mm: don't account memmap on failure

Patch series "Fixes for memmap accounting", v4.

Memmap accounting provides us with observability of how much memory is
used for per-page metadata: i.e. "struct page"'s and "struct page_ext".
It also provides with information of how much was allocated using
boot allocator (i.e. not part of MemTotal), and how much was allocated
using buddy allocated (i.e. part of MemTotal).

This small series fixes a few problems that were discovered with the
original patch.


This patch (of 3):

When we fail to allocate the mmemmap in alloc_vmemmap_page_list(), do not
account any already-allocated pages: we're going to free all them before
we return from the function.

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Fixes: 15995a3 ("mm: report per-page metadata information")
Signed-off-by: Pasha Tatashin <[email protected]>
Reviewed-by: Fan Ni <[email protected]>
Reviewed-by: Yosry Ahmed <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Tested-by: Alison Schofield <[email protected]>
Reviewed-by: Muchun Song <[email protected]>
Acked-by: David Rientjes <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Domenico Cerasuolo <[email protected]>
Cc: Joel Granados <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Li Zhijian <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Nhat Pham <[email protected]>
Cc: Sourav Panda <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Yi Zhang <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

mm/hugetlb_vmemmap.c

@@ -392,13 +392,10 @@ static int alloc_vmemmap_page_list(unsigned long start, unsigned long end,
 
 	for (i = 0; i < nr_pages; i++) {
 		page = alloc_pages_node(nid, gfp_mask, 0);
-		if (!page) {
-			mod_node_page_state(NODE_DATA(nid), NR_MEMMAP, i);
+		if (!page)
 			goto out;
-		}
 		list_add(&page->lru, list);
 	}
-
 	mod_node_page_state(NODE_DATA(nid), NR_MEMMAP, nr_pages);
 
 	return 0;