From: Ashok Raj This patch adds cpu_present_map, cpu_present() and for_each_cpu_present() to distinguish between possible cpu's in a system and cpu's physically present in a system. Before cpu hotplug was introduced cpu_possible() represented cpu's physically present in the system. With hotplug capable Kernel, there is a requirement to distinguish a cpu as possible verses a CPU physically present in the system. This is required so thta when smp_init() attempts to start all cpu's it should now only attempt to start cpu's present in the system. When a hotplug cpu is physically inserted cpu_present_map will have bits updated dynamically. --- 25-akpm/arch/ia64/kernel/smpboot.c | 21 +++++++++++++++++++-- 25-akpm/fs/proc/proc_misc.c | 4 ++-- 25-akpm/include/asm-ia64/cpumask.h | 3 +++ 25-akpm/include/asm-ia64/smp.h | 5 +++++ 25-akpm/include/linux/cpumask.h | 17 +++++++++++++++++ 25-akpm/init/main.c | 4 ++-- 25-akpm/kernel/cpu.c | 2 +- 7 files changed, 49 insertions(+), 7 deletions(-) diff -puN arch/ia64/kernel/smpboot.c~ia64-cpuhotplug-cpu_present_map arch/ia64/kernel/smpboot.c --- 25/arch/ia64/kernel/smpboot.c~ia64-cpuhotplug-cpu_present_map Thu Apr 29 13:22:03 2004 +++ 25-akpm/arch/ia64/kernel/smpboot.c Thu Apr 29 13:22:03 2004 @@ -87,9 +87,15 @@ DEFINE_PER_CPU(int, cpu_state); /* Bitmask of currently online CPUs */ cpumask_t cpu_online_map; EXPORT_SYMBOL(cpu_online_map); + cpumask_t phys_cpu_present_map; EXPORT_SYMBOL(phys_cpu_present_map); +#ifdef CONFIG_HOTPLUG_CPU +cpumask_t cpu_possible_map; +EXPORT_SYMBOL(cpu_possible_map); +#endif + /* which logical CPU number maps to which CPU (physical APIC ID) */ volatile int ia64_cpu_to_sapicid[NR_CPUS]; EXPORT_SYMBOL(ia64_cpu_to_sapicid); @@ -108,6 +114,7 @@ static int __init nointroute (char *str) { no_int_routing = 1; + printk ("no_int_routing on\n"); return 1; } @@ -472,13 +479,23 @@ smp_build_cpu_map (void) int sapicid, cpu, i; int boot_cpu_id = hard_smp_processor_id(); - for (cpu = 0; cpu < NR_CPUS; cpu++) + /* + * Since ACPI does not give us whats MAX cpu's + * possible in the entire platform, we will just have to use + * NR_CPUS set for possible map. cpu_present_map a.k.a + * phys_cpu_present_map can grow based on a new cpu + * becomming available to the system. + */ + cpus_clear(cpu_possible_map); + for (cpu=0; cpu < NR_CPUS; cpu++) { ia64_cpu_to_sapicid[cpu] = -1; + cpu_set(cpu, cpu_possible_map); + } ia64_cpu_to_sapicid[0] = boot_cpu_id; + cpus_clear(phys_cpu_present_map); cpu_set(0, phys_cpu_present_map); - for (cpu = 1, i = 0; i < smp_boot_data.cpu_count; i++) { sapicid = smp_boot_data.cpu_phys_id[i]; if (sapicid == boot_cpu_id) diff -puN fs/proc/proc_misc.c~ia64-cpuhotplug-cpu_present_map fs/proc/proc_misc.c --- 25/fs/proc/proc_misc.c~ia64-cpuhotplug-cpu_present_map Thu Apr 29 13:22:03 2004 +++ 25-akpm/fs/proc/proc_misc.c Thu Apr 29 13:22:03 2004 @@ -371,7 +371,7 @@ int show_stat(struct seq_file *p, void * if (wall_to_monotonic.tv_nsec) --jif; - for_each_cpu(i) { + for_each_online_cpu(i) { int j; user += kstat_cpu(i).cpustat.user; @@ -393,7 +393,7 @@ int show_stat(struct seq_file *p, void * (unsigned long long)jiffies_64_to_clock_t(iowait), (unsigned long long)jiffies_64_to_clock_t(irq), (unsigned long long)jiffies_64_to_clock_t(softirq)); - for_each_cpu(i) { + for_each_online_cpu(i) { /* Copy values here to work around gcc-2.95.3, gcc-2.96 */ user = kstat_cpu(i).cpustat.user; diff -puN include/asm-ia64/cpumask.h~ia64-cpuhotplug-cpu_present_map include/asm-ia64/cpumask.h --- 25/include/asm-ia64/cpumask.h~ia64-cpuhotplug-cpu_present_map Thu Apr 29 13:22:03 2004 +++ 25-akpm/include/asm-ia64/cpumask.h Thu Apr 29 13:22:03 2004 @@ -1,6 +1,9 @@ #ifndef _ASM_IA64_CPUMASK_H #define _ASM_IA64_CPUMASK_H +#ifdef CONFIG_HOTPLUG_CPU +#define ARCH_HAS_CPU_PRESENT_MAP +#endif #include #endif /* _ASM_IA64_CPUMASK_H */ diff -puN include/asm-ia64/smp.h~ia64-cpuhotplug-cpu_present_map include/asm-ia64/smp.h --- 25/include/asm-ia64/smp.h~ia64-cpuhotplug-cpu_present_map Thu Apr 29 13:22:03 2004 +++ 25-akpm/include/asm-ia64/smp.h Thu Apr 29 13:22:03 2004 @@ -48,7 +48,12 @@ extern volatile int ia64_cpu_to_sapicid[ extern unsigned long ap_wakeup_vector; +#ifdef CONFIG_HOTPLUG_CPU +extern cpumask_t cpu_possible_map; +#define cpu_present_map phys_cpu_present_map +#else #define cpu_possible_map phys_cpu_present_map +#endif /* * Function to map hard smp processor id to logical id. Slow, so don't use this in diff -puN include/linux/cpumask.h~ia64-cpuhotplug-cpu_present_map include/linux/cpumask.h --- 25/include/linux/cpumask.h~ia64-cpuhotplug-cpu_present_map Thu Apr 29 13:22:03 2004 +++ 25-akpm/include/linux/cpumask.h Thu Apr 29 13:22:03 2004 @@ -16,6 +16,16 @@ extern cpumask_t cpu_possible_map; #define cpu_online(cpu) cpu_isset(cpu, cpu_online_map) #define cpu_possible(cpu) cpu_isset(cpu, cpu_possible_map) +#ifdef ARCH_HAS_CPU_PRESENT_MAP +extern cpumask_t cpu_present_map; +#define cpu_present(cpu) cpu_isset(cpu, cpu_present_map) +#define num_present_cpus() cpus_weight(cpu_present_map) +#else +#define cpu_present_map cpu_possible_map +#define cpu_present(x) cpu_possible(x) +#define num_present_cpus() num_possible_cpus() +#endif + #define for_each_cpu_mask(cpu, mask) \ for (cpu = first_cpu_const(mk_cpumask_const(mask)); \ cpu < NR_CPUS; \ @@ -23,16 +33,23 @@ extern cpumask_t cpu_possible_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(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 #define cpumask_scnprintf(buf, buflen, map) \ diff -puN init/main.c~ia64-cpuhotplug-cpu_present_map init/main.c --- 25/init/main.c~ia64-cpuhotplug-cpu_present_map Thu Apr 29 13:22:03 2004 +++ 25-akpm/init/main.c Thu Apr 29 13:22:03 2004 @@ -360,10 +360,10 @@ static void __init smp_init(void) unsigned j = 1; /* FIXME: This should be done in userspace --RR */ - for (i = 0; i < NR_CPUS; i++) { + for_each_present_cpu(i) { if (num_online_cpus() >= max_cpus) break; - if (cpu_possible(i) && !cpu_online(i)) { + if (!cpu_online(i)) { cpu_up(i); j++; } diff -puN kernel/cpu.c~ia64-cpuhotplug-cpu_present_map kernel/cpu.c --- 25/kernel/cpu.c~ia64-cpuhotplug-cpu_present_map Thu Apr 29 13:22:03 2004 +++ 25-akpm/kernel/cpu.c Thu Apr 29 13:22:03 2004 @@ -180,7 +180,7 @@ int __devinit cpu_up(unsigned int cpu) if ((ret = down_interruptible(&cpucontrol)) != 0) return ret; - if (cpu_online(cpu)) { + if (cpu_online(cpu) || !cpu_present(cpu)) { ret = -EINVAL; goto out; } _