diff options
| -rw-r--r-- | Documentation/cpu-hotplug.txt | 17 | ||||
| -rw-r--r-- | arch/x86/kernel/apic.c | 20 | ||||
| -rw-r--r-- | arch/x86/kernel/smpboot.c | 25 |
3 files changed, 42 insertions, 20 deletions
diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt index 94bbc27ddd4f..9d620c153b04 100644 --- a/Documentation/cpu-hotplug.txt +++ b/Documentation/cpu-hotplug.txt @@ -50,16 +50,17 @@ additional_cpus=n (*) Use this to limit hotpluggable cpus. This option sets cpu_possible_map = cpu_present_map + additional_cpus (*) Option valid only for following architectures -- x86_64, ia64 +- ia64 -ia64 and x86_64 use the number of disabled local apics in ACPI tables MADT -to determine the number of potentially hot-pluggable cpus. The implementation -should only rely on this to count the # of cpus, but *MUST* not rely on the -apicid values in those tables for disabled apics. In the event BIOS doesn't -mark such hot-pluggable cpus as disabled entries, one could use this -parameter "additional_cpus=x" to represent those cpus in the cpu_possible_map. +ia64 uses the number of disabled local apics in ACPI tables MADT to +determine the number of potentially hot-pluggable cpus. The implementation +should only rely on this to count the # of cpus, but *MUST* not rely +on the apicid values in those tables for disabled apics. In the event +BIOS doesn't mark such hot-pluggable cpus as disabled entries, one could +use this parameter "additional_cpus=x" to represent those cpus in the +cpu_possible_map. -possible_cpus=n [s390 only] use this to set hotpluggable cpus. +possible_cpus=n [s390,x86_64] use this to set hotpluggable cpus. This option sets possible_cpus bits in cpu_possible_map. Thus keeping the numbers of bits set constant even if the machine gets rebooted. diff --git a/arch/x86/kernel/apic.c b/arch/x86/kernel/apic.c index 93cf2d13f335..f7a32a3beb2f 100644 --- a/arch/x86/kernel/apic.c +++ b/arch/x86/kernel/apic.c @@ -1819,28 +1819,32 @@ void disconnect_bsp_APIC(int virt_wire_setup) void __cpuinit generic_processor_info(int apicid, int version) { int cpu; - cpumask_t tmp_map; /* * Validate version */ if (version == 0x0) { pr_warning("BIOS bug, APIC version is 0 for CPU#%d! " - "fixing up to 0x10. (tell your hw vendor)\n", - version); + "fixing up to 0x10. (tell your hw vendor)\n", + version); version = 0x10; } apic_version[apicid] = version; - if (num_processors >= NR_CPUS) { - pr_warning("WARNING: NR_CPUS limit of %i reached." - " Processor ignored.\n", NR_CPUS); + if (num_processors >= nr_cpu_ids) { + int max = nr_cpu_ids; + int thiscpu = max + disabled_cpus; + + pr_warning( + "ACPI: NR_CPUS/possible_cpus limit of %i reached." + " Processor %d/0x%x ignored.\n", max, thiscpu, apicid); + + disabled_cpus++; return; } num_processors++; - cpus_complement(tmp_map, cpu_present_map); - cpu = first_cpu(tmp_map); + cpu = cpumask_next_zero(-1, cpu_present_mask); physid_set(apicid, phys_cpu_present_map); if (apicid == boot_cpu_physical_apicid) { diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index be9466788043..1a9941b11150 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1252,6 +1252,15 @@ void __init native_smp_cpus_done(unsigned int max_cpus) check_nmi_watchdog(); } +static int __initdata setup_possible_cpus = -1; +static int __init _setup_possible_cpus(char *str) +{ + get_option(&str, &setup_possible_cpus); + return 0; +} +early_param("possible_cpus", _setup_possible_cpus); + + /* * cpu_possible_map should be static, it cannot change as cpu's * are onlined, or offlined. The reason is per-cpu data-structures @@ -1264,7 +1273,7 @@ void __init native_smp_cpus_done(unsigned int max_cpus) * * Three ways to find out the number of additional hotplug CPUs: * - If the BIOS specified disabled CPUs in ACPI/mptables use that. - * - The user can overwrite it with additional_cpus=NUM + * - The user can overwrite it with possible_cpus=NUM * - Otherwise don't reserve additional CPUs. * We do this because additional CPUs waste a lot of memory. * -AK @@ -1277,9 +1286,17 @@ __init void prefill_possible_map(void) if (!num_processors) num_processors = 1; - possible = num_processors + disabled_cpus; - if (possible > NR_CPUS) - possible = NR_CPUS; + if (setup_possible_cpus == -1) + possible = num_processors + disabled_cpus; + else + possible = setup_possible_cpus; + + if (possible > CONFIG_NR_CPUS) { + printk(KERN_WARNING + "%d Processors exceeds NR_CPUS limit of %d\n", + possible, CONFIG_NR_CPUS); + possible = CONFIG_NR_CPUS; + } printk(KERN_INFO "SMP: Allowing %d CPUs, %d hotplug CPUs\n", possible, max_t(int, possible - num_processors, 0)); |
