Jenix ’s Blog - My name is Park, Jin Hyung :)

> 1, how does need_resched() work? I dont understand how the test_bit()
> called inside is doing

The bit can get set from interrupt context. All test_bit() does
is test if the bit is set.

> 2, how does default_idle work? what does it do? what does halt mean?

Halt basically tells the CPU to do nothing until something happens,
eg. an interrupt. This makes the CPU consume less power, yields the
hyperthread’s resources to the other thread, etc…

> 3, if once the cpu goes into idle with the while(1)-loop, will it be very
> busy (100% cpu utility) with looping around ??

Kind-of - if the cpu supports halt, it’ll actually get “stuck”
in that instruction until an interrupt happens.

> thx for helping….

Success with your homework

오늘 Kernel-Newbies Mailling list 에 posting 된 글인데요.
찬찬히 읽어보고 있는데, 마지막이 압권이군요.
thx for helping… -> Success with your homework

음.. 그런데 test_bit() 이 무엇을 하는거지..
빨랑 시험이 끝났으면 좋겠네요. 2.6 스케쥴링 포팅하기. 와와~