Ubuntu – Swap Not available in system monitor

i make a swap partition with 5 GB but i notice always that it is marked as "not available" on the system monitor plus when i do operations consume the whole RAM ubuntu starts to kill to relief the RAM with no use at all for SWAP

i typed in terminal sudo mountall -v
and this what i get

mounted event handled for /proc/sys/fs/binfmt_misc
local 1/5 remote 0/0 virtual 1/12 swap 0/1
mounted event handled for /sys
local 1/5 remote 0/0 virtual 2/12 swap 0/1
mounted event handled for /sys/fs/fuse/connections
local 1/5 remote 0/0 virtual 3/12 swap 0/1
mounted event handled for /sys/kernel/security
local 1/5 remote 0/0 virtual 4/12 swap 0/1
mounted event handled for /dev/pts
local 1/5 remote 0/0 virtual 5/12 swap 0/1
mounted event handled for /run/lock
local 1/5 remote 0/0 virtual 6/12 swap 0/1
mounted event handled for /run/shm
local 1/5 remote 0/0 virtual 7/12 swap 0/1
mounted event handled for /home/ahmed/.gvfs
local 2/5 remote 0/0 virtual 7/12 swap 0/1
mounted event handled for /media/UbuntuGeneralFiles
local 3/5 remote 0/0 virtual 7/12 swap 0/1
mounted event handled for /media/ONCE\040AND\040FOR\040ALL
local 4/5 remote 0/0 virtual 7/12 swap 0/1
mounting event handled for /tmp
mounted event handled for /dev
local 4/5 remote 0/0 virtual 8/12 swap 0/1
mounted event handled for /proc
local 4/5 remote 0/0 virtual 9/12 swap 0/1
mounted event handled for /sys/kernel/debug
local 4/5 remote 0/0 virtual 10/12 swap 0/1
mounted event handled for /run
local 4/5 remote 0/0 virtual 11/12 swap 0/1
mounted event handled for /home/ahmed
virtual finished
remote finished
local 4/5 remote 0/0 virtual 12/12 swap 0/1
mounted event handled for /tmp
local finished
All filesystems mounted
local 5/5 remote 0/0 virtual 12/12 swap 0/1


this is fstab output

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    nodev,noexec,nosuid 0       0
# / was on /dev/sdf1 during installation
UUID=34c3c29b-e5dd-4ed7-a49b-616afded4704 /               ext4    errors=remount-ro 0       1
# swap was on /dev/sdf2 during installation
#UUID=9a7f0b9c-9be9-4074-8957-afcf25072bbe none            swap    sw              0       0
/dev/mapper/cryptswap1 none swap sw 0 0
/dev/disk/by-label/swap /mnt/swap auto nosuid,nodev,nofail 0 0
/dev/sdb2 /mnt/sdb2 ext4 nosuid,nodev,nofail 0 0

this is the output of sudo blkid
`

  /dev/sda1: UUID="AC9C59EA9C59B016" TYPE="ntfs" 
/dev/sda2: LABEL="System" UUID="C26CFB2E6CFB1C3B" TYPE="ntfs" 
/dev/sda3: LABEL="ONCE AND FOR ALL" UUID="3EF60BD0F60B86FD" TYPE="ntfs" 
/dev/sdb1: UUID="34c3c29b-e5dd-4ed7-a49b-616afded4704" TYPE="ext4" 
/dev/sdb2: LABEL="Swap" UUID="21cf04d1-6c18-4ab7-a8c3-ec435ab3f43e" TYPE="ext4" 
/dev/sdb5: LABEL="UbuntuGeneralFiles" UUID="E636244736241AD7" TYPE="ntfs" 
/dev/sr1: LABEL="Etisalat 3.5G" TYPE="iso9660" 

`
sudo fdisk -l:

Disk /dev/sda: 1000.2 GB, 1000203804160 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953523055 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0d91aeaa

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048      206847      102400    7  HPFS/NTFS/exFAT
/dev/sda2          206848   209717247   104755200    7  HPFS/NTFS/exFAT
/dev/sda3       209717248  1953519615   871901184    7  HPFS/NTFS/exFAT

Disk /dev/sdb: 250.1 GB, 250059350016 bytes
64 heads, 32 sectors/track, 238475 cylinders, total 488397168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000001

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1            2048   236331007   118164480   83  Linux
/dev/sdb2       236333056   244148221     3907583   82  Linux swap / Solaris
/dev/sdb3       244148222   488396799   122124289    5  Extended
/dev/sdb5       244148224   488396799   122124288    7  HPFS/NTFS/exFAT`

i dont know what is going on actually , so any help ?