The patch titled
Subject: memblock: improve MEMBLOCK_HOTPLUG documentation
has been removed from the -mm tree. Its filename was
memblock-improve-memblock_hotplug-documentation.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: memblock: improve MEMBLOCK_HOTPLUG documentation
The description of MEMBLOCK_HOTPLUG is currently short and consequently
misleading: we're actually dealing with a memory region that might get
hotunplugged later (i.e., the platform+firmware supports it), yet it is
indicated in the firmware-provided memory map as system ram that will just
get used by the system for any purpose when not taking special care. The
firmware marked this memory region as a hot(un)plugged (e.g., hotplugged
before reboot), implying that it might get hotunplugged again later.
Whether we consider this information depends on the "movable_node" kernel
commandline parameter: only with "movable_node" set, we'll try keeping
this memory hotunpluggable, for example, by not serving early allocations
from this memory region and by letting the buddy manage it using the
ZONE_MOVABLE.
Let's make this clearer by extending the documentation.
Note: kexec *has to* indicate this memory to the second kernel. With
"movable_node" set, we don't want to place kexec-images on this memory.
Without "movable_node" set, we don't care and can place kexec-images on
this memory. In both cases, after successful memory hotunplug, kexec has
to be re-armed to update the memory map for the second kernel and to place
the kexec-images somewhere else.
Link: https://lkml.kernel.org/r/20211004093605.5830-3-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Huacai Chen <chenhuacai@xxxxxxxxxx>
Cc: Jianyong Wu <Jianyong.Wu@xxxxxxx>
Cc: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Shahab Vahedi <shahab@xxxxxxxxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Vineet Gupta <vgupta@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/memblock.h | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/include/linux/memblock.h~memblock-improve-memblock_hotplug-documentation
+++ a/include/linux/memblock.h
@@ -28,7 +28,11 @@ extern unsigned long long max_possible_p
/**
* enum memblock_flags - definition of memory region attributes
* @MEMBLOCK_NONE: no special request
- * @MEMBLOCK_HOTPLUG: hotpluggable region
+ * @MEMBLOCK_HOTPLUG: memory region indicated in the firmware-provided memory
+ * map during early boot as hot(un)pluggable system RAM (e.g., memory range
+ * that might get hotunplugged later). With "movable_node" set on the kernel
+ * commandline, try keeping this memory region hotunpluggable. Does not apply
+ * to memblocks added ("hotplugged") after early boot.
* @MEMBLOCK_MIRROR: mirrored region
* @MEMBLOCK_NOMAP: don't add to kernel direct mapping and treat as
* reserved in the memory map; refer to memblock_mark_nomap() description
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
