Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756868Ab3IPIzU (ORCPT ); Mon, 16 Sep 2013 04:55:20 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41271 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751470Ab3IPIzT (ORCPT ); Mon, 16 Sep 2013 04:55:19 -0400 Date: Mon, 16 Sep 2013 11:55:17 +0300 From: Gleb Natapov To: Andrew Jones Cc: kvm@vger.kernel.org, pbonzini@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] [RFC] x86: kvm: remove KVM_SOFT_MAX_VCPUS Message-ID: <20130916085517.GK17294@redhat.com> References: <1379161011-28239-1-git-send-email-drjones@redhat.com> <20130915090322.GV17294@redhat.com> <20130916082208.GA2101@hawk.usersys.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130916082208.GA2101@hawk.usersys.redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2355 Lines: 55 On Mon, Sep 16, 2013 at 10:22:09AM +0200, Andrew Jones wrote: > > > [1] Actually, until 972fc544b6034a in uq/master is merged there won't be > > > any warnings either. > > > > > > Signed-off-by: Andrew Jones > > > --- > > > arch/x86/include/asm/kvm_host.h | 1 - > > > arch/x86/kvm/x86.c | 2 +- > > > 2 files changed, 1 insertion(+), 2 deletions(-) > > > > > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > > > index c76ff74a98f2e..9236c63315a9b 100644 > > > --- a/arch/x86/include/asm/kvm_host.h > > > +++ b/arch/x86/include/asm/kvm_host.h > > > @@ -32,7 +32,6 @@ > > > #include > > > > > > #define KVM_MAX_VCPUS 255 > > > -#define KVM_SOFT_MAX_VCPUS 160 > > > #define KVM_USER_MEM_SLOTS 125 > > > /* memory slots that are not exposed to userspace */ > > > #define KVM_PRIVATE_MEM_SLOTS 3 > > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > > index e5ca72a5cdb6d..d9d3e2ed68ee9 100644 > > > --- a/arch/x86/kvm/x86.c > > > +++ b/arch/x86/kvm/x86.c > > > @@ -2604,7 +2604,7 @@ int kvm_dev_ioctl_check_extension(long ext) > > > r = !kvm_x86_ops->cpu_has_accelerated_tpr(); > > > break; > > > case KVM_CAP_NR_VCPUS: > > > - r = KVM_SOFT_MAX_VCPUS; > > > + r = min(num_online_cpus(), KVM_MAX_VCPUS); > > s/KVM_MAX_VCPUS/KVM_SOFT_MAX_VCPUS/. Also what about hotplug cpus? > > I'll send a v2 with this change. > > I thought a bit about hotplug, and thus using num_possible_cpus() > instead, but then decided it made more sense to stick to what's online now > for the recommended number. It's just a recommendation anyway. So as long > as KVM_MAX_VCPUS is >= num_possible_cpus(), then one can still configure > more vcpus to count for all hotplugable cpus, if they wish. > It is just recommended, but we do warn about it, so it is user visible. Well, the whole point of it existence is to be user visible ;). If user creates a guest with max cpus greater than current number if online cpus, taking into account feature grows, he will get a warning, but we should not warn about it. -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/