svn commit: r253996 - in head: . sys/cddl/compat/opensolaris/sys sys/cddl/dev/dtrace sys/conf sys/modules/cyclic sys/modules/dtrace/dtio sys/modules/dtrace/dtmalloc sys/modules/dtrace/dtnfscl sys/m...

[Andriy Gapon]

on 09/08/2013 18:48 David O'Brien said the following:
> On Tue, Aug 06, 2013 at 03:51:56PM +0000, Andriy Gapon wrote:
>> Log:
> ..
>>   Also, meaning of DEBUG was overloaded to enable WITNESS support for some
>>   OpenSolaris (primarily ZFS) locks.  Now this overloading is removed and
>>   that use of DEBUG is replaced with a new option OPENSOLARIS_WITNESS.
> 
> You state there is little value in witness tracking for ZFS in UPDATING.

That's not completely true.  If there is a new report then it deserves
attention.  The problem is that there are just too many reports.  So probably
only someone hacking on ZFS and knowing where to look / what to suspect can
benefit from OPENSOLARIS_WITNESS.

> Is there no reasonable way to gain useful lock tracking for ZFS?

Honestly - I don't know.

> At a minimum, shouldn't this also be added to sys/conf/NOTES in the
> "# SMP Debugging Options:" section?

This commit has not changed status quo.
But what you suggest does make sense.

-- 
Andriy Gapon