進程描述符

每個進程描述符都包括幾個與調度相關的字段，如下代碼所示：

//include/asm-arm/thread_info.h
/** low level task data that entry.S needs immediate access to.* __switch_to() assumes cpu_context follows immediately after cpu_domain.*/
struct thread_info {
//存放TIF NEED RESCHED標志，如果必須調用調度程序，則設置該標志 unsigned long		flags;		/* low level flags */
..