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SubjectRe: [RFC v8 PATCH 13/20] memory-hotplug: check page type in get_page_bootmem
On Tue, 28 Aug 2012 18:00:20 +0800
wency@cn.fujitsu.com wrote:

> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>
> There is a possibility that get_page_bootmem() is called to the same page many
> times. So when get_page_bootmem is called to the same page, the function only
> increments page->_count.

I really don't understand this explanation, even after having looked at
the code. Can you please have another attempt at the changelog?

> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -95,10 +95,17 @@ static void release_memory_resource(struct resource *res)
> static void get_page_bootmem(unsigned long info, struct page *page,
> unsigned long type)
> {
> - page->lru.next = (struct list_head *) type;
> - SetPagePrivate(page);
> - set_page_private(page, info);
> - atomic_inc(&page->_count);
> + unsigned long page_type;
> +
> + page_type = (unsigned long) page->lru.next;
> + if (page_type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
> + page_type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE){
> + page->lru.next = (struct list_head *) type;
> + SetPagePrivate(page);
> + set_page_private(page, info);
> + atomic_inc(&page->_count);
> + } else
> + atomic_inc(&page->_count);
> }

And a code comment which explains what is going on would be good. As
is always the case ;)



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