Subj : Re: Deadlock theorem
To   : comp.programming.threads
From : doug
Date : Sun May 01 2005 09:46 pm

'fraid this is just standard 'semaphore hierarchy'.

"Uenal Mutlu" <520001085531-0001@t-online.de> wrote in message 
news:d532nd$kln$03$1@news.t-online.com...
> Theorem:
>   a) "There will be no deadlock if the objects are locked in the same 
> order."
>   b) "Unlocking can be done in any order."
>
> Some explanation:
> "Order" in this context means sequence.
> The theorem applies equally well to both sequential and parallel 
> processing
> (ie. threads, tasks, processes, coroutines etc.), and regardless of the 
> number
> of objects one wishes to lock in any of the parallel running units (aka 
> threads).
> That is: the objects designated for locking, and the number of them, can 
> be
> different in each thread; only the locking sequence (order) must be the 
> same in all threads.
>
> (If this theorem is new then I would like to give it the name "Mutlu 
> theorem" :-)
>
>
>
>
>

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