[PATCH] cputopology: Add default CPU topology information [3rd try]

From: Ben Hutchings
Date: Sat May 31 2008 - 17:45:36 EST


Define the macros topology_{physical_package,core}_id() and
topology_{thread,core}_siblings() in <asm-generic/topology.h> if they are not
already defined.

Move inclusion of <asm-generic/topology.h> after definitions of these
macros in <asm-powerpc/topology.h> and <asm-x86/topology.h>.

Change drivers/base/topology.c to use the topology macros unconditionally and
to cope with definitions that aren't lvalues.

Update documentation accordingly.

Signed-off-by: Ben Hutchings <bhutchings@xxxxxxxxxxxxxx>
---
Documentation/cputopology.txt | 26 +++++++++-----------------
drivers/base/topology.c | 38 ++++++++++----------------------------
include/asm-generic/topology.h | 15 +++++++++++++++
include/asm-powerpc/topology.h | 4 ++--
include/asm-x86/topology.h | 4 ++--
5 files changed, 38 insertions(+), 49 deletions(-)

diff --git a/Documentation/cputopology.txt b/Documentation/cputopology.txt
index b61cb95..c035481 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:
+If one architecture wants 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/asm-generic/topology.h
+provides default definitions for any of the above macros that are
+not already defined:
+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 fdf4044..24d29a9 100644
--- a/drivers/base/topology.c
+++ b/drivers/base/topology.c
@@ -59,60 +59,42 @@ static ssize_t show_cpumap(int type, cpumask_t *mask, char *buf)
static inline 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 inline 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); \
}

#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/asm-generic/topology.h b/include/asm-generic/topology.h
index a6aea79..8ad8aa0 100644
--- a/include/asm-generic/topology.h
+++ b/include/asm-generic/topology.h
@@ -27,6 +27,8 @@
#ifndef _ASM_GENERIC_TOPOLOGY_H
#define _ASM_GENERIC_TOPOLOGY_H

+#include <linux/cpumask.h>
+
#ifndef CONFIG_NUMA

/* Other architectures wishing to use this simple topology API should fill
@@ -66,4 +68,17 @@
_##v = node_to_cpumask(node)
#endif

+#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 /* _ASM_GENERIC_TOPOLOGY_H */
diff --git a/include/asm-powerpc/topology.h b/include/asm-powerpc/topology.h
index 100c6fb..e587788 100644
--- a/include/asm-powerpc/topology.h
+++ b/include/asm-powerpc/topology.h
@@ -98,8 +98,6 @@ static inline void sysfs_remove_device_from_node(struct sys_device *dev,

#endif /* CONFIG_NUMA */

-#include <asm-generic/topology.h>
-
#ifdef CONFIG_SMP
#include <asm/cputable.h>
#define smt_capable() (cpu_has_feature(CPU_FTR_SMT))
@@ -111,5 +109,7 @@ static inline void sysfs_remove_device_from_node(struct sys_device *dev,
#endif
#endif

+#include <asm-generic/topology.h>
+
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_TOPOLOGY_H */
diff --git a/include/asm-x86/topology.h b/include/asm-x86/topology.h
index dcf3f81..c4c28c6 100644
--- a/include/asm-x86/topology.h
+++ b/include/asm-x86/topology.h
@@ -184,8 +184,6 @@ extern int __node_distance(int, int);

#endif

-#include <asm-generic/topology.h>
-
extern cpumask_t cpu_coregroup_map(int cpu);

#ifdef ENABLE_TOPO_DEFINES
@@ -220,4 +218,6 @@ static inline void set_mp_bus_to_node(int busnum, int node)
}
#endif

+#include <asm-generic/topology.h>
+
#endif

--
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
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