Date: Wed, 16 Jul 1997 15:59:26 -0600 From: Steve Passe <smp@csn.net> To: Terry Lambert <terry@lambert.org> Cc: smp@FreeBSD.ORG, peter@spinner.dialix.com.au, dyson@FreeBSD.ORG Subject: Re: pushdown of "giant lock" Message-ID: <199707162159.PAA10171@Ilsa.StevesCafe.com> In-Reply-To: Your message of "Wed, 16 Jul 1997 14:37:42 PDT." <199707162137.OAA01575@phaeton.artisoft.com>
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Hi, > 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... -- Steve Passe | powered by smp@csn.net | Symmetric MultiProcessor FreeBSD
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