From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754520AbdIFQEd (ORCPT ); Wed, 6 Sep 2017 12:04:33 -0400 Received: from bombadil.infradead.org ([65.50.211.133]:54278 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753896AbdIFQEc (ORCPT ); Wed, 6 Sep 2017 12:04:32 -0400 Date: Wed, 6 Sep 2017 18:04:15 +0200 From: Peter Zijlstra To: Waiman Long Cc: Juergen Gross , linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, virtualization@lists.linux-foundation.org, jeremy@goop.org, chrisw@sous-sol.org, akataria@vmware.com, rusty@rustcorp.com.au, boris.ostrovsky@oracle.com, hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com Subject: Re: [PATCH v2 1/2] paravirt/locks: use new static key for controlling call of virt_spin_lock() Message-ID: <20170906160415.crt2ajuf6553bit7@hirez.programming.kicks-ass.net> References: <20170906152928.8658-1-jgross@suse.com> <20170906152928.8658-2-jgross@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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?