Subject: [PATCH v1 0/4] powernv/memtrace: don't abuse memory hot(un)plug infrastructure for memory allocations

From: David Hildenbrand <[email-masked]>
Date: Thu, 29 Oct 2020 17:27:14 +0100

powernv/memtrace is the only in-kernel user that rips out random memory
it never added (doesn't own) in order to allocate memory without a
linear mapping. Let's stop abusing memory hot(un)plug infrastructure for
that - use alloc_contig_pages() for allocating memory and remove the
linear mapping manually.

The original idea was discussed in:
 https://lkml.kernel.org/r/[email-masked]

I only tested allocations briefly via QEMU TCG - see patch #4 for more
details.

David Hildenbrand (4):
  powerpc/mm: factor out creating/removing linear mapping
  powerpc/mm: print warning in arch_remove_linear_mapping()
  powerpc/mm: remove linear mapping if __add_pages() fails in
    arch_add_memory()
  powernv/memtrace: don't abuse memory hot(un)plug infrastructure for
    memory allocations

 arch/powerpc/mm/mem.c                     |  48 +++++---
 arch/powerpc/platforms/powernv/Kconfig    |   8 +-
 arch/powerpc/platforms/powernv/memtrace.c | 134 ++++++++--------------
 include/linux/memory_hotplug.h            |   3 +
 4 files changed, 86 insertions(+), 107 deletions(-)

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2.26.2