# HG changeset patch
# User sos22@xxxxxxxxxxxxxxxxxxxx
# Node ID 6e6cedc1763db80ac68fefbe6062594416c75aa1
# Parent 69f00d6ab5dcdfb440482315715522ee85e86f84
Make xm save/restore work for SMP guest domains.
Signed-off-by: Steven Smith, sos22@xxxxxxxxx
diff -r 69f00d6ab5dc -r 6e6cedc1763d
linux-2.6-xen-sparse/arch/xen/kernel/reboot.c
--- a/linux-2.6-xen-sparse/arch/xen/kernel/reboot.c Wed Aug 17 13:34:42 2005
+++ b/linux-2.6-xen-sparse/arch/xen/kernel/reboot.c Wed Aug 17 14:37:22 2005
@@ -16,6 +16,8 @@
#include <asm-xen/queues.h>
#include <asm-xen/xenbus.h>
#include <asm-xen/ctrl_if.h>
+#include <linux/cpu.h>
+#include <linux/kthread.h>
#define SHUTDOWN_INVALID -1
#define SHUTDOWN_POWEROFF 0
@@ -58,7 +60,12 @@
/* Ignore multiple shutdown requests. */
static int shutting_down = SHUTDOWN_INVALID;
-static void __do_suspend(void)
+#ifndef CONFIG_HOTPLUG_CPU
+#define cpu_down(x) (-EOPNOTSUPP)
+#define cpu_up(x) (-EOPNOTSUPP)
+#endif
+
+static int __do_suspend(void *ignore)
{
int i, j;
suspend_record_t *suspend_record;
@@ -104,10 +111,49 @@
extern unsigned long max_pfn;
extern unsigned int *pfn_to_mfn_frame_list;
+ cpumask_t feasible_cpus;
+ int err = 0;
+
+ BUG_ON(smp_processor_id() != 0);
+ BUG_ON(in_interrupt());
+
+#if defined(CONFIG_SMP) && !defined(CONFIG_HOTPLUG_CPU)
+ if (num_online_cpus() > 1) {
+ printk(KERN_WARNING "Can't suspend SMP guests without
CONFIG_HOTPLUG_CPU\n");
+ return -EOPNOTSUPP;
+ }
+#endif
+
suspend_record = (suspend_record_t *)__get_free_page(GFP_KERNEL);
if ( suspend_record == NULL )
goto out;
+ /* Take all of the other cpus offline. We need to be careful not
+ to get preempted between the final test for num_online_cpus()
+ == 1 and disabling interrupts, since otherwise userspace could
+ bring another cpu online, and then we'd be stuffed. At the
+ same time, cpu_down can reschedule, so we need to enable
+ preemption while doing that. This kind of sucks, but should be
+ correct. */
+ /* (We don't need to worry about other cpus bringing stuff up,
+ since by the time num_online_cpus() == 1, there aren't any
+ other cpus) */
+ cpus_clear(feasible_cpus);
+ preempt_disable();
+ while (num_online_cpus() > 1) {
+ preempt_enable();
+ for_each_online_cpu(i) {
+ if (i == 0)
+ continue;
+ err = cpu_down(i);
+ if (err != 0) {
+ printk(KERN_CRIT "Failed to take all CPUs down: %d.\n", err);
+ goto out_reenable_cpus;
+ }
+ cpu_set(i, feasible_cpus);
+ }
+ }
+
suspend_record->nr_pfns = max_pfn; /* final number of pfns */
__cli();
@@ -141,7 +187,10 @@
memcpy(&suspend_record->resume_info, &xen_start_info,
sizeof(xen_start_info));
+ /* We'll stop somewhere inside this hypercall. When it returns,
+ we'll start resuming after the restore. */
HYPERVISOR_suspend(virt_to_machine(suspend_record) >> PAGE_SHIFT);
+
shutting_down = SHUTDOWN_INVALID;
@@ -182,11 +231,26 @@
usbif_resume();
+ preempt_enable();
+
__sti();
+
+ out_reenable_cpus:
+ while (!cpus_empty(feasible_cpus)) {
+ i = first_cpu(feasible_cpus);
+ j = cpu_up(i);
+ if (j != 0) {
+ printk(KERN_CRIT "Failed to bring cpu %d back up (%d).\n",
+ i, j);
+ err = j;
+ }
+ cpu_clear(i, feasible_cpus);
+ }
out:
if ( suspend_record != NULL )
free_page((unsigned long)suspend_record);
+ return err;
}
static int shutdown_process(void *__unused)
@@ -233,6 +297,18 @@
return 0;
}
+static struct task_struct *kthread_create_on_cpu(int (*f)(void *arg),
+ void *arg,
+ const char *name,
+ int cpu)
+{
+ struct task_struct *p;
+ p = kthread_create(f, arg, name);
+ kthread_bind(p, cpu);
+ wake_up_process(p);
+ return p;
+}
+
static void __shutdown_handler(void *unused)
{
int err;
@@ -245,7 +321,7 @@
}
else
{
- __do_suspend();
+ kthread_create_on_cpu(__do_suspend, NULL, "suspender", 0);
}
}
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