On Fri, Aug 9, 2013 at 2:32 AM, Tang Chen <tangchen@xxxxxxxxxxxxxx> wrote: > 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. You already mark kernel position to be not hot-plugged, so near the kernel range should be safe to be put override acpi tables. also what I mean parse srat two times: parse to get hotplug range, and late parse other numa info again. Yinghai -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>