Re: WARNING: at mm/bootmem.c:535 alloc_arch_preferred_bootmem

[Jeremy Fitzhardinge <jeremy@goop.org>]

On 06/30/09 01:40, Pekka Enberg wrote:
> Hi Christian,
>
> On Mon, 2009-06-29 at 20:01 -0700, Christian Kujau wrote:
>   
>> Hi there,
>>
>> this topic has been discussed [0] already and a bug for powerpc[1] has 
>> been opened, I'm still seeing this with the latest -git in a x86_64 Xen 
>> DomU. The domain continues to boot however, no oopses or crashes so far, 
>> it's just this warning during bootup. The thread about the "early boot 
>> SLAB" came to a halt, but the warning is still there - is a fix for this 
>> still in the works?
>>
>> Full dmesg/.config: http://nerdbynature.de/bits/2.6.31-rc1/
>>
>> Thanks,
>> Christian.
>>
>> [0] http://bugzilla.kernel.org/show_bug.cgi?id=13650 / Badness on the Warp
>> [1] http://lkml.org/lkml/2009/6/10/396 / Early boot SLAB for 2.6.31
>>     
>
> I think you're the first one to report this. The warning is harmless but
> the following patch should fix things up. Thanks!
>   

Thanks for this.  I'd noticed it locally, but I hadn't got around to
checking to see if it affected mainline.

> 			Pekka
>
> >From dc231c59194a973b80e6932bb4c162f2076635cb Mon Sep 17 00:00:00 2001
> From: Pekka Enberg <penberg@cs.helsinki.fi>
> Date: Tue, 30 Jun 2009 11:35:19 +0300
> Subject: [PATCH] xen: Use kcalloc() in xen_init_IRQ()
>
> The init_IRQ() function is now called with slab allocator initialized.
> Therefore, we must not use the bootmem allocator in xen_init_IRQ().
> Fixes the following boot-time warning:
>
>   [    0.000000] Linux version 2.6.30 (dummy@sid) (gcc version 4.4.0 (Debian 4.4.0-8) ) #1 Tue Jun 23 02:13:42 CEST 2009
>   [    0.000000] Command line: root=/dev/xvda1 console=hvc0 init=/sbin/init
>   [    0.000000] KERNEL supported cpus:
>   [    0.000000]   Intel GenuineIntel
>   [    0.000000]   AMD AuthenticAMD
>   [    0.000000]   Centaur CentaurHauls
>   [    0.000000] BIOS-provided physical RAM map:
>   [    0.000000]  Xen: 0000000000000000 - 00000000000a0000 (usable)
>   [    0.000000]  Xen: 00000000000a0000 - 0000000000100000 (reserved)
>   [    0.000000]  Xen: 0000000000100000 - 0000000008000000 (usable)
>   [    0.000000] DMI not present or invalid.
>   [    0.000000] last_pfn = 0x8000 max_arch_pfn = 0x400000000
>   [    0.000000] initial memory mapped : 0 - 20000000
>
> Reported-by: Christian Kujau <lists@nerdbynature.de>
> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
>   

Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

> ---
>  drivers/xen/events.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/xen/events.c b/drivers/xen/events.c
> index 891d2e9..abad71b 100644
> --- a/drivers/xen/events.c
> +++ b/drivers/xen/events.c
> @@ -927,9 +927,9 @@ static struct irq_chip xen_dynamic_chip __read_mostly = {
>  void __init xen_init_IRQ(void)
>  {
>  	int i;
> -	size_t size = nr_cpu_ids * sizeof(struct cpu_evtchn_s);
>  
> -	cpu_evtchn_mask_p = alloc_bootmem(size);
> +	cpu_evtchn_mask_p = kcalloc(nr_cpu_ids, sizeof(struct cpu_evtchn_s),
> +				    GFP_KERNEL);
>  	BUG_ON(cpu_evtchn_mask_p == NULL);
>  
>  	init_evtchn_cpu_bindings();
>