From: Paul Jackson 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 Signed-off-by: Andrew Morton --- 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 Fri Jun 11 16:06:45 2004 +++ 25-akpm/include/linux/cpumask.h Fri Jun 11 16:08:19 2004 @@ -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 Fri Jun 11 16:06:45 2004 +++ 25-akpm/kernel/cpu.c Fri Jun 11 16:06:45 2004 @@ -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 Fri Jun 11 16:06:45 2004 +++ 25-akpm/kernel/sched.c Fri Jun 11 16:06:45 2004 @@ -3116,6 +3116,16 @@ 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 _