[PATCH v7 10/11] x86, xen: support vcpu preempted check

From: Juergen Gross Support the vcpu_is_preempted() functionality under Xen. This will enhance lock performance on overcommitted hosts (more runnable vcpus than physical cpus in the system) as doing busy waits for preempted vcpus will hurt system performance far worse than early

[PATCH v7 10/11] x86, xen: support vcpu preempted check

From: Juergen Gross Support the vcpu_is_preempted() functionality under Xen. This will enhance lock performance on overcommitted hosts (more runnable vcpus than physical cpus in the system) as doing busy waits for preempted vcpus will hurt system performance far worse than early yielding. A