[PATCH v1 0/4] mm/memory_hotplug: full support for

David Hildenbrand
2021-09-27T15:05:46Z

Architectures that require CONFIG_ARCH_KEEP_MEMBLOCK=y, such as arm64,
don't cleanly support add_memory_driver_managed() yet. Most prominently,
kexec_file can still end up placing images on such driver-managed memory,
resulting in undesired behavior.

Teaching kexec to not place images on driver-managed memory is especially
relevant for virtio-mem. Details can be found in commit 7b7b27214bba
("mm/memory_hotplug: introduce add_memory_driver_managed()").

Extend memblock with a new flag and set it from memory hotplug code
when applicable. This is required to fully support virtio-mem on
arm64, making also kexec_file behave like on x86-64.

Alternative A: Extend kexec_walk_memblock() to consult the kernel resource
tree whether IORESOURCE_SYSRAM_DRIVER_MANAGED is set. This feels wrong,
because the goal was to rely on memblock and not the resource tree.

Alternative B: Reuse MEMBLOCK_HOTPLUG. MEMBLOCK_HOTPLUG serves a different
purpose, though.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Jianyong Wu <Jianyong.Wu@arm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-m68k@lists.linux-m68k.org
Cc: linux-mips@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: kexec@lists.infradead.org

David Hildenbrand (4):
mm/memory_hotplug: handle memblock_add_node() failures in
add_memory_resource()
memblock: allow to specify flags with memblock_add_node()
memblock: add MEMBLOCK_DRIVER_MANAGED to mimic
IORESOURCE_SYSRAM_DRIVER_MANAGED
mm/memory_hotplug: indicate MEMBLOCK_DRIVER_MANAGED with
IORESOURCE_SYSRAM_DRIVER_MANAGED

arch/arc/mm/init.c | 4 ++--
arch/ia64/mm/contig.c | 2 +-
arch/ia64/mm/init.c | 2 +-
arch/m68k/mm/mcfmmu.c | 3 ++-
arch/m68k/mm/motorola.c | 6 ++++--
arch/mips/loongson64/init.c | 4 +++-
arch/mips/sgi-ip27/ip27-memory.c | 3 ++-
arch/s390/kernel/setup.c | 3 ++-
include/linux/memblock.h | 19 ++++++++++++++++---
include/linux/mm.h | 2 +-
kernel/kexec_file.c | 5 +++++
mm/memblock.c | 13 +++++++++----
mm/memory_hotplug.c | 11 +++++++++--
13 files changed, 57 insertions(+), 20 deletions(-)

base-commit: 5816b3e6577eaa676ceb00a848f0fd65fe2adc29
--
2.31.1