Re: Some highmem pages still in use after shrink_all_memory()?

From: Pavel Machek
Date: Mon Mar 08 2004 - 04:15:25 EST

On Po 08-03-04 00:36:39, Andy Isaacson wrote:
> On Sun, Mar 07, 2004 at 04:40:52PM -0800, Andrew Morton wrote:
> > Pavel Machek <pavel@xxxxxx> wrote:
> > > For swsusp, I need to free as much memory as possible. Well, and it
> > > would be great if no highmem pages remained, so that I would not have
> > > to deal with that. Is that possible?
> >
> > No, it isn't. There are pagetable pages and mlocked user pages which we
> > cannot do anything with.
> >
> > We could perhaps swap out the mlocked pages anyway if a suspend is in
> > progress, but the highmem pagetable pages are not presently reclaimed
> > by the VM.
> Note that there are some applications for which it is a *bug* if an
> mlocked page gets written out to magnetic media. (gpg, for example.)

Well, but that can not be solved. During suspend-to-disk, data (by
definition) go to magnetic media. We could block suspend, and we could
kill such application....
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]
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