DB21018E DB2 CLP cannot start

DB2 CLP refused to start after I killed some db2 processes. And finally I found this error from db2diag.log. Actually db2 and db2bp use message queue to communicate. And somehow all queues (16) are all used. use command "ipcs -qp" to show the current message queues

2011-12-29-05.01.05.656543-480 E46743E405          LEVEL: Severe (OS)
PID     : 29100                TID  : 47033606104272PROC : db2
INSTANCE: db2c97               NODE : 000
FUNCTION: DB2 UDB, oper system services, sqloexec, probe:20
MESSAGE : ZRC=0x870F00F2=-2029059854=SQLO_NORES
          "no resources to create process or thread"
CALLED  : OS, -, msgget                           OSERR: ENOSPC (28)

You can use "ipcrm -q msgid" to remove them. After removing all those message queues, db2 CLP starts.