Date: Sat, 02 Dec 2017 05:10:05 +0000 From: "K. Macy" <kmacy@freebsd.org> To: "Rodney W. Grimes" <freebsd-rwg@pdx.rh.cn85.dnsmgr.net> Cc: Shane Ambler <FreeBSD@shaneware.biz>, freebsd-virtualization@freebsd.org Subject: Re: bhyve uses all available memory during IO-intensive operations Message-ID: <CAHM0Q_OSXR8P_bmYq3i6H%2BQbwBYtjmBen1OJQhBU1t8_hHEy0g@mail.gmail.com> In-Reply-To: <201712020402.vB242DaJ032505@pdx.rh.CN85.dnsmgr.net> References: <5bb5649f-5785-7baf-6871-625d1f63bd8b@ShaneWare.Biz> <201712020402.vB242DaJ032505@pdx.rh.CN85.dnsmgr.net>
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On Fri, Dec 1, 2017 at 20:02 Rodney W. Grimes < freebsd-rwg@pdx.rh.cn85.dnsmgr.net> wrote: > > On 02/12/2017 08:11, Dustin Wenz wrote: > > > > > > The commit history shows that chyves defaults to -S if you are > > > hosting from FreeBSD 10.3 or later. I'm sure they had a reason for > > > doing that, but I don't know what that would be. It seems to an > > > inefficient use of main memory if you need to run a lot of VMs. > > > > It sounds like a reasonable solution to a problem. If host memory is > > full it swaps some out, so a bhyve might have free mem but some could be > > swapped out by the host. If the bhyve is out of mem, it's system swaps > > to it's disk, so the host swaps it back in so that the bhyve can then > > swap it to its disk... > > > > Wiring bhyve ram might be a reasonable solution as long as the hosts > > physical ram isn't over allocated by bhyve guests. > > > > The best solution would involve a host and guest talking to each other > > about used mem, but that would break the whole virtual machine illusion. > > At the least it would involve a system telling the hardware what memory > > is used and what is not, which just isn't something any system does. > > Maybe that is an idea for the vm guest aware systems of the future. > > Its actually old technology, its called the memory balloon driver, > but bhyve does not have that functionality, yet. > > The virtio ballon driver is already there. Implementing a kernel backend for it would be trivial. In kernel virtio-net and virtio-p9fs backends are already well underway. -M > -- > Rod Grimes > rgrimes@freebsd.org > _______________________________________________ > freebsd-virtualization@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-virtualization > To unsubscribe, send any mail to " > freebsd-virtualization-unsubscribe@freebsd.org" >
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