Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756906Ab3IOJIm (ORCPT ); Sun, 15 Sep 2013 05:08:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33067 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753787Ab3IOJIk (ORCPT ); Sun, 15 Sep 2013 05:08:40 -0400 Date: Sun, 15 Sep 2013 12:08:38 +0300 From: Gleb Natapov To: Andrew Jones Cc: kvm@vger.kernel.org, pbonzini@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86: kvm: introduce CONFIG_KVM_MAX_VCPUS Message-ID: <20130915090838.GW17294@redhat.com> References: <1379161129-28393-1-git-send-email-drjones@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1379161129-28393-1-git-send-email-drjones@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1927 Lines: 59 On Sat, Sep 14, 2013 at 02:18:49PM +0200, Andrew Jones wrote: > Take CONFIG_KVM_MAX_VCPUS from arm32, but set the default to 255. > > Signed-off-by: Andrew Jones > --- > arch/x86/include/asm/kvm_host.h | 5 +++-- > arch/x86/kvm/Kconfig | 10 ++++++++++ > 2 files changed, 13 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index c76ff74a98f2e..e7e9b523a8f7e 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -31,8 +31,9 @@ > #include > #include > > -#define KVM_MAX_VCPUS 255 > -#define KVM_SOFT_MAX_VCPUS 160 > +#define KVM_MAX_VCPUS CONFIG_KVM_MAX_VCPUS > +#define KVM_SOFT_MAX_VCPUS min(160, KVM_MAX_VCPUS) > + > #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/Kconfig b/arch/x86/kvm/Kconfig > index a47a3e54b964b..e9532c33527ee 100644 > --- a/arch/x86/kvm/Kconfig > +++ b/arch/x86/kvm/Kconfig > @@ -52,6 +52,16 @@ config KVM > > If unsure, say N. > > +config KVM_MAX_VCPUS > + int "Number maximum supported virtual CPUs per VM" > + depends on KVM > + default 255 > + help > + Static number of max supported virtual CPUs per VM. > + > + Set to a lower number to save some resources. Set to a higher > + number to test scalability. > + Maximum this can save is around 2K per VM. This is pretty insignificant considering overall memory footprint even smallest VM has. > config KVM_INTEL > tristate "KVM for Intel processors support" > depends on KVM > -- > 1.8.1.4 -- 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/