Date: Wed, 27 Sep 2000 00:47:56 -0700 From: Mike Smith <msmith@freebsd.org> To: Julian Elischer <julian@elischer.org> Cc: arch@FreeBSD.ORG Subject: Re: Mutexes and semaphores Message-ID: <200009270747.e8R7luA03450@mass.osd.bsdi.com> In-Reply-To: Your message of "Wed, 27 Sep 2000 00:43:05 PDT." <Pine.BSF.4.10.10009270022290.13148-100000@InterJet.elischer.org>
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> The point that was brought up a little while ago is more germaine to the
> discussion:
>
> Is there any documentation regarding the interaction between "lock
> manager" and the mutexes? There appears now to be several different
> sets of locking code in the kernel and I'm getting thoroughly confused in
> my efforts to try 'catch up' with what's going on in the SMP
> world..
You're correct, it is germane.
The simple answer is that right now, there is essentially no
documentation. There needs to be focussed discussion on the topic you
raise, and many others.
Note that the lock manager is responsible for broking relatively
long-term locks on filesystem objects, whilst mutexes are used for
protecting critical paths or data structures. They're largely (but not
entirely) orthagonal. It would be to your advantage to look at how the
BSD/OS code has been altered, to get a feel for one possible way of doing
it.
--
... every activity meets with opposition, everyone who acts has his
rivals and unfortunately opponents also. But not because people want
to be opponents, rather because the tasks and relationships force
people to take different points of view. [Dr. Fritz Todt]
V I C T O R Y N O T V E N G E A N C E
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