Andi Kleen wrote: >> This reserved portion of the KVA must be PMD aligned. > > Why do they need to be PMD aligned?
That comes from the fact that the KVA in x86 has traditionally been mapped with huge pages where at all possible, for performance reasons. The purpose of the remap itself always has been performance based, we are remapping node-local memory into KVA to hold the memmap in part to exploit locality of process to its memory, and to in part to distribute the load on the NUMA memory infrastructure by "striping" the storage. As a result it makes sense to map these remapped areas with huge pages also. As is evidenced by the fact this bug is only coming to light now, it is somewhat rare for the end of a NODE to be miss-aligned below the huge page level (2/4MB). -apw - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
