diff options
Diffstat (limited to 'mm/migrate.c')
| -rw-r--r-- | mm/migrate.c | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index b1092876e537..ae50d704e185 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1282,6 +1282,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, int page_was_mapped = 0; struct page *new_hpage; struct anon_vma *anon_vma = NULL; + struct address_space *mapping = NULL; /* * Migratability of hugepages depends on architectures and their size. @@ -1329,18 +1330,36 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, goto put_anon; if (page_mapped(hpage)) { + /* + * try_to_unmap could potentially call huge_pmd_unshare. + * Because of this, take semaphore in write mode here and + * set TTU_RMAP_LOCKED to let lower levels know we have + * taken the lock. + */ + mapping = hugetlb_page_mapping_lock_write(hpage); + if (unlikely(!mapping)) + goto unlock_put_anon; + try_to_unmap(hpage, - TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS); + TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS| + TTU_RMAP_LOCKED); page_was_mapped = 1; + /* + * Leave mapping locked until after subsequent call to + * remove_migration_ptes() + */ } if (!page_mapped(hpage)) rc = move_to_new_page(new_hpage, hpage, mode); - if (page_was_mapped) + if (page_was_mapped) { remove_migration_ptes(hpage, - rc == MIGRATEPAGE_SUCCESS ? new_hpage : hpage, false); + rc == MIGRATEPAGE_SUCCESS ? new_hpage : hpage, true); + i_mmap_unlock_write(mapping); + } +unlock_put_anon: unlock_page(new_hpage); put_anon: |