一开始是
------ Shared Memory Segments -------- key shmid owner perms bytes nattch status 0x00000000 0 root 600 134217728 129 dest 0x4405004b 32769 gyf 666 84032 1
ipcrm -M 0x4405004b 后变成
------ Shared Memory Segments -------- key shmid owner perms bytes nattch status 0x00000000 0 root 600 134217728 129 dest 0x00000000 32769 gyf 666 84032 1 dest
原因，还有进程占用着该共享内存，必须关闭该进程才会彻底清除