Re: 230-objrmap fixes for 2.6.3-mjb2

From: Andrea Arcangeli
Date: Wed Mar 03 2004 - 11:58:57 EST


On Wed, Mar 03, 2004 at 07:46:32AM -0800, Martin J. Bligh wrote:
> --Andrew Morton <akpm@xxxxxxxx> wrote (on Wednesday, March 03, 2004 02:58:20 -0800):
>
> > Andrea Arcangeli <andrea@xxxxxxx> 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.
-
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