You know, the more and more we run into these problems specific to how reference counting is performed, I keep wondering whether some cleverly defined macros for dealing with common reference counting operations would be worthwhile. I'm not saying "introduce a refcount_t type and a full-blown abstraction," but some template-like stuff might be useful. It took a while just to get the refcount decrement on free path free of races on SMP, and that's only in the mbuf code.
-Bosko On Tue, Mar 01, 2005 at 03:14:38PM -0800, Kris Kennaway wrote: > On Tue, Mar 01, 2005 at 06:04:27PM -0500, Bosko Milekic wrote: > > > This does not appear to explain the livelock. > > alc and dwhite tracked it down to a missing volatile causing gcc to > mis-optimize the loop: > > - cnt = *(m->m_ext.ref_cnt); > + cnt = *(volatile u_int *)(m->m_ext.ref_cnt); > > I'm currently testing that. > > Kris -- Bosko Milekic [EMAIL PROTECTED] [EMAIL PROTECTED] _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "[EMAIL PROTECTED]"
