title: DirectMap1G display a wired huge number
body: <p>I don't set any hugepages in the system. why direct mapping has a weired value
  DirectMap4k:      251600 kB
  DirectMap2M:     5941248 kB
  DirectMap1G:    130023424 kB</p>
  
  <p>Look at the cmdline, no hugepages specified. also the runtime hugepages, only 2M hugepage entries in the directory, and nothing specified.</p>
  
  <pre><code># cat /proc/cmdline 
  BOOT_IMAGE=/vmlinuz-3.11.0-26-generic root=UUID=7e5b93c9-ace5-4a9d-8623-c6718a2d720a ro console=ttyS0,9600 console=tty0 rootdelay=90 nomodes
  
  _hugepages 3:~# cat /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr 
  0                                               ^C
  _hugepages 3:~# cat /sys/devices/system/node/node1/hugepages/hugepages-2048kB/nr 
  0
  
  # free -k
               total       used       free     shared    buffers     cached
  Mem:     131911116   43668088   88243028          0     202272    2004796
  -/+ buffers/cache:   41461020   90450096
  Swap:      3999740          0    3999740
  
  
  
  # cat /proc/meminfo 
  MemTotal:       131911116 kB
  MemFree:        87704076 kB
  Buffers:          202272 kB
  Cached:          2004444 kB
  SwapCached:            0 kB
  Active:         38864132 kB
  Inactive:        1784416 kB
  Active(anon):   38441104 kB
  Inactive(anon):     7924 kB
  Active(file):     423028 kB
  Inactive(file):  1776492 kB
  Unevictable:        8384 kB
  Mlocked:            8384 kB
  SwapTotal:       3999740 kB
  SwapFree:        3999740 kB
  Dirty:               120 kB
  Writeback:             0 kB
  AnonPages:      38450956 kB
  Mapped:            29576 kB
  Shmem:               760 kB
  Slab:            1441772 kB
  SReclaimable:     184536 kB
  SUnreclaim:      1257236 kB
  KernelStack:       11632 kB
  PageTables:       146568 kB
  NFS_Unstable:          0 kB
  Bounce:                0 kB
  WritebackTmp:          0 kB
  CommitLimit:    69955296 kB
  Committed_AS:   81453204 kB
  VmallocTotal:   34359738367 kB
  VmallocUsed:      721460 kB
  VmallocChunk:   34291709228 kB
  HardwareCorrupted:     0 kB
  AnonHugePages:   5980160 kB
  HugePages_Total:       0
  HugePages_Free:        0
  HugePages_Rsvd:        0
  HugePages_Surp:        0
  Hugepagesize:       2048 kB
  DirectMap4k:      251600 kB
  DirectMap2M:     5941248 kB
  **DirectMap1G:    130023424 kB**
  </code></pre>