Protect vcpu->pid with a rwlock instead of RCU, so that running a vCPU with a different task doesn't require a full RCU synchronization, which can introduce a non-trivial amount of jitter, especially on large systems. I've had this mini-series sitting around for ~2 years, pretty much as-is. I could have sworn past me thought there was a flaw in using a rwlock, and so I never posted it, but for the life of me I can't think of any issues. Extra eyeballs would be much appreciated. Sean Christopherson (2): KVM: Return '0' directly when there's no task to yield to KVM: Protect vCPU's "last run PID" with rwlock, not RCU arch/arm64/include/asm/kvm_host.h | 2 +- include/linux/kvm_host.h | 3 ++- virt/kvm/kvm_main.c | 36 +++++++++++++++++-------------- 3 files changed, 23 insertions(+), 18 deletions(-) base-commit: 332d2c1d713e232e163386c35a3ba0c1b90df83f -- 2.46.0.rc2.264.g509ed76dc8-goog
