hulk inclusion
category: feature
bugzilla: 48159
CVE: N/A

------------------------------

The old method calls get_user_pages_remote to collect physical pages.

The cost time of get_user_pages_remote is longer than 100ms
when dumping mysql server with large memory.

In order to reduce the cost time of collecting physical pages,
we collect the physical page info by reading the page table,
which can collect the physical pages within 100ms.

v1->v2:
- Improved return value check of pagemap_get.

v2->v3:
- Added new ioctl cmd "INIT_PAGEMAP_READ" for pagemapread initialization.
- Removed free operation of initialized pagemapread.

v3->v4:
- Clean code for physical page collecting method.
Signed-off-by: NJingxian He <hejingxian@huawei.com>
Reviewed-by: Jing Xiangfeng<jingxiangfeng@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>