Messages in this thread | | | Subject | Re: [PATCH v2 1/2] paravirt/locks: use new static key for controlling call of virt_spin_lock() | From | Juergen Gross <> | Date | Wed, 6 Sep 2017 19:33:10 +0200 |
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On 06/09/17 18:13, Waiman Long wrote: > 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.
Hmm, right. I'll send V3 in some minutes.
Juergen
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