svn commit: r272032 - head/sys/conf

[Bryan Drewery]

On 9/23/2014 1:20 PM, Konstantin Belousov wrote:
> On Tue, Sep 23, 2014 at 05:04:21PM +0000, Bryan Drewery wrote:
>> Author: bdrewery
>> Date: Tue Sep 23 17:04:21 2014
>> New Revision: 272032
>> URL: http://svnweb.freebsd.org/changeset/base/272032
>>
>> Log:
>>   DEBUG_LOCKS no longer modifies 'struct vnode', nor does fstat(1) use it.
>>   fstat(1) now uses libprocstat(9).  There is no userland impact to using this.
> 
> DEBUG_VFS_LOCKS does modify KBI of VFS, by adding struct stack to
> lockmgr, and lockmgr is embedded into each struct vnode.
> 
> VFS modules, in particular, filesystems, compiled for mismatched
> kernel WRT DEBUG_VFS_LOCKS, would cause strange breakage.

Well, perhaps the comment needs to be updated to state that
DEBUG_VFS_LOCKS modifies VFS KBI so any VFS modules will need to recompiled.

I did see the stack was moved to lockmgr, but given the use of
libprocstat, and lockmgr being a kernel struct, I don't think it's worth
mentioning userland here.

Sound good?

> 
>>   
>>   MFC after:	3 days
>>
>> Modified:
>>   head/sys/conf/NOTES
>>
>> Modified: head/sys/conf/NOTES
>> ==============================================================================
>> --- head/sys/conf/NOTES	Tue Sep 23 16:06:28 2014	(r272031)
>> +++ head/sys/conf/NOTES	Tue Sep 23 17:04:21 2014	(r272032)
>> @@ -2625,9 +2625,7 @@ options 	NSFBUFS=1024
>>  # Enable extra debugging code for locks.  This stores the filename and
>>  # line of whatever acquired the lock in the lock itself, and changes a
>>  # number of function calls to pass around the relevant data.  This is
>> -# not at all useful unless you are debugging lock code.  Also note
>> -# that it is likely to break e.g. fstat(1) unless you recompile your
>> -# userland with -DDEBUG_LOCKS as well.
>> +# not at all useful unless you are debugging lock code.
>>  #
>>  options 	DEBUG_LOCKS
>>  


-- 
Regards,
Bryan Drewery

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