Date: Mon, 28 Apr 1997 21:08:15 +0200 (MET DST) From: Ingo Molnar <mingo@pc5829.hil.siemens.at> To: Terry Lambert <terry@lambert.org> Cc: Chris Csanady <ccsanady@nyx.pr.mcs.net>, black@zen.cypher.net, chuckr@mat.net, FreeBSD-SMP@freebsd.org Subject: Re: SMP Message-ID: <Pine.LNX.3.95.970428210208.16129A-100000@pc5829.hil.siemens.at> In-Reply-To: <199704281741.KAA02151@phaeton.artisoft.com>
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On Mon, 28 Apr 1997, Terry Lambert wrote: > > Actually, linux has moved to a slightly finer grain system. Now they > > have seperate locks for the run queues, scheduler, and some other > > things.. > This is not much of a symmetry win; it also isn't a scalable win if > they don't place the locks in a hierarchical relationship. Without > that change, they are subject to deadly embrace deadlocks if they get > any more complex in their locking structure. what kind of deadlocks do you picture. We only have spinlocks in Linux and we disallow scheduling with held spinlocks. [thus you can think of those locks like atomic operations]. There isnt much to be done wrong there. Anything that gets out of the big kernel lock is done via totally parallel code and spinlocks after that. [ and resource locking is just done the same way like on uniprocessor Linux, on a per-object basis ] -- mingo
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