On Thu, Oct 11, 2018 at 03:28:15PM +0300, Nikolay Borisov wrote: > > I noticed that there is a macro called SCRAMBLE_DELAYED_REFS in the > > extent-tree.c. I am a bit curious whether it has been forgotten by > > everyone, I have not found any test results about its performance impact. > > I guess it was used during testing but nothing currently sets it. I.e it > might make sense to enable it if BTRFS_DEBUG is set.
Agreed, the way the scrambling is supposed to be used does not align very well with the typical testing workflow so adding to ti the BTRFS_DEBUG set is ok, unless there are severe performance problems. The part in btrfs_run_delayed_refs would be better hidden in a function similar to btrfs_debug_check_extent_io_range or btrfs_leak_debug_check.
