Re: 230-objrmap fixes for 2.6.3-mjb2

[Andrea Arcangeli <andrea@suse.de>]

On Wed, Mar 03, 2004 at 07:46:32AM -0800, Martin J. Bligh wrote:
> --Andrew Morton <akpm@osdl.org> wrote (on Wednesday, March 03, 2004 02:58:20 -0800):
> 
> > Andrea Arcangeli <andrea@suse.de> wrote:
> >> 
> >> --- sles-objrmap/mm/rmap.c.~1~	2004-03-03 06:45:38.995594456 +0100
> >>  +++ sles-objrmap/mm/rmap.c	2004-03-03 07:01:39.200621104 +0100
> >>  @@ -470,7 +470,7 @@ try_to_unmap_obj_one(struct vm_area_stru
> >>   	if (!pte)
> >>   		goto out;
> >>   
> >>  -	if (vma->vm_flags & VM_LOCKED) {
> >>  +	if (vma->vm_flags & (VM_LOCKED|VM_RESERVED)) {
> >>   		ret =  SWAP_FAIL;
> >>   		goto out_unmap;
> > 
> > I keep on wanting to put that in there too.  But pages in a VM_RESERVED vma
> > should not find their way onto the LRU.  Maybe we should be checking for
> > that in do_no_page().
> 
> There was talk at one point of moving the "unswappable" state down into 
> the struct page. Is that still realistic? It would seem rather more
> efficient, but I forget what problem we ran into with it.

that already exists and it's PG_reserved, but it's inefficient compared
to VM_RESERVED, since it forces the vm to check all ptes.