Re: [RFC v8 PATCH 08/20] memory-hotplug: remove /sys/firmware/memmap/X sysfs

[Wen Congyang <wency@cn.fujitsu.com>]

At 09/05/2012 07:16 AM, Andrew Morton Wrote:
> On Mon, 03 Sep 2012 13:51:10 +0800
> Wen Congyang <wency@cn.fujitsu.com> wrote:
> 
>>>> +static void release_firmware_map_entry(struct kobject *kobj)
>>>> +{
>>>> +	struct firmware_map_entry *entry = to_memmap_entry(kobj);
>>>> +	struct page *page;
>>>> +
>>>> +	page = virt_to_page(entry);
>>>> +	if (PageSlab(page) || PageCompound(page))
>>>
>>> That PageCompound() test looks rather odd.  Why is this done?
>>
>> Liu Jiang and Christoph Lameter discussed how to find slab page
>> in this mail:
>> https://lkml.org/lkml/2012/7/6/333.
> 
> Well, please add a code comment to release_firmware_map_entry() which
> fully explains these things.
> 
> I see that Christoph and I agree: "It would be cleaner if memory
> hotplug had an indicator which allocation mechanism was used and would
> use the corresponding free action".  You didn't respond to this
> suggestion when he made it, nor when I made it.  What are your thoughts
> on this?

Hmm, I think it is better to use an indicator which allocation mechanism was
used. I will do it in the next version.

Thanks
Wen Congyang