On 2011/9/29 11:14, Chen Gong wrote:
于 2011/9/24 14:10, canquan.shen 写道:We run linux as a guest in Xen environment. When we used the xen tools (xm vcpu-set <n>) to hot add and remove vcpu to and from the guest, we encountered the failure on vcpu removal. We found the reason is that it did't go to really remove cpu in the cpu removal code path. This patch adds acpi_bus_hot_remove_device in acpi_process_hotplug_notify to fix this issue. With this patch, it works fine for us. Signed-off-by: Canquan Shen <shencanquan@xxxxxxxxxx> --- drivers/acpi/processor_driver.c | 13 +------------ drivers/acpi/scan.c | 4 ++-- include/acpi/acpi_bus.h | 1 + 3 files changed, 4 insertions(+), 14 deletions(-) diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c index a4e0f1b..8429688 100644 --- a/drivers/acpi/processor_driver.c +++ b/drivers/acpi/processor_driver.c @@ -665,18 +665,7 @@ static void acpi_processor_hotplug_notify(acpi_handle handle, case ACPI_NOTIFY_EJECT_REQUEST: ACPI_DEBUG_PRINT((ACPI_DB_INFO, "received ACPI_NOTIFY_EJECT_REQUEST\n")); - - if (acpi_bus_get_device(handle, &device)) { - printk(KERN_ERR PREFIX - "Device don't exist, dropping EJECT\n"); - break; - } - pr = acpi_driver_data(device); - if (!pr) { - printk(KERN_ERR PREFIX - "Driver data is NULL, dropping EJECT\n"); - return; - } + acpi_bus_hot_remove_device(handle);As the description in __acpi_os_execute(in acpi_os_hotplug_execute), /* * We can't run hotplug code in keventd_wq/kacpid_wq/kacpid_notify_wq * because the hotplug code may call driver .remove() functions, * which invoke flush_scheduled_work/acpi_os_wait_events_complete * to flush these workqueues. */ If so, why not using following call: acpi_os_hotplug_execute(acpi_bus_hot_remove_device, acpi_device->handle);
It is ok if using the acpi_os_hotplug_execute. but it is complex and more time for removal cpu because it is add to queue and some time the work will be called. I think that it is clear to call directly acpi_bus_hot_remove_device function in acpi_processor_hotplug_notify.
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