ZFS_DEBUG + enable ZFS ASSERTS with INVARIANTS any objections?

[Steven Hartland]

----- Original Message ----- 
From: "Andriy Gapon" <avg at FreeBSD.org>
>>> on 26/07/2013 17:09 Steven Hartland said the following:
>>>> I tried an alternative version (attached) based on Justin's feedback,
>>>> which but enables DEBUG in all opensolaris modules when INVARIANTS is in
>>>> effect.
>>>>
>>>> Unfortunately it results in all the LOR being printed so I'm not a fan
>>>> TBH, I prefer the option to enable ASSERTS ony by changing debug.h
>>>
>>> Hmm, I am not sure what exactly is the problem...
>>> LOR detection and reporting is controlled by WITNESS, as I understand, and
>>> WITNESS is orthogonal to INVARIANTS.
>> 
>> I believe theirs a connection between DEBUG and LOR reporting, specificaly
>> in rwlock.h when not under DEBUG RW_FLAGS includes SX_NOWITNESS.
> 
> ( I guessed that you mean sys/cddl/compat/opensolaris/sys/rwlock.h of all
> rwlock.h files under sys/)
> 
> Yes.  But I mean that if you don't have WITNESS in the first place, then you
> don't get any LOR reports.  And if you have WITNESS you should expect that ZFS
> is covered too.
> 
> On the other hand, I also think that DEBUG should not have grown any new
> meanings during porting.  E.g. in your example it should have been something
> like ZFS_WITNESS or OPENSOLARIS_WITNESS, but not DEBUG, because DEBUG already
> had specific meaning for osol code.  I think that this should be fixed as well.

That may be the best solution. The problem with LOR reporting in ZFS, from what
pjd said, is that the LOR's are false positives and there's a lot of them hence
why they are only reported under DEBUG.

    Regards
    Steve

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