On Tue, 5 Mar 2019 05:30:00 -0500 Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote: > Folks, > > this is a very simple variant to disable halt polling when the KVM host > is already running virtualized. We could imagine more complex variants > (like tuning down the halt polling value) but this seems to do the trick > for some kvm deployment scenarios on s390x. (e.g. having multiple LPARS > with KVMs that are in itself already overcommitted). Yes, it makes sense to disable halt polling in that scenario, but I wonder whether we can make "disable halt polling for high steal times" more architecture-independent (can we obtain steal time quickly in some kind of architecture-independent way?) Btw, power seems to have its own halt polling code; not sure if it makes sense there as well. > This still needs tuning and the right default value, but I want to start > the discussion. Maybe optionally log a stat? > > > Christian Borntraeger (2): > KVM: polling: add architecture backend to disable polling > KVM: s390: provide kvm_arch_no_poll function > > arch/s390/include/asm/kvm_host.h | 6 ++++++ > arch/s390/kvm/Kconfig | 1 + > include/linux/kvm_host.h | 10 ++++++++++ > virt/kvm/Kconfig | 3 +++ > virt/kvm/kvm_main.c | 2 +- > 5 files changed, 21 insertions(+), 1 deletion(-) >
