RE: RT patch acceptance

From: Sven Dietrich (sdietrich_at_mvista.com)
Date: 05/25/05

  • Next message: Andrew Morton: "Re: RT patch acceptance" 
    To: "'Esben Nielsen'" <simlo@phys.au.dk>, "'Christoph Hellwig'" <hch@infradead.org>
Date:	Tue, 24 May 2005 19:04:56 -0700

    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.

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