[PATCH 15/25] mm/fbatch: remove shake_folio() shake_page() from memory-failure

[Hugh Dickins]

shake_folio()'s lru_add_drain_all() no longer serves a purpose, now that
the per-cpu fbatch references are gone. Are the retries in get_any_page()
then still useful? Not obvious, so keep them.

Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
---
 mm/hwpoison-inject.c |  1 -
 mm/internal.h        |  1 -
 mm/memory-failure.c  | 38 +-------------------------------------
 3 files changed, 1 insertion(+), 39 deletions(-)

diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c
index a11222572f97..9eab4b7d25b2 100644
--- a/mm/hwpoison-inject.c
+++ b/mm/hwpoison-inject.c
@@ -118,7 +118,6 @@ static int hwpoison_inject(void *data, u64 val)
 	if (!hwpoison_filter_enable)
 		goto inject;
 
-	shake_folio(folio);
 	/*
 	 * This implies unable to support non-LRU pages except free page.
 	 */
diff --git a/mm/internal.h b/mm/internal.h
index ff4bd3a14539..9a25552cbd83 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1140,7 +1140,6 @@ static inline bool node_reclaim_enabled(void)
  */
 #ifdef CONFIG_MEMORY_FAILURE
 int unmap_poisoned_folio(struct folio *folio, unsigned long pfn, bool must_kill);
-void shake_folio(struct folio *folio);
 typedef int hwpoison_filter_func_t(struct page *p);
 void hwpoison_filter_register(hwpoison_filter_func_t *filter);
 void hwpoison_filter_unregister(void);
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index aaf14608b30e..2a6a01e260ed 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -310,30 +310,6 @@ static int kill_proc(struct to_kill *tk, unsigned long pfn, int flags)
 	return ret;
 }
 
-/*
- * Unknown page type encountered. Try to check whether it can turn PageLRU by
- * lru_add_drain_all.
- */
-void shake_folio(struct folio *folio)
-{
-	if (folio_test_hugetlb(folio))
-		return;
-	/*
-	 * TODO: Could shrink slab caches here if a lightweight range-based
-	 * shrinker will be available.
-	 */
-	if (folio_test_slab(folio))
-		return;
-
-	lru_add_drain_all();
-}
-EXPORT_SYMBOL_GPL(shake_folio);
-
-static void shake_page(struct page *page)
-{
-	shake_folio(page_folio(page));
-}
-
 static unsigned long dev_pagemap_mapping_shift(struct vm_area_struct *vma,
 		unsigned long address)
 {
@@ -1459,10 +1435,8 @@ static int get_any_page(struct page *p, unsigned long flags)
 			 * We raced with (possibly temporary) unhandlable
 			 * page, retry.
 			 */
-			if (pass++ < GET_PAGE_MAX_RETRY_NUM) {
-				shake_page(p);
+			if (pass++ < GET_PAGE_MAX_RETRY_NUM)
 				goto try_again;
-			}
 			ret = -EIO;
 			goto out;
 		}
@@ -1477,7 +1451,6 @@ static int get_any_page(struct page *p, unsigned long flags)
 		 */
 		if (pass++ < GET_PAGE_MAX_RETRY_NUM) {
 			put_page(p);
-			shake_page(p);
 			count_increased = false;
 			goto try_again;
 		}
@@ -1627,7 +1600,6 @@ static bool hwpoison_user_mappings(struct folio *folio, struct page *p,
 	LIST_HEAD(tokill);
 	bool unmap_success;
 	bool forcekill;
-	bool mlocked = folio_test_mlocked(folio);
 
 	/*
 	 * Here we are interested only in user-mapped pages, so skip any
@@ -1658,13 +1630,6 @@ static bool hwpoison_user_mappings(struct folio *folio, struct page *p,
 		pr_err("%#lx: failed to unmap page (folio mapcount=%d)\n",
 		       pfn, folio_mapcount(folio));
 
-	/*
-	 * try_to_unmap() might put mlocked page in lru cache, so call
-	 * shake_page() again to ensure that it's flushed.
-	 */
-	if (mlocked)
-		shake_folio(folio);
-
 	/*
 	 * Now that the dirty bit has been propagated to the
 	 * struct page and all unmaps done we can decide if
@@ -2554,7 +2519,6 @@ int memory_failure(unsigned long pfn, int flags)
 	 * The check (unnecessarily) ignores LRU pages being isolated and
 	 * walked by the page reclaim code, however that's not a big loss.
 	 */
-	shake_folio(folio);
 
 	folio_lock(folio);
 
-- 
2.51.0