topology: Create package_cpus sysfs attribute

The existing sysfs cpu/topology/core_siblings (and core_siblings_list)
attributes are documented, implemented, and used by programs to represent
set of logical CPUs sharing the same package.

This makes sense if the next topology level above a core is always a
package.  But on systems where there is a die topology level between a core
and a package, the name and its definition become inconsistent.

So without changing its function, add a name for this map that describes
what it actually is -- package CPUs -- the set of CPUs that share the same
package.

This new name will be immune to changes in topology, since it describes
threads at the current level, not siblings at a contained level.

Suggested-by: Brice Goglin <Brice.Goglin@inria.fr>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/d9d3228b82fb5665e6f93a0ccd033fe022558521.1557769318.git.len.brown@intel.com

2 files changed, 12 insertions, 6 deletions

diff --git a/Documentation/cputopology.txt b/Documentation/cputopology.txt
index 2ff8a1e9a2db..48af5c290e20 100644
--- a/Documentation/cputopology.txt
+++ b/Documentation/cputopology.txt
@@ -46,15 +46,15 @@ thread_siblings_list:
         human-readable list of cpuX's hardware threads within the same
         core as cpuX.
 
-core_siblings:
+package_cpus:
 
-        internal kernel map of cpuX's hardware threads within the same
-        physical_package_id.
+        internal kernel map of the CPUs sharing the same physical_package_id.
+        (deprecated name: "core_siblings")
 
-core_siblings_list:
+package_cpus_list:
 
-        human-readable list of cpuX's hardware threads within the same
-        physical_package_id.
+        human-readable list of CPUs sharing the same physical_package_id.
+        (deprecated name: "core_siblings_list")
 
 book_siblings:
 
diff --git a/drivers/base/topology.c b/drivers/base/topology.c
index 50352cf96f85..dc3c19b482f3 100644
--- a/drivers/base/topology.c
+++ b/drivers/base/topology.c
@@ -57,6 +57,10 @@ define_siblings_show_func(core_siblings, core_cpumask);
 static DEVICE_ATTR_RO(core_siblings);
 static DEVICE_ATTR_RO(core_siblings_list);
 
+define_siblings_show_func(package_cpus, core_cpumask);
+static DEVICE_ATTR_RO(package_cpus);
+static DEVICE_ATTR_RO(package_cpus_list);
+
 #ifdef CONFIG_SCHED_BOOK
 define_id_show_func(book_id);
 static DEVICE_ATTR_RO(book_id);
@@ -81,6 +85,8 @@ static struct attribute *default_attrs[] = {
         &dev_attr_thread_siblings_list.attr,
         &dev_attr_core_siblings.attr,
         &dev_attr_core_siblings_list.attr,
+        &dev_attr_package_cpus.attr,
+        &dev_attr_package_cpus_list.attr,
 #ifdef CONFIG_SCHED_BOOK
         &dev_attr_book_id.attr,
         &dev_attr_book_siblings.attr,