From: David Hildenbrand <david@xxxxxxxxxx> Subject: arm64/mm: add temporary arch_remove_memory() implementation A proper arch_remove_memory() implementation is on its way, which also cleanly removes page tables in arch_add_memory() in case something goes wrong. As we want to use arch_remove_memory() in case something goes wrong during memory hotplug after arch_add_memory() finished, let's add a temporary hack that is sufficient enough until we get a proper implementation that cleans up page table entries. We will remove CONFIG_MEMORY_HOTREMOVE around this code in follow up patches. Link: http://lkml.kernel.org/r/20190527111152.16324-5-david@xxxxxxxxxx Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Will Deacon <will.deacon@xxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> Cc: Chintan Pandya <cpandya@xxxxxxxxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx> Cc: Jun Yao <yaojun8558363@xxxxxxxxx> Cc: Yu Zhao <yuzhao@xxxxxxxxxx> Cc: Robin Murphy <robin.murphy@xxxxxxx> Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx> Cc: Alex Deucher <alexander.deucher@xxxxxxx> Cc: Andrew Banman <andrew.banman@xxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Arun KS <arunks@xxxxxxxxxxxxxx> Cc: Baoquan He <bhe@xxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Christophe Leroy <christophe.leroy@xxxxxx> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Logan Gunthorpe <logang@xxxxxxxxxxxx> Cc: Mark Brown <broonie@xxxxxxxxxx> Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> Cc: Mathieu Malaterre <malat@xxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> Cc: "mike.travis@xxxxxxx" <mike.travis@xxxxxxx> Cc: Nicholas Piggin <npiggin@xxxxxxxxx> Cc: Oscar Salvador <osalvador@xxxxxxxx> Cc: Oscar Salvador <osalvador@xxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Qian Cai <cai@xxxxxx> Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx> Cc: Rich Felker <dalias@xxxxxxxx> Cc: Rob Herring <robh@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Tony Luck <tony.luck@xxxxxxxxx> Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx> Cc: Wei Yang <richard.weiyang@xxxxxxxxx> Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/arm64/mm/mmu.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) --- a/arch/arm64/mm/mmu.c~arm64-mm-add-temporary-arch_remove_memory-implementation +++ a/arch/arm64/mm/mmu.c @@ -1074,4 +1074,23 @@ int arch_add_memory(int nid, u64 start, return __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, restrictions); } +#ifdef CONFIG_MEMORY_HOTREMOVE +void arch_remove_memory(int nid, u64 start, u64 size, + struct vmem_altmap *altmap) +{ + unsigned long start_pfn = start >> PAGE_SHIFT; + unsigned long nr_pages = size >> PAGE_SHIFT; + struct zone *zone; + + /* + * FIXME: Cleanup page tables (also in arch_add_memory() in case + * adding fails). Until then, this function should only be used + * during memory hotplug (adding memory), not for memory + * unplug. ARCH_ENABLE_MEMORY_HOTREMOVE must not be + * unlocked yet. + */ + zone = page_zone(pfn_to_page(start_pfn)); + __remove_pages(zone, start_pfn, nr_pages, altmap); +} +#endif #endif _
