81819f0fc8
This is a new slab allocator which was motivated by the complexity of the existing code in mm/slab.c. It attempts to address a variety of concerns with the existing implementation. A. Management of object queues A particular concern was the complex management of the numerous object queues in SLAB. SLUB has no such queues. Instead we dedicate a slab for each allocating CPU and use objects from a slab directly instead of queueing them up. B. Storage overhead of object queues SLAB Object queues exist per node, per CPU. The alien cache queue even has a queue array that contain a queue for each processor on each node. For very large systems the number of queues and the number of objects that may be caught in those queues grows exponentially. On our systems with 1k nodes / processors we have several gigabytes just tied up for storing references to objects for those queues This does not include the objects that could be on those queues. One fears that the whole memory of the machine could one day be consumed by those queues. C. SLAB meta data overhead SLAB has overhead at the beginning of each slab. This means that data cannot be naturally aligned at the beginning of a slab block. SLUB keeps all meta data in the corresponding page_struct. Objects can be naturally aligned in the slab. F.e. a 128 byte object will be aligned at 128 byte boundaries and can fit tightly into a 4k page with no bytes left over. SLAB cannot do this. D. SLAB has a complex cache reaper SLUB does not need a cache reaper for UP systems. On SMP systems the per CPU slab may be pushed back into partial list but that operation is simple and does not require an iteration over a list of objects. SLAB expires per CPU, shared and alien object queues during cache reaping which may cause strange hold offs. E. SLAB has complex NUMA policy layer support SLUB pushes NUMA policy handling into the page allocator. This means that allocation is coarser (SLUB does interleave on a page level) but that situation was also present before 2.6.13. SLABs application of policies to individual slab objects allocated in SLAB is certainly a performance concern due to the frequent references to memory policies which may lead a sequence of objects to come from one node after another. SLUB will get a slab full of objects from one node and then will switch to the next. F. Reduction of the size of partial slab lists SLAB has per node partial lists. This means that over time a large number of partial slabs may accumulate on those lists. These can only be reused if allocator occur on specific nodes. SLUB has a global pool of partial slabs and will consume slabs from that pool to decrease fragmentation. G. Tunables SLAB has sophisticated tuning abilities for each slab cache. One can manipulate the queue sizes in detail. However, filling the queues still requires the uses of the spin lock to check out slabs. SLUB has a global parameter (min_slab_order) for tuning. Increasing the minimum slab order can decrease the locking overhead. The bigger the slab order the less motions of pages between per CPU and partial lists occur and the better SLUB will be scaling. G. Slab merging We often have slab caches with similar parameters. SLUB detects those on boot up and merges them into the corresponding general caches. This leads to more effective memory use. About 50% of all caches can be eliminated through slab merging. This will also decrease slab fragmentation because partial allocated slabs can be filled up again. Slab merging can be switched off by specifying slub_nomerge on boot up. Note that merging can expose heretofore unknown bugs in the kernel because corrupted objects may now be placed differently and corrupt differing neighboring objects. Enable sanity checks to find those. H. Diagnostics The current slab diagnostics are difficult to use and require a recompilation of the kernel. SLUB contains debugging code that is always available (but is kept out of the hot code paths). SLUB diagnostics can be enabled via the "slab_debug" option. Parameters can be specified to select a single or a group of slab caches for diagnostics. This means that the system is running with the usual performance and it is much more likely that race conditions can be reproduced. I. Resiliency If basic sanity checks are on then SLUB is capable of detecting common error conditions and recover as best as possible to allow the system to continue. J. Tracing Tracing can be enabled via the slab_debug=T,<slabcache> option during boot. SLUB will then protocol all actions on that slabcache and dump the object contents on free. K. On demand DMA cache creation. Generally DMA caches are not needed. If a kmalloc is used with __GFP_DMA then just create this single slabcache that is needed. For systems that have no ZONE_DMA requirement the support is completely eliminated. L. Performance increase Some benchmarks have shown speed improvements on kernbench in the range of 5-10%. The locking overhead of slub is based on the underlying base allocation size. If we can reliably allocate larger order pages then it is possible to increase slub performance much further. The anti-fragmentation patches may enable further performance increases. Tested on: i386 UP + SMP, x86_64 UP + SMP + NUMA emulation, IA64 NUMA + Simulator SLUB Boot options slub_nomerge Disable merging of slabs slub_min_order=x Require a minimum order for slab caches. This increases the managed chunk size and therefore reduces meta data and locking overhead. slub_min_objects=x Mininum objects per slab. Default is 8. slub_max_order=x Avoid generating slabs larger than order specified. slub_debug Enable all diagnostics for all caches slub_debug=<options> Enable selective options for all caches slub_debug=<o>,<cache> Enable selective options for a certain set of caches Available Debug options F Double Free checking, sanity and resiliency R Red zoning P Object / padding poisoning U Track last free / alloc T Trace all allocs / frees (only use for individual slabs). To use SLUB: Apply this patch and then select SLUB as the default slab allocator. [hugh@veritas.com: fix an oops-causing locking error] [akpm@linux-foundation.org: various stupid cleanups and small fixes] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
632 lines
22 KiB
Plaintext
632 lines
22 KiB
Plaintext
config DEFCONFIG_LIST
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string
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depends on !UML
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option defconfig_list
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default "/lib/modules/$UNAME_RELEASE/.config"
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default "/etc/kernel-config"
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default "/boot/config-$UNAME_RELEASE"
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default "arch/$ARCH/defconfig"
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menu "Code maturity level options"
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config EXPERIMENTAL
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bool "Prompt for development and/or incomplete code/drivers"
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---help---
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Some of the various things that Linux supports (such as network
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drivers, file systems, network protocols, etc.) can be in a state
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of development where the functionality, stability, or the level of
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testing is not yet high enough for general use. This is usually
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known as the "alpha-test" phase among developers. If a feature is
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currently in alpha-test, then the developers usually discourage
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uninformed widespread use of this feature by the general public to
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avoid "Why doesn't this work?" type mail messages. However, active
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testing and use of these systems is welcomed. Just be aware that it
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may not meet the normal level of reliability or it may fail to work
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in some special cases. Detailed bug reports from people familiar
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with the kernel internals are usually welcomed by the developers
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(before submitting bug reports, please read the documents
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<file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
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<file:Documentation/BUG-HUNTING>, and
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<file:Documentation/oops-tracing.txt> in the kernel source).
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This option will also make obsoleted drivers available. These are
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drivers that have been replaced by something else, and/or are
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scheduled to be removed in a future kernel release.
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Unless you intend to help test and develop a feature or driver that
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falls into this category, or you have a situation that requires
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using these features, you should probably say N here, which will
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cause the configurator to present you with fewer choices. If
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you say Y here, you will be offered the choice of using features or
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drivers that are currently considered to be in the alpha-test phase.
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config BROKEN
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bool
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config BROKEN_ON_SMP
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bool
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depends on BROKEN || !SMP
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default y
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config LOCK_KERNEL
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bool
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depends on SMP || PREEMPT
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default y
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config INIT_ENV_ARG_LIMIT
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int
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default 32 if !UML
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default 128 if UML
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help
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Maximum of each of the number of arguments and environment
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variables passed to init from the kernel command line.
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endmenu
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menu "General setup"
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config LOCALVERSION
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string "Local version - append to kernel release"
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help
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Append an extra string to the end of your kernel version.
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This will show up when you type uname, for example.
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The string you set here will be appended after the contents of
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any files with a filename matching localversion* in your
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object and source tree, in that order. Your total string can
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be a maximum of 64 characters.
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config LOCALVERSION_AUTO
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bool "Automatically append version information to the version string"
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default y
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help
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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
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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
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by running the command:
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$ git rev-parse --verify HEAD
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which is done within the script "scripts/setlocalversion".)
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config SWAP
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bool "Support for paging of anonymous memory (swap)"
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depends on MMU && BLOCK
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default y
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help
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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
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in your computer. If unsure say Y.
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config SYSVIPC
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bool "System V IPC"
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---help---
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Inter Process Communication is a suite of library functions and
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system calls which let processes (running programs) synchronize and
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exchange information. It is generally considered to be a good thing,
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and some programs won't run unless you say Y here. In particular, if
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you want to run the DOS emulator dosemu under Linux (read the
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DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
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you'll need to say Y here.
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You can find documentation about IPC with "info ipc" and also in
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section 6.4 of the Linux Programmer's Guide, available from
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<http://www.tldp.org/guides.html>.
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config IPC_NS
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bool "IPC Namespaces"
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depends on SYSVIPC
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default n
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help
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Support ipc namespaces. This allows containers, i.e. virtual
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environments, to use ipc namespaces to provide different ipc
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objects for different servers. If unsure, say N.
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config SYSVIPC_SYSCTL
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bool
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depends on SYSVIPC
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depends on SYSCTL
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default y
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config POSIX_MQUEUE
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bool "POSIX Message Queues"
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depends on NET && EXPERIMENTAL
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---help---
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POSIX variant of message queues is a part of IPC. In POSIX message
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queues every message has a priority which decides about succession
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of receiving it by a process. If you want to compile and run
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programs written e.g. for Solaris with use of its POSIX message
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queues (functions mq_*) say Y here. To use this feature you will
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also need mqueue library, available from
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<http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
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POSIX message queues are visible as a filesystem called 'mqueue'
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and can be mounted somewhere if you want to do filesystem
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operations on message queues.
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If unsure, say Y.
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config BSD_PROCESS_ACCT
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bool "BSD Process Accounting"
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help
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If you say Y here, a user level program will be able to instruct the
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kernel (via a special system call) to write process accounting
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information to a file: whenever a process exits, information about
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that process will be appended to the file by the kernel. The
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information includes things such as creation time, owning user,
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command name, memory usage, controlling terminal etc. (the complete
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list is in the struct acct in <file:include/linux/acct.h>). It is
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up to the user level program to do useful things with this
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information. This is generally a good idea, so say Y.
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config BSD_PROCESS_ACCT_V3
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bool "BSD Process Accounting version 3 file format"
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depends on BSD_PROCESS_ACCT
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default n
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help
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If you say Y here, the process accounting information is written
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in a new file format that also logs the process IDs of each
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process and it's parent. Note that this file format is incompatible
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with previous v0/v1/v2 file formats, so you will need updated tools
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for processing it. A preliminary version of these tools is available
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at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
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config TASKSTATS
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bool "Export task/process statistics through netlink (EXPERIMENTAL)"
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depends on NET
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default n
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help
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Export selected statistics for tasks/processes through the
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generic netlink interface. Unlike BSD process accounting, the
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statistics are available during the lifetime of tasks/processes as
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responses to commands. Like BSD accounting, they are sent to user
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space on task exit.
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Say N if unsure.
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config TASK_DELAY_ACCT
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bool "Enable per-task delay accounting (EXPERIMENTAL)"
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depends on TASKSTATS
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help
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Collect information on time spent by a task waiting for system
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resources like cpu, synchronous block I/O completion and swapping
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in pages. Such statistics can help in setting a task's priorities
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relative to other tasks for cpu, io, rss limits etc.
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Say N if unsure.
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config TASK_XACCT
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bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
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depends on TASKSTATS
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help
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Collect extended task accounting data and send the data
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to userland for processing over the taskstats interface.
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Say N if unsure.
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config TASK_IO_ACCOUNTING
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bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
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depends on TASK_XACCT
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help
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Collect information on the number of bytes of storage I/O which this
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task has caused.
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Say N if unsure.
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config UTS_NS
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bool "UTS Namespaces"
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default n
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help
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Support uts namespaces. This allows containers, i.e.
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vservers, to use uts namespaces to provide different
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uts info for different servers. If unsure, say N.
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config AUDIT
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bool "Auditing support"
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depends on NET
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help
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Enable auditing infrastructure that can be used with another
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kernel subsystem, such as SELinux (which requires this for
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logging of avc messages output). Does not do system-call
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auditing without CONFIG_AUDITSYSCALL.
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config AUDITSYSCALL
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bool "Enable system-call auditing support"
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depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64)
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default y if SECURITY_SELINUX
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help
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Enable low-overhead system-call auditing infrastructure that
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can be used independently or with another kernel subsystem,
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such as SELinux. To use audit's filesystem watch feature, please
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ensure that INOTIFY is configured.
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config IKCONFIG
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tristate "Kernel .config support"
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---help---
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This option enables the complete Linux kernel ".config" file
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contents to be saved in the kernel. It provides documentation
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of which kernel options are used in a running kernel or in an
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on-disk kernel. This information can be extracted from the kernel
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image file with the script scripts/extract-ikconfig and used as
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input to rebuild the current kernel or to build another kernel.
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It can also be extracted from a running kernel by reading
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/proc/config.gz if enabled (below).
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config IKCONFIG_PROC
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bool "Enable access to .config through /proc/config.gz"
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depends on IKCONFIG && PROC_FS
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---help---
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This option enables access to the kernel configuration file
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through /proc/config.gz.
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config CPUSETS
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bool "Cpuset support"
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depends on SMP
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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
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Memory Nodes and assigning tasks to run only within those sets.
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This is primarily useful on large SMP or NUMA systems.
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Say N if unsure.
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config SYSFS_DEPRECATED
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bool "Create deprecated sysfs files"
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default y
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help
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This option creates deprecated symlinks such as the
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"device"-link, the <subsystem>:<name>-link, and the
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"bus"-link. It may also add deprecated key in the
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uevent environment.
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None of these features or values should be used today, as
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they export driver core implementation details to userspace
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or export properties which can't be kept stable across kernel
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releases.
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If enabled, this option will also move any device structures
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that belong to a class, back into the /sys/class heirachy, in
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order to support older versions of udev.
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If you are using a distro that was released in 2006 or later,
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it should be safe to say N here.
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config RELAY
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bool "Kernel->user space relay support (formerly relayfs)"
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help
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This option enables support for relay interface support in
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certain file systems (such as debugfs).
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It is designed to provide an efficient mechanism for tools and
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facilities to relay large amounts of data from kernel space to
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user space.
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If unsure, say N.
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config BLK_DEV_INITRD
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bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
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depends on BROKEN || !FRV
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help
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The initial RAM filesystem is a ramfs which is loaded by the
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boot loader (loadlin or lilo) and that is mounted as root
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before the normal boot procedure. It is typically used to
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load modules needed to mount the "real" root file system,
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etc. See <file:Documentation/initrd.txt> for details.
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If RAM disk support (BLK_DEV_RAM) is also included, this
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also enables initial RAM disk (initrd) support and adds
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15 Kbytes (more on some other architectures) to the kernel size.
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If unsure say Y.
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if BLK_DEV_INITRD
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source "usr/Kconfig"
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endif
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config CC_OPTIMIZE_FOR_SIZE
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bool "Optimize for size (Look out for broken compilers!)"
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default y
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depends on ARM || H8300 || EXPERIMENTAL
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help
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Enabling this option will pass "-Os" instead of "-O2" to gcc
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resulting in a smaller kernel.
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WARNING: some versions of gcc may generate incorrect code with this
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option. If problems are observed, a gcc upgrade may be needed.
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If unsure, say N.
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config SYSCTL
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bool
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menuconfig EMBEDDED
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bool "Configure standard kernel features (for small systems)"
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help
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This option allows certain base kernel options and settings
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to be disabled or tweaked. This is for specialized
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environments which can tolerate a "non-standard" kernel.
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Only use this if you really know what you are doing.
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config UID16
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bool "Enable 16-bit UID system calls" if EMBEDDED
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depends on ARM || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
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default y
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help
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This enables the legacy 16-bit UID syscall wrappers.
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config SYSCTL_SYSCALL
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bool "Sysctl syscall support" if EMBEDDED
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default y
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select SYSCTL
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---help---
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sys_sysctl uses binary paths that have been found challenging
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to properly maintain and use. The interface in /proc/sys
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using paths with ascii names is now the primary path to this
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information.
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Almost nothing using the binary sysctl interface so if you are
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trying to save some space it is probably safe to disable this,
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making your kernel marginally smaller.
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If unsure say Y here.
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config KALLSYMS
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bool "Load all symbols for debugging/ksymoops" if EMBEDDED
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default y
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help
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Say Y here to let the kernel print out symbolic crash information and
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symbolic stack backtraces. This increases the size of the kernel
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somewhat, as all symbols have to be loaded into the kernel image.
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config KALLSYMS_ALL
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bool "Include all symbols in kallsyms"
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depends on DEBUG_KERNEL && KALLSYMS
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help
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Normally kallsyms only contains the symbols of functions, for nicer
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OOPS messages. Some debuggers can use kallsyms for other
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symbols too: say Y here to include all symbols, if you need them
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and you don't care about adding 300k to the size of your kernel.
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Say N.
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config KALLSYMS_EXTRA_PASS
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bool "Do an extra kallsyms pass"
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depends on KALLSYMS
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help
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If kallsyms is not working correctly, the build will fail with
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inconsistent kallsyms data. If that occurs, log a bug report and
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turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
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Always say N here unless you find a bug in kallsyms, which must be
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reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
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you wait for kallsyms to be fixed.
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config HOTPLUG
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bool "Support for hot-pluggable devices" if EMBEDDED
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default y
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help
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This option is provided for the case where no hotplug or uevent
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capabilities is wanted by the kernel. You should only consider
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disabling this option for embedded systems that do not use modules, a
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dynamic /dev tree, or dynamic device discovery. Just say Y.
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config PRINTK
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default y
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bool "Enable support for printk" if EMBEDDED
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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.
|
|
|
|
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.
|
|
|
|
config ELF_CORE
|
|
default y
|
|
bool "Enable ELF core dumps" if EMBEDDED
|
|
help
|
|
Enable support for generating core dumps. Disabling saves about 4k.
|
|
|
|
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
|
|
select RT_MUTEXES
|
|
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
|
|
help
|
|
Disabling this option will cause the kernel to be built without
|
|
support for epoll family of system calls.
|
|
|
|
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.
|
|
|
|
config VM_EVENT_COUNTERS
|
|
default y
|
|
bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
|
|
help
|
|
VM event counters are needed for event counts to be shown.
|
|
This option allows the disabling of the VM event counters
|
|
on EMBEDDED systems. /proc/vmstat will only show page counts
|
|
if VM event counters are disabled.
|
|
|
|
choice
|
|
prompt "Choose SLAB allocator"
|
|
default SLAB
|
|
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
|
|
well in all environments. It organizes chache hot objects in
|
|
per cpu and per node queues. SLAB is the default choice for
|
|
slab allocator.
|
|
|
|
config SLUB
|
|
depends on EXPERIMENTAL && !ARCH_USES_SLAB_PAGE_STRUCT
|
|
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
|
|
way and has enhanced diagnostics.
|
|
|
|
config SLOB
|
|
#
|
|
# SLOB cannot support SMP because SLAB_DESTROY_BY_RCU does not work
|
|
# properly.
|
|
#
|
|
depends on EMBEDDED && !SMP && !SPARSEMEM
|
|
bool "SLOB (Simple Allocator)"
|
|
help
|
|
SLOB replaces the SLAB allocator with a drastically simpler
|
|
allocator. SLOB is more space efficient that SLAB but does not
|
|
scale well (single lock for all operations) and is more susceptible
|
|
to fragmentation. SLOB it is a great choice to reduce
|
|
memory usage and code size for embedded systems.
|
|
|
|
endchoice
|
|
|
|
endmenu # General setup
|
|
|
|
config RT_MUTEXES
|
|
boolean
|
|
select PLIST
|
|
|
|
config TINY_SHMEM
|
|
default !SHMEM
|
|
bool
|
|
|
|
config BASE_SMALL
|
|
int
|
|
default 0 if BASE_FULL
|
|
default 1 if !BASE_FULL
|
|
|
|
menu "Loadable module support"
|
|
|
|
config MODULES
|
|
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
|
|
bool "Module versioning support"
|
|
depends on MODULES
|
|
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.
|
|
endmenu
|
|
|
|
menu "Block layer"
|
|
source "block/Kconfig"
|
|
endmenu
|