OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.

 


Help: OASIS Mailing Lists Help | MarkMail Help

virtio-dev message

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]


Subject: Re: [virtio-comment] [PATCH v2 1/3] content: Document balloon feature free page hints


On Mon, May 18, 2020 at 11:54 PM Cornelia Huck <cohuck@redhat.com> wrote:
>
> On Mon, 18 May 2020 13:15:50 -0700
> Alexander Duyck <alexander.duyck@gmail.com> wrote:
>
> > On Mon, May 18, 2020 at 6:18 AM David Hildenbrand <david@redhat.com> wrote:
> > >
> > > On 15.05.20 19:33, Alexander Duyck wrote:
>
> > > > +\subsubsection{Free Page Hinting}\label{sec:Device Types / Memory Balloon Device / Device Operation / Free Page Hinting}
> > > > +
> > > > +Free page hinting is designed to be used during migration to determine what
> > > > +pages within the guest are currently unused so that they can be skipped over
> > > > +while migrating the guest. The device will indicate that it is ready to start
> > > > +performing hinting by setting the \field{free_page_hint_cmd_id} to one of the
> > > > +non-reserved values that can be used as a command ID. The following values
> > > > +are reserved:
> > > > +
> > > > +\begin{description}
> > > > +\item[VIRTIO_BALLOON_CMD_ID_STOP (0)] Any command ID previously supplied by
> > > > +  the device is invalid. The driver should halt all hinting until a new
> > > > +  command ID is supplied.
> > >
> > > Maybe "The driver should stop hinting free pages, but should not reuse
> > > all previously hinted pages."
> >
> > The "reuse all previously hinted pages" seems rather unclear to me. I
> > would like to make clear that in this case the "use" is the guest
> > making use of the memory, not the driver doing something like
> > recycling hints. So in the spots where you reference "the driver
> > reusing pages" I think I might prefer to go with something along the
> > lines of "releasing pages for use by the guest". The problem is that
> > when you have a balloon we were referencing using pages from the
> > balloon. Since we cannot reference the balloon I figure I will go with
> > language where we "supply" and "release" hinted pages. That way we
> > acknowledge that the driver is holding onto pages and not freeing them
> > for use by the guest.
> >
> > I'll probably go with something like:
> >   The driver should stop hinting free pages, but
> >   should not release any hinted pages for use by the guest.
>
> "The driver should stop hinting free pages until a new command ID is
> supplied, but should not release..."
>
> would sound good to me.

Thanks, I will make that tweak.


[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]