diff options
Diffstat (limited to 'Documentation/cpu-hotplug.txt')
| -rw-r--r-- | Documentation/cpu-hotplug.txt | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt index 9f401350f502..786dc82f98ce 100644 --- a/Documentation/cpu-hotplug.txt +++ b/Documentation/cpu-hotplug.txt @@ -128,7 +128,7 @@ A: When doing make defconfig, Enable CPU hotplug support "Processor type and Features" -> Support for Hotpluggable CPUs -Make sure that you have CONFIG_HOTPLUG, and CONFIG_SMP turned on as well. +Make sure that you have CONFIG_SMP turned on as well. You would need to enable CONFIG_HOTPLUG_CPU for SMP suspend/resume support as well. @@ -267,8 +267,8 @@ Q: If i have some kernel code that needs to be aware of CPU arrival and A: This is what you would need in your kernel code to receive notifications. #include <linux/cpu.h> - static int __cpuinit foobar_cpu_callback(struct notifier_block *nfb, - unsigned long action, void *hcpu) + static int foobar_cpu_callback(struct notifier_block *nfb, + unsigned long action, void *hcpu) { unsigned int cpu = (unsigned long)hcpu; @@ -285,7 +285,7 @@ A: This is what you would need in your kernel code to receive notifications. return NOTIFY_OK; } - static struct notifier_block __cpuinitdata foobar_cpu_notifer = + static struct notifier_block foobar_cpu_notifer = { .notifier_call = foobar_cpu_callback, }; @@ -370,8 +370,10 @@ A: There is no clear spec defined way from ACPI that can give us that CPUs in MADT as hotpluggable CPUS. In the case there are no disabled CPUS we assume 1/2 the number of CPUs currently present can be hotplugged. - Caveat: Today's ACPI MADT can only provide 256 entries since the apicid field - in MADT is only 8 bits. + Caveat: ACPI MADT can only provide 256 entries in systems with only ACPI 2.0c + or earlier ACPI version supported, because the apicid field in MADT is only + 8 bits. From ACPI 3.0, this limitation was removed since the apicid field + was extended to 32 bits with x2APIC introduced. User Space Notification |