linux/arch/powerpc
Rashmica Gupta 3f7daf3d75 powerpc/memtrace: Remove memory in chunks
When hot-removing memory release_mem_region_adjustable() splits iomem
resources if they are not the exact size of the memory being
hot-deleted. Adding this memory back to the kernel adds a new resource.

Eg a node has memory 0x0 - 0xfffffffff. Hot-removing 1GB from
0xf40000000 results in the single resource 0x0-0xfffffffff being split
into two resources: 0x0-0xf3fffffff and 0xf80000000-0xfffffffff.

When we hot-add the memory back we now have three resources:
0x0-0xf3fffffff, 0xf40000000-0xf7fffffff, and 0xf80000000-0xfffffffff.

This is an issue if we try to remove some memory that overlaps
resources. Eg when trying to remove 2GB at address 0xf40000000,
release_mem_region_adjustable() fails as it expects the chunk of memory
to be within the boundaries of a single resource. We then get the
warning: "Unable to release resource" and attempting to use memtrace
again gives us this error: "bash: echo: write error: Resource
temporarily unavailable"

This patch makes memtrace remove memory in chunks that are always the
same size from an address that is always equal to end_of_memory -
n*size, for some n. So hotremoving and hotadding memory of different
sizes will now not attempt to remove memory that spans multiple
resources.

Signed-off-by: Rashmica Gupta <rashmica.g@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-09-19 21:58:02 +10:00
..
boot powerpc updates for 4.19 2018-08-17 11:32:50 -07:00
configs powerpc/powernv: Don't select the cpufreq governors 2018-09-17 21:16:26 +10:00
crypto powerpc updates for 4.19 2018-08-17 11:32:50 -07:00
include powerpc/pseries/mm: call H_BLOCK_REMOVE 2018-09-17 21:17:25 +10:00
kernel powerpc/tm: Fix HTM documentation 2018-09-17 21:17:25 +10:00
kvm PPC KVM fixes for 4.19 2018-09-04 21:12:46 +02:00
lib powerpc/64: Remove static branch hints from memset() 2018-09-17 21:17:25 +10:00
math-emu License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mm Merge branch 'ida-4.19' of git://git.infradead.org/users/willy/linux-dax 2018-08-26 11:48:42 -07:00
net powerpc updates for 4.19 2018-08-17 11:32:50 -07:00
oprofile treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
perf powerpc updates for 4.19 2018-08-17 11:32:50 -07:00
platforms powerpc/memtrace: Remove memory in chunks 2018-09-19 21:58:02 +10:00
purgatory powerpc updates for 4.19 2018-08-17 11:32:50 -07:00
sysdev treewide: correct "differenciate" and "instanciate" typos 2018-08-23 18:48:43 -07:00
tools powerpc: Add a checkpatch wrapper with our preferred settings 2018-08-07 21:49:25 +10:00
xmon Merge branch 'fixes' into next 2018-08-13 15:59:06 +10:00
Kconfig powerpc: disable support for relative ksymtab references 2018-08-29 16:12:07 -07:00
Kconfig.debug Kconfig: consolidate the "Kernel hacking" menu 2018-08-02 08:06:48 +09:00
Makefile kbuild: rename LDFLAGS to KBUILD_LDFLAGS 2018-08-24 08:22:08 +09:00
Makefile.postlink License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00