Re: [RFC 3/3] x86, mirror: x86 enabling - find mirrored memory ranges and tell memblock

[Xishi Qiu]

On 2015/2/4 6:40, Tony Luck wrote:

> Can't post this part yet because it uses things in an upcoming[*] ACPI, UEFI, or some
> other four-letter-ending-in-I standard.  So just imagine a call someplace early
> in startup that reads information about mirrored address ranges and does:
> 

Hi Tony,

Does the upcoming[*] ACPI will add a new flag in SRAT tables? just like memory hotplug.

#define ACPI_SRAT_MEM_HOT_PLUGGABLE (1<<1)	/* 01: Memory region is hot pluggable */
+#define ACPI_SRAT_MEM_MIRROR	    (1<<3)	/* 03: Memory region is mirrored */

acpi_numa_memory_affinity_init()
	...
	hotpluggable = ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE;
+	mirrorable = ma->flags & ACPI_SRAT_MEM_MIRROR;
	...
+	if (mirrorable)
+		memblock_mark_mirror(start, size);
	...

Thanks,
Xishi Qiu

> +	for (...) {
> +		start = ...;
> +		size = ...;
> +		if (it looks mirrored)
> +			memblock_mark_mirror(start, size);
> +	}
> 
> Whole patch is pretty tiny:
> 
>  3 files changed, 19 insertions(+)
> 
> How much damage could I possibly do in just 19 lines?
> 
> -Tony
> 
> [*] very soon, I'm told
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