Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760305AbYFDPpg (ORCPT ); Wed, 4 Jun 2008 11:45:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750971AbYFDPp3 (ORCPT ); Wed, 4 Jun 2008 11:45:29 -0400 Received: from 82-69-137-158.dsl.in-addr.zen.co.uk ([82.69.137.158]:46035 "EHLO uklogin.uk.level5networks.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756823AbYFDPp2 (ORCPT ); Wed, 4 Jun 2008 11:45:28 -0400 Date: Wed, 4 Jun 2008 16:44:56 +0100 From: Ben Hutchings To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Vegard Nossum Subject: [PATCH] cputopology: Always define CPU topology information [4th try] Message-ID: <20080604154454.GD11300@solarflare.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6254 Lines: 172 Not all architectures and configurations define CPU topology information. This can result in an empty topology directory in sysfs, and requires in-kernel users to protect all uses with #ifdef - see . The documentation of CPU topology specifies what the defaults should be if only partial information is available from the hardware. So we can provide these defaults as a fallback. This patch: - Adds default definitions of the 4 topology macros to - Changes drivers/base/topology.c to use the topology macros unconditionally and to cope with definitions that aren't lvalues - Updates documentation accordingly Signed-off-by: Ben Hutchings --- Documentation/cputopology.txt | 26 +++++++++----------------- drivers/base/topology.c | 38 ++++++++++---------------------------- include/linux/topology.h | 13 +++++++++++++ 3 files changed, 32 insertions(+), 45 deletions(-) diff --git a/Documentation/cputopology.txt b/Documentation/cputopology.txt index b61cb95..bd699da 100644 --- a/Documentation/cputopology.txt +++ b/Documentation/cputopology.txt @@ -14,9 +14,8 @@ represent the thread siblings to cpu X in the same physical package; To implement it in an architecture-neutral way, a new source file, drivers/base/topology.c, is to export the 4 attributes. -If one architecture wants to support this feature, it just needs to -implement 4 defines, typically in file include/asm-XXX/topology.h. -The 4 defines are: +For an architecture to support this feature, it must define some of +these macros in include/asm-XXX/topology.h: #define topology_physical_package_id(cpu) #define topology_core_id(cpu) #define topology_thread_siblings(cpu) @@ -25,17 +24,10 @@ The 4 defines are: The type of **_id is int. The type of siblings is cpumask_t. -To be consistent on all architectures, the 4 attributes should have -default values if their values are unavailable. Below is the rule. -1) physical_package_id: If cpu has no physical package id, -1 is the -default value. -2) core_id: If cpu doesn't support multi-core, its core id is 0. -3) thread_siblings: Just include itself, if the cpu doesn't support -HT/multi-thread. -4) core_siblings: Just include itself, if the cpu doesn't support -multi-core and HT/Multi-thread. - -So be careful when declaring the 4 defines in include/asm-XXX/topology.h. - -If an attribute isn't defined on an architecture, it won't be exported. - +To be consistent on all architectures, include/linux/topology.h +provides default definitions for any of the above macros that are +not defined by include/asm-XXX/topology.h: +1) physical_package_id: -1 +2) core_id: 0 +3) thread_siblings: just the given CPU +4) core_siblings: just the given CPU diff --git a/drivers/base/topology.c b/drivers/base/topology.c index 1efe162..8999828 100644 --- a/drivers/base/topology.c +++ b/drivers/base/topology.c @@ -62,14 +62,16 @@ static ssize_t show_cpumap(int type, cpumask_t *mask, char *buf) static ssize_t show_##name(struct sys_device *dev, char *buf) \ { \ unsigned int cpu = dev->id; \ - return show_cpumap(0, &(topology_##name(cpu)), buf); \ + cpumask_t siblings = topology_##name(cpu); \ + return show_cpumap(0, &siblings, buf); \ } #define define_siblings_show_list(name) \ static ssize_t show_##name##_list(struct sys_device *dev, char *buf) \ { \ unsigned int cpu = dev->id; \ - return show_cpumap(1, &(topology_##name(cpu)), buf); \ + cpumask_t siblings = topology_##name(cpu); \ + return show_cpumap(1, &siblings, buf); \ } #else @@ -93,47 +95,27 @@ static ssize_t show_##name##_list(struct sys_device *dev, char *buf) \ #define define_siblings_show_func(name) \ define_siblings_show_map(name); define_siblings_show_list(name) -#ifdef topology_physical_package_id define_id_show_func(physical_package_id); define_one_ro(physical_package_id); -#define ref_physical_package_id_attr &attr_physical_package_id.attr, -#else -#define ref_physical_package_id_attr -#endif -#ifdef topology_core_id define_id_show_func(core_id); define_one_ro(core_id); -#define ref_core_id_attr &attr_core_id.attr, -#else -#define ref_core_id_attr -#endif -#ifdef topology_thread_siblings define_siblings_show_func(thread_siblings); define_one_ro(thread_siblings); define_one_ro(thread_siblings_list); -#define ref_thread_siblings_attr \ - &attr_thread_siblings.attr, &attr_thread_siblings_list.attr, -#else -#define ref_thread_siblings_attr -#endif -#ifdef topology_core_siblings define_siblings_show_func(core_siblings); define_one_ro(core_siblings); define_one_ro(core_siblings_list); -#define ref_core_siblings_attr \ - &attr_core_siblings.attr, &attr_core_siblings_list.attr, -#else -#define ref_core_siblings_attr -#endif static struct attribute *default_attrs[] = { - ref_physical_package_id_attr - ref_core_id_attr - ref_thread_siblings_attr - ref_core_siblings_attr + &attr_physical_package_id.attr, + &attr_core_id.attr, + &attr_thread_siblings.attr, + &attr_thread_siblings_list.attr, + &attr_core_siblings.attr, + &attr_core_siblings_list.attr, NULL }; diff --git a/include/linux/topology.h b/include/linux/topology.h index 24f3d22..2158fc0 100644 --- a/include/linux/topology.h +++ b/include/linux/topology.h @@ -179,4 +179,17 @@ void arch_update_cpu_topology(void); #endif #endif /* CONFIG_NUMA */ +#ifndef topology_physical_package_id +#define topology_physical_package_id(cpu) ((void)(cpu), -1) +#endif +#ifndef topology_core_id +#define topology_core_id(cpu) ((void)(cpu), 0) +#endif +#ifndef topology_thread_siblings +#define topology_thread_siblings(cpu) cpumask_of_cpu(cpu) +#endif +#ifndef topology_core_siblings +#define topology_core_siblings(cpu) cpumask_of_cpu(cpu) +#endif + #endif /* _LINUX_TOPOLOGY_H */ -- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job. -- 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/