* Li, Liang Z (liang.z.li@xxxxxxxxx) wrote:
> > Because writing to this file is a nondestructive operation and dirty objects are
> > not freeable, the user should run sync(1) first.
> > [/quote]
> >
> > IOW, by 'slab' you mean dentries and inodes ?
> >
> Yes.
>
> > > +##
> > > +{ 'command': 'balloon_drop_cache', 'data': {'value': 'DropCacheType'}
> > > +}
> >
> > Also, as noted in the man page quote above, it is recommended to call
> > sync() to minimise dirty pages. Should we have a way to request a sync as
> > part of this monitor command.
> >
> > More generally, it feels like this is taking as down a path towards actively
> > managing the guest kernel VM from the host. Is this really a path we want to
> > be going down, given that its going to take us into increasing non-portable
> > concepts which are potentially different for each guest OS kernel. Is this
> > drop caches feature at all applicable to Windows, OS-X, *BSD guest OS impls
> > of the balloon driver ? If it is applicable, are the 3 fixed constants you've
>
> No.
>
> > defined at all useful to those other OS ?
> >
>
> Maybe they are not.
> I agree that there are too Linux specific. And I did more than needed.
> Actually, I just want to drop the clean cache, do more than that is too heavy
> and no good for performance.
>
> > I'm warying of us taking a design path which is so Linux specific it isn't useful
> > elsewhere. IOW, just because we can do this, doesn't mean we should do
> > this...
> >
>
> Agree.
I can see an argument for giving the guest a hint about what's going on and letting
the guest decide what it's going to do - so telling the guest that a migration
is happening and you'd like it to make the hosts life easy seems reasonable
and it doesn't make any guest OS assumptions.
Dave
>
> Thanks!
>
> Liang
> > Regards,
> > Daniel
> > --
> > |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :|
> > |: http://libvirt.org -o- http://virt-manager.org :|
> > |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
> > |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
--
Dr. David Alan Gilbert / dgilbert@xxxxxxxxxx / Manchester, UK
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