Re: [PATCH][RFC] add MAP_UNLOCKED mmap flag

[Arnd Bergmann <arnd@arndb.de>]

On Tuesday 06 October 2009, Gleb Natapov wrote:
> If application does mlockall(MCL_FUTURE) it is no longer possible to
> mmap file bigger than main memory or allocate big area of anonymous
> memory. Sometimes it is desirable to lock everything related to program
> execution into memory, but still be able to mmap big file or allocate
> huge amount of memory and allow OS to swap them on demand. MAP_UNLOCKED
> allows to do that.
> 
> Signed-off-by: Gleb Natapov <gleb@redhat.com>
> diff --git a/include/asm-generic/mman.h b/include/asm-generic/mman.h
> index 32c8bd6..0ab4c74 100644
> --- a/include/asm-generic/mman.h
> +++ b/include/asm-generic/mman.h
> @@ -12,6 +12,7 @@
>  #define MAP_NONBLOCK   0x10000         /* do not block on IO */
>  #define MAP_STACK      0x20000         /* give out an address that is best suited for process/thread stacks */
>  #define MAP_HUGETLB    0x40000         /* create a huge page mapping */
> +#define MAP_UNLOKED    0x80000         /* pages are unlocked */
>  
>  #define MCL_CURRENT    1               /* lock all current mappings */
>  #define MCL_FUTURE     2               /* lock all future mappings */

Not all architectures use asm-generic/mman.h, so you have to change
the other architectures separately if you add a flag.

	Arnd <><

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