Re: [PATCH 00/16] mm: prepare for converting vm->vm_flags to 64-bit

Andrew Morton
2012-03-22T21:26:52Z

On Wed, 21 Mar 2012 17:16:06 +0400
Konstantin Khlebnikov <khlebnikov@openvz.org> wrote:

> Minchan Kim wrote:
> > Hi Konstantin,
> >
> > It seems to be nice clean up to me and you are a volunteer we have been wanted
> > for a long time. Thanks!
> > I am one of people who really want to expand vm_flags to 64 bit but when KOSAKI
> > tried it, Linus said his concerning, I guess you already saw that.
> >
> > He want to tidy vm_flags's usage up rather than expanding it.
> > Without the discussion about that, just expanding vm_flags would make us use
> > it up easily so that we might need more space.
>
> Strictly speaking, my pachset does not expands vm_flags, it just prepares to this.
> Anyway vm_flags_t looks better than hard-coded "unsigned long" and messy type-casts around it.

It would be nice to find some way of triggering compiler warnings or
sparse warnings if someone mixes a 32-bit type with a vm_flags_t. Any
thoughts on this?

(Maybe that's what __nocast does, but Documentation/sparse.txt doesn't
describe it)