.254 | 5.283 | +0.030 | +0.56 |
150 | 8.012 | 8.074 | +0.061 | +0.76 |
200 | 11.172 | 11.000 | -0.172 | -1.54 |
250 | 13.917 | 14.036 | +0.119 | +0.86 |
300 | 16.905 | 16.543 | -0.362 | -2.14 |
350 | 19.901 | 20.036 | +0.135 | +0.68 |
400 | 22.908 | 23.094 | +0.186 | +0.81 |
450 | 26.273 | 26.101 | -0.172 | -0.66 |
500 | 29.554 | 29.092 | -0.461 | -1.56 |
550 | 32.377 | 32.274 | -0.103 | -0.32 |
600 | 35.855 | 35.322 | -0.533 | -1.49 |
650 | 39.192 | 38.388 | -0.804 | -2.05 |
700 | 41.744 | 41.719 | -0.025 | -0.06 |
750 | 45.016 | 44.496 | -0.520 | -1.16 |
800 | 48.212 | 47.603 | -0.609 | -1.26 |
--------------------------------------------------------------
* 8 CPUs
Number of | without | with | diff | diff |
processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] |
--------------------------------------------------------------
50 | 2.094 | 2.072 | -0.022 | -1.07 |
100 | 4.162 | 4.273 | +0.111 | +2.66 |
150 | 6.485 | 6.540 | +0.055 | +0.84 |
200 | 8.556 | 8.478 | -0.078 | -0.91 |
250 | 10.458 | 10.258 | -0.200 | -1.91 |
300 | 12.425 | 12.750 | +0.325 | +2.62 |
350 | 14.807 | 14.839 | +0.032 | +0.22 |
400 | 16.801 | 16.959 | +0.158 | +0.94 |
450 | 19.478 | 19.009 | -0.470 | -2.41 |
500 | 21.296 | 21.504 | +0.208 | +0.98 |
550 | 23.842 | 23.979 | +0.137 | +0.57 |
600 | 26.309 | 26.111 | -0.198 | -0.75 |
650 | 28.705 | 28.446 | -0.259 | -0.9 |
700 | 31.233 | 31.394 | +0.161 | +0.52 |
750 | 34.064 | 33.720 | -0.344 | -1.01 |
800 | 36.320 | 36.114 | -0.206 | -0.57 |
--------------------------------------------------------------
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: 'Peter Zijlstra' <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-18 20:16:16 +04:00
2008-02-02 23:10:36 +03:00
config MARKERS
bool "Activate markers"
2009-02-20 19:34:06 +03:00
select TRACEPOINTS
2008-02-02 23:10:36 +03:00
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"
2009-04-03 19:42:35 +04:00
config SLOW_WORK
default n
2009-04-06 18:47:25 +04:00
bool
2009-04-03 19:42:35 +04:00
help
The slow work thread pool provides a number of dynamically allocated
threads that can be used by the kernel to perform operations that
take a relatively long time.
An example of this would be CacheFiles doing a path lookup followed
by a series of mkdirs and a create call, all of which have to touch
disk.
2009-04-06 18:47:25 +04:00
See Documentation/slow-work.txt.
2005-04-17 02:20:36 +04:00
endmenu # General setup
2008-06-29 14:18:46 +04:00
config HAVE_GENERIC_DMA_COHERENT
bool
default n
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
2008-01-03 00:04:48 +03:00
default y
2006-09-16 23:15:53 +04:00
config RT_MUTEXES
boolean
2005-04-17 02:20:36 +04:00
config BASE_SMALL
int
default 0 if BASE_FULL
default 1 if !BASE_FULL
2007-07-16 10:39:29 +04:00
menuconfig MODULES
2005-04-17 02:20:36 +04:00
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.
2008-08-04 21:31:32 +04:00
if MODULES
2008-05-05 04:04:16 +04:00
config MODULE_FORCE_LOAD
bool "Forced module loading"
default n
help
2008-05-09 10:25:28 +04:00
Allow loading of modules without version information (ie. modprobe
--force). Forced module loading sets the 'F' (forced) taint flag and
is usually a really bad idea.
2008-05-05 04:04:16 +04:00
2005-04-17 02:20:36 +04:00
config MODULE_UNLOAD
bool "Module unloading"
help
Without this option you will not be able to unload any
modules (note that some modules may not be unloadable
2008-07-23 04:24:26 +04:00
anyway), which makes your kernel smaller, faster
and simpler. If unsure, say Y.
2005-04-17 02:20:36 +04:00
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
2005-12-27 01:04:02 +03:00
bool "Module versioning support"
2005-04-17 02:20:36 +04:00
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"
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.
2008-08-04 21:31:32 +04:00
endif # MODULES
2008-12-13 13:49:41 +03:00
config INIT_ALL_POSSIBLE
bool
help
Back when each arch used to define their own cpu_online_map and
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
2009-01-26 13:12:25 +03:00
and have several arch maintainers pursuing me down dark alleys.
2008-12-13 13:49:41 +03:00
2005-04-17 02:20:36 +04:00
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
2008-01-25 23:08:24 +03:00