In 5-level paging mode, allocating memory with the size of NR_MEM_SECTIONS is a bad idea. So in this patchset, trying to optimize to save memory. Othersise kdump kernel can't boot up with normal crashkernel reservation setting. And for normal kernel, the 512M consumption is not also not wise, though it's a temporary allocation. Baoquan He (2): mm/sparsemem: Defer the ms->section_mem_map clearing a little later mm/sparse.c: Add nr_present_sections to change the mem_map allocation mm/sparse-vmemmap.c | 9 +++++---- mm/sparse.c | 54 ++++++++++++++++++++++++++++++++++++----------------- 2 files changed, 42 insertions(+), 21 deletions(-) -- 2.13.6 -- 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>