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author | Alex Nixon <alex.nixon@citrix.com> | 2008-08-22 11:52:15 +0100 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2008-08-25 11:25:14 +0200 |
commit | d68d82afd4c88e25763b23cd9cd4974573a3706f (patch) | |
tree | 42a3fb93a5cef70db7ad01fda1ed0dc68dbe6110 /drivers/xen | |
parent | 8227dce7dc2cfdcc28ee0eadfb482a7ee77fba03 (diff) | |
download | kernel_samsung_tuna-d68d82afd4c88e25763b23cd9cd4974573a3706f.zip kernel_samsung_tuna-d68d82afd4c88e25763b23cd9cd4974573a3706f.tar.gz kernel_samsung_tuna-d68d82afd4c88e25763b23cd9cd4974573a3706f.tar.bz2 |
xen: implement CPU hotplugging
Note the changes from 2.6.18-xen CPU hotplugging:
A vcpu_down request from the remote admin via Xenbus both hotunplugs the
CPU, and disables it by removing it from the cpu_present map, and removing
its entry in /sys.
A vcpu_up request from the remote admin only re-enables the CPU, and does
not immediately bring the CPU up. A udev event is emitted, which can be
caught by the user if he wishes to automatically re-up CPUs when available,
or implement a more complex policy.
Signed-off-by: Alex Nixon <alex.nixon@citrix.com>
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'drivers/xen')
-rw-r--r-- | drivers/xen/Makefile | 2 | ||||
-rw-r--r-- | drivers/xen/cpu_hotplug.c | 90 | ||||
-rw-r--r-- | drivers/xen/events.c | 4 |
3 files changed, 95 insertions, 1 deletions
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile index 363286c..f62d8df 100644 --- a/drivers/xen/Makefile +++ b/drivers/xen/Makefile @@ -1,4 +1,4 @@ -obj-y += grant-table.o features.o events.o manage.o +obj-y += grant-table.o features.o events.o manage.o cpu_hotplug.o obj-y += xenbus/ obj-$(CONFIG_XEN_XENCOMM) += xencomm.o obj-$(CONFIG_XEN_BALLOON) += balloon.o diff --git a/drivers/xen/cpu_hotplug.c b/drivers/xen/cpu_hotplug.c new file mode 100644 index 0000000..1bc0035 --- /dev/null +++ b/drivers/xen/cpu_hotplug.c @@ -0,0 +1,90 @@ +#include <linux/notifier.h> + +#include <xen/xenbus.h> + +#include <asm-x86/xen/hypervisor.h> +#include <asm/cpu.h> + +static void enable_hotplug_cpu(int cpu) +{ + if (!cpu_present(cpu)) + arch_register_cpu(cpu); + + cpu_set(cpu, cpu_present_map); +} + +static void disable_hotplug_cpu(int cpu) +{ + if (cpu_present(cpu)) + arch_unregister_cpu(cpu); + + cpu_clear(cpu, cpu_present_map); +} + +static void vcpu_hotplug(unsigned int cpu) +{ + int err; + char dir[32], state[32]; + + if (!cpu_possible(cpu)) + return; + + sprintf(dir, "cpu/%u", cpu); + err = xenbus_scanf(XBT_NIL, dir, "availability", "%s", state); + if (err != 1) { + printk(KERN_ERR "XENBUS: Unable to read cpu state\n"); + return; + } + + if (strcmp(state, "online") == 0) { + enable_hotplug_cpu(cpu); + } else if (strcmp(state, "offline") == 0) { + (void)cpu_down(cpu); + disable_hotplug_cpu(cpu); + } else { + printk(KERN_ERR "XENBUS: unknown state(%s) on CPU%d\n", + state, cpu); + } +} + +static void handle_vcpu_hotplug_event(struct xenbus_watch *watch, + const char **vec, unsigned int len) +{ + unsigned int cpu; + char *cpustr; + const char *node = vec[XS_WATCH_PATH]; + + cpustr = strstr(node, "cpu/"); + if (cpustr != NULL) { + sscanf(cpustr, "cpu/%u", &cpu); + vcpu_hotplug(cpu); + } +} + +static int setup_cpu_watcher(struct notifier_block *notifier, + unsigned long event, void *data) +{ + static struct xenbus_watch cpu_watch = { + .node = "cpu", + .callback = handle_vcpu_hotplug_event}; + + (void)register_xenbus_watch(&cpu_watch); + + return NOTIFY_DONE; +} + +static int __init setup_vcpu_hotplug_event(void) +{ + static struct notifier_block xsn_cpu = { + .notifier_call = setup_cpu_watcher }; + + if (!is_running_on_xen()) + return -ENODEV; + + register_xenstore_notifier(&xsn_cpu); + + return 0; +} + +arch_initcall(setup_vcpu_hotplug_event); + diff --git a/drivers/xen/events.c b/drivers/xen/events.c index b6c2b8f..c3290bc 100644 --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -360,6 +360,10 @@ static void unbind_from_irq(unsigned int irq) per_cpu(virq_to_irq, cpu_from_evtchn(evtchn)) [index_from_irq(irq)] = -1; break; + case IRQT_IPI: + per_cpu(ipi_to_irq, cpu_from_evtchn(evtchn)) + [index_from_irq(irq)] = -1; + break; default: break; } |