Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756439Ab2EGNYj (ORCPT ); Mon, 7 May 2012 09:24:39 -0400 Received: from mail-wi0-f172.google.com ([209.85.212.172]:40036 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756068Ab2EGNYi (ORCPT ); Mon, 7 May 2012 09:24:38 -0400 Date: Mon, 7 May 2012 15:24:33 +0200 From: Ingo Molnar To: Ido Yariv Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Shai Fultheim Subject: Re: [PATCH v2 1/2] vsmp: Fix number of CPUs when vsmp is disabled Message-ID: <20120507132433.GA9808@gmail.com> References: <1333715987-26059-2-git-send-email-ido@wizery.com> <1334561976-13965-1-git-send-email-ido@wizery.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1334561976-13965-1-git-send-email-ido@wizery.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2996 Lines: 116 * Ido Yariv wrote: > From: Shai Fultheim > > In case CONFIG_X86_VSMP is not set, limit the number of CPUs to the > number of CPUs of the first board. > > Signed-off-by: Shai Fultheim > [ido@wizery.com: rebased, fixed minor coding-style issues] > Signed-off-by: Ido Yariv > --- > arch/x86/kernel/vsmp_64.c | 48 +++++++++++++++++++++++++++++++++++++++++++++ > 1 files changed, 48 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/kernel/vsmp_64.c b/arch/x86/kernel/vsmp_64.c > index a1d804b..61571fd 100644 > --- a/arch/x86/kernel/vsmp_64.c > +++ b/arch/x86/kernel/vsmp_64.c > @@ -15,6 +15,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -22,6 +23,8 @@ > #include > #include > > +#define TOPOLOGY_REGISTER_OFFSET 0x10 > + > #if defined CONFIG_PCI && defined CONFIG_PARAVIRT > /* > * Interrupt control on vSMPowered systems: > @@ -149,12 +152,57 @@ int is_vsmp_box(void) > return 0; > } > #endif > + > +#ifdef CONFIG_X86_VSMP > + > +static void __init vsmp_cap_cpus(void) > +{ > + /* VSMP is enabled, no need to cap cpus */ > +} > + > +#else Please move this int the vsmp_cap_cpus() function and you can simplify the #ifdef block to: #ifdef CONFIG_X86_VSMP /* VSMP is enabled, no need to cap cpus */ return; #endif > + > +static void __init vsmp_cap_cpus(void) > +{ > + /* > + * CONFIG_X86_VSMP is not configured, so limit the number CPUs to the > + * ones present in the first board, unless explicitly overridden by > + * setup_max_cpus > + */ > + if (setup_max_cpus == NR_CPUS) { you can simplify the function and save a level of indentation by turning this into: if (setup_max_cpus != NR_CPUS) return; > + void __iomem *address; > + unsigned int cfg, topology, node_shift, maxcpus; > + > + /* Read the vSMP Foundation topology register */ > + cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0); > + address = early_ioremap(cfg + TOPOLOGY_REGISTER_OFFSET, 4); > + if (WARN_ON(!address)) > + return; > + > + topology = readl(address); > + node_shift = (topology >> 16) & 0x7; > + if (!node_shift) > + /* The value 0 should be decoded as 8 */ > + node_shift = 8; > + maxcpus = (topology & ((1 << node_shift) - 1)) + 1; > + > + printk(KERN_INFO "vSMP CTL: Capping CPUs to %d " > + "(CONFIG_X86_VSMP is unset)\n", maxcpus); Please don't break up format strings - just leave them long and use pr_info(). > + setup_max_cpus = maxcpus; > + early_iounmap(address, 4); > + } > +} > + > +#endif Looks good and useful otherwise. Thanks, Ingo -- 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/