Re: [PATCH v2][RFC] add MAP_UNLOCKED mmap flag

From: Gleb Natapov
Date: Tue Oct 06 2009 - 14:55:07 EST


On Tue, Oct 06, 2009 at 08:34:36PM +0200, Johannes Weiner wrote:
> On Tue, Oct 06, 2009 at 07:02:18PM +0200, Gleb Natapov wrote:
> > diff --git a/include/asm-generic/mman.h b/include/asm-generic/mman.h
> > index 32c8bd6..59e0f29 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_UNLOCKED 0x80000 /* force page unlocking */
> >
> > #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;
>
> That needs changing into MAP_UNLOCKED as well.
>
That's for editing patch manually :(

> Should we do something special about (MAP_UNLOCKED | MAP_LOCKED)?
It is simpler to just ignore it. What do you think?

--
Gleb.
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