thp_size
BUG_ON(len < ceph_fscrypt_page_offset(page) + thp_size(page) - offset);
len += thp_size(page);
u64 min_len = len + 1 - thp_size(page);
if (end > ceph_fscrypt_page_offset(page) + thp_size(page))
end = ceph_fscrypt_page_offset(page) + thp_size(page);
size_t thp_size = read_pmd_pagesize();
if (!thp_size)
thp_size = TWOMEG;
thp_size / 4, /* quarter THP */
thp_size / 2, /* half THP */
thp_size, /* single THP */
thp_size * 2, /* two THPs */
thp_size * 4, /* four THPs */
thp_size * 8, /* eight THPs */
thp_size * 128, /* one twenty eight THPs */