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Re: [Qemu-devel] [QEMU 3/7] Add the hmp and qmp interface for dropping c
From: |
Li, Liang Z |
Subject: |
Re: [Qemu-devel] [QEMU 3/7] Add the hmp and qmp interface for dropping cache |
Date: |
Fri, 17 Jun 2016 01:35:19 +0000 |
> > > > +{ '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.
>
That's much better. Thanks!
Liang
- Re: [Qemu-devel] [QEMU 4/7] balloon: get free page info from guest, (continued)
- [Qemu-devel] [QEMU 3/7] Add the hmp and qmp interface for dropping cache, Liang Li, 2016/06/13
- Re: [Qemu-devel] [QEMU 3/7] Add the hmp and qmp interface for dropping cache, Li, Liang Z, 2016/06/13
- Re: [Qemu-devel] [QEMU 3/7] Add the hmp and qmp interface for dropping cache, Dr. David Alan Gilbert, 2016/06/13
- Re: [Qemu-devel] [QEMU 3/7] Add the hmp and qmp interface for dropping cache, Li, Liang Z, 2016/06/13
- Re: [Qemu-devel] [QEMU 3/7] Add the hmp and qmp interface for dropping cache,
Li, Liang Z <=
[Qemu-devel] [QEMU 5/7] bitmap: Add a new bitmap_move function, Liang Li, 2016/06/13
[Qemu-devel] [QEMU 6/7] kvm: Add two new arch specific functions, Liang Li, 2016/06/13
[Qemu-devel] [QEMU 7/7] migration: skip free pages during live migration, Liang Li, 2016/06/13