Re: 3-order allocation failed

From: Pasi Kärkkäinen (pk@edu.joroinen.fi)
Date: Wed Nov 01 2000 - 06:13:04 EST


On Thu, 26 Oct 2000, Rik van Riel wrote:

> On Thu, 26 Oct 2000, Forever shall I be. wrote:
> > On Thu, Oct 26, 2000 at 02:57:30PM +0300, Pasi Kärkkäinen wrote:
>
> > > __alloc_pages: 2-order allocation failed.
> > > __alloc_pages: 2-order allocation failed.
> > > __alloc_pages: 5-order allocation failed.
> > > __alloc_pages: 4-order allocation failed.
> > > __alloc_pages: 3-order allocation failed.
> > > __alloc_pages: 2-order allocation failed.
> > > __alloc_pages: 5-order allocation failed.
> > >
> > > Any ideas?
> >
> > I'm getting __alloc_pages: 7-order allocation failed.
> > all the time in 2.4.0-test9 on my "pIII (Katmai)".. kernel's
> > compiled with 2.95.2 + bounds, without -fbounds-checking
>
> It means something in the system is trying to allocate a
> large continuous area of memory that isn't available...
>
> The printk is basically a debug output indicating that we
> don't have the large physically contiguous area available
> that's being requested.
>
> Basically everything bigger than order-1 (2 contiguous
> pages) is unreliable at runtime. Orders 2 and 3 should
> usually be available (if you only allocate very few of
> them) and higher orders should not be relied upon.
>
> If somebody is seeing a lot of these messages, it means
> that some driver in the system is asking unreasonable
> things from the VM subsystem ;)
>
> (and buffer allocations are failing)
>

I added show_stack(0); to the mm/page_alloc.c :

        /* No luck.. */
        printk(KERN_ERR "__alloc_pages: %lu-order allocation failed.\n", order)
        show_stack(0);
        return NULL;

Then, when the first stack-dump came to kern.log, I gave it to
ksymoops. The result can be seen on

http://edu.joroinen.fi/~pk/ksymoops-output.

Hope that helps someone. If not, I may do further tests.

- Pasi Kärkkäinen
       
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