[PATCH] Export cpu topology in sysfs

Export cpu topology info 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.

	int i, err = 0;

#ifdef CONFIG_NUMA

	sysfs_nodes = kmalloc(sizeof(struct node) * MAX_NUMNODES, GFP_KERNEL);

	sysfs_nodes = kzalloc(sizeof(struct node) * MAX_NUMNODES, GFP_KERNEL);

	if (!sysfs_nodes) {

		err = -ENOMEM;

		goto out;

	}

	memset(sysfs_nodes, 0, sizeof(struct node) * MAX_NUMNODES);

	/* MCD - Do we want to register all ONLINE nodes, or all POSSIBLE nodes? */

	for_each_online_node(i)

	/*

	 * MCD - Do we want to register all ONLINE nodes, or all POSSIBLE nodes?

	 */

	for_each_online_node(i) {

		if ((err = register_node(&sysfs_nodes[i], i, 0)))

			goto out;

	}

#endif

	sysfs_cpus = kmalloc(sizeof(struct ia64_cpu) * NR_CPUS, GFP_KERNEL);

	sysfs_cpus = kzalloc(sizeof(struct ia64_cpu) * NR_CPUS, GFP_KERNEL);

	if (!sysfs_cpus) {

		err = -ENOMEM;

		goto out;

	}

	memset(sysfs_cpus, 0, sizeof(struct ia64_cpu) * NR_CPUS);

	for_each_present_cpu(i)

	for_each_present_cpu(i) {

		if((err = arch_register_cpu(i)))

			goto out;

	}

out:

	return err;

}

__initcall(topology_init);

subsys_initcall(topology_init);

obj-$(CONFIG_FW_LOADER)	+= firmware_class.o

obj-$(CONFIG_NUMA)	+= node.o

obj-$(CONFIG_MEMORY_HOTPLUG) += memory.o

obj-$(CONFIG_SMP)	+= topology.o

ifeq ($(CONFIG_DEBUG_DRIVER),y)

EXTRA_CFLAGS += -DDEBUG

/*

 * driver/base/topology.c - Populate sysfs with cpu topology information

 *

 * Written by: Zhang Yanmin, Intel Corporation

 *

 * Copyright (C) 2006, Intel Corp.

 *

 * All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or

 * NON INFRINGEMENT.  See the GNU General Public License for more

 * details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 *

 */

#include <linux/sysdev.h>

#include <linux/init.h>

#include <linux/mm.h>

#include <linux/cpu.h>

#include <linux/module.h>

#include <linux/topology.h>

#define define_one_ro(_name) 		\

static SYSDEV_ATTR(_name, 0444, show_##_name, NULL)

#define define_id_show_func(name)				\

static ssize_t show_##name(struct sys_device *dev, char *buf)	\

{								\

	unsigned int cpu = dev->id;				\

	return sprintf(buf, "%d\n", topology_##name(cpu));	\

}

#define define_siblings_show_func(name)					\

static ssize_t show_##name(struct sys_device *dev, char *buf)		\

{									\

	ssize_t len = -1;						\

	unsigned int cpu = dev->id;					\

	len = cpumask_scnprintf(buf, NR_CPUS+1, topology_##name(cpu));	\

	return (len + sprintf(buf + len, "\n"));			\

}

#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 ref_thread_siblings_attr	&attr_thread_siblings.attr,

#else

#define ref_thread_siblings_attr

#endif

#ifdef topology_core_siblings

define_siblings_show_func(core_siblings);

define_one_ro(core_siblings);

#define ref_core_siblings_attr		&attr_core_siblings.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

	NULL

};

static struct attribute_group topology_attr_group = {

	.attrs = default_attrs,

	.name = "topology"

};

/* Add/Remove cpu_topology interface for CPU device */

static int __cpuinit topology_add_dev(struct sys_device * sys_dev)

{

	sysfs_create_group(&sys_dev->kobj, &topology_attr_group);

	return 0;

}

static int __cpuinit topology_remove_dev(struct sys_device * sys_dev)

{

	sysfs_remove_group(&sys_dev->kobj, &topology_attr_group);

	return 0;

}

static int __cpuinit topology_cpu_callback(struct notifier_block *nfb,

		unsigned long action, void *hcpu)

{

	unsigned int cpu = (unsigned long)hcpu;

	struct sys_device *sys_dev;

	sys_dev = get_cpu_sysdev(cpu);

	switch (action) {

	case CPU_ONLINE:

		topology_add_dev(sys_dev);

		break;

	case CPU_DEAD:

		topology_remove_dev(sys_dev);

		break;

	}

	return NOTIFY_OK;

}

static struct notifier_block topology_cpu_notifier =

{

	.notifier_call = topology_cpu_callback,

};

static int __cpuinit topology_sysfs_init(void)

{

	int i;

	for_each_online_cpu(i) {

		topology_cpu_callback(&topology_cpu_notifier, CPU_ONLINE,

				(void *)(long)i);

	}

	register_cpu_notifier(&topology_cpu_notifier);

	return 0;

}

device_initcall(topology_sysfs_init);

#ifndef _ASM_I386_TOPOLOGY_H

#define _ASM_I386_TOPOLOGY_H

#ifdef CONFIG_SMP

#define topology_physical_package_id(cpu)				\

	(phys_proc_id[cpu] == BAD_APICID ? -1 : phys_proc_id[cpu])

#define topology_core_id(cpu)						\

	(cpu_core_id[cpu] == BAD_APICID ? 0 : cpu_core_id[cpu])

#define topology_core_siblings(cpu)		(cpu_core_map[cpu])

#define topology_thread_siblings(cpu)		(cpu_sibling_map[cpu])

#endif

#ifdef CONFIG_NUMA

#include <asm/mpspec.h>