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| author | Ingo Molnar <mingo@elte.hu> | 2009-12-28 09:23:13 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-12-28 09:23:13 +0100 |
| commit | 605c1a187f3ce82fbc243e2163c5ca8d1926df8e (patch) | |
| tree | c8065a8c5606a66f81dc494ce22a5baa5e0dfe7e /init/Kconfig | |
| parent | 17a2a9b57a9a7d2fd8f97df951b5e63e0bd56ef5 (diff) | |
| parent | ce9277fb08e6e721482f7011ca28dcd0449b197c (diff) | |
Merge branch 'iommu/fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/linux-2.6-iommu into x86/urgent
Diffstat (limited to 'init/Kconfig')
| -rw-r--r-- | init/Kconfig | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig index 54c655ce9c0..a23da9f0180 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1079,6 +1079,28 @@ config SLOB endchoice +config MMAP_ALLOW_UNINITIALIZED + bool "Allow mmapped anonymous memory to be uninitialized" + depends on EMBEDDED && !MMU + default n + help + Normally, and according to the Linux spec, anonymous memory obtained + from mmap() has it's contents cleared before it is passed to + userspace. Enabling this config option allows you to request that + mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus + providing a huge performance boost. If this option is not enabled, + then the flag will be ignored. + + This is taken advantage of by uClibc's malloc(), and also by + ELF-FDPIC binfmt's brk and stack allocator. + + Because of the obvious security issues, this option should only be + enabled on embedded devices where you control what is run in + userspace. Since that isn't generally a problem on no-MMU systems, + it is normally safe to say Y here. + + See Documentation/nommu-mmap.txt for more information. + config PROFILING bool "Profiling support (EXPERIMENTAL)" help |