On Tue, Sep 12, 2017 at 09:38:20AM -0600, Ross Zwisler wrote: > On Tue, Sep 12, 2017 at 04:44:11PM +1000, Dave Chinner wrote: > > On Fri, Sep 08, 2017 at 03:21:53PM -0600, Ross Zwisler wrote: > > > This adds a regression test for the following kernel patch: > > > > > > xfs: always use DAX if mount option is used > > > > > > This test will also pass with kernel v4.14-rc1 and beyond because the XFS > > > DAX I/O mount option has been disabled (but not removed), so the > > > "chattr -x" to turn off DAX doesn't actually do anything. > > > > > > Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> > > > Suggested-by: Christoph Hellwig <hch@xxxxxxxxxxxxx> > > ..... > > > +pgsize=`$here/src/feature -s` > > > + > > > +# disable tracing, clear the existing trace buffer and turn on dax tracepoints > > > +echo 0 > /sys/kernel/debug/tracing/tracing_on > > > +echo > /sys/kernel/debug/tracing/trace > > > +echo 1 > /sys/kernel/debug/tracing/events/fs_dax/enable > > > + > > > +# enable tracing for our one mmap I/O, then see if dax was used > > > +echo 1 > /sys/kernel/debug/tracing/tracing_on > > > +xfs_io -t -c "truncate $pgsize" \ > > > + -c "chattr -x" \ > > > + -c "mmap -r 0 $pgsize" -c "mread 0 $pgsize" -c "munmap" \ > > > + -f $SCRATCH_MNT/testfile >> $seqres.full > > > +echo 0 > /sys/kernel/debug/tracing/tracing_on > > > > So what happens when the user is already tracing the test to > > find a bug and the test turns all their tracing off? > > > > Regardless of this screwing up developer bug triage, do we really > > want to add a dependency on kernel tracing into the test harness? > > Yep, these are both valid concerns. I ended up trying to get around both of > them by using perf instead in my v2, as suggested by Dan: > > https://www.spinics.net/lists/linux-xfs/msg10420.html I think similar concerns exist with using perf, too.... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
