Date: Sun, 24 Sep 2000 20:38:56 -0700 (PDT) From: Matthew Jacob <mjacob@feral.com> To: Terry Lambert <tlambert@primenet.com> Cc: Brian Somers <brian@Awfulhak.org>, Greg Lehey <grog@wantadilla.lemis.com>, Chuck Paterson <cp@bsdi.com>, Archie Cobbs <archie@whistle.com>, Joerg Micheel <joerg@cs.waikato.ac.nz>, Frank Mayhar <frank@exit.com>, John Baldwin <jhb@pike.osd.bsdi.com>, Mark Murray <markm@FreeBSD.ORG>, FreeBSD-arch@FreeBSD.ORG Subject: Re: Mutexes and semaphores (was: cvs commit: src/sys/conf files Message-ID: <Pine.GSO.4.21.0009242036250.506-100000@bird.feral.com> In-Reply-To: <200009250330.UAA05163@usr05.primenet.com>
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> > This is easy: mark them non-reentrant. You can either acquire a > mutex on descent into them and release it on exit/sleep, or (and > this is better), have a per-module mutex that's acquired on the > descent/wakeup and released on the ascent, if the flag is present. > This will let the modules be corrected on a per FS and per CAM > driver basis, while maintaining legacy compatability. We do not > need another ethnic clensing of the drivers, such as what we went > through when CAM went in, or when the X.25 and ISODE stuff was > murdered. Hmm, but I sure don't want the pain of the 'unsafe_driver' mutex that Sun went thru. Still- your point has a lot of maerit. > > > > You're missing the point. If you're on Solaris, you are making a mistake in > > your coding if you're recursing. If you're on FreeBSD, then too many things > > have still to be redesigned to make that claim. > > I think he understands that, I just think he's unwilling to live > with a kludge, which will have no incentive to be de-kludged, as > it wouldn't actually not work. Whatever... :-) > > It's much better to be able to _know_ what code is OK and what > code isn't, instead of pretending that it's all OK, when it's not. Aw, that's not what I was getting at. I think getting the current set going should be allowed to proceed as is. If there is a roadmap for strengthening the semantics, great. Just don't make the bar too high at first. -matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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