Re: Using debug and tracing features in 2.4.26

[Steve Lord <lord@xxxxxxx>]

Craig Tierney wrote:
> I have enabled debugging and tracing features in XFS
> using the 2.4.26 kernel.  When I load the xfs module,
> it reports that tracing and debugging are enabled.
>
> (From dmesg)
> SGI XFS with tracing, debug enabled
> SGI XFS Quota Management subsystem
>
> To enable tracing, the Configure.help file says to set
> /proc/sys/vm/pagebuf/debug.  However, I could not find this
> sysctl, or anything that was similar in the /proc/fs/xfs or
> /proc/sys/fs/xfs directories.
>
> How do I turn this on?
>
> Also, with debugging enabled, do all debug messages go to the
> kernel log?


The tracing is to internal kernel buffers and is not much use
unless you have a debugger capable of looking at them, which
means kdb and the xfs support for kdb.

Any reason for turning on debug? It adds thousands of checks to
the code base, any one of them will oops if it triggers. Never
run this way with data you care about.

Steve