新手请教，mysqld经常自动关闭是什么原因？

错误日志如下：

61103 22:12:15 mysqld_safe Number of processes running now: 0
161103 22:12:15 mysqld_safe mysqld restarted
2016-11-03 22:12:18 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2016-11-03 22:12:18 17857 [Note] Plugin 'FEDERATED' is disabled.
2016-11-03 22:12:18 17857 [Note] InnoDB: Using atomics to ref count buffer pool pages
2016-11-03 22:12:18 17857 [Note] InnoDB: The InnoDB memory heap is disabled
2016-11-03 22:12:18 17857 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2016-11-03 22:12:18 17857 [Note] InnoDB: Memory barrier is not used
2016-11-03 22:12:18 17857 [Note] InnoDB: Compressed tables use zlib 1.2.3
2016-11-03 22:12:18 17857 [Note] InnoDB: Using Linux native AIO
2016-11-03 22:12:19 17857 [Note] InnoDB: Using CPU crc32 instructions
2016-11-03 22:12:19 17857 [Note] InnoDB: Initializing buffer pool, size = 128.0M
InnoDB: mmap(137363456 bytes) failed; errno 12
2016-11-03 22:12:19 17857 [ERROR] InnoDB: Cannot allocate memory for the buffer pool
2016-11-03 22:12:19 17857 [ERROR] Plugin 'InnoDB' init function returned error.
2016-11-03 22:12:19 17857 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2016-11-03 22:12:19 17857 [ERROR] Unknown/unsupported storage engine: InnoDB
2016-11-03 22:12:19 17857 [ERROR] Aborting