On 02/16/15 18:17, Dave Chinner wrote: > On Mon, Feb 16, 2015 at 11:35:50AM -0600, Mark Tinguely wrote: >> Thanks Michael, you don't need to hold your test box for me. I do >> have a way to recreate these ABBA AGF buffer allocation deadlocks >> and understand the whys and hows very well. I don't have a community >> way to make a xfstest for it but I think your test is getting close. > > If you know what is causing them, then please explain how it occurs > and how you think it needs to be fixed. Just telling us that you know > something that we don't doesn't help us solve the problem. :( > > In general, the use of the args->firstblock is supposed to avoid the > ABBA locking order issues with multiple allocations in the one > transaction by preventing AG selection loops from looping back into > AGs with a lower index than the first allocation that was made. > > So if you are seeing deadlocks, then it may be that we aren't > following this constraint correctly in all locations.... > > Cheers, > > Dave. Will this be a classic deadlock that will cause problems when trying to kill processes and unmount filesystems? If so, then I was unable to use generic/224 to trigger a deadlock. If not, then I'll need a better way of looking at the problem. The longest generic/224 loop lasted only 3-1/2 hours, though. The fstests enospc group was given some consideration as well. If this issue does not require a lot of files, I might see if fio can be helpful here. Hints on whether to us a fast kernel or a miserably slow kernel would be rather helpful. My test setup is torn because most of the recent warning messages are coming from the CONFIG_XFS_WARN kernels. The i686 Pentium 4 box will be left that way. However, the Core 2 box was configured per Documentation/SubmitChecklist from the kernel source, adding debug XFS and locktorture. The locktorture settings are in flux, exercising spinlocks at present. There was a mild halt in I/O for generic/017, but that was XFS waiting on kmem-something waiting on a kmemleak function. kmemleak was removed, and I'll continue from there. Thanks! Michael _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
