DragonFly kernel List (threaded) for 2004-02
Re: lkwt in DragonFly
Matthew Dillon wrote:
:Your explanation is interesting, I am sorry that I am new to DFly,That's the thing I need, thanks !
:but if two threads on same CPU wants to exclusivly access a data
:structure, what lock should be used ? does token still work ? on
:FreeBSD, one can use mutex, but token is holden by CPU on DFly not by
:thread, so a thread really does not know if it already held the lock
:or not, although its CPU already hold the token.
If you want something that stays valid through a switch or a blocking
condition then you would need to use a lockmgr lock. If you just
need atomicy across a short period of time in which you know the
thread will not block, or in a situation where the code does the
right thing if another piece of code operates on the same
data structure while the first piece is blocked, then a token
would be sufficient.
And sorry a bit OT, what's the plan of pthread supports in DFly, I am
very interested to work on it in near future.