From: Mike Rapoport <rppt@xxxxxxxxxxxxx> Hi, These patches aim to remove CONFIG_HOLES_IN_ZONE and essentially hardwire pfn_valid_within() to 1. The idea is to mark NOMAP pages as reserved in the memory map and restore the intended semantics of pfn_valid() to designate availability of struct page for a pfn. With this the core mm will be able to cope with the fact that it cannot use NOMAP pages and the holes created by NOMAP ranges within MAX_ORDER blocks will be treated correctly even without the need for pfn_valid_within. The patches are only boot tested on qemu-system-aarch64 so I'd really appreciate memory stress tests on real hardware. If this actually works we'll be one step closer to drop custom pfn_valid() on arm64 altogether. Changes since RFC Link: https://lore.kernel.org/lkml/20210407172607.8812-1-rppt@xxxxxxxxxx * Add comment about the semantics of pfn_valid() as Anshuman suggested * Extend comments about MEMBLOCK_NOMAP, per Anshuman * Use pfn_is_map_memory() name for the exported wrapper for memblock_is_map_memory(). It is still local to arch/arm64 in the end because of header dependency issues. Mike Rapoport (4): include/linux/mmzone.h: add documentation for pfn_valid() memblock: update initialization of reserved pages arm64: decouple check whether pfn is in linear map from pfn_valid() arm64: drop pfn_valid_within() and simplify pfn_valid() arch/arm64/Kconfig | 3 --- arch/arm64/include/asm/memory.h | 2 +- arch/arm64/include/asm/page.h | 1 + arch/arm64/kvm/mmu.c | 2 +- arch/arm64/mm/init.c | 10 ++++++++-- arch/arm64/mm/ioremap.c | 4 ++-- arch/arm64/mm/mmu.c | 2 +- include/linux/memblock.h | 4 +++- include/linux/mmzone.h | 11 +++++++++++ mm/memblock.c | 28 ++++++++++++++++++++++++++-- 10 files changed, 54 insertions(+), 13 deletions(-) base-commit: e49d033bddf5b565044e2abe4241353959bc9120 -- 2.28.0
