Re: DragonFly site

[Erik Wikström <erik-wikstrom@xxxxxxxxx>]

On 2006-04-01 05:50, Trevor Kendall wrote:
> Hi,
>
> On the site I have noticed a number of issues. Most are easily fixed,
> but I'm not sure about this one.
>
> On http://www.dragonflybsd.org/docs/goals.cgi
> Serializing tokens may also be used to protect threads from preempting
> interrupts that attempt to obtain the same token. This is a slightly
> different effect from the Big Giant Lock (also known as the MP lock),
> which does not interlock against interrupts on the same cpu. It is
> important to note that token atomicity is maintained through
> preemptive conditions, even though preemption involves a temporary
> switch to another thread. It is not necessary to enter a spl() level
> or critical section to preserve token atomicity.
>
> Weren't the spl set of functions removed?

Yes, since they are no longer necessary, just as it says. As I 
understand things the above text explains the difference between using 
serializing tokens and BGL when dealing with preemption, and says that 
with tokens there is not need for spl().

--
Erik Wikström


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