From: Keith Owens <kaos@melbourne.sgi.com>
To: Ralf Baechle <ralf@oss.sgi.com>
Cc: linux-mips@oss.sgi.com, linux-mips@fnet.fr
Subject: Re: sysmips syscall
Date: Sun, 19 Nov 2000 00:46:19 +1100 [thread overview]
Message-ID: <23098.974555179@ocs3.ocs-net> (raw)
In-Reply-To: Your message of "Sat, 18 Nov 2000 11:59:09 BST." <20001118115909.D8672@bacchus.dhis.org>
On Sat, 18 Nov 2000 11:59:09 +0100,
Ralf Baechle <ralf@oss.sgi.com> wrote:
>You can base a spinlock implementation on the fact that the register k0
>will be left at a value != zero after any exception, also including context
>switches.
>
>Problem: this solution breaks silently on multiproessor systems.
Use Dekker's algorithm between systems. It requires cache coherent
memory but does not need any inter cpu locking mechanisms.
http://www.cs.wvu.edu/~jdm/classes/cs356/notes/mutex/Dekker.html
describes the algorithm for the two cpu case. It assumes no preemption
on each cpu so it has to be modified to handle interrupts. Add a local
lock so you are the only code on this processor trying to use Dekker
between processors.
next prev parent reply other threads:[~2000-11-18 13:47 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2000-11-18 1:28 sysmips syscall rajesh.palani
2000-11-18 1:28 ` rajesh.palani
2000-11-18 10:59 ` Ralf Baechle
2000-11-18 13:46 ` Keith Owens [this message]
2000-11-18 14:13 ` Ralf Baechle
2000-11-18 17:26 ` Alan Cox
2000-11-18 17:26 ` Alan Cox
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