From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752666AbbEHKZx (ORCPT ); Fri, 8 May 2015 06:25:53 -0400 Received: from mga09.intel.com ([134.134.136.24]:52289 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752048AbbEHKZw (ORCPT ); Fri, 8 May 2015 06:25:52 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,390,1427785200"; d="scan'208";a="707207658" From: "Kirill A. Shutemov" To: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" Cc: x86@kernel.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCH] x86: bump default NR_CPUS for 64-bit configuration Date: Fri, 8 May 2015 13:25:45 +0300 Message-Id: <1431080745-19792-1-git-send-email-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Default NR_CPUS==8 is not enough to cover high-end desktop configuration: Haswell-E has upto 16 threads. Let's increase default NR_CPUS to 64 on 64-bit configuration. With this value CPU bitmask will still fit into one unsinged long. Default for 32-bit configuration is still 8: it's unlikely anybody will run 32-bit kernel on modern hardware. As alternative we could bump NR_CPUS to 128 to cover all dual-processor servers with some margin. For reference: Debian and Suse build their kernels with NR_CPUS==512, Fedora -- 1024. Signed-off-by: Kirill A. Shutemov --- arch/x86/Kconfig | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 6aaf38ac417d..c3333e5be5d7 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -851,7 +851,8 @@ config NR_CPUS default "1" if !SMP default "8192" if MAXSMP default "32" if SMP && X86_BIGSMP - default "8" if SMP + default "8" if SMP && X86_32 + default "64" if SMP ---help--- This allows you to specify the maximum number of CPUs which this kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum -- 2.1.4