InnoDB: Fatal error: cannot allocate memory for the buffer pool (2 replies)

140922 9:30:55 [Warning] Using unique option prefix myisam-recover instead of myisam-recover-options is deprecated and will be removed in a future release. Please use the full$
140922 9:30:55 [Note] Plugin 'FEDERATED' is disabled.
140922 9:30:55 InnoDB: The InnoDB memory heap is disabled
140922 9:30:55 InnoDB: Mutexes and rw_locks use GCC atomic builtins
140922 9:30:55 InnoDB: Compressed tables use zlib 1.2.8
140922 9:30:55 InnoDB: Using Linux native AIO
140922 9:30:55 InnoDB: Initializing buffer pool, size = 128.0M
InnoDB: mmap(137363456 bytes) failed; errno 12
140922 9:30:55 InnoDB: Completed initialization of buffer pool
140922 9:30:55 InnoDB: Fatal error: cannot allocate memory for the buffer pool
140922 9:30:55 [ERROR] Plugin 'InnoDB' init function returned error.
140922 9:30:55 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
140922 9:30:55 [ERROR] Unknown/unsupported storage engine: InnoDB
140922 9:30:55 [ERROR] Aborting

140922 9:30:55 [Note] /usr/sbin/mysqld: Shutdown complete

top -c

Tasks: 109 total, 5 running, 104 sleeping, 0 stopped, 0 zombie
%Cpu(s): 75.8 us, 6.3 sy, 0.0 ni, 17.9 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem: 2049968 total, 1007952 used, 1042016 free, 24752 buffers
KiB Swap: 0 total, 0 used, 0 free. 251604 cached Mem

Happened for the first time yesterday and second time today. How can i fix it?