* Andi Kleen : Converted to new state machine.
* Various cleanups.
* Probably mostly hotplug CPU ready now.
+ * Ashok Raj : CPU hotplug support
*/
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
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);
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) {
/*
* 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)
{
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) {
while (!cpu_isset(cpu, cpu_online_map))
cpu_relax();
- return 0;
+ err = 0;
+
+ return err;
}
/*
*/
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
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 */
projects / linux-2.6 / commitdiff