Re: Documentation on top half and bottom halves

From: Arnd Bergmann
Date: Sat Dec 18 2004 - 09:17:09 EST

On Sünnavend 18 Dezember 2004 14:41, you wrote:
> How to understand when to use which mechanism depending upon the hardware:
> 1) If DMA support is not there and If it is there.
> 2) If Shared Interrupts are there and not there.
> 3) If there are multiple same Host controllers and single Host Controller.

It's independent of these questions. The decision between tasklet and
workqueue is mostly:

- If you need non-atomic operations (e.g. allocate memory with GFP_KERNEL),
you have to use work queues.
- If you need very low latencies for processing the interrupts, you should
use tasklets.
- When in doubt, use work queues.

Arnd <><

PS: pleas read

Attachment: pgp00000.pgp
Description: signature