Re: "0-order allocation failed"

[Seth Mos <knuffie@xs4all.nl>]

At 15:26 19-8-2001 -0400, tls@reefedge.com wrote:
>On Sun, Aug 19, 2001 at 09:15:55PM +0200, Seth Mos wrote:
> > >
> > >I noticed a later list message suggesting that a change to XFS in the 
> 2.4.6
> > >timeframe should significantly improve stability on highmem machines; 
> I also
> > >found a message suggesting that there were deadlocks elsewhere in the 
> Linux
> > >kernel on highmem machines until 2.4.7.  So I had high hopes for the 2.4.9
> > >patch.
> >
> > 2.4.9 is not available as a patch on the FTP site yet and you will need to
> > fetch it from CVS.
>
>Actually, it appears to have been on the FTP site for a couple of days.  Do
>you see any reason I shouldn't run it?

I have been tied up last week which means I have not completely tracked all 
changes or additions to the FTP site.

You can run it safely, it works on my home box but you might check for some 
patches mentioned on the lkml list for making some stuff compile.

> > >Unfortunately, though I haven't gotten the machine to hang hard yet, I'm
> > >now running 2.4.9 and a simple cp -R of our CVS repository from one 
> directory
> > >on an XFS filesystem to another produces the "0 order alloc" messages.
> >
> > These are rather irritating but not related to XFS. If you push ext2 or
> > reiserfs hard enough they will  show up as well.
>
>Hm.  I can't seem to make it happen, but I'll take your word for it.
>
>Is it too complex, or would you mind giving me a thumbnail sketch of how
>the memory-allocation path differs in highmem systems that would cause
>allocation to fail more frequently?  I've got a decent background WRT the
>Unix kernel but the guts of the Linux VM system aren't something I've looked
>at before in any detail.

I can't give you an explanation because I have no clue whatsoever. I just 
follow the list and remember what the smart people say about it so I can 
answer questions, and they can code.

> > >Is this actually believed to be fixed at the moment, or not?  Looks like
> > >not, but I'll leave this running for a few hours and see if I can get an
> > >actual hang.
> >
> > The message is fairly harmless for now but the box should at least survive
> > this. Stability on highmem is at least better then what it used to be.
>
>My copy-copy-delete test has, indeed, been running since I sent the original
>message and so far it hasn't hung, with 2.4.9 and the patch from the FTP
>site.  I guess I'll have to get over my nervousness about the messages. :-/

Ok :-)

>Thanks for the help!
>
>Thor

--
Seth
Every program has two purposes one for which
it was written and another for which it wasn't
I use the last kind.