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topology/sysfs: rework book and drawer topology ifdefery
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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.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20211129130309.3256168-4-hca@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Heiko Carstens authored and Greg Kroah-Hartman committed Dec 3, 2021
1 parent e795707 commit f104505
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Showing 3 changed files with 39 additions and 27 deletions.
36 changes: 15 additions & 21 deletions Documentation/admin-guide/cputopology.rst
Original file line number Diff line number Diff line change
Expand Up @@ -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::
Expand All @@ -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
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12 changes: 6 additions & 6 deletions drivers/base/topology.c
Original file line number Diff line number Diff line change
Expand Up @@ -86,15 +86,15 @@ 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
#ifdef TOPOLOGY_BOOK_SYSFS
define_id_show_func(book_id);
static DEVICE_ATTR_RO(book_id);
define_siblings_read_func(book_siblings, book_cpumask);
static BIN_ATTR_RO(book_siblings, 0);
static BIN_ATTR_RO(book_siblings_list, 0);
#endif

#ifdef CONFIG_SCHED_DRAWER
#ifdef TOPOLOGY_DRAWER_SYSFS
define_id_show_func(drawer_id);
static DEVICE_ATTR_RO(drawer_id);
define_siblings_read_func(drawer_siblings, drawer_cpumask);
Expand All @@ -119,11 +119,11 @@ static struct bin_attribute *bin_attrs[] = {
#endif
&bin_attr_package_cpus,
&bin_attr_package_cpus_list,
#ifdef CONFIG_SCHED_BOOK
#ifdef TOPOLOGY_BOOK_SYSFS
&bin_attr_book_siblings,
&bin_attr_book_siblings_list,
#endif
#ifdef CONFIG_SCHED_DRAWER
#ifdef TOPOLOGY_DRAWER_SYSFS
&bin_attr_drawer_siblings,
&bin_attr_drawer_siblings_list,
#endif
Expand All @@ -139,10 +139,10 @@ static struct attribute *default_attrs[] = {
&dev_attr_cluster_id.attr,
#endif
&dev_attr_core_id.attr,
#ifdef CONFIG_SCHED_BOOK
#ifdef TOPOLOGY_BOOK_SYSFS
&dev_attr_book_id.attr,
#endif
#ifdef CONFIG_SCHED_DRAWER
#ifdef TOPOLOGY_DRAWER_SYSFS
&dev_attr_drawer_id.attr,
#endif
NULL
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18 changes: 18 additions & 0 deletions include/linux/topology.h
Original file line number Diff line number Diff line change
Expand Up @@ -186,6 +186,12 @@ static inline int cpu_to_mem(int cpu)
#if defined(topology_cluster_id) && defined(topology_cluster_cpumask)
#define TOPOLOGY_CLUSTER_SYSFS
#endif
#if defined(topology_book_id) && defined(topology_book_cpumask)
#define TOPOLOGY_BOOK_SYSFS
#endif
#if defined(topology_drawer_id) && defined(topology_drawer_cpumask)
#define TOPOLOGY_DRAWER_SYSFS
#endif

#ifndef topology_physical_package_id
#define topology_physical_package_id(cpu) ((void)(cpu), -1)
Expand All @@ -199,6 +205,12 @@ 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)
#endif
#ifndef topology_drawer_id
#define topology_drawer_id(cpu) ((void)(cpu), -1)
#endif
#ifndef topology_sibling_cpumask
#define topology_sibling_cpumask(cpu) cpumask_of(cpu)
#endif
Expand All @@ -211,6 +223,12 @@ static inline int cpu_to_mem(int cpu)
#ifndef topology_die_cpumask
#define topology_die_cpumask(cpu) cpumask_of(cpu)
#endif
#ifndef topology_book_cpumask
#define topology_book_cpumask(cpu) cpumask_of(cpu)
#endif
#ifndef topology_drawer_cpumask
#define topology_drawer_cpumask(cpu) cpumask_of(cpu)
#endif

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