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-rw-r--r--mm/memory-failure.c31
1 files changed, 27 insertions, 4 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 77391b6f9f76..1f7fb9bf287a 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1659,12 +1659,13 @@ static int identify_page_state(unsigned long pfn, struct page *p,
* there is still more to do, hence the page refcount we took earlier
* is still needed.
*/
-static int try_to_split_thp_page(struct page *page, bool release)
+static int try_to_split_thp_page(struct page *page, unsigned int new_order,
+ bool release)
{
int ret;
lock_page(page);
- ret = split_huge_page(page);
+ ret = split_huge_page_to_order(page, new_order);
unlock_page(page);
if (ret && release)
@@ -2420,6 +2421,9 @@ try_again:
folio_unlock(folio);
if (folio_test_large(folio)) {
+ const int new_order = min_order_for_split(folio);
+ int err;
+
/*
* The flag must be set after the refcount is bumped
* otherwise it may race with THP split.
@@ -2434,7 +2438,16 @@ try_again:
* page is a valid handlable page.
*/
folio_set_has_hwpoisoned(folio);
- if (try_to_split_thp_page(p, false) < 0) {
+ err = try_to_split_thp_page(p, new_order, /* release= */ false);
+ /*
+ * If splitting a folio to order-0 fails, kill the process.
+ * Split the folio regardless to minimize unusable pages.
+ * Because the memory failure code cannot handle large
+ * folios, this split is always treated as if it failed.
+ */
+ if (err || new_order) {
+ /* get folio again in case the original one is split */
+ folio = page_folio(p);
res = -EHWPOISON;
kill_procs_now(p, pfn, flags, folio);
put_page(p);
@@ -2761,7 +2774,17 @@ static int soft_offline_in_use_page(struct page *page)
};
if (!huge && folio_test_large(folio)) {
- if (try_to_split_thp_page(page, true)) {
+ const int new_order = min_order_for_split(folio);
+
+ /*
+ * If new_order (target split order) is not 0, do not split the
+ * folio at all to retain the still accessible large folio.
+ * NOTE: if minimizing the number of soft offline pages is
+ * preferred, split it to non-zero new_order like it is done in
+ * memory_failure().
+ */
+ if (new_order || try_to_split_thp_page(page, /* new_order= */ 0,
+ /* release= */ true)) {
pr_info("%#lx: thp split failed\n", pfn);
return -EBUSY;
}