[PATCH 4/4] mm: hwpoison: handle non-anonymous THP correctly
From: Yang Shi <hidden>
Date: 2021-09-14 18:37:45
Also in:
linux-fsdevel, lkml
Subsystem:
hwpoison memory failure handling, memory management, the rest · Maintainers:
Miaohe Lin, Andrew Morton, Linus Torvalds
Currently hwpoison doesn't handle non-anonymous THP, but since v4.8 THP support for tmpfs and read-only file cache has been added. They could be offlined by split THP, just like anonymous THP. Signed-off-by: Yang Shi <redacted> --- mm/memory-failure.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 3e06cb9d5121..6f72aab8ec4a 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c@@ -1150,13 +1150,16 @@ static int __get_hwpoison_page(struct page *page) if (PageTransHuge(head)) { /* - * Non anonymous thp exists only in allocation/free time. We - * can't handle such a case correctly, so let's give it up. - * This should be better than triggering BUG_ON when kernel - * tries to touch the "partially handled" page. + * We can't handle allocating or freeing THPs, so let's give + * it up. This should be better than triggering BUG_ON when + * kernel tries to touch the "partially handled" page. + * + * page->mapping won't be initialized until the page is added + * to rmap or page cache. Use this as an indicator for if + * this is an instantiated page. */ - if (!PageAnon(head)) { - pr_err("Memory failure: %#lx: non anonymous thp\n", + if (!head->mapping) { + pr_err("Memory failure: %#lx: non instantiated thp\n", page_to_pfn(page)); return 0; }
@@ -1415,12 +1418,12 @@ static int identify_page_state(unsigned long pfn, struct page *p, static int try_to_split_thp_page(struct page *page, const char *msg) { lock_page(page); - if (!PageAnon(page) || unlikely(split_huge_page(page))) { + if (!page->mapping || unlikely(split_huge_page(page))) { unsigned long pfn = page_to_pfn(page); unlock_page(page); - if (!PageAnon(page)) - pr_info("%s: %#lx: non anonymous thp\n", msg, pfn); + if (!page->mapping) + pr_info("%s: %#lx: not instantiated thp\n", msg, pfn); else pr_info("%s: %#lx: thp split failed\n", msg, pfn); put_page(page);
--
2.26.2