We're going to use migration entries instead of compound_lock() to stabilize page refcounts. Setup and remove migration entries require page to be locked. Some of split_huge_page() callers already have the page locked. Let's require everybody to lock the page before calling split_huge_page(). Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Tested-by: Sasha Levin <sasha.levin@xxxxxxxxxx> Tested-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> --- mm/memory-failure.c | 10 ++++++++-- mm/migrate.c | 8 ++++++-- 2 files changed, 14 insertions(+), 4 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index ef33ccf37224..f32a607d1aa3 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1143,15 +1143,18 @@ int memory_failure(unsigned long pfn, int trapno, int flags) put_page(hpage); return -EBUSY; } + lock_page(hpage); if (unlikely(split_huge_page(hpage))) { pr_err("MCE: %#lx: thp split failed\n", pfn); if (TestClearPageHWPoison(p)) atomic_long_sub(nr_pages, &num_poisoned_pages); + unlock_page(hpage); put_page(p); if (p != hpage) put_page(hpage); return -EBUSY; } + unlock_page(hpage); VM_BUG_ON_PAGE(!page_count(p), p); hpage = compound_head(p); } @@ -1714,10 +1717,13 @@ int soft_offline_page(struct page *page, int flags) return -EBUSY; } if (!PageHuge(page) && PageTransHuge(hpage)) { - if (PageAnon(hpage) && unlikely(split_huge_page(hpage))) { + lock_page(page); + ret = split_huge_page(hpage); + unlock_page(page); + if (unlikely(ret)) { pr_info("soft offline: %#lx: failed to split THP\n", pfn); - return -EBUSY; + return ret; } } diff --git a/mm/migrate.c b/mm/migrate.c index 67970faf544d..a9dbfd356e9d 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -933,9 +933,13 @@ static ICE_noinline int unmap_and_move(new_page_t get_new_page, goto out; } - if (unlikely(PageTransHuge(page))) - if (unlikely(split_huge_page(page))) + if (unlikely(PageTransHuge(page))) { + lock_page(page); + rc = split_huge_page(page); + unlock_page(page); + if (rc) goto out; + } rc = __unmap_and_move(page, newpage, force, mode); -- 2.1.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>