Date: Wed, 16 Jul 1997 15:10:57 -0700 (MST) From: Terry Lambert <terry@lambert.org> To: smp@csn.net (Steve Passe) Cc: terry@lambert.org, smp@FreeBSD.ORG, peter@spinner.dialix.com.au, dyson@FreeBSD.ORG Subject: Re: pushdown of "giant lock" Message-ID: <199707162210.PAA01775@phaeton.artisoft.com> In-Reply-To: <199707162159.PAA10171@Ilsa.StevesCafe.com> from "Steve Passe" at Jul 16, 97 03:59:26 pm
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> > The ONLY issue I have with this proposed implementation is "what > > happens if...": > > > > A) getSYS_mplock > > B) getTRAP_mplock > > A) getTRAP_mplock << BLOCK > > B) getSYS_mplock << DEADLOCK > > this wont happen as B would block on getTRAP_mplock (A holds GL). so the > following A wont block, no deadlock. this assummes the 1st step, ie both > SYS & TRAP continue to use the GL. > > When we take the next step and make SYS/TRAP MP-safe we may need to make them > completely MP-safe in one step to avoid some deadlock issues... Yes, this is the occasion I meant; using one lock from three macros is not a very interesting case. ;-). Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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