Re: Panic on 8-node system in memblock_virt_alloc_try_nid()

[Yinghai Lu <yinghai@kernel.org>]

On Fri, Jan 24, 2014 at 10:42 AM, Dave Hansen <dave.hansen@intel.com> wrote:
> On 01/24/2014 10:24 AM, Yinghai Lu wrote:
>> On Fri, Jan 24, 2014 at 10:19 AM, Dave Hansen <dave.hansen@intel.com> wrote:
>>> FWIW, I did turn of memblock=debug.  It eventually booted, but
>>> slooooooooooowly.
>>
>> then that is not a problem, as you are using 4k page mapping only.
>> and that printout is too spew...
>
> This means that, essentially, memblock=debug and
> KMEMCHECK/DEBUG_PAGEALLOC can't be used together.  That's a shame
> because my DEBUG_PAGEALLOC config *broke* this code a few months ago,
> right?  Oh well.

should only be broken when MOVABLE_NODE is enabled on big system.

>
>>> How many problems in this code are we tracking, btw?  This is at least
>>> 3, right?
>>
>> two problems:
>> 1. big numa system.
>> 2. Andrew's system with swiotlb.
>
> Can I ask politely for some more caution on your part in this area?
> This is two consecutive kernels where this code has broken my system.

I agree, the code get messy as now we have top_down and bottom up
mapping for different configuration.

I already tried hard to make parsing srat early solution instead that split.

Yinghai

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