Re: [RFC] Reproducible OOM with just a few sleeps

Dave Hansen
2013-01-17T21:55:41Z

On 01/17/2013 01:04 PM, paul.szabo@sydney.edu.au wrote:
>>> On my large machine, 'free' fails to show about 2GB memory ...
>> You probably have a memory hole. ...
>> The e820 map (during early boot in dmesg) or /proc/iomem will let you
>> locate your memory holes.
>
> Now that my machine is running an amd64 kernel, 'free' shows total Mem
> 65854128 (up from 64447796 with PAE kernel), and I do not see much
> change in /proc/iomem output (below). Is that as should be?

Yeah, that all looks sane. Your increased memory is because your 64GB
machine had some of its memory mapped _above_ the 64GB physical memory
limit that PAE has.

/proc/iomem is generally just a dump of what the hardware *is*, so it
shouldn't change between kernels.