On Wed, Sep 15, 2010 at 11:03:14PM +0200, Michael S. Tsirkin wrote:
> On Wed, Sep 15, 2010 at 07:08:24PM +0200, Andrea Arcangeli wrote:
> > From: Andrea Arcangeli <aarca...@redhat.com>
> >
> > All allocated guest physical memory shall be marked MADV_DONTFORK, otherwise
> > fork will fail because of accounting issues preventing migration or
> > netdev_add
> > when the guest allocated more than half of host physical memory.
> >
> > Signed-off-by: Andrea Arcangeli <aarca...@redhat.com>
> > ---
> >
> > diff --git a/exec.c b/exec.c
> > index 380dab5..e2bdf19 100644
> > --- a/exec.c
> > +++ b/exec.c
> > @@ -2861,6 +2861,9 @@ ram_addr_t qemu_ram_alloc_from_ptr(DeviceState *dev,
> > const char *name,
> > #ifdef MADV_MERGEABLE
> > madvise(new_block->host, size, MADV_MERGEABLE);
> > #endif
> > +#ifdef MADV_DONTFORK
> > + madvise(new_block->host, size, MADV_DONTFORK);
> > +#endif
> > }
> > }
>
> Is this always a number of full host pages? If not, we'd get trouble
> when trying to call helpers.
>
How it can be not a number of full host pages? This is guest memory.
--
Gleb.
