anonymous pages and memory from /proc/meminfo

$cat /proc/meminfo
MemTotal:        3495924 kB
MemFree:         1465276 kB
MemAvailable:    2353604 kB
Buffers:          126008 kB
Cached:           962924 kB
SwapCached:            0 kB
Active:          1330576 kB
Inactive:         452848 kB
Active(anon):     695532 kB
Inactive(anon):    29420 kB
Active(file):     635044 kB
Inactive(file):   423428 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:       7259132 kB
SwapFree:        7259132 kB
Dirty:               232 kB
Writeback:             0 kB
AnonPages:        694488 kB
Mapped:           291508 kB
Shmem:             30464 kB
Slab:              97912 kB
SReclaimable:      65988 kB
SUnreclaim:        31924 kB
KernelStack:        7808 kB
PageTables:        30060 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:     9007092 kB
Committed_AS:    3508024 kB
VmallocTotal:   34359738367 kB
VmallocUsed:           0 kB
VmallocChunk:          0 kB
HardwareCorrupted:     0 kB
AnonHugePages:         0 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
DirectMap4k:      198692 kB
DirectMap2M:     3432448 kB
DirectMap1G:           0 kB
$


https://blogs.oracle.com/cwb/entry/so_what_the_heck_is