Messages in this thread | | | Date | Tue, 2 Nov 2004 09:02:36 +0100 | From | Ingo Molnar <> | Subject | Re: [Fwd: Re: [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0.4] |
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* Bill Huey <bhuey@lnxw.com> wrote:
> The lock chains aren't that deep in Linux so the algorithmic > complexity is not going to hit some crazy polynomial time unless > there's some seriously nasty contention at a certain point in the > kernel (billions of readers for example against a write aquire). But > when we start to see things like that under pressure is when we need > to start shortening the need for that/those lock(s) for that/those > critical section(s) in question.
also note that in the -U series i removed the true 'read' logic from semaphores. What we have now are single writers only, plus readers emulated as a writer plus the ability to self-recurse. ('writers' are not allowed to self-recurse.) This is quite close to the semantic needs of Linux rwlocks and rwsems and it simplified both locking, deadlock detection and PI quite significantly.
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