Re: 2.6.23 boot failures on x86-64.

Zou Nan hai
2007-10-31T06:26:31Z

On Wed, 2007-10-31 at 14:04, Zou Nan hai wrote:
> On Tue, 2007-10-30 at 05:21, Martin Ebourne wrote:
> > On Mon, 2007-10-29 at 15:43 -0400, Dave Jones wrote:
> > > On Mon, Oct 29, 2007 at 08:03:09PM +0100, Andi Kleen wrote:
> > > > > > But if allocating bootmem >4G doesn't work on these systems
> > > > > > most likely they have more problems anyways. It might be better
> > > > > > to find out what goes wrong exactly.
> > > > > Any ideas on what to instrument ?
> > > >
> > > > See what address the bootmem_alloc_high returns; check if it overlaps
> > > > with something etc.
> > > >
> > > > Fill the memory on the system and see if it can access all of its memory.
> > >
> > > Martin, as you have one of the affected systems, do you feel up to this?
> >
> > Faking a node at 0000000000000000-000000001fff0000
> > Bootmem setup node 0 0000000000000000-000000001fff0000
> > sparse_early_mem_map_alloc: returned address ffff81000070b000
> >
> > My box has 512MB of RAM.
> >
> > Cheers,
> >
> > Martin.
>
> Oops, sorry,
> seem to be a mistake of me.
> I forget to exclude the DMA range.
>
> Does the following patch fix the issue?
>
> Thanks
> Zou Nan hai
>
> --- a/arch/x86/mm/init_64.c 2007-10-31 11:24:11.000000000 +0800
> +++ b/arch/x86/mm/init_64.c 2007-10-31 12:31:02.000000000 +0800
> @@ -731,7 +731,7 @@ int in_gate_area_no_task(unsigned long a
> void * __init alloc_bootmem_high_node(pg_data_t *pgdat, unsigned long size)
> {
> return __alloc_bootmem_core(pgdat->bdata, size,
> - SMP_CACHE_BYTES, (4UL*1024*1024*1024), 0);
> + SMP_CACHE_BYTES, (4UL*1024*1024*1024), __pa(MAX_DMA_ADDRESS));
> }
>
> const char *arch_vma_name(struct vm_area_struct *vma)
>
>
>
>

Please ignore the patch, the patch is wrong.

However I think the root cause is when __alloc_bootmem_core fail to
allocate a memory above 4G it will fall back to allocate from the lowest
page.
Then happens to be allocated in DMA region sometimes...

Since this code path is dead, I am OK to revert the patch.

Suresh and I will check the CONFIG_SPARSE_VMEMMAP path.
Thanks
Zou Nan hai