The patch titled Subject: mm: fix accounting of memmap pages for early sections has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-fix-accounting-of-memmap-pages-for-early-sections.patch
This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...
This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days
------------------------------------------------------ From: Sumanth Korikkar sumanthk@linux.ibm.com Subject: mm: fix accounting of memmap pages for early sections Date: Mon, 4 Aug 2025 10:40:15 +0200
memmap pages can be allocated either from the memblock (boot) allocator during early boot or from the buddy allocator.
When these memmap pages are removed via arch_remove_memory(), the deallocation path depends on their source:
* For pages from the buddy allocator, depopulate_section_memmap() is called, which also decrements the count of nr_memmap_pages.
* For pages from the boot allocator, free_map_bootmem() is called. But it currently does not adjust the nr_memmap_boot_pages.
To fix this inconsistency, update free_map_bootmem() to also decrement the nr_memmap_boot_pages count by invoking memmap_boot_pages_add(), mirroring how free_vmemmap_page() handles this for boot-allocated pages.
This ensures correct tracking of memmap pages regardless of allocation source.
Link: https://lkml.kernel.org/r/20250804084015.270570-1-sumanthk@linux.ibm.com Fixes: 15995a352474 ("mm: report per-page metadata information") Signed-off-by: Sumanth Korikkar sumanthk@linux.ibm.com Cc: Alexander Gordeev agordeev@linux.ibm.com Cc: David Hildenbrand david@redhat.com Cc: Gerald Schaefer gerald.schaefer@linux.ibm.com Cc: Heiko Carstens hca@linux.ibm.com Cc: Vasily Gorbik gor@linux.ibm.com Cc: David Rientjes rientjes@google.com Cc: Pasha Tatashin pasha.tatashin@soleen.com Cc: Sourav Panda souravpanda@google.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
mm/sparse.c | 1 + 1 file changed, 1 insertion(+)
--- a/mm/sparse.c~mm-fix-accounting-of-memmap-pages-for-early-sections +++ a/mm/sparse.c @@ -688,6 +688,7 @@ static void free_map_bootmem(struct page unsigned long start = (unsigned long)memmap; unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);
+ memmap_boot_pages_add(-1L * (DIV_ROUND_UP(end - start, PAGE_SIZE))); vmemmap_free(start, end, NULL); }
_
Patches currently in -mm which might be from sumanthk@linux.ibm.com are
mm-fix-accounting-of-memmap-pages-for-early-sections.patch