Merge tag 'mm-hotfixes-stable-2023-12-15-07-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "17 hotfixes. 8 are cc:stable and the other 9 pertain to post-6.6
  issues"

* tag 'mm-hotfixes-stable-2023-12-15-07-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mm/mglru: reclaim offlined memcgs harder
  mm/mglru: respect min_ttl_ms with memcgs
  mm/mglru: try to stop at high watermarks
  mm/mglru: fix underprotected page cache
  mm/shmem: fix race in shmem_undo_range w/THP
  Revert "selftests: error out if kernel header files are not yet built"
  crash_core: fix the check for whether crashkernel is from high memory
  x86, kexec: fix the wrong ifdeffery CONFIG_KEXEC
  sh, kexec: fix the incorrect ifdeffery and dependency of CONFIG_KEXEC
  mips, kexec: fix the incorrect ifdeffery and dependency of CONFIG_KEXEC
  m68k, kexec: fix the incorrect ifdeffery and build dependency of CONFIG_KEXEC
  loongarch, kexec: change dependency of object files
  mm/damon/core: make damon_start() waits until kdamond_fn() starts
  selftests/mm: cow: print ksft header before printing anything else
  mm: fix VMA heap bounds checking
  riscv: fix VMALLOC_START definition
  kexec: drop dependency on ARCH_SUPPORTS_KEXEC from CRASH_DUMP

1 files changed, 14 insertions, 9 deletions

diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index 9ae7def16cb2..f4fe593c1400 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -232,22 +232,27 @@ static inline bool lru_gen_add_folio(struct lruvec *lruvec, struct folio *folio,
 	if (folio_test_unevictable(folio) || !lrugen->enabled)
 		return false;
 	/*
-	 * There are three common cases for this page:
-	 * 1. If it's hot, e.g., freshly faulted in or previously hot and
-	 *    migrated, add it to the youngest generation.
-	 * 2. If it's cold but can't be evicted immediately, i.e., an anon page
-	 *    not in swapcache or a dirty page pending writeback, add it to the
-	 *    second oldest generation.
-	 * 3. Everything else (clean, cold) is added to the oldest generation.
+	 * There are four common cases for this page:
+	 * 1. If it's hot, i.e., freshly faulted in, add it to the youngest
+	 *    generation, and it's protected over the rest below.
+	 * 2. If it can't be evicted immediately, i.e., a dirty page pending
+	 *    writeback, add it to the second youngest generation.
+	 * 3. If it should be evicted first, e.g., cold and clean from
+	 *    folio_rotate_reclaimable(), add it to the oldest generation.
+	 * 4. Everything else falls between 2 & 3 above and is added to the
+	 *    second oldest generation if it's considered inactive, or the
+	 *    oldest generation otherwise. See lru_gen_is_active().
 	 */
 	if (folio_test_active(folio))
 		seq = lrugen->max_seq;
 	else if ((type == LRU_GEN_ANON && !folio_test_swapcache(folio)) ||
 		 (folio_test_reclaim(folio) &&
 		  (folio_test_dirty(folio) || folio_test_writeback(folio))))
-		seq = lrugen->min_seq[type] + 1;
-	else
+		seq = lrugen->max_seq - 1;
+	else if (reclaiming || lrugen->min_seq[type] + MIN_NR_GENS >= lrugen->max_seq)
 		seq = lrugen->min_seq[type];
+	else
+		seq = lrugen->min_seq[type] + 1;
 
 	gen = lru_gen_from_seq(seq);
 	flags = (gen + 1UL) << LRU_GEN_PGOFF;