linux-kernel - RE: [PATCH] X86/acpi: remove redundant logic of acpi memory hotadd

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Date:	Wed, 12 Dec 2012 14:37:09 +0000
From:	"Liu, Jinsong" <jinsong.liu@...el.com>
To:	Wen Congyang <wency@...fujitsu.com>,
	"Rafael J. Wysocki" <rjw@...k.pl>
CC:	Toshi Kani <toshi.kani@...com>,
	"Wysocki, Rafael J" <rafael.j.wysocki@...el.com>,
	"lenb@...nel.org" <lenb@...nel.org>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Jiang Liu <jiang.liu@...wei.com>
Subject: RE: [PATCH] X86/acpi: remove redundant logic of acpi memory hotadd

Wen Congyang wrote:
> At 12/08/2012 06:19 AM, Rafael J. Wysocki Wrote:
>> On Tuesday, December 04, 2012 01:39:54 AM Liu, Jinsong wrote:
>>> Resend it, add Rafael and linux-acpi@...r.kernel.org
>> 
>> I wonder what memory hotplug people think about that.
>> 
>> Thanks,
>> Rafael
>> 
>> 
>>> ===============
>>> From 1d39279e45c54ce531691da5ffe261e7689dd92c Mon Sep 17 00:00:00
>>> 2001 
>>> From: Liu Jinsong <jinsong.liu@...el.com>
>>> Date: Wed, 14 Nov 2012 18:52:06 +0800
>>> Subject: [PATCH] X86/acpi: remove redundant logic of acpi memory
>>> hotadd 
>>> 
>>> When memory hotadd, acpi_memory_enable_device has already been done
>>> at drv->ops.add (acpi_memory_device_add), no need to do it again
>>> at notify callback.
>>> 
>>> At acpi_memory_enable_device, acpi_memory_get_device_resources
>>> is also a redundant action, since it has been done at drv->ops.add.
>>> 
>>> Signed-off-by: Liu Jinsong <jinsong.liu@...el.com>
>>> ---
>>>  drivers/acpi/acpi_memhotplug.c |   17 -----------------
>>>  1 files changed, 0 insertions(+), 17 deletions(-)
>>> 
>>> diff --git a/drivers/acpi/acpi_memhotplug.c
>>> b/drivers/acpi/acpi_memhotplug.c 
>>> index 24c807f..a6489fd 100644
>>> --- a/drivers/acpi/acpi_memhotplug.c
>>> +++ b/drivers/acpi/acpi_memhotplug.c
>>> @@ -220,15 +220,6 @@ static int acpi_memory_enable_device(struct
>>>  	acpi_memory_device *mem_device) struct acpi_memory_info *info;
>>>  	int node;
>>> 
>>> -
>>> -	/* Get the range from the _CRS */
>>> -	result = acpi_memory_get_device_resources(mem_device);
>>> -	if (result) {
>>> -		printk(KERN_ERR PREFIX "get_device_resources failed\n");
>>> -		mem_device->state = MEMORY_INVALID_STATE;
>>> -		return result;
>>> -	}
>>> -
>>>  	node = acpi_get_node(mem_device->device->handle);  	/*
>>>  	 * Tell the VM there is more memory here...
>>> @@ -357,14 +348,6 @@ static void
>>>  		acpi_memory_device_notify(acpi_handle handle, u32 event, void
>>> *data)  			break; } 
>>> 
>>> -		if (acpi_memory_check_device(mem_device))
>>> -			break;
> 
> Hmm, if acpi_memory_check_device() fails, it means the memory device
> disappears 
> I don't know if a real hardware uses this way to remove memory device.
> 
>>> -
>>> -		if (acpi_memory_enable_device(mem_device)) {
>>> -			printk(KERN_ERR PREFIX "Cannot enable memory device\n");
>>> -			break;
>>> -		}
> 
> If acpi_memory_get_device() doesn't fail, it means that the device
> has been managed by this driver, so I think we can do this cleanup.
> 
> Thanks
> Wen Congyang
> 

Thanks! any comments from Huawei side, Jiang?


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