On Tue, Dec 01, 2009 at 01:39:06PM -0500, Justin Piszcz wrote:
> On Tue, 1 Dec 2009, Dave Chinner wrote:
>> On Mon, Nov 30, 2009 at 08:22:03AM -0500, Justin Piszcz wrote:
>>> I wanted to compile my kernel with DEBUG for XFS and also kernel frame
>>> to catch any issues.
>>> However, DEBUG for XFS does more harm than good?
>> DEBUG is there for developers, not end users. Often the debug code
>> will assert fail or panic where the situation is not fatal but
>> indicative of some problem that should be looked into further.
> Recall that issue that I was having with asterisk installed?
Yes, it appeared to be caused by log IO not completing, right?
> How should
> one get more information on a filesystem lockup if we cannot have debug
> enabled for the filesystem?
The debug code in XFS won't tell you anything extra about a lock-up
unless it trips an ASSERT before the lockup that is related to the
lock-up. My experience with hangs like the above are that they
generally are not related to the filesystem at all; most of the time
it is IO not being completed by the lower layers for some reason,
and no amount of filesystem level debug will help solve that
> Should there be a user-debug option which it
> will include more verbosity if/when the xfs kernel processes lockup?
See /proc/sys/fs/xfs/error_level. That can turn up the verbosity of
error reporting without needing DEBUG compiled in.