Re: [PATCH v2] acpi: Fix CPU hot removal problem

From: canquan.shen
Date: Tue Sep 13 2011 - 01:58:28 EST


On 2011/9/8 10:39, canquan.shen wrote:
We run Linux as a guest in Xen environment. When used 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 didn't go to really remove cpu in the cpu removal code path.

This patch adds acpi_bus_trim 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 | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/drivers/acpi/processor_driver.c
b/drivers/acpi/processor_driver.c
index a1c564f..114592f 100644
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -678,7 +678,11 @@ static void
acpi_processor_hotplug_notify(acpi_handle handle,
return;
}

+ if (acpi_bus_trim(device, 1)) {
+ printk(KERN_ERR PREFIX
+ "Removing device failed\n");
+ return;
+ }
break;
default:
ACPI_DEBUG_PRINT((ACPI_DB_INFO,

Hi Len,
I just see your email in linux-kernel maillist and known that your kernel.org email is kaput, so I resend this email to your intel email address.

Thanks,
- Canquan Shen

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