On 09/06/2017 12:04 PM, Peter Zijlstra wrote: > On Wed, Sep 06, 2017 at 11:49:49AM -0400, Waiman Long wrote: >>> #define virt_spin_lock virt_spin_lock >>> static inline bool virt_spin_lock(struct qspinlock *lock) >>> { >>> + if (!static_branch_likely(&virt_spin_lock_key)) >>> + return false; >>> if (!static_cpu_has(X86_FEATURE_HYPERVISOR)) >>> return false; >>> > Now native has two NOPs instead of one. Can't we merge these two static > branches?
I guess we can remove the static_cpu_has() call. Just that any spin_lock calls before native_pv_lock_init() will use the virt_spin_lock(). That is still OK as the init call is done before SMP starts. Cheers, Longman _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel