Background When kaslr kernel can be guaranteed to sit inside unmovable node after [1]. But if kaslr kernel is located near the end of the movable node, then bottom-up allocator may create pagetable which crosses the boundary between unmovable node and movable node. It is a probability issue, two factors include -1. how big the gap between kernel end and unmovable node's end. -2. how many memory does the system own. Alternative way to fix this issue is by increasing the gap by boot/compressed/kaslr*. But taking the scenario of PB level memory, the pagetable will take server MB even if using 1GB page, different page attr and fragment will make things worse. So it is hard to decide how much should the gap increase. The following figure show the defection of current bottom-up style: [startA, endA][startB, "kaslr kernel verly close to" endB][startC, endC]
If nodeA,B is unmovable, while nodeC is movable, then init_mem_mapping() can generate pgtable on nodeC, which stain movable node. This patch makes it certainty instead of a probablity problem. It achieves this by pushing forward the parsing of mem hotplug info ahead of init_mem_mapping(). Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: "Rafael J. Wysocki" <[email protected]> Cc: Len Brown <[email protected]> Cc: Yinghai Lu <[email protected]> Cc: Tejun Heo <[email protected]> Cc: Chao Fan <[email protected]> Cc: Baoquan He <[email protected]> Cc: Juergen Gross <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Mike Rapoport <[email protected]> Cc: Vlastimil Babka <[email protected]> Cc: Michal Hocko <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Pingfan Liu (7): x86/mm: concentrate the code to memblock allocator enabled acpi: change the topo of acpi_table_upgrade() mm/memblock: introduce allocation boundary for tracing purpose x86/setup: parse acpi to get hotplug info before init_mem_mapping() x86/mm: set allowed range for memblock allocator x86/mm: remove bottom-up allocation style for x86_64 x86/mm: isolate the bottom-up style to init_32.c arch/arm/mm/init.c | 3 +- arch/arm/mm/mmu.c | 4 +- arch/arm/mm/nommu.c | 2 +- arch/arm64/kernel/setup.c | 2 +- arch/csky/kernel/setup.c | 2 +- arch/microblaze/mm/init.c | 2 +- arch/mips/kernel/setup.c | 2 +- arch/powerpc/mm/40x_mmu.c | 6 +- arch/powerpc/mm/44x_mmu.c | 2 +- arch/powerpc/mm/8xx_mmu.c | 2 +- arch/powerpc/mm/fsl_booke_mmu.c | 5 +- arch/powerpc/mm/hash_utils_64.c | 4 +- arch/powerpc/mm/init_32.c | 2 +- arch/powerpc/mm/pgtable-radix.c | 2 +- arch/powerpc/mm/ppc_mmu_32.c | 8 +- arch/powerpc/mm/tlb_nohash.c | 6 +- arch/unicore32/mm/mmu.c | 2 +- arch/x86/kernel/setup.c | 93 ++++++++++++++--------- arch/x86/mm/init.c | 163 +++++----------------------------------- arch/x86/mm/init_32.c | 147 ++++++++++++++++++++++++++++++++++++ arch/x86/mm/mm_internal.h | 8 +- arch/xtensa/mm/init.c | 2 +- drivers/acpi/tables.c | 4 +- include/linux/acpi.h | 5 +- include/linux/memblock.h | 10 ++- mm/memblock.c | 23 ++++-- 26 files changed, 290 insertions(+), 221 deletions(-) -- 2.7.4
