Re: [Qemu-devel] [PATCH 0/5] s390x/kvm: avoid synchronize_rcu's in kernel

[Christian Borntraeger <borntraeger@de.ibm.com>]

On 28/08/14 13:58, Jens Freimann wrote:
> Whenever we call an ioctl from a wrong vcpu thread, the next ioctl will be
> painfully slow because a synchronize_rcu thread has to be performed, therefore
> involving all vcpu.
> 
> This patch series forces most ioctls to run on the associated vcpu.
> It speeds up all start/restart/reset operations involving cpus drastically.
> 
> 
> David Hildenbrand (5):
>   kvm: run cpu state synchronization on target vcpu thread
>   s390x/kvm: run guest triggered resets on the target vcpu thread
>   s390x/kvm: execute sigp orders on the target vcpu thread
>   s390x/kvm: execute "system reset" cpu resets on the vcpu thread
>   s390x/kvm: execute the first cpu reset on the vcpu thread
> 
>  kvm-all.c                  | 18 ++++++++++++++++--
>  target-s390x/cpu.c         |  6 +++++-
>  target-s390x/cpu.h         | 15 +++++++++++++++
>  target-s390x/kvm.c         | 23 ++++++++++++++++-------
>  target-s390x/misc_helper.c | 30 ++++++++----------------------
>  5 files changed, 60 insertions(+), 32 deletions(-)
> 
Thanks.

Applied 2-5 to https://github.com/borntraeger/qemu.git s390-next.
Patch 1 will be taken care of in Paolos kvm tree.

I will wait some more days before sending the pull request to give others a chance for feedback.

Christian