[merged mm-hotfixes-stable] mm-fix-accounting-of-memmap-pages.patch removed from -mm tree
From: Andrew Morton <akpm@linux-foundation.org>
Date: 2025-08-28 05:46:26
Also in:
mm-commits
The quilt patch titled
Subject: mm: fix accounting of memmap pages
has been removed from the -mm tree. Its filename was
mm-fix-accounting-of-memmap-pages.patch
This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Sumanth Korikkar <redacted>
Subject: mm: fix accounting of memmap pages
Date: Thu, 7 Aug 2025 20:35:45 +0200
For !CONFIG_SPARSEMEM_VMEMMAP, memmap page accounting is currently done
upfront in sparse_buffer_init(). However, sparse_buffer_alloc() may
return NULL in failure scenario.
Also, memmap pages may be allocated either from the memblock allocator
during early boot or from the buddy allocator. When removed via
arch_remove_memory(), accounting of memmap pages must reflect the original
allocation source.
To ensure correctness:
* Account memmap pages after successful allocation in sparse_init_nid()
and section_activate().
* Account memmap pages in section_deactivate() based on allocation
source.
Link: https://lkml.kernel.org/r/20250807183545.1424509-1-sumanthk@linux.ibm.com
Fixes: 15995a352474 ("mm: report per-page metadata information")
Signed-off-by: Sumanth Korikkar <redacted>
Suggested-by: David Hildenbrand <redacted>
Reviewed-by: Wei Yang <redacted>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: <redacted>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/sparse-vmemmap.c | 5 -----
mm/sparse.c | 15 +++++++++------
2 files changed, 9 insertions(+), 11 deletions(-)
--- a/mm/sparse.c~mm-fix-accounting-of-memmap-pages
+++ a/mm/sparse.c@@ -454,9 +454,6 @@ static void __init sparse_buffer_init(un */ sparsemap_buf = memmap_alloc(size, section_map_size(), addr, nid, true); sparsemap_buf_end = sparsemap_buf + size; -#ifndef CONFIG_SPARSEMEM_VMEMMAP - memmap_boot_pages_add(DIV_ROUND_UP(size, PAGE_SIZE)); -#endif } static void __init sparse_buffer_fini(void)
@@ -567,6 +564,8 @@ static void __init sparse_init_nid(int n sparse_buffer_fini(); goto failed; } + memmap_boot_pages_add(DIV_ROUND_UP(PAGES_PER_SECTION * sizeof(struct page), + PAGE_SIZE)); sparse_init_early_section(nid, map, pnum, 0); } }
@@ -680,7 +679,6 @@ static void depopulate_section_memmap(un unsigned long start = (unsigned long) pfn_to_page(pfn); unsigned long end = start + nr_pages * sizeof(struct page); - memmap_pages_add(-1L * (DIV_ROUND_UP(end - start, PAGE_SIZE))); vmemmap_free(start, end, altmap); } static void free_map_bootmem(struct page *memmap)
@@ -856,10 +854,14 @@ static void section_deactivate(unsigned * The memmap of early sections is always fully populated. See * section_activate() and pfn_valid() . */ - if (!section_is_early) + if (!section_is_early) { + memmap_pages_add(-1L * (DIV_ROUND_UP(nr_pages * sizeof(struct page), PAGE_SIZE))); depopulate_section_memmap(pfn, nr_pages, altmap); - else if (memmap) + } else if (memmap) { + memmap_boot_pages_add(-1L * (DIV_ROUND_UP(nr_pages * sizeof(struct page), + PAGE_SIZE))); free_map_bootmem(memmap); + } if (empty) ms->section_mem_map = (unsigned long)NULL;
@@ -904,6 +906,7 @@ static struct page * __meminit section_a section_deactivate(pfn, nr_pages, altmap); return ERR_PTR(-ENOMEM); } + memmap_pages_add(DIV_ROUND_UP(nr_pages * sizeof(struct page), PAGE_SIZE)); return memmap; } --- a/mm/sparse-vmemmap.c~mm-fix-accounting-of-memmap-pages +++ a/mm/sparse-vmemmap.c
@@ -578,11 +578,6 @@ struct page * __meminit __populate_secti if (r < 0) return NULL; - if (system_state == SYSTEM_BOOTING) - memmap_boot_pages_add(DIV_ROUND_UP(end - start, PAGE_SIZE)); - else - memmap_pages_add(DIV_ROUND_UP(end - start, PAGE_SIZE)); - return pfn_to_page(pfn); }
_ Patches currently in -mm which might be from sumanthk@linux.ibm.com are