From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752193AbdIFRgb (ORCPT ); Wed, 6 Sep 2017 13:36:31 -0400 Received: from mx2.suse.de ([195.135.220.15]:54993 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751994AbdIFRg3 (ORCPT ); Wed, 6 Sep 2017 13:36:29 -0400 From: Juergen Gross To: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, virtualization@lists.linux-foundation.org Cc: 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, peterz@infradead.org, longman@redhat.com, Juergen Gross Subject: [PATCH v3 0/2] guard virt_spin_lock() with a static key Date: Wed, 6 Sep 2017 19:36:23 +0200 Message-Id: <20170906173625.18158-1-jgross@suse.com> X-Mailer: git-send-email 2.12.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org With virt_spin_lock() being guarded by a static key the bare metal case can be optimized by patching the call away completely. In case a kernel running as a guest it can decide whether to use paravitualized spinlocks, the current fallback to the unfair test-and-set scheme, or to mimic the bare metal behavior. V3: - remove test for hypervisor environment from virt_spin_lock(9 as suggested by Waiman Long V2: - use static key instead of making virt_spin_lock() a pvops function Juergen Gross (2): paravirt/locks: use new static key for controlling call of virt_spin_lock() paravirt,xen: correct xen_nopvspin case arch/x86/include/asm/qspinlock.h | 11 ++++++++++- arch/x86/kernel/paravirt-spinlocks.c | 6 ++++++ arch/x86/kernel/smpboot.c | 2 ++ arch/x86/xen/spinlock.c | 2 ++ kernel/locking/qspinlock.c | 4 ++++ 5 files changed, 24 insertions(+), 1 deletion(-) -- 2.12.3