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The patch implements cpu topology exportation by sysfs. Items (attributes) are similar to /proc/cpuinfo. 1) /sys/devices/system/cpu/cpuX/topology/physical_package_id: represent the physical package id of cpu X; 2) /sys/devices/system/cpu/cpuX/topology/core_id: represent the cpu core id to cpu X; 3) /sys/devices/system/cpu/cpuX/topology/thread_siblings: represent the thread siblings to cpu X in the same core; 4) /sys/devices/system/cpu/cpuX/topology/core_siblings: represent the thread siblings to cpu X in the same physical package; To implement it in an architecture-neutral way, a new source file, driver/base/topology.c, is to export the 5 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: #define topology_physical_package_id(cpu) #define topology_core_id(cpu) #define topology_thread_siblings(cpu) #define topology_core_siblings(cpu) The type of **_id is int. The type of siblings is cpumask_t. To be consistent on all architectures, the 4 attributes should have deafult 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. Thank Nathan, Greg, Andi, Paul and Venki. The patch provides defines for i386/x86_64/ia64. Signed-off-by: Zhang, Yanmin <yanmin.zhang@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
149 lines
3.7 KiB
C
149 lines
3.7 KiB
C
/*
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* driver/base/topology.c - Populate sysfs with cpu topology information
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*
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* Written by: Zhang Yanmin, Intel Corporation
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*
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* Copyright (C) 2006, Intel Corp.
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include <linux/sysdev.h>
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/cpu.h>
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#include <linux/module.h>
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#include <linux/topology.h>
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#define define_one_ro(_name) \
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static SYSDEV_ATTR(_name, 0444, show_##_name, NULL)
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#define define_id_show_func(name) \
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static ssize_t show_##name(struct sys_device *dev, char *buf) \
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{ \
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unsigned int cpu = dev->id; \
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return sprintf(buf, "%d\n", topology_##name(cpu)); \
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}
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#define define_siblings_show_func(name) \
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static ssize_t show_##name(struct sys_device *dev, char *buf) \
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{ \
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ssize_t len = -1; \
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unsigned int cpu = dev->id; \
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len = cpumask_scnprintf(buf, NR_CPUS+1, topology_##name(cpu)); \
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return (len + sprintf(buf + len, "\n")); \
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}
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#ifdef topology_physical_package_id
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define_id_show_func(physical_package_id);
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define_one_ro(physical_package_id);
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#define ref_physical_package_id_attr &attr_physical_package_id.attr,
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#else
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#define ref_physical_package_id_attr
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#endif
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#ifdef topology_core_id
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define_id_show_func(core_id);
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define_one_ro(core_id);
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#define ref_core_id_attr &attr_core_id.attr,
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#else
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#define ref_core_id_attr
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#endif
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#ifdef topology_thread_siblings
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define_siblings_show_func(thread_siblings);
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define_one_ro(thread_siblings);
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#define ref_thread_siblings_attr &attr_thread_siblings.attr,
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#else
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#define ref_thread_siblings_attr
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#endif
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#ifdef topology_core_siblings
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define_siblings_show_func(core_siblings);
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define_one_ro(core_siblings);
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#define ref_core_siblings_attr &attr_core_siblings.attr,
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#else
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#define ref_core_siblings_attr
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#endif
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static struct attribute *default_attrs[] = {
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ref_physical_package_id_attr
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ref_core_id_attr
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ref_thread_siblings_attr
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ref_core_siblings_attr
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NULL
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};
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static struct attribute_group topology_attr_group = {
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.attrs = default_attrs,
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.name = "topology"
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};
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/* Add/Remove cpu_topology interface for CPU device */
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static int __cpuinit topology_add_dev(struct sys_device * sys_dev)
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{
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sysfs_create_group(&sys_dev->kobj, &topology_attr_group);
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return 0;
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}
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static int __cpuinit topology_remove_dev(struct sys_device * sys_dev)
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{
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sysfs_remove_group(&sys_dev->kobj, &topology_attr_group);
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return 0;
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}
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static int __cpuinit topology_cpu_callback(struct notifier_block *nfb,
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unsigned long action, void *hcpu)
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{
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unsigned int cpu = (unsigned long)hcpu;
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struct sys_device *sys_dev;
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sys_dev = get_cpu_sysdev(cpu);
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switch (action) {
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case CPU_ONLINE:
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topology_add_dev(sys_dev);
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break;
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case CPU_DEAD:
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topology_remove_dev(sys_dev);
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break;
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}
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return NOTIFY_OK;
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}
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static struct notifier_block topology_cpu_notifier =
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{
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.notifier_call = topology_cpu_callback,
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};
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static int __cpuinit topology_sysfs_init(void)
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{
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int i;
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for_each_online_cpu(i) {
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topology_cpu_callback(&topology_cpu_notifier, CPU_ONLINE,
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(void *)(long)i);
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}
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register_cpu_notifier(&topology_cpu_notifier);
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return 0;
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}
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device_initcall(topology_sysfs_init);
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