The bottom-up allocation style is introduced to cope with movable_node, where the limit inferior of allocation starts from kernel's end, due to lack of knowledge of memory hotplug info at this early time. Beside this original aim, 'kexec -c' prefers to reuse this style to alloc mem at lower address, since if the reserved region is beyond 4G, then it requires extra mem (default is 16M) for swiotlb. But at this time hotplug info has been got, the limit inferior can be extend to 0, which is done by this series Cc: Tang Chen <tangchen@xxxxxxxxxxxxxx> Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx> Cc: Len Brown <lenb@xxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Jonathan Corbet <corbet@xxxxxxx> Cc: Yaowei Bai <baiyaowei@xxxxxxxxxxxxxxxxxxxx> Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> Cc: Nicholas Piggin <npiggin@xxxxxxxxx> Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> Cc: Daniel Vacek <neelx@xxxxxxxxxx> Cc: Mathieu Malaterre <malat@xxxxxxxxxx> Cc: Stefan Agner <stefan@xxxxxxxx> Cc: Dave Young <dyoung@xxxxxxxxxx> Cc: Baoquan He <bhe@xxxxxxxxxx> Cc: yinghai@xxxxxxxxxx, Cc: vgoyal@xxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Pingfan Liu (2): mm/memblock: extend the limit inferior of bottom-up after parsing hotplug attr x86/kdump: bugfix, make the behavior of crashkernel=X consistent with kaslr arch/x86/kernel/setup.c | 9 +++++--- drivers/acpi/numa.c | 4 ++++ include/linux/memblock.h | 1 + mm/memblock.c | 58 +++++++++++++++++++++++++++++------------------- 4 files changed, 46 insertions(+), 26 deletions(-) -- 2.7.4