Re: [PATCH] mm: Introduce kernelcore=reliable option

[Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

On 2015/10/22 3:17, Luck, Tony wrote:
> +	if (reliable_kernelcore) {
> +		for_each_memblock(memory, r) {
> +			if (memblock_is_mirror(r))
> +				continue;
>
> Should we have a safety check here that there is some mirrored memory?  If you give
> the kernelcore=reliable option on a machine which doesn't have any mirror configured,
> then we'll mark all memory as removable.

You're right.

> What happens then?  Do kernel allocations fail?  Or do they fall back to using removable memory?

Maybe the kernel cannot boot because NORMAL zone is empty.

> Is there a /proc or /sys file that shows the current counts for the removable zone?  I just
> tried this patch with a high percentage of memory marked as mirror ... but I'd like to see
> how much is actually being used to tune things a bit.
>

I think /proc/zoneinfo can show detailed numbers per zone. Do we need some for meminfo ?

Thanks,
-Kame


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