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From: dswartz@bigbootay.sw.stratus.com (Dan Swartzendruber)
Newsgroups: comp.os.mach
Subject: Re: interrupt and simple_locks
Message-ID: <4821@lectroid.sw.stratus.com>
Date: 5 Apr 91 00:24:52 GMT
References: <1991Apr3.184610.12580@m.cs.uiuc.edu> <4799@lectroid.sw.stratus.com> <1991Apr4.035548.25439@m.cs.uiuc.edu> <4813@lectroid.sw.stratus.com> <1991Apr4.225931.20534@ready.eng.ready.com>
Sender: usenet@lectroid.sw.stratus.com
Reply-To: dswartz@bigbootay.sw.stratus.com (Dan Swartzendruber)
Distribution: comp
Organization: Stratus Computer, Software Engineering.
Lines: 37

In article <1991Apr4.225931.20534@ready.eng.ready.com> buz@ready.com (Greg Buzzard) writes:
>
>In article <4813@lectroid.sw.stratus.com>, dswartz@bigbootay.sw.stratus.com (Dan Swartzendruber) writes:
:|: In article <1991Apr4.035548.25439@m.cs.uiuc.edu> rchen@m.cs.uiuc.edu (Rong Chen) writes:
:|: ...
:|: Just out of curiosity, how do you suggest that the interrupt handler
:|: "change the volatile structure" in kernel space in a multiprocessor
:|: environment when there are other threads of control trying to do the
:|: same thing?
:
:Certainly one possibility is to not expect the interrupt level code to
:"change the volatile structure" -- it could queue a request for a
:non-interrupt thread to do it.  If there is a synchronization
:"problem" the onus ought to be on the non-interrupt threads to "do the
:right thing"

Ummmm, just where is the interrupt level code supposed to queue this
request of yours?  And how is it supposed to arbitrate for access to
that queue with the non-interrupt thread which will be looking on
that queue for requests???  As an aside, are you seriously proposing
TWO contexts switches for every interrupt or page fault which occurs?

:-- 
:Greg Buzzard, Ph.D. 			internet:  buz@eng.ready.com
:Ready Systems
:470 Potrero Ave.			phone:     408/736-2600
:Sunnyvale, CA  94086
:-- 
:Greg Buzzard	 			internet:  buz@eng.ready.com
:Ready Systems
:470 Potrero Ave.			phone:     408/736-2600
:Sunnyvale, CA  94086


--

Dan S.