RE: RT patch acceptance

Sven Dietrich
2005-05-25T02:05:08Z

Esben Nielsen wrote:
> On Tue, 24 May 2005, Christoph Hellwig wrote:
>
> > On Mon, May 23, 2005 at 04:14:26PM -0700, Daniel Walker wrote:
> >
> > Personally I think interrupt threads, spinlocks as sleeping mutexes
> > and PI is something we should keep out of the kernel tree.
>
> A general threaded interrupt is not a good thing. Ingo made
> this to see how far he can press it. But having serial
> drivers running in interrupt is way overkill. Even network
> drivers can (provided they use DMA) run in interrupt without
> hurting the overall latencies. It all depends on the driver
> and how it interfaces with the rest of the kernel, especially
> what locks are shared and how long the lock are taken. If
> they are small enough, interrupt context and thus raw
> spinlocks are good enough. In general, I think each driver
> ought to be configurable: Either it runs in interrupt context
> or it runs in a thread. The locks have to be changed
> accordingly from raw spinlocks to mutexes.
>

You can run interrupts in threads without any mutex.

There is a /proc interface to switch between threads / mutex.