On Wed, Jun 13, 2007 at 10:23:36AM -0700, [EMAIL PROTECTED] wrote: > On Wed, 13 Jun 2007, Joerg Sonnenberger wrote: > > Should I briefly lock (flock) the file when running open/fstat/fchmod then > to avoid issues? This may become a problem as pkg_*/make becomes more > parallelized (another student's goals for his SoC project).
I wouldn't bother. What issue are you trying to avoid? If one process is trying to chmod +x and another is trying to do a chmod -x, it shouldn't matter if you lock between the fstat/fchmod-- someone is going to win anyway. This operation is not something that needs to be thread-safe. > Needless to say, pkg_* is by no means threadsafe in its current form > though. It uses some global vars that are currently not mutex locked, and > this type of file access is another issue (I wonder if spinlocking or > sleeping waiting for flock to finish would be better in this case). Does pkg_* use multiple threads? I was under the impression each pkg tool used a single thread (i.e. no threads) to do its operations and that they wait for system(2)-type calls as needed. Maybe I'm not clear by what you mean when you say "global vars". Now another question is whether the pkg_* tools can handle multiple processes managing the ports at the same time. For the mostpart, this is true. Without looking at the code, I would expect that the only contentions would be when trying to update the +REQUIRED_BY files. Everything else should be just fine; you're not supposed to be installing the same port multiple times at the exact same time, but maybe a lock could be held on the package directory (i.e. /var/db/pkg/$PKG_NAME). Again, I don't believe this is strictly necessary. -- Rick C. Petty _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
