[PATCH 3/3] topology/sysfs: rework book and drawer topology ifdefery

From: Heiko Carstens
Date: Sun Nov 28 2021 - 16:24:49 EST


Provide default defines for the topology_book_[id|cpumask] and
topology_drawer_[id|cpumask] macros just like for each other topology
level.
This way all topology levels are handled in a similar way. Still the
the book and drawer levels are only used on s390, and also the sysfs
attributes are only created on s390. However other architectures may
opt in if wanted.

Signed-off-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
---
Documentation/admin-guide/cputopology.rst | 36 ++++++++++-------------
drivers/base/topology.c | 12 ++++----
include/linux/topology.h | 16 ++++++++++
3 files changed, 37 insertions(+), 27 deletions(-)

diff --git a/Documentation/admin-guide/cputopology.rst b/Documentation/admin-guide/cputopology.rst
index ad2238b41439..677ba1c2c820 100644
--- a/Documentation/admin-guide/cputopology.rst
+++ b/Documentation/admin-guide/cputopology.rst
@@ -8,14 +8,9 @@ to /proc/cpuinfo output of some architectures. They reside in
Documentation/ABI/stable/sysfs-devices-system-cpu.

Architecture-neutral, drivers/base/topology.c, exports these attributes.
-However, the book and drawer related sysfs files will only be created if
-CONFIG_SCHED_BOOK and CONFIG_SCHED_DRAWER are selected, respectively.
-
-The die and cluster hierarchy related sysfs files will only be created if an
-architecture provides the related macros as described below.
-
-CONFIG_SCHED_BOOK and CONFIG_SCHED_DRAWER are currently only used on s390,
-where they reflect the cpu and cache hierarchy.
+However the die, cluster, book, and drawer hierarchy related sysfs files will
+only be created if an architecture provides the related macros as described
+below.

For an architecture to support this feature, it must define some of
these macros in include/asm-XXX/topology.h::
@@ -42,19 +37,18 @@ To be consistent on all architectures, include/linux/topology.h
provides default definitions for any of the above macros that are
not defined by include/asm-XXX/topology.h:

-1) topology_physical_package_id: -1
-2) topology_die_id: -1
-3) topology_cluster_id: -1
-4) topology_core_id: 0
-5) topology_sibling_cpumask: just the given CPU
-6) topology_core_cpumask: just the given CPU
-7) topology_cluster_cpumask: just the given CPU
-8) topology_die_cpumask: just the given CPU
-
-For architectures that don't support books (CONFIG_SCHED_BOOK) there are no
-default definitions for topology_book_id() and topology_book_cpumask().
-For architectures that don't support drawers (CONFIG_SCHED_DRAWER) there are
-no default definitions for topology_drawer_id() and topology_drawer_cpumask().
+ 1) topology_physical_package_id: -1
+ 2) topology_die_id: -1
+ 3) topology_cluster_id: -1
+ 4) topology_core_id: 0
+ 5) topology_book_id: -1
+ 6) topology_drawer_id: -1
+ 7) topology_sibling_cpumask: just the given CPU
+ 8) topology_core_cpumask: just the given CPU
+ 9) topology_cluster_cpumask: just the given CPU
+10) topology_die_cpumask: just the given CPU
+11) topology_book_cpumask: just the given CPU
+12) topology_drawer_cpumask: just the given CPU

Additionally, CPU topology information is provided under
/sys/devices/system/cpu and includes these files. The internal
diff --git a/drivers/base/topology.c b/drivers/base/topology.c
index 1a288eac2c44..a942fadd3c5b 100644
--- a/drivers/base/topology.c
+++ b/drivers/base/topology.c
@@ -86,7 +86,7 @@ define_siblings_read_func(package_cpus, core_cpumask);
static BIN_ATTR_RO(package_cpus, 0);
static BIN_ATTR_RO(package_cpus_list, 0);

-#ifdef CONFIG_SCHED_BOOK
+#ifndef topology_book_no_sysfs
define_id_show_func(book_id);
static DEVICE_ATTR_RO(book_id);
define_siblings_read_func(book_siblings, book_cpumask);
@@ -94,7 +94,7 @@ static BIN_ATTR_RO(book_siblings, 0);
static BIN_ATTR_RO(book_siblings_list, 0);
#endif

-#ifdef CONFIG_SCHED_DRAWER
+#ifndef topology_drawer_no_sysfs
define_id_show_func(drawer_id);
static DEVICE_ATTR_RO(drawer_id);
define_siblings_read_func(drawer_siblings, drawer_cpumask);
@@ -119,11 +119,11 @@ static struct bin_attribute *bin_attrs[] = {
#endif
&bin_attr_package_cpus,
&bin_attr_package_cpus_list,
-#ifdef CONFIG_SCHED_BOOK
+#ifndef topology_book_no_sysfs
&bin_attr_book_siblings,
&bin_attr_book_siblings_list,
#endif
-#ifdef CONFIG_SCHED_DRAWER
+#ifndef topology_drawer_no_sysfs
&bin_attr_drawer_siblings,
&bin_attr_drawer_siblings_list,
#endif
@@ -139,10 +139,10 @@ static struct attribute *default_attrs[] = {
&dev_attr_cluster_id.attr,
#endif
&dev_attr_core_id.attr,
-#ifdef CONFIG_SCHED_BOOK
+#ifndef topology_book_no_sysfs
&dev_attr_book_id.attr,
#endif
-#ifdef CONFIG_SCHED_DRAWER
+#ifndef topology_drawer_no_sysfs
&dev_attr_drawer_id.attr,
#endif
NULL
diff --git a/include/linux/topology.h b/include/linux/topology.h
index cf57413f7c28..20c1a41c1670 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -194,6 +194,14 @@ static inline int cpu_to_mem(int cpu)
#ifndef topology_core_id
#define topology_core_id(cpu) ((void)(cpu), 0)
#endif
+#ifndef topology_book_id
+#define topology_book_id(cpu) ((void)(cpu), -1)
+#define topology_book_no_sysfs 1
+#endif
+#ifndef topology_drawer_id
+#define topology_drawer_id(cpu) ((void)(cpu), -1)
+#define topology_drawer_no_sysfs 1
+#endif
#ifndef topology_sibling_cpumask
#define topology_sibling_cpumask(cpu) cpumask_of(cpu)
#endif
@@ -208,6 +216,14 @@ static inline int cpu_to_mem(int cpu)
#define topology_die_cpumask(cpu) cpumask_of(cpu)
#define topology_die_no_sysfs 1
#endif
+#ifndef topology_book_cpumask
+#define topology_book_cpumask(cpu) cpumask_of(cpu)
+#define topology_book_no_sysfs 1
+#endif
+#ifndef topology_drawer_cpumask
+#define topology_drawer_cpumask(cpu) cpumask_of(cpu)
+#define topology_drawer_no_sysfs 1
+#endif

#if defined(CONFIG_SCHED_SMT) && !defined(cpu_smt_mask)
static inline const struct cpumask *cpu_smt_mask(int cpu)
--
2.32.0