Re: pg->offset and pg->flags

[David Laight <david%l8s.co.uk@localhost>]

On Sun, Apr 03, 2011 at 07:35:04PM +1000, matthew green wrote:
> 
> > Ignoring the free page allocator which abuses pg->offset, is there any
> > reason we cannot fold pg->flags into pg->offset?  The lower PAGE_SHIFT bits
> > of pg->offset are not used.
> 
> is this about making vm_page smaller?  if so, and it works, i guess that
> seems fine, but how many bits do you want to use?  ie, what is the
> smallest PAGE_SIZE we will support?
> 
> if not that, why?

And is the memory saved enough to be significant compared to the
number of masking operations needed to get pg->offset.

        David

-- 
David Laight: david%l8s.co.uk@localhost