On Mon, Dec 13, 2010 at 03:44:39PM +1100, Dave Chinner wrote: > From: Dave Chinner <dchinner@xxxxxxxxxx> > > log->l_tail_lsn is currently protected by the log grant lock. The > lock is only needed for serialising readers against writers, so we > don't really need the lock if we make the l_tail_lsn variable an > atomic. Converting the l_tail_lsn variable to an atomic64_t means we > can start to peel back the grant lock from various operations. > > Also, provide functions to safely crack an atomic LSN variable into > it's component pieces and to recombined the components into an > atomic variable. Use them where appropriate. > > This also removes the need for explicitly holding a spinlock to read > the l_tail_lsn on 32 bit platforms. I know I suggested this, but I think the atomic read of l_tail_lsn in xlog_space_left might be problemetic for the call from xlog_grant_push_ail, where we read it twice now. Maybe split xlog_space_left into a __xlog_space_left that gets the already cracked values, and xlog_space_left as a wrapper around it? _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
