帮忙看下这个mysql出现了什么问题

[Note] Plugin 'FEDERATED' is disabled.
180505  8:48:01 InnoDB: The InnoDB memory heap is disabled
180505  8:48:01 InnoDB: Mutexes and rw_locks use GCC atomic builtins
180505  8:48:01 InnoDB: Compressed tables use zlib 1.2.3
180505  8:48:01 InnoDB: Using Linux native AIO
180505  8:48:01 InnoDB: Initializing buffer pool, size = 384.0M
InnoDB: mmap(412090368 bytes) failed; errno 12
180505  8:48:01 InnoDB: Completed initialization of buffer pool
180505  8:48:01 InnoDB: Fatal error: cannot allocate memory for the buffer pool
180505  8:48:01 [ERROR] Plugin 'InnoDB' init function returned error.
180505  8:48:01 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
180505  8:48:01 [ERROR] Unknown/unsupported storage engine: InnoDB
180505  8:48:01 [ERROR] Aborting
该怎么修改(吐槽卸载mysql需要删除所有数据库，删除数据库需要启动mysql,能启动mysql我还会去卸载么……脑壳疼的设计)

爆内存自动停止了mysql 你用的什么mysql版本？
另外不是有强行卸载命令么

内存占用很低mysql5.5在去年9月安装后除了控制面板升级其他没有改动。昨天出现问题之前升级了一下面板应该不搭噶而且在数据库无链接情况下会有mysql cpu占用200情况。且重启的五分钟内奔溃…最主要4G+2G虚拟，一个小站不应该出现故障内存爆满的情况吧

看了下服务器界面与记录内存在40%多mysql退出一次50多一次。请问把mysql更换成mariandb的会不会解决问题，以前四个月不间断运行没什么问题的