Re: [RFC] Track mlock()ed pages

[Nick Piggin]

Andrew Morton wrote:
> On Thu, 25 Jan 2007 22:36:17 -0800 (PST)
> Christoph Lameter <clameter@xxxxxxx> wrote:

> > > I can't think of an easy way to do this without per-page state. ie.
> > > another page flag.
> >
> > Thats what I am trying to avoid.
>
>
> You could perhaps go for a walk across all the other vmas which presently
> map this page.  If any of them have VM_LOCKED, don't increment the counter.
> Similar on removal: only decrement the counter when the final mlocked VMA
> is dropping the pte.

Can't do with un-racily because you can't get that information
atomically, AFAIKS. When / if we ever lock the page in fault handler,
this could become easier... but that seems nasty to do in fault path,
even if only for VM_LOCKED vmas.

--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com 
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/