ps查看进程的stat状态

These are indeed the process states. Processes states that ps indicate are:

D Uninterruptible sleep (usually IO)R Running or runnable (on run queue)S Interruptible sleep (waiting for an event to complete)T Stopped, either by a job control signal or because it is being traced.W paging (not valid since the 2.6.xx kernel)X dead (should never be seen)Z Defunct ("zombie") process, terminated but not reaped by its parent.

and the additional characters are:

< high-priority (not nice to other users)N low-priority (nice to other users)L has pages locked into memory (for real-time and custom IO)s is a session leaderl is multi-threaded (using CLONE_THREAD, like NPTL pthreads do)+ is in the foreground process group