diff options
| -rw-r--r-- | include/linux/mmzone.h | 4 | ||||
| -rw-r--r-- | mm/sparse.c | 3 |
2 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 09d381b71fd..ae19af5ec02 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1137,6 +1137,10 @@ struct mem_section { struct page_cgroup *page_cgroup; unsigned long pad; #endif + /* + * WARNING: mem_section must be a power-of-2 in size for the + * calculation and use of SECTION_ROOT_MASK to make sense. + */ }; #ifdef CONFIG_SPARSEMEM_EXTREME diff --git a/mm/sparse.c b/mm/sparse.c index 1c91f0d3f6a..3194ec41472 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -481,6 +481,9 @@ void __init sparse_init(void) struct page **map_map; #endif + /* see include/linux/mmzone.h 'struct mem_section' definition */ + BUILD_BUG_ON(!is_power_of_2(sizeof(struct mem_section))); + /* Setup pageblock_order for HUGETLB_PAGE_SIZE_VARIABLE */ set_pageblock_order(); |