Messages in this thread Patch in this message | | | Date | Fri, 18 Apr 2008 17:11:22 +0100 | From | Ben Hutchings <> | Subject | [PATCH][RFC] Add default CPU topology information (try #2) |
| |
Not all architectures and configurations define CPU topology information. This can result in an empty topology directory in sysfs, and requires in-kernel users to protect all uses with #ifdef - see <http://marc.info/?l=linux-netdev&m=120639033904472&w=2>.
The documentation of CPU topology specifies what the defaults should be if only partial information is available from the hardware. So we can provide these defaults as a fallback.
This patch:
- Adds default definitions of the 4 topology macros to include/asm-generic/topology_cpu.h. - Changes include/asm-*/topology.h to include <asm-generic/topology_cpu.h> unless all 4 macros are defined. - Changes drivers/base/topology.c to use the topology macros unconditionally and to cope with definitions that aren't lvalues. - Updates documentation accordingly.
Unlike the previous version of this patch, it does not add inclusion of <asm-generic/topology.h>.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> diff --git a/Documentation/cputopology.txt b/Documentation/cputopology.txt index b61cb95..fb9bbe4 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 +24,11 @@ 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. - +Any architecture or configuration that does not define all these +macros must include <asm-generic/topology_cpu.h> which 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 e1d3ad4..dfcb2e2 100644 --- a/drivers/base/topology.c +++ b/drivers/base/topology.c @@ -45,47 +45,28 @@ static ssize_t show_##name(struct sys_device *dev, char *buf) \ { \ ssize_t len = -1; \ unsigned int cpu = dev->id; \ - len = cpumask_scnprintf(buf, NR_CPUS+1, topology_##name(cpu)); \ + cpumask_t siblings = topology_##name(cpu); \ + len = cpumask_scnprintf(buf, NR_CPUS+1, siblings); \ return (len + sprintf(buf + len, "\n")); \ } -#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 ref_thread_siblings_attr &attr_thread_siblings.attr, -#else -#define ref_thread_siblings_attr -#endif -#ifdef topology_core_siblings define_siblings_show_func(core_siblings); define_one_ro(core_siblings); -#define ref_core_siblings_attr &attr_core_siblings.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_core_siblings.attr, NULL }; diff --git a/include/asm-alpha/topology.h b/include/asm-alpha/topology.h index 420ccde..57ef8b1 100644 --- a/include/asm-alpha/topology.h +++ b/include/asm-alpha/topology.h @@ -41,6 +41,8 @@ static inline cpumask_t node_to_cpumask(int node) #define pcibus_to_cpumask(bus) (cpu_online_map) +#include <asm-generic/topology_cpu.h> + #else /* CONFIG_NUMA */ # include <asm-generic/topology.h> #endif /* !CONFIG_NUMA */ diff --git a/include/asm-generic/topology.h b/include/asm-generic/topology.h index 342a2a0..f784625 100644 --- a/include/asm-generic/topology.h +++ b/include/asm-generic/topology.h @@ -52,4 +52,6 @@ ) #endif +#include <asm-generic/topology_cpu.h> + #endif /* _ASM_GENERIC_TOPOLOGY_H */ diff --git a/include/asm-generic/topology_cpu.h b/include/asm-generic/topology_cpu.h new file mode 100644 index 0000000..fac1258 --- /dev/null +++ b/include/asm-generic/topology_cpu.h @@ -0,0 +1,19 @@ +#ifndef _ASM_GENERIC_TOPOLOGY_CPU_H +#define _ASM_GENERIC_TOPOLOGY_CPU_H + +#include <linux/cpumask.h> + +#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_CPU_H */ diff --git a/include/asm-powerpc/topology.h b/include/asm-powerpc/topology.h index ca23b68..abcfdf4 100644 --- a/include/asm-powerpc/topology.h +++ b/include/asm-powerpc/topology.h @@ -97,8 +97,6 @@ static inline void sysfs_remove_device_from_node(struct sys_device *dev, } -#include <asm-generic/topology.h> - #endif /* CONFIG_NUMA */ #ifdef CONFIG_SMP @@ -112,5 +110,11 @@ static inline void sysfs_remove_device_from_node(struct sys_device *dev, #endif #endif +#ifdef CONFIG_NUMA +#include <asm-generic/topology_cpu.h> +#else +#include <asm-generic/topology.h> +#endif + #endif /* __KERNEL__ */ #endif /* _ASM_POWERPC_TOPOLOGY_H */ diff --git a/include/asm-x86/topology.h b/include/asm-x86/topology.h index 8af05a9..49b1a73 100644 --- a/include/asm-x86/topology.h +++ b/include/asm-x86/topology.h @@ -178,6 +178,8 @@ extern cpumask_t cpu_coregroup_map(int cpu); #define topology_core_id(cpu) (cpu_data(cpu).cpu_core_id) #define topology_core_siblings(cpu) (per_cpu(cpu_core_map, cpu)) #define topology_thread_siblings(cpu) (per_cpu(cpu_sibling_map, cpu)) +#else +#include <asm-generic/topology_cpu.h> #endif #ifdef CONFIG_SMP -- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job.
| |