Re: [evlog-dev] evlog module

Hi Larry,

Addressing your points:

1) i think *I* could live without the early boot
   messages.  our use of evlog is based on having
   one of our evlog plugins receive events and
   then do "stuff".  During boot time we can't
   do that "stuff" since it requires our other
   user-space applications to be up and running.
   Having evlog as a module would give an option
   for those like me who can afford to miss those
   early messages.

2) I'm not sure i understand.  Where are we defining
   new logging functions?  In evlog?  User apps?

From what our hardware vendor tells us, RH simply
will not support any kernel that they didn't 
compile.  If you use the same sources but change
the page table size they will not support it.  I'm
told they do md5 sum's on the kernel to see if
anything
is different...


Thanks!

/steve


--- Larry Kessler <[email protected]> wrote:
> Steve Woodruff wrote:
> > 
> > Is there any way that evlog could be modified
> > such that it could be entirely contained as
> > a loadable module?  ie: no kernel patch required?
> > 
> 
> I will not say that it _cannot_ be implemented as a 
> loadable module, but instead can give you some
> reasons
> that in the beginning, this approach was shelved in 
> favor of the current approach.  Remember, this
> assessment
> was made in mid-2000 when we were all relatively new
> to
> Linux.  Perhaps these issues could be addressed
> today.
> 
> 1) In order to capture the very earliest events 
> after bootup, before you are able to load modules,
> you
> need event logging built-in to the kernel. 
> Similiarly,
> we use a static buffer for events, so events before
> you 
> are able to dynamically allocate memory can be
> captured.
> 
> 2) If you define new functions for logging events,
> you
> still need these defined in the kernel so that
> drivers,
> etc. that use these functions don't get unresolved
> symbols when they try to link.  
> (Of course, inside these
> logging functions you could simply return if the
> "evlog
> module" was not loaded.)
> 
> Even if you only wanted to just forward printks()
> and turn
> them into event records, you still need to patch
> printk to 
> tap into the message stream.
> 
> > The reason I ask is that CGL vendors like RedHat
> > and HP have no desire to support CGL installations
> > in which the kernel is tainted or changed from
> > the kernel they ship.  This is a big issue for
> > us since RH flat out refuses to support any kernel
> > that has evlog in it 
> 
> Do they give any reasons why ?  The only reason I've
> heard is they are worried that if they include, say,
> evlog vers. X, but evlog vers. Y gets accepted into
> the upstream (2.5) kernel this creates awful
> compatibility
> problems. I understand this completely, but I think
> we
> have a migration story that _might_ address this
> issue.
> I do know that UL 1.0 includes evlog-1.4.2, and they
> never
> raised this issue. 
> 
> 
> > Having evlog as a loadable module which wouldn't
> > need a kernel patch would be a lifesaver.  Is
> there
> > any technical way evlog could go in that
> direction?
> > 
> 
> I'm not against saving your life :-), but I'm not
> sure we
> can spend the time right now to investigate this. 
> Although,
> it may serve _us_ well in the long-run too.  We'll
> have
> to discuss it more.
> 
> Any other thoughts from you or the evlog team ?
> 
> Thanks,
> Larry


=====
----------------------------------------------------------
 Steve Woodruff, N9OH @ 42.18N 88.34W, [email protected]

__________________________________________________
Do you Yahoo!?
Yahoo! Mail Plus - Powerful. Affordable. Sign up now.
http://mailplus.yahoo.com


-------------------------------------------------------
This SF.NET email is sponsored by:
SourceForge Enterprise Edition + IBM + LinuxWorld = Something 2 See!
http://www.vasoftware.com