On Mon, 2011-08-08 at 16:40 +1000, Dave Chinner wrote: > From: Dave Chinner <dchinner@xxxxxxxxxx> > > There is no need to grab the i_mutex of the IO lock in exclusive > mode if we don't need to invalidate the page cache. Taking these > locks on every direct IO effective serialises them as taking the IO > lock in exclusive mode has to wait for all shared holders to drop > the lock. That only happens when IO is complete, so effective it > prevents dispatch of concurrent direct IO reads to the same inode. > > Fix this by taking the IO lock shared to check the page cache state, > and only then drop it and take the IO lock exclusively if there is > work to be done. Hence for the normal direct IO case, no exclusive > locking will occur. > > Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx> > Tested-by: Joern Engel <joern@xxxxxxxxx> Looks good. Reviewed-by: Alex Elder <aelder@xxxxxxx> _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
