spinlock semantics

Nuno Antunes nuno.antunes at gmail.com
Sun Feb 17 08:49:54 PST 2008


While reading about DragonFlys locking primitives in a quest to try to
understand which kind of lock best applies in each situation, I found
the following at the spinlock(9) manpage.

"If you wish to disable FAST interrupts and IPIs you need to enter a
critical section prior to obtaining the spinlock."

But then, on the mailing list archive, I found a message [1] where one
can read the following with regards to spinlocks:

"Automatically enters a critical section."

So, naturally, my question is which statement is true? Looking at the
implementation, i don't see any calls to crit_* there, so I assume
that the manpage is correct.


[1] http://leaf.dragonflybsd.org/mailarchive/kernel/2006-11/msg00026.html

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