diff options
Diffstat (limited to 'mm/huge_memory.c')
| -rw-r--r-- | mm/huge_memory.c | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 1a168e4..86975de 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2390,6 +2390,21 @@ int page_trans_huge_mapcount(struct page *page, int *total_mapcount) return ret; } +/* Racy check whether the huge page can be split */ +bool can_split_huge_page(struct page *page, int *pextra_pins) +{ + int extra_pins; + + /* Additional pins from radix tree */ + if (PageAnon(page)) + extra_pins = PageSwapCache(page) ? HPAGE_PMD_NR : 0; + else + extra_pins = HPAGE_PMD_NR; + if (pextra_pins) + *pextra_pins = extra_pins; + return total_mapcount(page) == page_count(page) - extra_pins - 1; +} + /* * This function splits huge page into normal pages. @page can point to any * subpage of huge page to split. Split doesn't change the position of @page. @@ -2437,7 +2452,6 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) ret = -EBUSY; goto out; } - extra_pins = PageSwapCache(page) ? HPAGE_PMD_NR : 0; mapping = NULL; anon_vma_lock_write(anon_vma); } else { @@ -2449,8 +2463,6 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) goto out; } - /* Addidional pins from radix tree */ - extra_pins = HPAGE_PMD_NR; anon_vma = NULL; i_mmap_lock_read(mapping); } @@ -2459,7 +2471,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) * Racy check if we can split the page, before freeze_page() will * split PMDs */ - if (total_mapcount(head) != page_count(head) - extra_pins - 1) { + if (!can_split_huge_page(head, &extra_pins)) { ret = -EBUSY; goto out_unlock; } |
