From 69aa234b918c0d9bc4a20cd6d4453aaa3418f457 Mon Sep 17 00:00:00 2001 From: Ashok Raj Date: Tue, 14 Feb 2006 15:01:11 -0800 Subject: [IA64] Dont set NR_CPUS for cpu_possible_map when CPU hotplug is enabled. Do not set cpu_possible_map for NR_CPUS when ACPI_CONFIG_HOTPLUG_CPU is set. Signed-off-by: Ashok Raj Signed-off-by: Tony Luck --- arch/ia64/kernel/smpboot.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'arch/ia64') diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c index 8f44e7d2df6..b681ef34a86 100644 --- a/arch/ia64/kernel/smpboot.c +++ b/arch/ia64/kernel/smpboot.c @@ -129,7 +129,7 @@ DEFINE_PER_CPU(int, cpu_state); /* Bitmasks of currently online, and possible CPUs */ cpumask_t cpu_online_map; EXPORT_SYMBOL(cpu_online_map); -cpumask_t cpu_possible_map; +cpumask_t cpu_possible_map = CPU_MASK_NONE; EXPORT_SYMBOL(cpu_possible_map); cpumask_t cpu_core_map[NR_CPUS] __cacheline_aligned; @@ -506,9 +506,6 @@ smp_build_cpu_map (void) for (cpu = 0; cpu < NR_CPUS; cpu++) { ia64_cpu_to_sapicid[cpu] = -1; -#ifdef CONFIG_HOTPLUG_CPU - cpu_set(cpu, cpu_possible_map); -#endif } ia64_cpu_to_sapicid[0] = boot_cpu_id; -- cgit v1.2.3-18-g5258 From a6b14fa6fdc01ab3519c2729624f808677539b59 Mon Sep 17 00:00:00 2001 From: Ashok Raj Date: Tue, 14 Feb 2006 15:01:12 -0800 Subject: [IA64] Count disabled cpus as potential hot-pluggable CPUs Have a facility to account for potentially hot-pluggable CPUs. ACPI doesnt give a determinstic method to find hot-pluggable CPUs. Hence we use 2 methods to assist. - BIOS can mark potentially hot-pluggable CPUs as disabled in the MADT tables. - User can specify the number of hot-pluggable CPUs via parameter additional_cpus=X The option is enabled only if ACPI_CONFIG_HOTPLUG_CPU=y which enables the physical hotplug option. Without which user can still use logical onlining and offlining of CPUs by enabling CONFIG_HOTPLUG_CPU=y Adds more bits to cpu_possible_map for potentially hot-pluggable cpus. Signed-off-by: Ashok Raj Signed-off-by: Tony Luck --- arch/ia64/kernel/acpi.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++ arch/ia64/kernel/setup.c | 4 ++++ 2 files changed, 60 insertions(+) (limited to 'arch/ia64') diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c index d2702c419cf..34795ede72e 100644 --- a/arch/ia64/kernel/acpi.c +++ b/arch/ia64/kernel/acpi.c @@ -761,6 +761,62 @@ int acpi_map_cpu2node(acpi_handle handle, int cpu, long physid) return (0); } +int additional_cpus __initdata = -1; + +static __init int setup_additional_cpus(char *s) +{ + if (s) + additional_cpus = simple_strtol(s, NULL, 0); + + return 0; +} + +early_param("additional_cpus", setup_additional_cpus); + +/* + * cpu_possible_map should be static, it cannot change as cpu's + * are onlined, or offlined. The reason is per-cpu data-structures + * are allocated by some modules at init time, and dont expect to + * do this dynamically on cpu arrival/departure. + * cpu_present_map on the other hand can change dynamically. + * In case when cpu_hotplug is not compiled, then we resort to current + * behaviour, which is cpu_possible == cpu_present. + * - Ashok Raj + * + * 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 + * - Otherwise don't reserve additional CPUs. + */ +__init void prefill_possible_map(void) +{ + int i; + int possible, disabled_cpus; + + disabled_cpus = total_cpus - available_cpus; + if (additional_cpus == -1) { + if (disabled_cpus > 0) { + possible = total_cpus; + additional_cpus = disabled_cpus; + } + else { + possible = available_cpus; + additional_cpus = 0; + } + } else { + possible = available_cpus + additional_cpus; + } + if (possible > NR_CPUS) + possible = NR_CPUS; + + printk(KERN_INFO "SMP: Allowing %d CPUs, %d hotplug CPUs\n", + possible, + max_t(int, additional_cpus, 0)); + + for (i = 0; i < possible; i++) + cpu_set(i, cpu_possible_map); +} + int acpi_map_lsapic(acpi_handle handle, int *pcpu) { struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; diff --git a/arch/ia64/kernel/setup.c b/arch/ia64/kernel/setup.c index 35f7835294a..3258e09278d 100644 --- a/arch/ia64/kernel/setup.c +++ b/arch/ia64/kernel/setup.c @@ -430,6 +430,7 @@ setup_arch (char **cmdline_p) if (early_console_setup(*cmdline_p) == 0) mark_bsp_online(); + parse_early_param(); #ifdef CONFIG_ACPI /* Initialize the ACPI boot-time table parser */ acpi_table_init(); @@ -688,6 +689,9 @@ void setup_per_cpu_areas (void) { /* start_kernel() requires this... */ +#ifdef CONFIG_ACPI_HOTPLUG_CPU + prefill_possible_map(); +#endif } /* -- cgit v1.2.3-18-g5258