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From: mitchalsup@aol.com (MitchAlsup1)
Newsgroups: comp.arch
Subject: Re: MSI interrupts
Date: Wed, 26 Mar 2025 00:56:27 +0000
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On Tue, 25 Mar 2025 22:19:07 +0000, Dan Cross wrote:

> In article <e4ecfb53ef4f33f10b6d2548d5930159@www.novabbs.org>,
> MitchAlsup1 <mitchalsup@aol.com> wrote:
>
>>> Your stuff sounds fine for getting into the critsec; but it
>>> doesn't help you once you're in it, and it seems like it may
>>> hurt you if some higher-priority thing comes along and yanks
>>> your lock out from under you.
>>
>>I conceded that point at least 2 days ago.
>
> Ok, now we're back to the question then: what purpose does it
> serve?

You (well Chris) can write critical sections where a low priority
holder can give way to the higher priority requestor such that
the low priority holder reverts back to before it entered CS,
and does not see the lock being stolen.

For the sizes of CSs this covers--it prevent priority inversion.

>        It doesn't seem like it can be usefully applied to
> anything other than building traditional mutexes based on spin
> locks, and even then I'm not sure if that's correct (see above).

And here I thought you had an imagination .....

> 	- Dan C.