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Merge patch series "mm/mm_init: don't overlap zones with kernelcore=mirror"

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Mike Rapoport <rppt@kernel.org> says:

Make the behaviour of kernelcore= parameter uniform and treat mirror
just as another way to size the zones and cleanup a weird part of the
memory map initialization.

For example, for the memory layout below with the first two memory
ranges being mirrored (flags=0x2)

  memory[0x0]     [0x0000000000001000-0x000000000009efff], 0x000000000009e000 bytes on node 0 flags: 0x2
  memory[0x1]     [0x0000000000100000-0x00000000bffdefff], 0x00000000bfedf000 bytes on node 0 flags: 0x2
  memory[0x2]     [0x0000000100000000-0x000000013fffffff], 0x0000000040000000 bytes on node 0 flags: 0x2
  memory[0x3]     [0x0000000140000000-0x00000001bfffffff], 0x0000000080000000 bytes on node 0 flags: 0x0

with kernelcore=mirror set zone ranges would be

  Normal  [100000, 1c0000]
  Movable [140000, 1c0000]

and range [140000, 1c0000] is spanned by both NORMAL and MOVABLE zones.

This range will be passed twice to memmap_init_range() - once for each
zone that spans it.
The memory map for this range will be initialized as ZONE_NORMAL during the
first pass and skipped because of overlap_memmap_init() during the second
pass (ZONE_MOVABLE initialization), although the pages in this range
actually belong to ZONE_MOVABLE.

Aligning kernelcore=mirror behaviour with other variants of
kernelcore=/movablecore= resolves this issue and makes the code less
obfuscated.

patches from https://patch.msgid.link/20260630072212.624305-1-rppt@kernel.org
  mm/mm_init: don't overlap NORMAL and MOVABLE zones with kernelcore=mirror
  mm/mm_init: drop overlap_memmap_init()

Link: https://patch.msgid.link/20260630072212.624305-1-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
This commit is contained in:
Mike Rapoport (Microsoft) 2026-07-02 09:26:57 +03:00
commit b69c2a1fa9
1 changed files with 3 additions and 57 deletions
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60
mm/mm_init.c
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@ -799,28 +799,6 @@ void __meminit init_deferred_page(unsigned long pfn, int nid)
__init_deferred_page(pfn, nid);
}
/* If zone is ZONE_MOVABLE but memory is mirrored, it is an overlapped init */
static bool __meminit
overlap_memmap_init(unsigned long zone, unsigned long *pfn)
{
static struct memblock_region *r __meminitdata;
if (mirrored_kernelcore && zone == ZONE_MOVABLE) {
if (!r || *pfn >= memblock_region_memory_end_pfn(r)) {
for_each_mem_region(r) {
if (*pfn < memblock_region_memory_end_pfn(r))
break;
}
}
if (*pfn >= memblock_region_memory_base_pfn(r) &&
memblock_is_mirror(r)) {
*pfn = memblock_region_memory_end_pfn(r);
return true;
}
}
return false;
}
/*
* Only struct pages that correspond to ranges defined by memblock.memory
* are zeroed and initialized by going through __init_single_page() during
@ -907,8 +885,6 @@ void __meminit memmap_init_range(unsigned long size, int nid, unsigned long zone
* function. They do not exist on hotplugged memory.
*/
if (context == MEMINIT_EARLY) {
if (overlap_memmap_init(zone, &pfn))
continue;
if (defer_init(nid, pfn, zone_end_pfn)) {
deferred_struct_pages = true;
break;
@ -1174,9 +1150,8 @@ static void __init adjust_zone_range_for_zone_movable(int nid,
arch_zone_highest_possible_pfn[movable_zone]);
/* Adjust for ZONE_MOVABLE starting within this range */
} else if (!mirrored_kernelcore &&
*zone_start_pfn < zone_movable_pfn[nid] &&
*zone_end_pfn > zone_movable_pfn[nid]) {
} else if (*zone_start_pfn < zone_movable_pfn[nid] &&
*zone_end_pfn > zone_movable_pfn[nid]) {
*zone_end_pfn = zone_movable_pfn[nid];
/* Check if this whole range is within ZONE_MOVABLE */
@ -1224,40 +1199,11 @@ static unsigned long __init zone_absent_pages_in_node(int nid,
unsigned long zone_start_pfn,
unsigned long zone_end_pfn)
{
unsigned long nr_absent;
/* zone is empty, we don't have any absent pages */
if (zone_start_pfn == zone_end_pfn)
return 0;
nr_absent = __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
/*
* ZONE_MOVABLE handling.
* Treat pages to be ZONE_MOVABLE in ZONE_NORMAL as absent pages
* and vice versa.
*/
if (mirrored_kernelcore && zone_movable_pfn[nid]) {
unsigned long start_pfn, end_pfn;
struct memblock_region *r;
for_each_mem_region(r) {
start_pfn = clamp(memblock_region_memory_base_pfn(r),
zone_start_pfn, zone_end_pfn);
end_pfn = clamp(memblock_region_memory_end_pfn(r),
zone_start_pfn, zone_end_pfn);
if (zone_type == ZONE_MOVABLE &&
memblock_is_mirror(r))
nr_absent += end_pfn - start_pfn;
if (zone_type == ZONE_NORMAL &&
!memblock_is_mirror(r))
nr_absent += end_pfn - start_pfn;
}
}
return nr_absent;
return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
}
/*