* Li, Liang Z (liang.z...@intel.com) 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 / dgilb...@redhat.com / Manchester, UK