From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935842AbdIYN7W (ORCPT ); Mon, 25 Sep 2017 09:59:22 -0400 Received: from mx2.suse.de ([195.135.220.15]:52056 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S934254AbdIYN7V (ORCPT ); Mon, 25 Sep 2017 09:59:21 -0400 Subject: Re: [PATCH v3 0/2] guard virt_spin_lock() with a static key 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 References: <20170906173625.18158-1-jgross@suse.com> From: Juergen Gross Message-ID: <780c50a0-160b-24e3-a5b2-6685953882e5@suse.com> Date: Mon, 25 Sep 2017 15:59:14 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: <20170906173625.18158-1-jgross@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: de-DE Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ping? On 06/09/17 19:36, Juergen Gross wrote: > 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(-) >