Date: Thu, 18 May 2000 23:19:32 -0600 From: Wes Peters <wes@softweyr.com> To: Chuck Paterson <cp@bsdi.com> Cc: Doug Rabson <dfr@nlsystems.com>, arch@FreeBSD.ORG Subject: Re: A new api for asynchronous task execution Message-ID: <3924CEE4.55551D82@softweyr.com> References: <200005181557.JAA05148@berserker.bsdi.com>
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Chuck Paterson wrote:
>
> }
> }Wouldn't it make more sense to provide an inversion-proof semaphore?
> }Or is that what they're doing?
>
> Not quite sure what you mean. The lock checking done
> now is to detect without actually having to have the deadlock
> occur the following
>
> thread 1 acquires lock "a" and then tries to acquire lock "b"
> thread 2 acquires lock "b" and then tries to acquire lock "a"
>
> There isn't really any automagic fix for this.
Ah, I misunderstood, this is a deadly embrace. There are automagic
fixes, but they get expensive REALLY fast. Still, it's a good
option to turn on for debugging.
> If you are talking about running processes in
> order based on scheduling priority, this is propagated
> though mutexs which have been blocked on.
No, speaking of temporarily elevating the priority of a process holding
a lock to the highest priority of all processes blocking on the lock.
--
"Where am I, and what am I doing in this handbasket?"
Wes Peters Softweyr LLC
wes@softweyr.com http://softweyr.com/
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