[PATCH v3 0/3] acpi,memory-hotplug : implement framework for hot removing memory

[PATCH v3 0/3] acpi,memory-hotplug : implement framework for hot removing memory

[wency]

From: Wen Congyang <wency@cn.fujitsu.com>

The patch-set implements a framework for hot removing memory.

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

In the 1st case, acpi_memory_disable_device() will be called.
In the 2nd case, acpi_memory_device_remove() will be called.
acpi_memory_device_remove() will also be called when we unbind the
memory device from the driver acpi_memhotplug or a driver initialization
fails.

acpi_memory_disable_device() has already implemented a code which
offlines memory and releases acpi_memory_info struct . But
acpi_memory_device_remove() has not implemented it yet.

So the patch prepares the framework for hot removing memory and
adds the framework into acpi_memory_device_remove().

The last version of this patchset is here:
https://lkml.org/lkml/2012/10/19/156

Changelogs from v2 to v3:
  Patch2: rename lock to list_lock

Changelogs from v1 to v2:
  Patch1: use acpi_bus_trim() instead of acpi_bus_remove()
  Patch2: new patch, introduce a lock to protect the list
  Patch3: remove memory too when type is ACPI_BUS_REMOVAL_NORMAL
  Note: I don't send [Patch2-4 v1] in this series because they
  are no logical changes in these 3 patches.

Wen Congyang (2):
  acpi,memory-hotplug: call acpi_bus_trim() to remove memory device
  acpi,memory-hotplug: introduce a mutex lock to protect the list in
    acpi_memory_device

Yasuaki Ishimatsu (1):
  acpi,memory-hotplug : add memory offline code to
    acpi_memory_device_remove()

 drivers/acpi/acpi_memhotplug.c | 51 +++++++++++++++++++++++++++++++++---------
 1 file changed, 41 insertions(+), 10 deletions(-)

-- 
1.8.0

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[PATCH v3 1/3] acpi,memory-hotplug: call acpi_bus_trim() to remove memory device

[wency]

From: Wen Congyang <wency@cn.fujitsu.com>

The memory device has been ejected and powoffed, so we can call
acpi_bus_trim() to remove the memory device from acpi bus.

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Christoph Lameter <cl@linux.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
 drivers/acpi/acpi_memhotplug.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 24c807f..1e90e8f 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -401,8 +401,9 @@ static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
 		}
 
 		/*
-		 * TBD: Invoke acpi_bus_remove to cleanup data structures
+		 * Invoke acpi_bus_trim() to remove memory device
 		 */
+		acpi_bus_trim(device, 1);
 
 		/* _EJ0 succeeded; _OST is not necessary */
 		return;
-- 
1.8.0

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[PATCH v3 2/3] acpi,memory-hotplug: introduce a mutex lock to protect the list in acpi_memory_device

[wency]

From: Wen Congyang <wency@cn.fujitsu.com>

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

This 2 events may happen at the same time, so we may touch
acpi_memory_device.res_list at the same time. This patch
introduce a lock to protect this list.

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
CC: Christoph Lameter <cl@linux.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
 drivers/acpi/acpi_memhotplug.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 1e90e8f..666dac6 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -83,7 +83,8 @@ struct acpi_memory_info {
 struct acpi_memory_device {
 	struct acpi_device * device;
 	unsigned int state;	/* State of the memory device */
-	struct list_head res_list;
+	struct mutex list_lock;
+	struct list_head res_list;	/* protected by list_lock */
 };
 
 static int acpi_hotmem_initialized;
@@ -101,19 +102,23 @@ acpi_memory_get_resource(struct acpi_resource *resource, void *context)
 	    (address64.resource_type != ACPI_MEMORY_RANGE))
 		return AE_OK;
 
+	mutex_lock(&mem_device->list_lock);
 	list_for_each_entry(info, &mem_device->res_list, list) {
 		/* Can we combine the resource range information? */
 		if ((info->caching == address64.info.mem.caching) &&
 		    (info->write_protect == address64.info.mem.write_protect) &&
 		    (info->start_addr + info->length == address64.minimum)) {
 			info->length += address64.address_length;
+			mutex_unlock(&mem_device->list_lock);
 			return AE_OK;
 		}
 	}
 
 	new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
-	if (!new)
+	if (!new) {
+		mutex_unlock(&mem_device->list_lock);
 		return AE_ERROR;
+	}
 
 	INIT_LIST_HEAD(&new->list);
 	new->caching = address64.info.mem.caching;
@@ -121,6 +126,7 @@ acpi_memory_get_resource(struct acpi_resource *resource, void *context)
 	new->start_addr = address64.minimum;
 	new->length = address64.address_length;
 	list_add_tail(&new->list, &mem_device->res_list);
+	mutex_unlock(&mem_device->list_lock);
 
 	return AE_OK;
 }
@@ -138,9 +144,11 @@ acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
 	status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS,
 				     acpi_memory_get_resource, mem_device);
 	if (ACPI_FAILURE(status)) {
+		mutex_lock(&mem_device->list_lock);
 		list_for_each_entry_safe(info, n, &mem_device->res_list, list)
 			kfree(info);
 		INIT_LIST_HEAD(&mem_device->res_list);
+		mutex_unlock(&mem_device->list_lock);
 		return -EINVAL;
 	}
 
@@ -236,6 +244,7 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 	 * We don't have memory-hot-add rollback function,now.
 	 * (i.e. memory-hot-remove function)
 	 */
+	mutex_lock(&mem_device->list_lock);
 	list_for_each_entry(info, &mem_device->res_list, list) {
 		if (info->enabled) { /* just sanity check...*/
 			num_enabled++;
@@ -256,6 +265,7 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 		info->enabled = 1;
 		num_enabled++;
 	}
+	mutex_unlock(&mem_device->list_lock);
 	if (!num_enabled) {
 		printk(KERN_ERR PREFIX "add_memory failed\n");
 		mem_device->state = MEMORY_INVALID_STATE;
@@ -316,6 +326,7 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
 	 * Ask the VM to offline this memory range.
 	 * Note: Assume that this function returns zero on success
 	 */
+	mutex_lock(&mem_device->list_lock);
 	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
 		if (info->enabled) {
 			result = remove_memory(info->start_addr, info->length);
@@ -324,6 +335,7 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
 		}
 		kfree(info);
 	}
+	mutex_unlock(&mem_device->list_lock);
 
 	/* Power-off and eject the device */
 	result = acpi_memory_powerdown_device(mem_device);
@@ -438,6 +450,7 @@ static int acpi_memory_device_add(struct acpi_device *device)
 	mem_device->device = device;
 	sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
 	sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
+	mutex_init(&mem_device->list_lock);
 	device->driver_data = mem_device;
 
 	/* Get the range from the _CRS */
-- 
1.8.0

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[PATCH v3 3/3] acpi,memory-hotplug : add memory offline code to acpi_memory_device_remove()

[wency]

From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>

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

In the 1st case, acpi_memory_disable_device() will be called.
In the 2nd case, acpi_memory_device_remove() will be called.
acpi_memory_device_remove() will also be called when we unbind the
memory device from the driver acpi_memhotplug or a driver initialization
fails.

acpi_memory_disable_device() has already implemented a code which
offlines memory and releases acpi_memory_info struct. But
acpi_memory_device_remove() has not implemented it yet.

So the patch move offlining memory and releasing acpi_memory_info struct
codes to a new function acpi_memory_remove_memory(). And it is used by both
acpi_memory_device_remove() and acpi_memory_disable_device().

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
CC: Christoph Lameter <cl@linux.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
 drivers/acpi/acpi_memhotplug.c | 31 ++++++++++++++++++++++++-------
 1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 666dac6..92c973a 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -316,16 +316,11 @@ static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device)
 	return 0;
 }
 
-static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
+static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
 {
 	int result;
 	struct acpi_memory_info *info, *n;
 
-
-	/*
-	 * Ask the VM to offline this memory range.
-	 * Note: Assume that this function returns zero on success
-	 */
 	mutex_lock(&mem_device->list_lock);
 	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
 		if (info->enabled) {
@@ -333,10 +328,27 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
 			if (result)
 				return result;
 		}
+
+		list_del(&info->list);
 		kfree(info);
 	}
 	mutex_unlock(&mem_device->list_lock);
 
+	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) {
@@ -487,12 +499,17 @@ static int acpi_memory_device_add(struct acpi_device *device)
 static int acpi_memory_device_remove(struct acpi_device *device, int type)
 {
 	struct acpi_memory_device *mem_device = NULL;
-
+	int result;
 
 	if (!device || !acpi_driver_data(device))
 		return -EINVAL;
 
 	mem_device = acpi_driver_data(device);
+
+	result = acpi_memory_remove_memory(mem_device);
+	if (result)
+		return result;
+
 	kfree(mem_device);
 
 	return 0;
-- 
1.8.0

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Re: [PATCH v3 3/3] acpi,memory-hotplug : add memory offline code to acpi_memory_device_remove()

[Toshi Kani]

On Fri, 2012-10-26 at 18:31 +0800, wency@cn.fujitsu.com wrote:
> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> 
> 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
> 
> In the 1st case, acpi_memory_disable_device() will be called.
> In the 2nd case, acpi_memory_device_remove() will be called.

Hi Yasuaki, Wen,

Why do you need to have separate code design & implementation for the
two cases?  In other words, can the 1st case simply use the same code
path of the 2nd case, just like I did for the CPU hot-remove patch
below?  It will simplify the code and make the memory notify handler
more consistent with other handlers.
https://lkml.org/lkml/2012/10/19/456

Thanks,
-Toshi


> acpi_memory_device_remove() will also be called when we unbind the
> memory device from the driver acpi_memhotplug or a driver initialization
> fails.
> 
> acpi_memory_disable_device() has already implemented a code which
> offlines memory and releases acpi_memory_info struct. But
> acpi_memory_device_remove() has not implemented it yet.
> 
> So the patch move offlining memory and releasing acpi_memory_info struct
> codes to a new function acpi_memory_remove_memory(). And it is used by both
> acpi_memory_device_remove() and acpi_memory_disable_device().
> 
> CC: David Rientjes <rientjes@google.com>
> CC: Jiang Liu <liuj97@gmail.com>
> CC: Len Brown <len.brown@intel.com>
> CC: Christoph Lameter <cl@linux.com>
> Cc: Minchan Kim <minchan.kim@gmail.com>
> CC: Andrew Morton <akpm@linux-foundation.org>
> CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
> ---
>  drivers/acpi/acpi_memhotplug.c | 31 ++++++++++++++++++++++++-------
>  1 file changed, 24 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
> index 666dac6..92c973a 100644
> --- a/drivers/acpi/acpi_memhotplug.c
> +++ b/drivers/acpi/acpi_memhotplug.c
> @@ -316,16 +316,11 @@ static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device)
>  	return 0;
>  }
>  
> -static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
> +static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
>  {
>  	int result;
>  	struct acpi_memory_info *info, *n;
>  
> -
> -	/*
> -	 * Ask the VM to offline this memory range.
> -	 * Note: Assume that this function returns zero on success
> -	 */
>  	mutex_lock(&mem_device->list_lock);
>  	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
>  		if (info->enabled) {
> @@ -333,10 +328,27 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
>  			if (result)
>  				return result;
>  		}
> +
> +		list_del(&info->list);
>  		kfree(info);
>  	}
>  	mutex_unlock(&mem_device->list_lock);
>  
> +	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) {
> @@ -487,12 +499,17 @@ static int acpi_memory_device_add(struct acpi_device *device)
>  static int acpi_memory_device_remove(struct acpi_device *device, int type)
>  {
>  	struct acpi_memory_device *mem_device = NULL;
> -
> +	int result;
>  
>  	if (!device || !acpi_driver_data(device))
>  		return -EINVAL;
>  
>  	mem_device = acpi_driver_data(device);
> +
> +	result = acpi_memory_remove_memory(mem_device);
> +	if (result)
> +		return result;
> +
>  	kfree(mem_device);
>  
>  	return 0;


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Re: [PATCH v3 3/3] acpi,memory-hotplug : add memory offline code to acpi_memory_device_remove()

[Wen Congyang]

At 10/27/2012 01:14 AM, Toshi Kani Wrote:
> On Fri, 2012-10-26 at 18:31 +0800, wency@cn.fujitsu.com wrote:
>> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>
>> 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
>>
>> In the 1st case, acpi_memory_disable_device() will be called.
>> In the 2nd case, acpi_memory_device_remove() will be called.
> 
> Hi Yasuaki, Wen,
> 
> Why do you need to have separate code design & implementation for the
> two cases?  In other words, can the 1st case simply use the same code
> path of the 2nd case, just like I did for the CPU hot-remove patch
> below?  It will simplify the code and make the memory notify handler
> more consistent with other handlers.
> https://lkml.org/lkml/2012/10/19/456

Yes, the 1st case can simply reuse the same code of the 2nd case.
It is another issue. The memory is not offlined and removed in 2nd
case. This patchset tries to fix this problem. After doing this,
we can merge the codes for the two cases.

But there is some bug in the code for 2nd case:
If offlining memory failed, we don't know such error in 2nd case, and
the kernel will in a dangerous state: the memory device is poweroffed
but the kernel is using it.

We should fix this bug before merging them.

Thanks
Wen Congyang

> 
> Thanks,
> -Toshi
> 
> 
>> acpi_memory_device_remove() will also be called when we unbind the
>> memory device from the driver acpi_memhotplug or a driver initialization
>> fails.
>>
>> acpi_memory_disable_device() has already implemented a code which
>> offlines memory and releases acpi_memory_info struct. But
>> acpi_memory_device_remove() has not implemented it yet.
>>
>> So the patch move offlining memory and releasing acpi_memory_info struct
>> codes to a new function acpi_memory_remove_memory(). And it is used by both
>> acpi_memory_device_remove() and acpi_memory_disable_device().
>>
>> CC: David Rientjes <rientjes@google.com>
>> CC: Jiang Liu <liuj97@gmail.com>
>> CC: Len Brown <len.brown@intel.com>
>> CC: Christoph Lameter <cl@linux.com>
>> Cc: Minchan Kim <minchan.kim@gmail.com>
>> CC: Andrew Morton <akpm@linux-foundation.org>
>> CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
>> ---
>>  drivers/acpi/acpi_memhotplug.c | 31 ++++++++++++++++++++++++-------
>>  1 file changed, 24 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
>> index 666dac6..92c973a 100644
>> --- a/drivers/acpi/acpi_memhotplug.c
>> +++ b/drivers/acpi/acpi_memhotplug.c
>> @@ -316,16 +316,11 @@ static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device)
>>  	return 0;
>>  }
>>  
>> -static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
>> +static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
>>  {
>>  	int result;
>>  	struct acpi_memory_info *info, *n;
>>  
>> -
>> -	/*
>> -	 * Ask the VM to offline this memory range.
>> -	 * Note: Assume that this function returns zero on success
>> -	 */
>>  	mutex_lock(&mem_device->list_lock);
>>  	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
>>  		if (info->enabled) {
>> @@ -333,10 +328,27 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
>>  			if (result)
>>  				return result;
>>  		}
>> +
>> +		list_del(&info->list);
>>  		kfree(info);
>>  	}
>>  	mutex_unlock(&mem_device->list_lock);
>>  
>> +	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) {
>> @@ -487,12 +499,17 @@ static int acpi_memory_device_add(struct acpi_device *device)
>>  static int acpi_memory_device_remove(struct acpi_device *device, int type)
>>  {
>>  	struct acpi_memory_device *mem_device = NULL;
>> -
>> +	int result;
>>  
>>  	if (!device || !acpi_driver_data(device))
>>  		return -EINVAL;
>>  
>>  	mem_device = acpi_driver_data(device);
>> +
>> +	result = acpi_memory_remove_memory(mem_device);
>> +	if (result)
>> +		return result;
>> +
>>  	kfree(mem_device);
>>  
>>  	return 0;
> 
> 
> 

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Re: [PATCH v3 3/3] acpi,memory-hotplug : add memory offline code to acpi_memory_device_remove()

[Toshi Kani]

On Mon, 2012-10-29 at 06:16 +0000, Wen Congyang wrote:
> At 10/27/2012 01:14 AM, Toshi Kani Wrote:
> > On Fri, 2012-10-26 at 18:31 +0800, wency@cn.fujitsu.com wrote:
> >> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> >>
> >> 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
> >>
> >> In the 1st case, acpi_memory_disable_device() will be called.
> >> In the 2nd case, acpi_memory_device_remove() will be called.
> > 
> > Hi Yasuaki, Wen,
> > 
> > Why do you need to have separate code design & implementation for the
> > two cases?  In other words, can the 1st case simply use the same code
> > path of the 2nd case, just like I did for the CPU hot-remove patch
> > below?  It will simplify the code and make the memory notify handler
> > more consistent with other handlers.
> > https://lkml.org/lkml/2012/10/19/456
> 
> Yes, the 1st case can simply reuse the same code of the 2nd case.
> It is another issue. The memory is not offlined and removed in 2nd
> case. This patchset tries to fix this problem. After doing this,
> we can merge the codes for the two cases.
> 
> But there is some bug in the code for 2nd case:
> If offlining memory failed, we don't know such error in 2nd case, and
> the kernel will in a dangerous state: the memory device is poweroffed
> but the kernel is using it.
> 
> We should fix this bug before merging them.

Hi Wen,

Sounds good.  Thanks for the clarification!

-Toshi



> Thanks
> Wen Congyang
> 


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Re: [PATCH v3 0/3] acpi,memory-hotplug : implement framework for hot removing memory

[Rafael J. Wysocki]

On Friday, October 26, 2012 06:31:00 PM wency@cn.fujitsu.com wrote:
> From: Wen Congyang <wency@cn.fujitsu.com>
> 
> The patch-set implements a framework for hot removing memory.
> 
> 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
> 
> In the 1st case, acpi_memory_disable_device() will be called.
> In the 2nd case, acpi_memory_device_remove() will be called.
> acpi_memory_device_remove() will also be called when we unbind the
> memory device from the driver acpi_memhotplug or a driver initialization
> fails.
> 
> acpi_memory_disable_device() has already implemented a code which
> offlines memory and releases acpi_memory_info struct . But
> acpi_memory_device_remove() has not implemented it yet.
> 
> So the patch prepares the framework for hot removing memory and
> adds the framework into acpi_memory_device_remove().
> 
> The last version of this patchset is here:
> https://lkml.org/lkml/2012/10/19/156
> 
> Changelogs from v2 to v3:
>   Patch2: rename lock to list_lock
> 
> Changelogs from v1 to v2:
>   Patch1: use acpi_bus_trim() instead of acpi_bus_remove()
>   Patch2: new patch, introduce a lock to protect the list
>   Patch3: remove memory too when type is ACPI_BUS_REMOVAL_NORMAL
>   Note: I don't send [Patch2-4 v1] in this series because they
>   are no logical changes in these 3 patches.
> 
> Wen Congyang (2):
>   acpi,memory-hotplug: call acpi_bus_trim() to remove memory device
>   acpi,memory-hotplug: introduce a mutex lock to protect the list in
>     acpi_memory_device
> 
> Yasuaki Ishimatsu (1):
>   acpi,memory-hotplug : add memory offline code to
>     acpi_memory_device_remove()
> 
>  drivers/acpi/acpi_memhotplug.c | 51 +++++++++++++++++++++++++++++++++---------
>  1 file changed, 41 insertions(+), 10 deletions(-)

All patches in the series applied to the linux-next branch of the linux-pm.git
tree as v3.8 material.

Thanks,
Rafael


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.

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Re: [PATCH v3 0/3] acpi,memory-hotplug : implement framework for hot removing memory

[Andrew Morton]

On Fri, 02 Nov 2012 13:51:49 +0100
"Rafael J. Wysocki" <rjw@sisk.pl> wrote:

> On Friday, October 26, 2012 06:31:00 PM wency@cn.fujitsu.com wrote:
> > From: Wen Congyang <wency@cn.fujitsu.com>
> > 
> > The patch-set implements a framework for hot removing memory.
> > 
> > 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
> > 
> > In the 1st case, acpi_memory_disable_device() will be called.
> > In the 2nd case, acpi_memory_device_remove() will be called.
> > acpi_memory_device_remove() will also be called when we unbind the
> > memory device from the driver acpi_memhotplug or a driver initialization
> > fails.
> > 
> > acpi_memory_disable_device() has already implemented a code which
> > offlines memory and releases acpi_memory_info struct . But
> > acpi_memory_device_remove() has not implemented it yet.
> > 
> > So the patch prepares the framework for hot removing memory and
> > adds the framework into acpi_memory_device_remove().
> > 
> > The last version of this patchset is here:
> > https://lkml.org/lkml/2012/10/19/156
> > 
> > Changelogs from v2 to v3:
> >   Patch2: rename lock to list_lock
> > 
> > Changelogs from v1 to v2:
> >   Patch1: use acpi_bus_trim() instead of acpi_bus_remove()
> >   Patch2: new patch, introduce a lock to protect the list
> >   Patch3: remove memory too when type is ACPI_BUS_REMOVAL_NORMAL
> >   Note: I don't send [Patch2-4 v1] in this series because they
> >   are no logical changes in these 3 patches.
> > 
> > Wen Congyang (2):
> >   acpi,memory-hotplug: call acpi_bus_trim() to remove memory device
> >   acpi,memory-hotplug: introduce a mutex lock to protect the list in
> >     acpi_memory_device
> > 
> > Yasuaki Ishimatsu (1):
> >   acpi,memory-hotplug : add memory offline code to
> >     acpi_memory_device_remove()
> > 
> >  drivers/acpi/acpi_memhotplug.c | 51 +++++++++++++++++++++++++++++++++---------
> >  1 file changed, 41 insertions(+), 10 deletions(-)
> 
> All patches in the series applied to the linux-next branch of the linux-pm.git
> tree as v3.8 material.
> 

That merge made a big mess of some patches I had queued, so I dropped
them all:

acpi_memhotplugc-fix-memory-leak-when-memory-device-is-unbound-from-the-module-acpi_memhotplug.patch
acpi_memhotplugc-free-memory-device-if-acpi_memory_enable_device-failed.patch
acpi_memhotplugc-remove-memory-info-from-list-before-freeing-it.patch
acpi_memhotplugc-dont-allow-to-eject-the-memory-device-if-it-is-being-used.patch
acpi_memhotplugc-bind-the-memory-device-when-the-driver-is-being-loaded.patch
acpi_memhotplugc-auto-bind-the-memory-device-which-is-hotplugged-before-the-driver-is-loaded.patch

I merged these all the way back in July, actually.  I sent them to Len
in August to no effect and they've been sitting there since then.

If they're still relevant and needed then they will need to be redone,
retested and resent, sorry.

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