Hello Gleb,
On Tue, Oct 06, 2009 at 11:51:11AM +0200, 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 <[email protected]>
> 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 */
^^^
You're missing a 'C' here and below. Also '/* force page unlocking */'
seems a better comment?
Regards,
Frederik
>
> #define MCL_CURRENT 1 /* lock all current mappings */
> #define MCL_FUTURE 2 /* lock all future mappings */
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 73f5e4b..7c2abdb 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -985,6 +985,9 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned
> long addr,
> if (!can_do_mlock())
> return -EPERM;
>
> + if (flags & MAP_UNLOKED)
> + vm_flags &= ~VM_LOCKED;
> +
> /* mlock MCL_FUTURE? */
> if (vm_flags & VM_LOCKED) {
> unsigned long locked, lock_limit;
> --
> Gleb.
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