[PATCH] Export cpu topology in sysfs
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>
diff --git a/arch/ia64/kernel/topology.c b/arch/ia64/kernel/topology.c
index 706b773..6e5eea1 100644
--- a/arch/ia64/kernel/topology.c
+++ b/arch/ia64/kernel/topology.c
@@ -71,31 +71,33 @@
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);