Re: Vanilla-Kernel 3 - page allocation failure

[Philipp Herz - Profihost AG]

Am 24.10.2011 09:03, schrieb Eric Dumazet:
> Le lundi 24 octobre 2011 Ã 08:33 +0200, Philipp Herz - Profihost AG a
> Ãcrit :
> > Am 19.10.2011 03:58, schrieb David Rientjes:
> > > On Tue, 18 Oct 2011, Andi Kleen wrote:
> > >
> > > > Philipp Herz - Profihost AG<p.herz@xxxxxxxxxxxx>   writes:
> > > >
> > > > > After updating kernel (x86_64) to stable version 3 there are a few
> > > > > messages appearing in the kernel log such as
> > > > >
> > > > > kworker/0:1: page allocation failure: order:1, mode:0x20
> > > > > mysql: page allocation failure: order:1, mode:0x20
> > > > > php5: page allocation failure: order:1, mode:0x20
> > > >
> > > > You just ran out of memory.
> > >
> > > He ran out of order-1 physically contiguous memory and was unable to
> > > compact or reclaim because of the atomic context.
> > >
> > > Philipp, based on your pastes from another post, it's evident you're using
> > > CONFIG_SLAB and, unfortunately, it's not possible to change to single
> > > page allocations (which would only result in a page allocation failure if
> > > you were completely out of memory) without recompiling.
> > >
> > > You have a couple options:
> > >
> > >    - recompile with BREAK_GFP_ORDER_HI redefined to 0 in mm/slab.c, or
> > >
> > >    - recompile with CONFIG_SLUB instead of CONFIG_SLAB.
> > >
> > > It's very possible that neither of these will help, but it will tell you
> > > whether you need to go out and buy more RAM or not.  If you try to
> > > recompile with BREAK_GFP_ORDER_HI, these may turn into order-0
> > > allocations.  If you can't reboot, send the output of
> > > /proc/<pid>/net/protocols where<pid>   is the pid of one of the above tasks
> > > (kworker, mysql, php5) when they are running and we'll know.
> > >
> > >    [ Changing slab_break_gfp_order should really be a CONFIG_SLAB command-
> > >      line option.  It can't be runtime because slab depends on the order for
> > >      caches remaining constant, but we can certainly change it on boot. ]
> > >
> > > If you try CONFIG_SLUB instead of CONFIG_SLAB, you can pass
> > > slub_max_order=0 on the command line and see if it helps.
> >
> > Hi David,
> >
> > we have recompiled the kernel of one machine with CONFIG_SLUB instead of
> > CONFIG_SLAB, but it is showing similar message.
> >
> > Now it's showing failure at "order:5, mode:0x4020".
> >
> > Call trace can be found at:
> > * http://pastebin.com/uGJiwvG1
> >
> > Comparing kernel 2.6.32 (mm/page_alloc.c) there seams to be the same way
> > of dealing with page allocation.
> >
> > Do you have an idea why these (warning) messages do never appear running
> > 2.6.32?
>
> Your tg3 has a firmware limitation, and some skbs using fragments have
> to be reallocated using a single and contiguous area of memory.
>
> Initial skb delivered by tcp stack only uses order-0 pages, but the
> reallocated one, being 64K, can be order-5
>
> You can avoid this by following tuning :
>
> ethtool -K eth0 sg off

ok,

does that mean that there was no firmware limitation with kernel 2.6.32 
or that the tg3 module has any "disable warnings" flag matching 
__GFP_NOWARN?

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