On 08/09/2013 12:41 AM, Yinghai Lu wrote:
On Thu, Aug 8, 2013 at 2:41 AM, Tang Chen<tangchen@xxxxxxxxxxxxxx> wrote:
In ACPI SRAT(System Resource Affinity Table), there is a memory affinity for each
memory range in the system. In each memory affinity, there is a field indicating
that if the memory range is hotpluggable.
This patch parses all the memory affinities in SRAT only, and find out all the
hotpluggable memory ranges in the system.
oh, no.
How do you make sure the SRAT's entries are right ?
later numa_init could reject srat table if srat ranges does not cover
e820 memmap.
In numa_meminfo_cover_memory(), it checks if SRAT covers the e820 ranges.
And it uses
e820ram = max_pfn - absent_pages_in_range(0, max_pfn)
to calculate the e820 ram size.
Since max_pfn is initialized before memblock.memory is fulfilled, I think
we can also do this check at earlier time.
Also parse srat table two times looks silly.
By parsing SRAT twice, I can avoid memory allocation for acpi_tables_addr
in acpi_initrd_override_copy() procedure at such an early time. This memory
could also be in hotpluggable area.
I think, parsing SRAT memory affinities one more time is clean, no memory
allocation, no global variable initialization. All the current numa init
pathes will work as before.
Thanks.
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