diff options
| -rw-r--r-- | arch/i386/mach-default/topology.c | 15 | ||||
| -rw-r--r-- | arch/x86_64/Kconfig | 9 | ||||
| -rw-r--r-- | arch/x86_64/kernel/irq.c | 29 | ||||
| -rw-r--r-- | arch/x86_64/kernel/process.c | 29 | ||||
| -rw-r--r-- | arch/x86_64/kernel/smpboot.c | 205 | ||||
| -rw-r--r-- | arch/x86_64/kernel/traps.c | 8 | ||||
| -rw-r--r-- | include/asm-x86_64/irq.h | 5 | ||||
| -rw-r--r-- | include/asm-x86_64/smp.h | 2 |
8 files changed, 277 insertions, 25 deletions
diff --git a/arch/i386/mach-default/topology.c b/arch/i386/mach-default/topology.c index 5b3e8817dae..23395fff35d 100644 --- a/arch/i386/mach-default/topology.c +++ b/arch/i386/mach-default/topology.c @@ -73,12 +73,11 @@ static int __init topology_init(void) { int i; - for (i = 0; i < MAX_NUMNODES; i++) { - if (node_online(i)) - arch_register_node(i); - } - for (i = 0; i < NR_CPUS; i++) - if (cpu_possible(i)) arch_register_cpu(i); + for_each_online_node(i) + arch_register_node(i); + + for_each_cpu(i) + arch_register_cpu(i); return 0; } @@ -88,8 +87,8 @@ static int __init topology_init(void) { int i; - for (i = 0; i < NR_CPUS; i++) - if (cpu_possible(i)) arch_register_cpu(i); + for_each_cpu(i) + arch_register_cpu(i); return 0; } diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig index db259757dc8..92f5a526602 100644 --- a/arch/x86_64/Kconfig +++ b/arch/x86_64/Kconfig @@ -313,6 +313,15 @@ config NR_CPUS This is purely to save memory - each supported CPU requires memory in the static kernel configuration. +config HOTPLUG_CPU + bool "Support for hot-pluggable CPUs (EXPERIMENTAL)" + depends on SMP && HOTPLUG && EXPERIMENTAL + help + Say Y here to experiment with turning CPUs off and on. CPUs + can be controlled through /sys/devices/system/cpu/cpu#. + Say N if you want to disable CPU hotplug. + + config HPET_TIMER bool default y diff --git a/arch/x86_64/kernel/irq.c b/arch/x86_64/kernel/irq.c index 62b112e4deb..cc3fb85f514 100644 --- a/arch/x86_64/kernel/irq.c +++ b/arch/x86_64/kernel/irq.c @@ -14,6 +14,7 @@ #include <linux/interrupt.h> #include <linux/seq_file.h> #include <linux/module.h> +#include <linux/delay.h> #include <asm/uaccess.h> #include <asm/io_apic.h> @@ -106,3 +107,31 @@ asmlinkage unsigned int do_IRQ(struct pt_regs *regs) return 1; } +#ifdef CONFIG_HOTPLUG_CPU +void fixup_irqs(cpumask_t map) +{ + unsigned int irq; + static int warned; + + for (irq = 0; irq < NR_IRQS; irq++) { + cpumask_t mask; + if (irq == 2) + continue; + + cpus_and(mask, irq_affinity[irq], map); + if (any_online_cpu(mask) == NR_CPUS) { + printk("Breaking affinity for irq %i\n", irq); + mask = map; + } + if (irq_desc[irq].handler->set_affinity) + irq_desc[irq].handler->set_affinity(irq, mask); + else if (irq_desc[irq].action && !(warned++)) + printk("Cannot set affinity for irq %i\n", irq); + } + + /* That doesn't seem sufficient. Give it 1ms. */ + local_irq_enable(); + mdelay(1); + local_irq_disable(); +} +#endif diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c index 15fa35a81a7..1d91271796e 100644 --- a/arch/x86_64/kernel/process.c +++ b/arch/x86_64/kernel/process.c @@ -8,7 +8,8 @@ * * X86-64 port * Andi Kleen. - * + * + * CPU hotplug support - ashok.raj@intel.com * $Id: process.c,v 1.38 2002/01/15 10:08:03 ak Exp $ */ @@ -18,6 +19,7 @@ #include <stdarg.h> +#include <linux/cpu.h> #include <linux/errno.h> #include <linux/sched.h> #include <linux/kernel.h> @@ -154,6 +156,29 @@ void cpu_idle_wait(void) } EXPORT_SYMBOL_GPL(cpu_idle_wait); +#ifdef CONFIG_HOTPLUG_CPU +DECLARE_PER_CPU(int, cpu_state); + +#include <asm/nmi.h> +/* We don't actually take CPU down, just spin without interrupts. */ +static inline void play_dead(void) +{ + idle_task_exit(); + wbinvd(); + mb(); + /* Ack it */ + __get_cpu_var(cpu_state) = CPU_DEAD; + + while (1) + safe_halt(); +} +#else +static inline void play_dead(void) +{ + BUG(); +} +#endif /* CONFIG_HOTPLUG_CPU */ + /* * The idle thread. There's no useful work to be * done, so just try to conserve power and have a @@ -174,6 +199,8 @@ void cpu_idle (void) idle = pm_idle; if (!idle) idle = default_idle; + if (cpu_is_offline(smp_processor_id())) + play_dead(); idle(); } diff --git a/arch/x86_64/kernel/smpboot.c b/arch/x86_64/kernel/smpboot.c index bc98a6722cb..5a3f955b657 100644 --- a/arch/x86_64/kernel/smpboot.c +++ b/arch/x86_64/kernel/smpboot.c @@ -34,6 +34,7 @@ * Andi Kleen : Converted to new state machine. * Various cleanups. * Probably mostly hotplug CPU ready now. + * Ashok Raj : CPU hotplug support */ @@ -98,6 +99,37 @@ EXPORT_SYMBOL(cpu_core_map); extern unsigned char trampoline_data[]; extern unsigned char trampoline_end[]; +/* State of each CPU */ +DEFINE_PER_CPU(int, cpu_state) = { 0 }; + +/* + * Store all idle threads, this can be reused instead of creating + * a new thread. Also avoids complicated thread destroy functionality + * for idle threads. + */ +struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ; + +#define get_idle_for_cpu(x) (idle_thread_array[(x)]) +#define set_idle_for_cpu(x,p) (idle_thread_array[(x)] = (p)) + +/* + * 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. + * If cpu-hotplug is supported, then we need to preallocate for all + * those NR_CPUS, hence cpu_possible_map represents entire NR_CPUS range. + * - Ashok Raj + */ +#ifdef CONFIG_HOTPLUG_CPU +#define fixup_cpu_possible_map(x) cpu_set((x), cpu_possible_map) +#else +#define fixup_cpu_possible_map(x) +#endif + /* * Currently trivial. Write the real->protected mode * bootstrap into the page concerned. The caller @@ -623,33 +655,77 @@ static int __cpuinit wakeup_secondary_via_INIT(int phys_apicid, unsigned int sta return (send_status | accept_status); } +struct create_idle { + struct task_struct *idle; + struct completion done; + int cpu; +}; + +void do_fork_idle(void *_c_idle) +{ + struct create_idle *c_idle = _c_idle; + + c_idle->idle = fork_idle(c_idle->cpu); + complete(&c_idle->done); +} + /* * Boot one CPU. */ static int __cpuinit do_boot_cpu(int cpu, int apicid) { - struct task_struct *idle; unsigned long boot_error; int timeout; unsigned long start_rip; + struct create_idle c_idle = { + .cpu = cpu, + .done = COMPLETION_INITIALIZER(c_idle.done), + }; + DECLARE_WORK(work, do_fork_idle, &c_idle); + + c_idle.idle = get_idle_for_cpu(cpu); + + if (c_idle.idle) { + c_idle.idle->thread.rsp = (unsigned long) (((struct pt_regs *) + (THREAD_SIZE + (unsigned long) c_idle.idle->thread_info)) - 1); + init_idle(c_idle.idle, cpu); + goto do_rest; + } + /* - * We can't use kernel_thread since we must avoid to - * reschedule the child. + * During cold boot process, keventd thread is not spun up yet. + * When we do cpu hot-add, we create idle threads on the fly, we should + * not acquire any attributes from the calling context. Hence the clean + * way to create kernel_threads() is to do that from keventd(). + * We do the current_is_keventd() due to the fact that ACPI notifier + * was also queuing to keventd() and when the caller is already running + * in context of keventd(), we would end up with locking up the keventd + * thread. */ - idle = fork_idle(cpu); - if (IS_ERR(idle)) { + if (!keventd_up() || current_is_keventd()) + work.func(work.data); + else { + schedule_work(&work); + wait_for_completion(&c_idle.done); + } + + if (IS_ERR(c_idle.idle)) { printk("failed fork for CPU %d\n", cpu); - return PTR_ERR(idle); + return PTR_ERR(c_idle.idle); } - cpu_pda[cpu].pcurrent = idle; + set_idle_for_cpu(cpu, c_idle.idle); + +do_rest: + + cpu_pda[cpu].pcurrent = c_idle.idle; start_rip = setup_trampoline(); - init_rsp = idle->thread.rsp; + init_rsp = c_idle.idle->thread.rsp; per_cpu(init_tss,cpu).rsp0 = init_rsp; initial_code = start_secondary; - clear_ti_thread_flag(idle->thread_info, TIF_FORK); + clear_ti_thread_flag(c_idle.idle->thread_info, TIF_FORK); printk(KERN_INFO "Booting processor %d/%d rip %lx rsp %lx\n", cpu, apicid, start_rip, init_rsp); @@ -925,10 +1001,9 @@ void __init smp_prepare_cpus(unsigned int max_cpus) int apicid = cpu_present_to_apicid(i); if (physid_isset(apicid, phys_cpu_present_map)) { cpu_set(i, cpu_present_map); - /* possible map would be different if we supported real - CPU hotplug. */ cpu_set(i, cpu_possible_map); } + fixup_cpu_possible_map(i); } if (smp_sanity_check(max_cpus) < 0) { @@ -977,9 +1052,6 @@ void __init smp_prepare_boot_cpu(void) /* * Entry point to boot a CPU. - * - * This is all __cpuinit, not __devinit for now because we don't support - * CPU hotplug (yet). */ int __cpuinit __cpu_up(unsigned int cpu) { @@ -996,6 +1068,14 @@ int __cpuinit __cpu_up(unsigned int cpu) return -EINVAL; } + /* + * Already booted CPU? + */ + if (cpu_isset(cpu, cpu_callin_map)) { + Dprintk("do_boot_cpu %d Already started\n", cpu); + return -ENOSYS; + } + /* Boot it! */ err = do_boot_cpu(cpu, apicid); if (err < 0) { @@ -1008,7 +1088,9 @@ int __cpuinit __cpu_up(unsigned int cpu) while (!cpu_isset(cpu, cpu_online_map)) cpu_relax(); - return 0; + err = 0; + + return err; } /* @@ -1016,7 +1098,9 @@ int __cpuinit __cpu_up(unsigned int cpu) */ void __init smp_cpus_done(unsigned int max_cpus) { +#ifndef CONFIG_HOTPLUG_CPU zap_low_mappings(); +#endif smp_cleanup_boot(); #ifdef CONFIG_X86_IO_APIC @@ -1028,3 +1112,94 @@ void __init smp_cpus_done(unsigned int max_cpus) check_nmi_watchdog(); } + +#ifdef CONFIG_HOTPLUG_CPU + +static void +remove_siblinginfo(int cpu) +{ + int sibling; + + for_each_cpu_mask(sibling, cpu_sibling_map[cpu]) + cpu_clear(cpu, cpu_sibling_map[sibling]); + for_each_cpu_mask(sibling, cpu_core_map[cpu]) + cpu_clear(cpu, cpu_core_map[sibling]); + cpus_clear(cpu_sibling_map[cpu]); + cpus_clear(cpu_core_map[cpu]); + phys_proc_id[cpu] = BAD_APICID; + cpu_core_id[cpu] = BAD_APICID; +} + +void remove_cpu_from_maps(void) +{ + int cpu = smp_processor_id(); + + cpu_clear(cpu, cpu_callout_map); + cpu_clear(cpu, cpu_callin_map); + clear_bit(cpu, &cpu_initialized); /* was set by cpu_init() */ +} + +int __cpu_disable(void) +{ + int cpu = smp_processor_id(); + + /* + * Perhaps use cpufreq to drop frequency, but that could go + * into generic code. + * + * We won't take down the boot processor on i386 due to some + * interrupts only being able to be serviced by the BSP. + * Especially so if we're not using an IOAPIC -zwane + */ + if (cpu == 0) + return -EBUSY; + + disable_APIC_timer(); + + /* + * HACK: + * Allow any queued timer interrupts to get serviced + * This is only a temporary solution until we cleanup + * fixup_irqs as we do for IA64. + */ + local_irq_enable(); + mdelay(1); + + local_irq_disable(); + remove_siblinginfo(cpu); + + /* It's now safe to remove this processor from the online map */ + cpu_clear(cpu, cpu_online_map); + remove_cpu_from_maps(); + fixup_irqs(cpu_online_map); + return 0; +} + +void __cpu_die(unsigned int cpu) +{ + /* We don't do anything here: idle task is faking death itself. */ + unsigned int i; + + for (i = 0; i < 10; i++) { + /* They ack this in play_dead by setting CPU_DEAD */ + if (per_cpu(cpu_state, cpu) == CPU_DEAD) + return; + current->state = TASK_UNINTERRUPTIBLE; + schedule_timeout(HZ/10); + } + printk(KERN_ERR "CPU %u didn't die...\n", cpu); +} + +#else /* ... !CONFIG_HOTPLUG_CPU */ + +int __cpu_disable(void) +{ + return -ENOSYS; +} + +void __cpu_die(unsigned int cpu) +{ + /* We said "no" in __cpu_disable */ + BUG(); +} +#endif /* CONFIG_HOTPLUG_CPU */ diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c index 121646fc43f..10273663000 100644 --- a/arch/x86_64/kernel/traps.c +++ b/arch/x86_64/kernel/traps.c @@ -586,11 +586,17 @@ static void unknown_nmi_error(unsigned char reason, struct pt_regs * regs) asmlinkage void default_do_nmi(struct pt_regs *regs) { unsigned char reason = 0; + int cpu; + + cpu = smp_processor_id(); /* Only the BSP gets external NMIs from the system. */ - if (!smp_processor_id()) + if (!cpu) reason = get_nmi_reason(); + if (!cpu_online(cpu)) + return; + if (!(reason & 0xc0)) { if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 0, SIGINT) == NOTIFY_STOP) diff --git a/include/asm-x86_64/irq.h b/include/asm-x86_64/irq.h index 3af50b3c3b0..eb3b7aa9eb9 100644 --- a/include/asm-x86_64/irq.h +++ b/include/asm-x86_64/irq.h @@ -52,4 +52,9 @@ struct irqaction; struct pt_regs; int handle_IRQ_event(unsigned int, struct pt_regs *, struct irqaction *); +#ifdef CONFIG_HOTPLUG_CPU +#include <linux/cpumask.h> +extern void fixup_irqs(cpumask_t map); +#endif + #endif /* _ASM_IRQ_H */ diff --git a/include/asm-x86_64/smp.h b/include/asm-x86_64/smp.h index a7425aa5a3b..9c6242fb99d 100644 --- a/include/asm-x86_64/smp.h +++ b/include/asm-x86_64/smp.h @@ -77,6 +77,8 @@ extern __inline int hard_smp_processor_id(void) } extern int safe_smp_processor_id(void); +extern int __cpu_disable(void); +extern void __cpu_die(unsigned int cpu); #endif /* !ASSEMBLY */ |