[PATCH] x86_64: CPU hotplug support
Experimental CPU hotplug patch for x86_64 ----------------------------------------- This supports logical CPU online and offline. - Test with maxcpus=1, and then kick other cpu's off to test if init code is all cleaned up. CONFIG_SCHED_SMT works as well. - idle threads are forked on demand from keventd threads for clean startup TBD: 1. Not tested on a real NUMA machine (tested with numa=fake=2) 2. Handle ACPI pieces for physical hotplug support. Signed-off-by: Ashok Raj <ashok.raj@intel.com> Acked-by: Andi Kleen <ak@muc.de> Acked-by: Zwane Mwaikambo <zwane@arm.linux.org.uk> Signed-off-by: Shaohua.li<shaohua.li@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Ashok Raj
Linus Torvalds
parent
e6982c671c
commit
76e4f660d9
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@ -73,12 +73,11 @@ static int __init topology_init(void)
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{
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int i;
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for (i = 0; i < MAX_NUMNODES; i++) {
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if (node_online(i))
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arch_register_node(i);
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}
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for (i = 0; i < NR_CPUS; i++)
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if (cpu_possible(i)) arch_register_cpu(i);
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for_each_online_node(i)
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arch_register_node(i);
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for_each_cpu(i)
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arch_register_cpu(i);
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return 0;
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}
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@ -88,8 +87,8 @@ static int __init topology_init(void)
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{
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int i;
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for (i = 0; i < NR_CPUS; i++)
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if (cpu_possible(i)) arch_register_cpu(i);
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for_each_cpu(i)
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arch_register_cpu(i);
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return 0;
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}
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@ -313,6 +313,15 @@ config NR_CPUS
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This is purely to save memory - each supported CPU requires
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memory in the static kernel configuration.
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config HOTPLUG_CPU
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bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
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depends on SMP && HOTPLUG && EXPERIMENTAL
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help
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Say Y here to experiment with turning CPUs off and on. CPUs
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can be controlled through /sys/devices/system/cpu/cpu#.
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Say N if you want to disable CPU hotplug.
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config HPET_TIMER
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bool
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default y
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@ -14,6 +14,7 @@
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#include <linux/interrupt.h>
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#include <linux/seq_file.h>
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#include <linux/module.h>
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#include <linux/delay.h>
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#include <asm/uaccess.h>
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#include <asm/io_apic.h>
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@ -106,3 +107,31 @@ asmlinkage unsigned int do_IRQ(struct pt_regs *regs)
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return 1;
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}
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#ifdef CONFIG_HOTPLUG_CPU
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void fixup_irqs(cpumask_t map)
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{
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unsigned int irq;
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static int warned;
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for (irq = 0; irq < NR_IRQS; irq++) {
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cpumask_t mask;
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if (irq == 2)
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continue;
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cpus_and(mask, irq_affinity[irq], map);
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if (any_online_cpu(mask) == NR_CPUS) {
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printk("Breaking affinity for irq %i\n", irq);
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mask = map;
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}
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if (irq_desc[irq].handler->set_affinity)
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irq_desc[irq].handler->set_affinity(irq, mask);
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else if (irq_desc[irq].action && !(warned++))
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printk("Cannot set affinity for irq %i\n", irq);
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}
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/* That doesn't seem sufficient. Give it 1ms. */
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local_irq_enable();
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mdelay(1);
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local_irq_disable();
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}
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#endif
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@ -8,7 +8,8 @@
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*
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* X86-64 port
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* Andi Kleen.
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*
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*
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* CPU hotplug support - ashok.raj@intel.com
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* $Id: process.c,v 1.38 2002/01/15 10:08:03 ak Exp $
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*/
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@ -18,6 +19,7 @@
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#include <stdarg.h>
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#include <linux/cpu.h>
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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@ -154,6 +156,29 @@ void cpu_idle_wait(void)
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}
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EXPORT_SYMBOL_GPL(cpu_idle_wait);
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#ifdef CONFIG_HOTPLUG_CPU
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DECLARE_PER_CPU(int, cpu_state);
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#include <asm/nmi.h>
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/* We don't actually take CPU down, just spin without interrupts. */
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static inline void play_dead(void)
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{
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idle_task_exit();
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wbinvd();
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mb();
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/* Ack it */
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__get_cpu_var(cpu_state) = CPU_DEAD;
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while (1)
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safe_halt();
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}
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#else
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static inline void play_dead(void)
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{
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BUG();
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}
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#endif /* CONFIG_HOTPLUG_CPU */
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/*
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* The idle thread. There's no useful work to be
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* done, so just try to conserve power and have a
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@ -174,6 +199,8 @@ void cpu_idle (void)
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idle = pm_idle;
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if (!idle)
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idle = default_idle;
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if (cpu_is_offline(smp_processor_id()))
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play_dead();
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idle();
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}
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@ -34,6 +34,7 @@
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* Andi Kleen : Converted to new state machine.
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* Various cleanups.
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* Probably mostly hotplug CPU ready now.
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* Ashok Raj : CPU hotplug support
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*/
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@ -98,6 +99,37 @@ EXPORT_SYMBOL(cpu_core_map);
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extern unsigned char trampoline_data[];
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extern unsigned char trampoline_end[];
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/* State of each CPU */
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DEFINE_PER_CPU(int, cpu_state) = { 0 };
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/*
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* Store all idle threads, this can be reused instead of creating
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* a new thread. Also avoids complicated thread destroy functionality
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* for idle threads.
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*/
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struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ;
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#define get_idle_for_cpu(x) (idle_thread_array[(x)])
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#define set_idle_for_cpu(x,p) (idle_thread_array[(x)] = (p))
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/*
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* cpu_possible_map should be static, it cannot change as cpu's
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* are onlined, or offlined. The reason is per-cpu data-structures
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* are allocated by some modules at init time, and dont expect to
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* do this dynamically on cpu arrival/departure.
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* cpu_present_map on the other hand can change dynamically.
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* In case when cpu_hotplug is not compiled, then we resort to current
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* behaviour, which is cpu_possible == cpu_present.
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* If cpu-hotplug is supported, then we need to preallocate for all
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* those NR_CPUS, hence cpu_possible_map represents entire NR_CPUS range.
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* - Ashok Raj
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*/
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#ifdef CONFIG_HOTPLUG_CPU
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#define fixup_cpu_possible_map(x) cpu_set((x), cpu_possible_map)
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#else
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#define fixup_cpu_possible_map(x)
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#endif
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/*
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* Currently trivial. Write the real->protected mode
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* bootstrap into the page concerned. The caller
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@ -623,33 +655,77 @@ static int __cpuinit wakeup_secondary_via_INIT(int phys_apicid, unsigned int sta
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return (send_status | accept_status);
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}
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struct create_idle {
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struct task_struct *idle;
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struct completion done;
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int cpu;
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};
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void do_fork_idle(void *_c_idle)
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{
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struct create_idle *c_idle = _c_idle;
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c_idle->idle = fork_idle(c_idle->cpu);
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complete(&c_idle->done);
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}
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/*
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* Boot one CPU.
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*/
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static int __cpuinit do_boot_cpu(int cpu, int apicid)
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{
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struct task_struct *idle;
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unsigned long boot_error;
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int timeout;
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unsigned long start_rip;
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/*
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* We can't use kernel_thread since we must avoid to
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* reschedule the child.
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*/
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idle = fork_idle(cpu);
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if (IS_ERR(idle)) {
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printk("failed fork for CPU %d\n", cpu);
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return PTR_ERR(idle);
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struct create_idle c_idle = {
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.cpu = cpu,
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.done = COMPLETION_INITIALIZER(c_idle.done),
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};
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DECLARE_WORK(work, do_fork_idle, &c_idle);
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c_idle.idle = get_idle_for_cpu(cpu);
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if (c_idle.idle) {
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c_idle.idle->thread.rsp = (unsigned long) (((struct pt_regs *)
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(THREAD_SIZE + (unsigned long) c_idle.idle->thread_info)) - 1);
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init_idle(c_idle.idle, cpu);
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goto do_rest;
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}
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cpu_pda[cpu].pcurrent = idle;
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/*
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* During cold boot process, keventd thread is not spun up yet.
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* When we do cpu hot-add, we create idle threads on the fly, we should
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* not acquire any attributes from the calling context. Hence the clean
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* way to create kernel_threads() is to do that from keventd().
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* We do the current_is_keventd() due to the fact that ACPI notifier
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* was also queuing to keventd() and when the caller is already running
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* in context of keventd(), we would end up with locking up the keventd
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* thread.
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*/
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if (!keventd_up() || current_is_keventd())
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work.func(work.data);
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else {
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schedule_work(&work);
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wait_for_completion(&c_idle.done);
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}
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if (IS_ERR(c_idle.idle)) {
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printk("failed fork for CPU %d\n", cpu);
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return PTR_ERR(c_idle.idle);
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}
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set_idle_for_cpu(cpu, c_idle.idle);
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do_rest:
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cpu_pda[cpu].pcurrent = c_idle.idle;
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start_rip = setup_trampoline();
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init_rsp = idle->thread.rsp;
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init_rsp = c_idle.idle->thread.rsp;
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per_cpu(init_tss,cpu).rsp0 = init_rsp;
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initial_code = start_secondary;
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clear_ti_thread_flag(idle->thread_info, TIF_FORK);
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clear_ti_thread_flag(c_idle.idle->thread_info, TIF_FORK);
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printk(KERN_INFO "Booting processor %d/%d rip %lx rsp %lx\n", cpu, apicid,
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start_rip, init_rsp);
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@ -925,10 +1001,9 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
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int apicid = cpu_present_to_apicid(i);
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if (physid_isset(apicid, phys_cpu_present_map)) {
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cpu_set(i, cpu_present_map);
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/* possible map would be different if we supported real
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CPU hotplug. */
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cpu_set(i, cpu_possible_map);
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}
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fixup_cpu_possible_map(i);
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}
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if (smp_sanity_check(max_cpus) < 0) {
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@ -977,9 +1052,6 @@ void __init smp_prepare_boot_cpu(void)
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/*
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* Entry point to boot a CPU.
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*
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* This is all __cpuinit, not __devinit for now because we don't support
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* CPU hotplug (yet).
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*/
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int __cpuinit __cpu_up(unsigned int cpu)
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{
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@ -996,6 +1068,14 @@ int __cpuinit __cpu_up(unsigned int cpu)
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return -EINVAL;
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}
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/*
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* Already booted CPU?
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*/
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if (cpu_isset(cpu, cpu_callin_map)) {
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Dprintk("do_boot_cpu %d Already started\n", cpu);
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return -ENOSYS;
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}
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/* Boot it! */
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err = do_boot_cpu(cpu, apicid);
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if (err < 0) {
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@ -1008,7 +1088,9 @@ int __cpuinit __cpu_up(unsigned int cpu)
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while (!cpu_isset(cpu, cpu_online_map))
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cpu_relax();
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return 0;
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err = 0;
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return err;
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}
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/*
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@ -1016,7 +1098,9 @@ int __cpuinit __cpu_up(unsigned int cpu)
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*/
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void __init smp_cpus_done(unsigned int max_cpus)
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{
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#ifndef CONFIG_HOTPLUG_CPU
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zap_low_mappings();
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#endif
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smp_cleanup_boot();
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#ifdef CONFIG_X86_IO_APIC
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@ -1028,3 +1112,94 @@ void __init smp_cpus_done(unsigned int max_cpus)
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check_nmi_watchdog();
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}
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#ifdef CONFIG_HOTPLUG_CPU
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static void
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remove_siblinginfo(int cpu)
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{
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int sibling;
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for_each_cpu_mask(sibling, cpu_sibling_map[cpu])
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cpu_clear(cpu, cpu_sibling_map[sibling]);
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for_each_cpu_mask(sibling, cpu_core_map[cpu])
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cpu_clear(cpu, cpu_core_map[sibling]);
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cpus_clear(cpu_sibling_map[cpu]);
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cpus_clear(cpu_core_map[cpu]);
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phys_proc_id[cpu] = BAD_APICID;
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cpu_core_id[cpu] = BAD_APICID;
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}
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void remove_cpu_from_maps(void)
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{
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int cpu = smp_processor_id();
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cpu_clear(cpu, cpu_callout_map);
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cpu_clear(cpu, cpu_callin_map);
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clear_bit(cpu, &cpu_initialized); /* was set by cpu_init() */
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}
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int __cpu_disable(void)
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{
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int cpu = smp_processor_id();
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/*
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* Perhaps use cpufreq to drop frequency, but that could go
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* into generic code.
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*
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* We won't take down the boot processor on i386 due to some
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* interrupts only being able to be serviced by the BSP.
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* Especially so if we're not using an IOAPIC -zwane
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*/
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if (cpu == 0)
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return -EBUSY;
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disable_APIC_timer();
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/*
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* HACK:
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* Allow any queued timer interrupts to get serviced
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* This is only a temporary solution until we cleanup
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* fixup_irqs as we do for IA64.
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*/
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local_irq_enable();
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mdelay(1);
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local_irq_disable();
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remove_siblinginfo(cpu);
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/* It's now safe to remove this processor from the online map */
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cpu_clear(cpu, cpu_online_map);
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remove_cpu_from_maps();
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fixup_irqs(cpu_online_map);
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return 0;
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}
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void __cpu_die(unsigned int cpu)
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{
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/* We don't do anything here: idle task is faking death itself. */
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unsigned int i;
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for (i = 0; i < 10; i++) {
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/* They ack this in play_dead by setting CPU_DEAD */
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if (per_cpu(cpu_state, cpu) == CPU_DEAD)
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return;
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current->state = TASK_UNINTERRUPTIBLE;
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schedule_timeout(HZ/10);
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}
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printk(KERN_ERR "CPU %u didn't die...\n", cpu);
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}
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#else /* ... !CONFIG_HOTPLUG_CPU */
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int __cpu_disable(void)
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{
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return -ENOSYS;
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}
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void __cpu_die(unsigned int cpu)
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{
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/* We said "no" in __cpu_disable */
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BUG();
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}
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#endif /* CONFIG_HOTPLUG_CPU */
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@ -586,11 +586,17 @@ static void unknown_nmi_error(unsigned char reason, struct pt_regs * regs)
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asmlinkage void default_do_nmi(struct pt_regs *regs)
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{
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unsigned char reason = 0;
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int cpu;
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cpu = smp_processor_id();
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/* Only the BSP gets external NMIs from the system. */
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if (!smp_processor_id())
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if (!cpu)
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reason = get_nmi_reason();
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if (!cpu_online(cpu))
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return;
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if (!(reason & 0xc0)) {
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if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 0, SIGINT)
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== NOTIFY_STOP)
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|
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@ -52,4 +52,9 @@ struct irqaction;
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struct pt_regs;
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int handle_IRQ_event(unsigned int, struct pt_regs *, struct irqaction *);
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#ifdef CONFIG_HOTPLUG_CPU
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#include <linux/cpumask.h>
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extern void fixup_irqs(cpumask_t map);
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#endif
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#endif /* _ASM_IRQ_H */
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@ -77,6 +77,8 @@ extern __inline int hard_smp_processor_id(void)
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}
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extern int safe_smp_processor_id(void);
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extern int __cpu_disable(void);
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extern void __cpu_die(unsigned int cpu);
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#endif /* !ASSEMBLY */
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Reference in a new issue