About interrupt handler

[Dave Hylands]

Hi cheneydeng,

2012/2/22 cheneydeng <cheneydeng at qq.com>:
> hi all,
>      I'm begin to learn the Kernel and i'm reading <<Linux kernel
> development>>.It says "This is an important point, always keep in mind that
> all interrupt handler has interrupted other code(possibly even another
> interrupt handler on a different line)".What i am not able to understand is
> how a interrupt handler be interrupted ? DID NOT it uninterrupted?

It depends on the architecture and the interrupt controller being
used, and the driver code itself.

Normally, when an interrupt fires, that particular interrupt will be
masked and your own handler won't interrupt itself, but you may very
well be interrupted by other interrupts.

It is possible to arrange things so that your interrupt handler
interrupts itself, although you need to be really careful when doing
this as if your interrupt fires too quickly things can escalate out of
control pretty quickly.

-- 
Dave Hylands
Shuswap, BC, Canada
http://www.davehylands.com