Messages in this thread | | | Date | Wed, 22 Nov 2006 00:51:43 +0100 | From | "Jesper Juhl" <> | Subject | Re: 2.6.19-rc6 : Spontaneous reboots, stack overflows - seems to implicate xfs, scsi, networking, SMP |
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On 22/11/06, David Chinner <dgc@sgi.com> wrote: > On Tue, Nov 21, 2006 at 11:02:23PM +0100, Jesper Juhl wrote: > > On 21/11/06, David Chatterton <chatz@melbourne.sgi.com> wrote: ... > > > >Audits have been done in the past and will again be done in the future to > > >try to > > >identify areas where XFS could use less stack space by reducing/avoid large > > >local variables. Reducing the code path is far more difficult. > > > > > I realize that fixing the problem may be difficult. I just wanted to > > make sure that people were informed that there is an actual problem > > and provide as much info as possible so that perhaps in the future it > > can be fixed... :) > > I've got one that prevents gcc from inlining single use functions in XFS > that I need to finish off, and that results in some significant stack > usage reductions in some XFS functions. > That sounds good. I'll be keeping an eye out for that one :)
> However, XFS is only one part of the picture - when you put NFS on top, > DM+md then scsi/FC below and then you nest a soft irq that might go > 20 functions deep as well - then 4k stacks simply aren't big enough. > True, there are a lot of players involved here, although XFS seems (to me) to be the biggest one.
> > I'm reading through the XFS code myself at the moment and I'll be sure > > to submit patches if I spot something that could help reduce stack > > usage. > > Most of the low hanging fruit is already gone. The problem we are > facing now for further reductions in stack usage is the fact that we > need to factor code. That is a major undertaking and has a _lot_ of > risk associated with it.... > I'll try to spot some of the remaining low hanging fruit ;)
> > >There is active discussion about reducing inlining: > > >http://bugzilla.kernel.org/show_bug.cgi?id=7364 > > > > Thanks, I'll check that out. > > That's one of the few remaining low hanging fruit, and that's fixed > in the patches I already have. > Nice. Will be good to get that in.
> > >Thanks for traces, I've captured this information. > > > > > You are welcome. If you want/need more traces then I've got ~2.1G > > worth of traces that you can have :) > > Well, we don't need that many, but it would be nice to have a > set of unique traces that lead to overflows - could you process > them in some way just to extract just the unique XFS traces that > occur? > I'll try to extract a copy of each unique trace that involves xfs, sometime tomorrow or the day after, and then send you the result.
-- Jesper Juhl <jesper.juhl@gmail.com> Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html Plain text mails only, please http://www.expita.com/nomime.html - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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