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Date: Fri, 16 Nov 2012 09:54:43 +0800
From: Wen Congyang <wency@...fujitsu.com>
To: David Rientjes <rientjes@...gle.com>
CC: linux-kernel@...r.kernel.org, linux-mm@...ck.org,
linux-acpi@...r.kernel.org, Len Brown <len.brown@...el.com>,
"Rafael J. Wysocki" <rjw@...k.pl>,
Andrew Morton <akpm@...ux-foundation.org>,
Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>,
Lai Jiangshan <laijs@...fujitsu.com>,
Jiang Liu <jiang.liu@...wei.com>,
KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
Minchan Kim <minchan.kim@...il.com>,
Mel Gorman <mgorman@...e.de>,
Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
Toshi Kani <toshi.kani@...com>, Jiang Liu <liuj97@...il.com>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Christoph Lameter <cl@...ux.com>
Subject: Re: [Patch v5 2/7] acpi,memory-hotplug: deal with eject request in
hotplug queue
At 11/16/2012 07:32 AM, David Rientjes Wrote:
> On Thu, 15 Nov 2012, Wen Congyang wrote:
>
>> The memory device can be removed by 2 ways:
>> 1. send eject request by SCI
>> 2. echo 1 >/sys/bus/pci/devices/PNP0C80:XX/eject
>>
>> We handle the 1st case in the module acpi_memhotplug, and handle
>> the 2nd case in ACPI eject notification. This 2 events may happen
>> at the same time, so we may touch acpi_memory_device.res_list at
>> the same time. This patch reimplements memory-hotremove support
>> through an ACPI eject notification. Now the memory device is
>> offlined and hotremoved only in the function acpi_memory_device_remove()
>> which is protected by device_lock().
>>
>
> You mean it's protected by device_lock() before calling the remove()
> function for eject?
Yes. We call device_release_driver() to unbind the device from the driver
(the memory will be offlined/removed when it is unbound from the driver).
we call device_lock() in device_release_driver(), so we only unbind it
from the driver once.
Thanks
Wen Congyang
>
>> CC: David Rientjes <rientjes@...gle.com>
>> CC: Jiang Liu <liuj97@...il.com>
>> CC: Len Brown <len.brown@...el.com>
>> CC: Benjamin Herrenschmidt <benh@...nel.crashing.org>
>> CC: Paul Mackerras <paulus@...ba.org>
>> CC: Christoph Lameter <cl@...ux.com>
>> Cc: Minchan Kim <minchan.kim@...il.com>
>> CC: Andrew Morton <akpm@...ux-foundation.org>
>> CC: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
>> CC: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
>> CC: Rafael J. Wysocki <rjw@...k.pl>
>> CC: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
>> Signed-off-by: Wen Congyang <wency@...fujitsu.com>
>> ---
>> drivers/acpi/acpi_memhotplug.c | 87 +++++-------------------------------------
>> 1 file changed, 9 insertions(+), 78 deletions(-)
>>
>> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
>> index 2918be1..6e12042 100644
>> --- a/drivers/acpi/acpi_memhotplug.c
>> +++ b/drivers/acpi/acpi_memhotplug.c
>> @@ -272,40 +272,6 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
>> return 0;
>> }
>>
>> -static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device)
>> -{
>> - acpi_status status;
>> - struct acpi_object_list arg_list;
>> - union acpi_object arg;
>> - unsigned long long current_status;
>> -
>> -
>> - /* Issue the _EJ0 command */
>> - arg_list.count = 1;
>> - arg_list.pointer = &arg;
>> - arg.type = ACPI_TYPE_INTEGER;
>> - arg.integer.value = 1;
>> - status = acpi_evaluate_object(mem_device->device->handle,
>> - "_EJ0", &arg_list, NULL);
>> - /* Return on _EJ0 failure */
>> - if (ACPI_FAILURE(status)) {
>> - ACPI_EXCEPTION((AE_INFO, status, "_EJ0 failed"));
>> - return -ENODEV;
>> - }
>> -
>> - /* Evalute _STA to check if the device is disabled */
>> - status = acpi_evaluate_integer(mem_device->device->handle, "_STA",
>> - NULL, ¤t_status);
>> - if (ACPI_FAILURE(status))
>> - return -ENODEV;
>> -
>> - /* Check for device status. Device should be disabled */
>> - if (current_status & ACPI_STA_DEVICE_ENABLED)
>> - return -EINVAL;
>> -
>> - return 0;
>> -}
>> -
>> static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
>> {
>> int result;
>> @@ -325,34 +291,11 @@ static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
>> return 0;
>> }
>>
>> -static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
>> -{
>> - int result;
>> -
>> - /*
>> - * Ask the VM to offline this memory range.
>> - * Note: Assume that this function returns zero on success
>> - */
>> - result = acpi_memory_remove_memory(mem_device);
>> - if (result)
>> - return result;
>> -
>> - /* Power-off and eject the device */
>> - result = acpi_memory_powerdown_device(mem_device);
>> - if (result) {
>> - /* Set the status of the device to invalid */
>> - mem_device->state = MEMORY_INVALID_STATE;
>> - return result;
>> - }
>> -
>> - mem_device->state = MEMORY_POWER_OFF_STATE;
>> - return result;
>> -}
>> -
>> static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
>> {
>> struct acpi_memory_device *mem_device;
>> struct acpi_device *device;
>> + struct acpi_eject_event *ej_event = NULL;
>> u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
>>
>> switch (event) {
>> @@ -394,31 +337,19 @@ static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
>> break;
>> }
>>
>> - /*
>> - * Currently disabling memory device from kernel mode
>> - * TBD: Can also be disabled from user mode scripts
>> - * TBD: Can also be disabled by Callback registration
>> - * with generic sysfs driver
>> - */
>> - if (acpi_memory_disable_device(mem_device)) {
>> - printk(KERN_ERR PREFIX "Disable memory device\n");
>> - /*
>> - * If _EJ0 was called but failed, _OST is not
>> - * necessary.
>> - */
>> - if (mem_device->state == MEMORY_INVALID_STATE)
>> - return;
>> -
>> + ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
>> + if (!ej_event) {
>> + pr_err(PREFIX "No memory, dropping EJECT\n");
>> break;
>> }
>>
>> - /*
>> - * TBD: Invoke acpi_bus_remove to cleanup data structures
>> - */
>> + ej_event->handle = handle;
>> + ej_event->event = ACPI_NOTIFY_EJECT_REQUEST;
>> + acpi_os_hotplug_execute(acpi_bus_hot_remove_device,
>> + (void *)ej_event);
>>
>> - /* _EJ0 succeeded; _OST is not necessary */
>> + /* eject is performed asynchronously */
>> return;
>> -
>> default:
>> ACPI_DEBUG_PRINT((ACPI_DB_INFO,
>> "Unsupported event [0x%x]\n", event));
>
--
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