On 04.08.25 17:13, Sumanth Korikkar wrote:
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 should decrement the count of nr_memmap_pages.
* For pages from the boot allocator, free_map_bootmem() is called, which
should decrement the count of the nr_memmap_boot_pages.
Ensure correct tracking of memmap pages for both early sections and non
early sections by adjusting the accounting in section_deactivate().
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 15995a352474 ("mm: report per-page metadata information")
Suggested-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Sumanth Korikkar <sumanthk@xxxxxxxxxxxxx>
---
v2: consider accounting for !CONFIG_SPARSEMEM_VMEMMAP.
mm/sparse.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/mm/sparse.c b/mm/sparse.c
index 3c012cf83cc2..b9cc9e548f80 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -680,7 +680,6 @@ static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages,
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 +855,14 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
* 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;
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Hopefully we're not missing anything important.
--
Cheers,
David / dhildenb
