diff options
Diffstat (limited to 'mm/util.c')
| -rw-r--r-- | mm/util.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/mm/util.c b/mm/util.c index 8acb936a52c8..6d1f9200f74e 100644 --- a/mm/util.c +++ b/mm/util.c @@ -407,6 +407,20 @@ struct address_space *page_mapping(struct page *page) return mapping; } +/* Slow path of page_mapcount() for compound pages */ +int __page_mapcount(struct page *page) +{ + int ret; + + ret = atomic_read(&page->_mapcount) + 1; + page = compound_head(page); + ret += atomic_read(compound_mapcount_ptr(page)) + 1; + if (PageDoubleMap(page)) + ret--; + return ret; +} +EXPORT_SYMBOL_GPL(__page_mapcount); + int overcommit_ratio_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) |