From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Zick" Subject: Re: [parisc-linux] User space locks -- what's wrong Date: Sat, 10 Jun 2006 12:41:13 -0500 Message-ID: <200606101241.13801.mszick@morethan.org> References: <200606070409.k5749BK4009914@hiauly1.hia.nrc.ca> <200606070725.43473.mszick@morethan.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: parisc-linux@lists.parisc-linux.org Return-Path: In-Reply-To: <200606070725.43473.mszick@morethan.org> List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: parisc-linux-bounces@lists.parisc-linux.org On Wed June 7 2006 07:25, Michael S. Zick wrote: > On Tue June 6 2006 23:09, John David Anglin wrote: > > > > > > I've looked at the locking in hpux a bit. As far as I can tell, > > the kernel never really spins. It has code to do pre-arbitration > > and keeps track of tasks and priorities. When a lock is released, > > the code calls into suwaiters to see if the lock should be handed > > over to another task or released. When we just spin, we are relying > > on the bus arbitration to select a winner. So, when we have a > > highly contended lock, it might be possible for a cpu to get locked > > out for sufficient time to cause a softlockup. > > > > I never went back to correct the state tables in the document I worked > up to match the most recent code snippets... > > I will fix that and then post a link on this list. > Document is now updated. Intended to be a continuation of Dave's one spinlock per cache-line experimental patch. See: http://www.morethan.org/parisc/pa-spinlocks.html http://www.morethan.org/parisc/pa-spinlocks.pdf > > Right or wrong - that document gives us the ground work for lock passing > and lock failure recovery without ever having seen HPUX. > Document does not yet have pa-risc examples of lock passing and lock failure recovery - you need to consult the references made for those at this point. > > > Dave > > Mike Mike _______________________________________________ parisc-linux mailing list parisc-linux@lists.parisc-linux.org http://lists.parisc-linux.org/mailman/listinfo/parisc-linux