From: Paul Jackson <pj@sgi.com>
This patch makes cpu_present_map a real map for all configurations, instead of
a constant for non-SMP. It also moves the definition of cpu_present_map out
of kernel/cpu.c into kernel/sched.c, because cpu.c isn't compiled into non-SMP
kernels.
The pattern is that each of the possible, present and online cpu maps are
actual kernel global cpumask_t variables, for all configurations. They are
documented in include/linux/cpumask.h. Some of the UP (NR_CPUS=1) code
cheats, and hardcodes the assumption that the single bit position of these
maps is always set, as an optimization.
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/include/linux/cpumask.h | 13 +++++--------
25-akpm/kernel/cpu.c | 8 --------
25-akpm/kernel/sched.c | 10 ++++++++++
3 files changed, 15 insertions(+), 16 deletions(-)
diff -puN include/linux/cpumask.h~cpumask-1-10-cpu_present_map-real-even-on-non-smp include/linux/cpumask.h
--- 25/include/linux/cpumask.h~cpumask-1-10-cpu_present_map-real-even-on-non-smp 2004-06-23 21:44:03.308562856 -0700
+++ 25-akpm/include/linux/cpumask.h 2004-06-23 21:44:03.316561640 -0700
@@ -10,15 +10,12 @@
extern cpumask_t cpu_online_map;
extern cpumask_t cpu_possible_map;
-extern cpumask_t cpu_present_map;
#define num_online_cpus() cpus_weight(cpu_online_map)
#define num_possible_cpus() cpus_weight(cpu_possible_map)
-#define num_present_cpus() cpus_weight(cpu_present_map)
#define cpu_online(cpu) cpu_isset(cpu, cpu_online_map)
#define cpu_possible(cpu) cpu_isset(cpu, cpu_possible_map)
-#define cpu_present(cpu) cpu_isset(cpu, cpu_present_map)
#define for_each_cpu_mask(cpu, mask) \
for (cpu = first_cpu_const(mk_cpumask_const(mask)); \
@@ -27,26 +24,26 @@ extern cpumask_t cpu_present_map;
#define for_each_cpu(cpu) for_each_cpu_mask(cpu, cpu_possible_map)
#define for_each_online_cpu(cpu) for_each_cpu_mask(cpu, cpu_online_map)
-#define for_each_present_cpu(cpu) for_each_cpu_mask(cpu, cpu_present_map)
#else
#define cpu_online_map cpumask_of_cpu(0)
#define cpu_possible_map cpumask_of_cpu(0)
-#define cpu_present_map cpumask_of_cpu(0)
#define num_online_cpus() 1
#define num_possible_cpus() 1
-#define num_present_cpus() 1
#define cpu_online(cpu) ({ BUG_ON((cpu) != 0); 1; })
#define cpu_possible(cpu) ({ BUG_ON((cpu) != 0); 1; })
-#define cpu_present(cpu) ({ BUG_ON((cpu) != 0); 1; })
#define for_each_cpu_mask(cpu, mask) for (cpu = 0; cpu < 1; cpu++)
#define for_each_cpu(cpu) for (cpu = 0; cpu < 1; cpu++)
#define for_each_online_cpu(cpu) for (cpu = 0; cpu < 1; cpu++)
-#define for_each_present_cpu(cpu) for (cpu = 0; cpu < 1; cpu++)
#endif
+extern cpumask_t cpu_present_map;
+#define num_present_cpus() cpus_weight(cpu_present_map)
+#define cpu_present(cpu) cpu_isset(cpu, cpu_present_map)
+#define for_each_present_cpu(cpu) for_each_cpu_mask(cpu, cpu_present_map)
+
#define cpumask_scnprintf(buf, buflen, map) \
bitmap_scnprintf(buf, buflen, cpus_addr(map), NR_CPUS)
diff -puN kernel/cpu.c~cpumask-1-10-cpu_present_map-real-even-on-non-smp kernel/cpu.c
--- 25/kernel/cpu.c~cpumask-1-10-cpu_present_map-real-even-on-non-smp 2004-06-23 21:44:03.310562552 -0700
+++ 25-akpm/kernel/cpu.c 2004-06-23 21:44:03.316561640 -0700
@@ -20,14 +20,6 @@
DECLARE_MUTEX(cpucontrol);
static struct notifier_block *cpu_chain;
-/*
- * Represents all cpu's present in the system
- * In systems capable of hotplug, this map could dynamically grow
- * as new cpu's are detected in the system via any platform specific
- * method, such as ACPI for e.g.
- */
-cpumask_t cpu_present_map;
-EXPORT_SYMBOL(cpu_present_map);
/* Need to know about CPUs going up/down? */
int register_cpu_notifier(struct notifier_block *nb)
diff -puN kernel/sched.c~cpumask-1-10-cpu_present_map-real-even-on-non-smp kernel/sched.c
--- 25/kernel/sched.c~cpumask-1-10-cpu_present_map-real-even-on-non-smp 2004-06-23 21:44:03.312562248 -0700
+++ 25-akpm/kernel/sched.c 2004-06-23 21:44:03.319561184 -0700
@@ -2948,6 +2948,16 @@ out_unlock:
return retval;
}
+/*
+ * Represents all cpu's present in the system
+ * In systems capable of hotplug, this map could dynamically grow
+ * as new cpu's are detected in the system via any platform specific
+ * method, such as ACPI for e.g.
+ */
+
+cpumask_t cpu_present_map;
+EXPORT_SYMBOL(cpu_present_map);
+
/**
* sys_sched_getaffinity - get the cpu affinity of a process
* @pid: pid of the process
_