AI Trajectory

Trajectory: (Expand/Collapse All)
Seq	Timestamp	Type	Name	Duration
0/0	2026/08/03 17:58	flow	patch-triage	12m Args: null Results: { "EnableConfigs": [ "TRANSPARENT_HUGEPAGE", "MEMCG", "SHMEM" ], "FocusSymbols": [ "shmem_unused_huge_scan", "shmem_unused_huge_count", "shmem_evict_inode", "shmem_fill_super" ], "Reasoning": "The patch modifies the tmpfs/shmem unused huge page shrinker to use a per-memcg list_lru instead of a global list. This involves functional changes to the shrinker entry points (shmem_unused_huge_scan, shmem_unused_huge_count), inode eviction (shmem_evict_inode), and superblock initialization (shmem_fill_super). The code is reachable in standard environments when tmpfs is used with transparent huge pages and memory cgroups.", "WorthFuzzing": true }
1/1	2026/08/03 17:58	action	read-patch-diff	0m Args: null Results: { "PatchDiff": "commit 2299e5bef46e9b07b0292fcac4e0d82980481cb7\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Mon Aug 3 17:58:53 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/fs/super.c b/fs/super.c\nindex 5feecf5d9038d..36b249f002a9a 100644\n--- a/fs/super.c\n+++ b/fs/super.c\n@@ -171,19 +171,6 @@ static void super_wake(struct super_block sb, unsigned int flag)\n \twake_up_var(\u0026sb-\u003es_flags);\n }\n \n-/\n- * The s_op-\u003enr_cached_objects hooks (used for example by btrfs and xfs)\n- * operate on filesystem-global state and ignore sc-\u003ememcg. Driving them\n- * from per-memcg shrink_slab_memcg() invocations only burns CPU walking\n- * per-cpu counters and queueing duplicate work: the actual reclaim happens on\n- * the global path (kswapd or root direct reclaim) regardless. Restrict them\n- * to that path.\n- /\n-static inline bool super_fs_objects_eligible(struct shrink_control sc)\n-{\n-\treturn !sc-\u003ememcg \|\| mem_cgroup_is_root(sc-\u003ememcg);\n-}\n-\n /\n One thing we have to be careful of with a per-sb shrinker is that we don't\n * drop the last active reference to the superblock from within the shrinker.\n@@ -213,7 +200,7 @@ static unsigned long super_cache_scan(struct shrinker shrink,\n \tif (!super_trylock_shared(sb))\n \t\treturn SHRINK_STOP;\n \n-\tif (sb-\u003es_op-\u003enr_cached_objects \u0026\u0026 super_fs_objects_eligible(sc))\n+\tif (sb-\u003es_op-\u003enr_cached_objects)\n \t\tfs_objects = sb-\u003es_op-\u003enr_cached_objects(sb, sc);\n \n \tinodes = list_lru_shrink_count(\u0026sb-\u003es_inode_lru, sc);\n@@ -274,8 +261,7 @@ static unsigned long super_cache_count(struct shrinker shrink,\n \t\treturn 0;\n \tsmp_rmb();\n \n-\tif (sb-\u003es_op \u0026\u0026 sb-\u003es_op-\u003enr_cached_objects \u0026\u0026\n-\t super_fs_objects_eligible(sc))\n+\tif (sb-\u003es_op \u0026\u0026 sb-\u003es_op-\u003enr_cached_objects)\n \t\ttotal_objects = sb-\u003es_op-\u003enr_cached_objects(sb, sc);\n \n \ttotal_objects += list_lru_shrink_count(\u0026sb-\u003es_dentry_lru, sc);\ndiff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h\nindex 5663dff53186e..aeb59901a840c 100644\n--- a/include/linux/shmem_fs.h\n+++ b/include/linux/shmem_fs.h\n@@ -11,6 +11,7 @@\n #include \u003clinux/fs_parser.h\u003e\n #include \u003clinux/userfaultfd_k.h\u003e\n #include \u003clinux/bits.h\u003e\n+#include \u003clinux/list_lru.h\u003e\n \n /* inode in-kernel data /\n \n@@ -54,6 +55,11 @@ struct shmem_inode_info {\n \tstruct dquot __rcu\ti_dquot[MAXQUOTAS];\n #endif\n \tstruct inode\t\tvfs_inode;\n+\n+#ifdef CONFIG_TRANSPARENT_HUGEPAGE\n+\tstruct mem_cgroup\tshrinklist_memcg;\n+\tint\t\t\tshrinklist_nid;\n+#endif\n };\n \n #define SHMEM_FL_USER_VISIBLE\t\t(FS_FL_USER_VISIBLE \| FS_CASEFOLD_FL)\n@@ -83,9 +89,9 @@ struct shmem_sb_info {\n \tino_t next_ino;\t\t / The next per-sb inode number to use /\n \tino_t __percpu ino_batch; /* The next per-cpu inode number to use /\n \tstruct mempolicy mpol; /* default memory policy for mappings /\n-\tspinlock_t shrinklist_lock; / Protects shrinklist /\n-\tstruct list_head shrinklist; / List of shinkable inodes /\n-\tunsigned long shrinklist_len; / Length of shrinklist /\n+#ifdef CONFIG_TRANSPARENT_HUGEPAGE\n+\tstruct list_lru shrinklist; / List of shrinkable inodes /\n+#endif\n \tstruct shmem_quota_limits qlimits; / Default quota limits /\n \tstruct simple_xattr_cache xa_cache;\n };\ndiff --git a/mm/shmem.c b/mm/shmem.c\nindex 74dc3d900067a..704353852ae26 100644\n--- a/mm/shmem.c\n+++ b/mm/shmem.c\n@@ -724,51 +724,237 @@ static const char shmem_format_huge(int huge)\n }\n #endif\n \n-static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info sbinfo,\n-\t\tstruct shrink_control sc, unsigned long nr_to_free)\n+static bool is_shmem_unused_huge_isolated(struct shmem_inode_info info)\n {\n-\tLIST_HEAD(list), pos, next;\n-\tstruct inode inode;\n+\n+\treturn info-\u003eshrinklist_nid == -1;\n+}\n+\n+static void set_shmem_unused_huge_isolated(struct shmem_inode_info info)\n+{\n+\tinfo-\u003eshrinklist_nid = -1;\n+}\n+\n+static struct mem_cgroup shmem_get_and_clear_memcg(struct shmem_inode_info info)\n+{\n+\tstruct mem_cgroup memcg = info-\u003eshrinklist_memcg;\n+\n+\tinfo-\u003eshrinklist_memcg = NULL;\n+\n+\treturn memcg;\n+}\n+\n+#ifdef CONFIG_MEMCG\n+static struct mem_cgroup \n+shmem_unused_huge_alloc_lru(struct shmem_sb_info sbinfo, struct folio folio,\n+\t\t\t gfp_t gfp)\n+{\n+\tstruct mem_cgroup memcg;\n+\tint ret;\n+\n+\tmemcg = get_mem_cgroup_from_folio(folio);\n+\tif (!memcg)\n+\t\treturn NULL;\n+\n+\tret = memcg_list_lru_alloc(memcg, \u0026sbinfo-\u003eshrinklist, gfp);\n+\tif (ret) {\n+\t\tmem_cgroup_put(memcg);\n+\t\treturn ERR_PTR(ret);\n+\t}\n+\n+\treturn memcg;\n+}\n+#else\n+static struct mem_cgroup \n+shmem_unused_huge_alloc_lru(struct shmem_sb_info sbinfo, struct folio folio,\n+\t\t\t gfp_t gfp)\n+{\n+\treturn NULL;\n+}\n+#endif\n+\n+static void shmem_unused_huge_add(struct inode inode, struct folio folio,\n+\t\t\t\t gfp_t gfp)\n+{\n+\tstruct shmem_inode_info info = SHMEM_I(inode);\n+\tstruct shmem_sb_info sbinfo = SHMEM_SB(inode-\u003ei_sb);\n+\tint nid = folio_nid(folio);\n+\tstruct mem_cgroup memcg = NULL, old_memcg = NULL;\n+\n+\tmemcg = shmem_unused_huge_alloc_lru(sbinfo, folio, gfp);\n+\tif (IS_ERR(memcg))\n+\t\treturn;\n+\n+\tspin_lock(\u0026info-\u003elock);\n+\tif (!list_empty(\u0026info-\u003eshrinklist)) {\n+\t\t/ isolated on scan list, let shrink handle it /\n+\t\tif (is_shmem_unused_huge_isolated(info))\n+\t\t\tgoto unlock;\n+\n+\t\tif (info-\u003eshrinklist_nid == nid \u0026\u0026\n+\t\t info-\u003eshrinklist_memcg == memcg)\n+\t\t\tgoto unlock;\n+\n+\t\tlist_lru_del(\u0026sbinfo-\u003eshrinklist, \u0026info-\u003eshrinklist,\n+\t\t\t info-\u003eshrinklist_nid, info-\u003eshrinklist_memcg);\n+\t\told_memcg = shmem_get_and_clear_memcg(info);\n+\t}\n+\n+\tinfo-\u003eshrinklist_memcg = memcg;\n+\tinfo-\u003eshrinklist_nid = nid;\n+\tlist_lru_add(\u0026sbinfo-\u003eshrinklist, \u0026info-\u003eshrinklist, nid, memcg);\n+\tmemcg = NULL;\n+unlock:\n+\tspin_unlock(\u0026info-\u003elock);\n+\tmem_cgroup_put(old_memcg);\n+\tmem_cgroup_put(memcg);\n+}\n+\n+static void shmem_unused_huge_del(struct inode inode)\n+{\n+\tstruct shmem_inode_info info = SHMEM_I(inode);\n+\tstruct shmem_sb_info sbinfo = SHMEM_SB(inode-\u003ei_sb);\n+\tstruct mem_cgroup memcg = NULL;\n+\n+\tspin_lock(\u0026info-\u003elock);\n+\tif (!list_empty(\u0026info-\u003eshrinklist)) {\n+\t\tlist_lru_del(\u0026sbinfo-\u003eshrinklist, \u0026info-\u003eshrinklist,\n+\t\t\t info-\u003eshrinklist_nid, info-\u003eshrinklist_memcg);\n+\t\tmemcg = shmem_get_and_clear_memcg(info);\n+\t}\n+\tspin_unlock(\u0026info-\u003elock);\n+\n+\tmem_cgroup_put(memcg);\n+}\n+\n+struct shmem_unused_huge_scan {\n+\tstruct list_head list;\n+\tstruct shrink_control sc;\n+};\n+\n+static enum lru_status shmem_unused_huge_isolate(struct list_head item,\n+\t\t\t\t\t\t struct list_lru_one lru,\n+\t\t\t\t\t\t void arg)\n+{\n+\tstruct shmem_unused_huge_scan scan = arg;\n \tstruct shmem_inode_info info;\n-\tstruct folio folio;\n-\tunsigned long batch = sc ? sc-\u003enr_to_scan : 128;\n-\tunsigned long split = 0, freed = 0;\n+\tstruct inode inode;\n+\tstruct mem_cgroup memcg = NULL;\n \n-\tif (list_empty(\u0026sbinfo-\u003eshrinklist))\n-\t\treturn SHRINK_STOP;\n+\tinfo = list_entry(item, struct shmem_inode_info, shrinklist);\n \n-\tspin_lock(\u0026sbinfo-\u003eshrinklist_lock);\n-\tlist_for_each_safe(pos, next, \u0026sbinfo-\u003eshrinklist) {\n-\t\tinfo = list_entry(pos, struct shmem_inode_info, shrinklist);\n+\t/\n+\t Use trylock to avoid ABBA deadlock: add/del path takes info-\u003elock\n+\t * before the list_lru bucket lock, while here the order is reversed.\n+\t /\n+\tif (!spin_trylock(\u0026info-\u003elock))\n+\t\treturn LRU_SKIP;\n \n-\t\t/ pin the inode /\n-\t\tinode = igrab(\u0026info-\u003evfs_inode);\n+\t/ pin the inode /\n+\tinode = igrab(\u0026info-\u003evfs_inode);\n+\t/ inode is about to be evicted /\n+\tif (!inode) {\n+\t\tlist_lru_isolate(lru, item);\n+\t\tmemcg = shmem_get_and_clear_memcg(info);\n+\t\tspin_unlock(\u0026info-\u003elock);\n+\t\tmem_cgroup_put(memcg);\n+\t\treturn LRU_REMOVED;\n+\t}\n \n-\t\t/ inode is about to be evicted /\n-\t\tif (!inode) {\n-\t\t\tlist_del_init(\u0026info-\u003eshrinklist);\n-\t\t\tgoto next;\n-\t\t}\n+\tlist_lru_isolate(lru, item);\n+\tmemcg = shmem_get_and_clear_memcg(info);\n+\tset_shmem_unused_huge_isolated(info);\n+\tlist_add_tail(\u0026info-\u003eshrinklist, \u0026scan-\u003elist);\n+\tspin_unlock(\u0026info-\u003elock);\n+\tmem_cgroup_put(memcg);\n \n-\t\tlist_move(\u0026info-\u003eshrinklist, \u0026list);\n-next:\n-\t\tsbinfo-\u003eshrinklist_len--;\n-\t\tif (!--batch)\n-\t\t\tbreak;\n+\treturn LRU_REMOVED;\n+}\n+\n+static bool is_shmem_unused_huge_match(struct folio folio,\n+\t\t\t\t struct shrink_control sc)\n+{\n+\tstruct mem_cgroup memcg = NULL;\n+\tbool match;\n+\n+\t/\n+\t Only non-root memcg reclaim needs to match the folio charge against\n+\t * sc-\u003ememcg. Skip the folio memcg check for the following cases:\n+\t * 1. shmem quota reclaim (sc == NULL)\n+\t * 2. global shrinker reclaim\n+\t * 3. root memcg reclaim\n+\t /\n+\tif (!sc \|\| !sc-\u003ememcg \|\| mem_cgroup_is_root(sc-\u003ememcg))\n+\t\treturn true;\n+\n+\tif (folio_nid(folio) != sc-\u003enid)\n+\t\treturn false;\n+\n+\tmemcg = get_mem_cgroup_from_folio(folio);\n+\tmatch = memcg == sc-\u003ememcg;\n+\tmem_cgroup_put(memcg);\n+\n+\treturn match;\n+}\n+\n+static void shmem_unused_huge_drop(struct inode inode)\n+{\n+\tstruct shmem_inode_info info = SHMEM_I(inode);\n+\n+\tspin_lock(\u0026info-\u003elock);\n+\tlist_del_init(\u0026info-\u003eshrinklist);\n+\tspin_unlock(\u0026info-\u003elock);\n+}\n+\n+static void shmem_unused_huge_requeue(struct inode inode, struct folio folio)\n+{\n+\tstruct shmem_inode_info info = SHMEM_I(inode);\n+\tstruct shmem_sb_info sbinfo = SHMEM_SB(inode-\u003ei_sb);\n+\tstruct mem_cgroup memcg;\n+\tint nid = folio_nid(folio);\n+\n+\tmemcg = shmem_unused_huge_alloc_lru(sbinfo, folio, GFP_NOWAIT);\n+\tif (IS_ERR(memcg)) {\n+\t\tshmem_unused_huge_drop(inode);\n+\t\treturn;\n \t}\n-\tspin_unlock(\u0026sbinfo-\u003eshrinklist_lock);\n \n-\tlist_for_each_safe(pos, next, \u0026list) {\n-\t\tpgoff_t next, end;\n+\tspin_lock(\u0026info-\u003elock);\n+\t/* Requeue the inode to shrinklist /\n+\tlist_del_init(\u0026info-\u003eshrinklist);\n+\tlist_lru_add(\u0026sbinfo-\u003eshrinklist, \u0026info-\u003eshrinklist, nid, memcg);\n+\tinfo-\u003eshrinklist_memcg = memcg;\n+\tinfo-\u003eshrinklist_nid = nid;\n+\tspin_unlock(\u0026info-\u003elock);\n+}\n+\n+static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info sbinfo,\n+\t\tstruct shrink_control sc, unsigned long nr_to_free)\n+{\n+\tstruct shmem_unused_huge_scan scan;\n+\tstruct inode inode;\n+\tstruct shmem_inode_info info;\n+\tstruct folio folio;\n+\tstruct list_head pos, next;\n+\tunsigned long split = 0, freed = 0;\n+\n+\tINIT_LIST_HEAD(\u0026scan.list);\n+\tscan.sc = sc;\n+\tif (sc)\n+\t\tlist_lru_shrink_walk(\u0026sbinfo-\u003eshrinklist, sc,\n+\t\t\t\t shmem_unused_huge_isolate, \u0026scan);\n+\telse\n+\t\tlist_lru_walk(\u0026sbinfo-\u003eshrinklist, shmem_unused_huge_isolate,\n+\t\t\t \u0026scan, 128);\n+\n+\tlist_for_each_safe(pos, next, \u0026scan.list) {\n+\t\tpgoff_t folio_end, end;\n \t\tloff_t i_size;\n \t\tint ret;\n \n \t\tinfo = list_entry(pos, struct shmem_inode_info, shrinklist);\n \t\tinode = \u0026info-\u003evfs_inode;\n \n-\t\tif (nr_to_free \u0026\u0026 freed \u003e= nr_to_free)\n-\t\t\tgoto move_back;\n-\n \t\ti_size = i_size_read(inode);\n \t\tfolio = filemap_get_entry(inode-\u003ei_mapping, i_size / PAGE_SIZE);\n \t\tif (!folio \|\| xa_is_value(folio))\n@@ -781,13 +967,19 @@ static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info sbinfo,\n \t\t}\n \n \t\t/ Check if there is anything to gain from splitting /\n-\t\tnext = folio_next_index(folio);\n+\t\tfolio_end = folio_next_index(folio);\n \t\tend = shmem_fallocend(inode, DIV_ROUND_UP(i_size, PAGE_SIZE));\n-\t\tif (end \u003c= folio-\u003eindex \|\| end \u003e= next) {\n+\t\tif (end \u003c= folio-\u003eindex \|\| end \u003e= folio_end) {\n \t\t\tfolio_put(folio);\n \t\t\tgoto drop;\n \t\t}\n \n+\t\tif (!is_shmem_unused_huge_match(folio, scan.sc))\n+\t\t\tgoto move_back;\n+\n+\t\tif (nr_to_free \u0026\u0026 freed \u003e= nr_to_free)\n+\t\t\tgoto move_back;\n+\n \t\t/\n \t\t * Move the inode on the list back to shrinklist if we failed\n \t\t * to lock the page at this time.\n@@ -795,35 +987,30 @@ static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info sbinfo,\n \t\t Waiting for the lock may lead to deadlock in the\n \t\t * reclaim path.\n \t\t /\n-\t\tif (!folio_trylock(folio)) {\n-\t\t\tfolio_put(folio);\n+\t\tif (!folio_trylock(folio))\n+\t\t\tgoto move_back;\n+\n+\t\tif (!is_shmem_unused_huge_match(folio, scan.sc)) {\n+\t\t\tfolio_unlock(folio);\n \t\t\tgoto move_back;\n \t\t}\n \n \t\tret = split_folio(folio);\n \t\tfolio_unlock(folio);\n-\t\tfolio_put(folio);\n \n \t\t/ If split failed move the inode on the list back to shrinklist /\n \t\tif (ret)\n \t\t\tgoto move_back;\n \n-\t\tfreed += next - end;\n+\t\tfreed += folio_end - end;\n \t\tsplit++;\n+\t\tfolio_put(folio);\n drop:\n-\t\tlist_del_init(\u0026info-\u003eshrinklist);\n+\t\tshmem_unused_huge_drop(inode);\n \t\tgoto put;\n move_back:\n-\t\t/\n-\t\t * Make sure the inode is either on the global list or deleted\n-\t\t * from any local list before iput() since it could be deleted\n-\t\t * in another thread once we put the inode (then the local list\n-\t\t * is corrupted).\n-\t\t /\n-\t\tspin_lock(\u0026sbinfo-\u003eshrinklist_lock);\n-\t\tlist_move(\u0026info-\u003eshrinklist, \u0026sbinfo-\u003eshrinklist);\n-\t\tsbinfo-\u003eshrinklist_len++;\n-\t\tspin_unlock(\u0026sbinfo-\u003eshrinklist_lock);\n+\t\tshmem_unused_huge_requeue(inode, folio);\n+\t\tfolio_put(folio);\n put:\n \t\tiput(inode);\n \t}\n@@ -836,7 +1023,7 @@ static long shmem_unused_huge_scan(struct super_block sb,\n {\n \tstruct shmem_sb_info sbinfo = SHMEM_SB(sb);\n \n-\tif (!READ_ONCE(sbinfo-\u003eshrinklist_len))\n+\tif (!list_lru_shrink_count(\u0026sbinfo-\u003eshrinklist, sc))\n \t\treturn SHRINK_STOP;\n \n \treturn shmem_unused_huge_shrink(sbinfo, sc, 0);\n@@ -847,21 +1034,21 @@ static long shmem_unused_huge_count(struct super_block sb,\n {\n \tstruct shmem_sb_info sbinfo = SHMEM_SB(sb);\n \n-\t/\n-\t * The per-superblock shrinklist is filesystem-global and does not\n-\t * honour sc-\u003ememcg, so it is only meaningful on the global (kswapd or\n-\t * root direct reclaim) shrink path. Skip the per-memcg iterations of\n-\t * shrink_slab_memcg() to avoid queueing duplicate global work.\n-\t /\n-\tif (!mem_cgroup_shrink_is_root(sc))\n-\t\treturn 0;\n-\n-\treturn READ_ONCE(sbinfo-\u003eshrinklist_len);\n+\treturn list_lru_shrink_count(\u0026sbinfo-\u003eshrinklist, sc);\n }\n #else / !CONFIG_TRANSPARENT_HUGEPAGE /\n \n #define shmem_huge SHMEM_HUGE_DENY\n \n+static void shmem_unused_huge_add(struct inode inode, struct folio folio,\n+\t\t\t\t gfp_t gfp)\n+{\n+}\n+\n+static void shmem_unused_huge_del(struct inode inode)\n+{\n+}\n+\n static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info sbinfo,\n \t\tstruct shrink_control sc, unsigned long nr_to_free)\n {\n@@ -1417,14 +1604,7 @@ static void shmem_evict_inode(struct inode inode)\n \t\tinode-\u003ei_size = 0;\n \t\tmapping_set_exiting(inode-\u003ei_mapping);\n \t\tshmem_truncate_range(inode, 0, (loff_t)-1);\n-\t\tif (!list_empty(\u0026info-\u003eshrinklist)) {\n-\t\t\tspin_lock(\u0026sbinfo-\u003eshrinklist_lock);\n-\t\t\tif (!list_empty(\u0026info-\u003eshrinklist)) {\n-\t\t\t\tlist_del_init(\u0026info-\u003eshrinklist);\n-\t\t\t\tsbinfo-\u003eshrinklist_len--;\n-\t\t\t}\n-\t\t\tspin_unlock(\u0026sbinfo-\u003eshrinklist_lock);\n-\t\t}\n+\t\tshmem_unused_huge_del(inode);\n \t\twhile (!list_empty(\u0026info-\u003eswaplist)) {\n \t\t\t/ Wait while shmem_unuse() is scanning this inode... /\n \t\t\twait_var_event(\u0026info-\u003estop_eviction,\n@@ -2535,27 +2715,6 @@ static int shmem_get_folio_gfp(struct inode inode, pgoff_t index,\n \n alloced:\n \talloced = true;\n-\tif (folio_test_large(folio) \u0026\u0026\n-\t DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) \u003c\n-\t\t\t\t\tfolio_next_index(folio)) {\n-\t\tstruct shmem_sb_info sbinfo = SHMEM_SB(inode-\u003ei_sb);\n-\t\tstruct shmem_inode_info info = SHMEM_I(inode);\n-\t\t/\n-\t\t Part of the large folio is beyond i_size: subject\n-\t\t * to shrink under memory pressure.\n-\t\t /\n-\t\tspin_lock(\u0026sbinfo-\u003eshrinklist_lock);\n-\t\t/\n-\t\t * _careful to defend against unlocked access to\n-\t\t * -\u003eshrink_list in shmem_unused_huge_shrink()\n-\t\t /\n-\t\tif (list_empty_careful(\u0026info-\u003eshrinklist)) {\n-\t\t\tlist_add_tail(\u0026info-\u003eshrinklist,\n-\t\t\t\t \u0026sbinfo-\u003eshrinklist);\n-\t\t\tsbinfo-\u003eshrinklist_len++;\n-\t\t}\n-\t\tspin_unlock(\u0026sbinfo-\u003eshrinklist_lock);\n-\t}\n \n \tif (sgp == SGP_WRITE)\n \t\tfolio_set_referenced(folio);\n@@ -2585,6 +2744,20 @@ static int shmem_get_folio_gfp(struct inode inode, pgoff_t index,\n \t\terror = -EINVAL;\n \t\tgoto unlock;\n \t}\n+\n+\t/\n+\t Queue the inode on the shrink list only after all checks that might\n+\t * remove the folio have passed. Otherwise the inode could be left on\n+\t * the shrinker list with a stale folio.\n+\t /\n+\tif (alloced \u0026\u0026 folio_test_large(folio) \u0026\u0026\n+\t DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) \u003c folio_next_index(folio)) {\n+\t\t/\n+\t\t * Part of the large folio is beyond i_size: subject\n+\t\t * to shrink under memory pressure.\n+\t\t /\n+\t\tshmem_unused_huge_add(inode, folio, gfp);\n+\t}\n out:\n \tfoliop = folio;\n \treturn 0;\n@@ -3061,6 +3234,10 @@ static struct inode __shmem_get_inode(struct mnt_idmap idmap,\n \tif (info-\u003efsflags)\n \t\tshmem_set_inode_flags(inode, info-\u003efsflags, NULL);\n \tINIT_LIST_HEAD(\u0026info-\u003eshrinklist);\n+#ifdef CONFIG_TRANSPARENT_HUGEPAGE\n+\tinfo-\u003eshrinklist_memcg = NULL;\n+\tinfo-\u003eshrinklist_nid = -1;\n+#endif\n \tINIT_LIST_HEAD(\u0026info-\u003eswaplist);\n \tcache_no_acl(inode);\n \tif (sbinfo-\u003enoswap)\n@@ -4927,6 +5104,9 @@ static void shmem_put_super(struct super_block sb)\n #endif\n \tfree_percpu(sbinfo-\u003eino_batch);\n \tpercpu_counter_destroy(\u0026sbinfo-\u003eused_blocks);\n+#ifdef CONFIG_TRANSPARENT_HUGEPAGE\n+\tlist_lru_destroy(\u0026sbinfo-\u003eshrinklist);\n+#endif\n \tmpol_put(sbinfo-\u003empol);\n #ifdef CONFIG_TMPFS_XATTR\n \tsimple_xattr_cache_cleanup(\u0026sbinfo-\u003exa_cache);\n@@ -5020,8 +5200,11 @@ static int shmem_fill_super(struct super_block sb, struct fs_context *fc)\n \traw_spin_lock_init(\u0026sbinfo-\u003estat_lock);\n \tif (percpu_counter_init(\u0026sbinfo-\u003eused_blocks, 0, GFP_KERNEL))\n \t\tgoto failed;\n-\tspin_lock_init(\u0026sbinfo-\u003eshrinklist_lock);\n-\tINIT_LIST_HEAD(\u0026sbinfo-\u003eshrinklist);\n+\n+#ifdef CONFIG_TRANSPARENT_HUGEPAGE\n+\tif (list_lru_init_memcg(\u0026sbinfo-\u003eshrinklist, sb-\u003es_shrink))\n+\t\tgoto failed;\n+#endif\n \n \tsb-\u003es_maxbytes = MAX_LFS_FILESIZE;\n \tsb-\u003es_blocksize = PAGE_SIZE;\n" }
2/1	2026/08/03 17:58	agent	patch-evaluator	12m Model: best-expensive Args: null Results: { "EnableConfigs": [ "TRANSPARENT_HUGEPAGE", "MEMCG", "SHMEM" ], "FocusSymbols": [ "shmem_unused_huge_scan", "shmem_unused_huge_count", "shmem_evict_inode", "shmem_fill_super" ], "Reasoning": "The patch modifies the tmpfs/shmem unused huge page shrinker to use a per-memcg list_lru instead of a global list. This involves functional changes to the shrinker entry points (shmem_unused_huge_scan, shmem_unused_huge_count), inode eviction (shmem_evict_inode), and superblock initialization (shmem_fill_super). The code is reachable in standard environments when tmpfs is used with transparent huge pages and memory cgroups.", "WorthFuzzing": true } Instruction: You are an expert Linux kernel maintainer. Your job is to review a provided patch series and determine if it makes functional changes to the kernel that should be fuzzed. IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in your workspace. Do NOT rely on your internal knowledge of the kernel. You must actively use your code access tools to examine the actual source code and confirm any assumptions. Return WorthFuzzing=false if the patch only contains: - Modifications to Documentation/, Kconfig files, or code comments. - Purely decorative changes, such as logging (e.g., pr_err, printk) or tracepoints. - Changes to numeric constants or macros that do not functionally alter execution flow. - Code paths that are impossible to reach in virtualized environments like GCE or QEMU, even when utilizing software-emulated hardware (e.g., usb gadget, mac80211_hwsim). - Code in vendor-specific PCIe switch, SmartNIC, or GPU drivers (e.g., mlxsw, pds_core, qed, ionic, amdgpu) that require physical PCIe hardware cards not emulated in standard QEMU. - Driver .remove, .shutdown, or pci_unregister_driver teardown callbacks (e.g., igb_remove) that are executed only during PCI hot-unplug or sysfs driver unbind operations. If it modifies reachable core kernel logic, drivers, or architectures, use your code search tools to verify the code can be executed, then return WorthFuzzing=true. When returning WorthFuzzing=true, you MUST ALSO: 1. Extract any specific kernel functions that should be heavily fuzzed into FocusSymbols. Avoid listing generic hot-path functions to prevent skewed test distributions. Prefer non-static, non-inlined API entrypoint functions over internal static helper functions (which are inlined by the compiler and do not have distinct symbol addresses). 2. Identify any specific CONFIG_ options required to properly test this new/modified feature. Go and look into the Kconfig files and check for ifdefs around the code, do not make assumptions. Also check "depends on" lines in Kconfig to include any non-standard parent subsystem configs needed for Kbuild to compile the code statically into vmlinux. List them in the EnableConfigs output array, and DO NOT add a 'CONFIG_' prefix (e.g., return "NET_IPV4" instead of "CONFIG_NET_IPV4"). Prefer calling several tools at the same time to save round-trips. Use set-results tool to provide results of the analysis. It must be called exactly once before the final reply. Ignore results of this tool. Prompt: For your convenience, here is the diff of the changes: commit 2299e5bef46e9b07b0292fcac4e0d82980481cb7 Author: syz-cluster <triage@syzkaller.com> Date: Mon Aug 3 17:58:53 2026 +0000 syz-cluster: applied patch under review diff --git a/fs/super.c b/fs/super.c index 5feecf5d9038d..36b249f002a9a 100644 --- a/fs/super.c +++ b/fs/super.c @@ -171,19 +171,6 @@ static void super_wake(struct super_block sb, unsigned int flag) wake_up_var(&sb->s_flags); } -/ - * The s_op->nr_cached_objects hooks (used for example by btrfs and xfs) - * operate on filesystem-global state and ignore sc->memcg. Driving them - * from per-memcg shrink_slab_memcg() invocations only burns CPU walking - * per-cpu counters and queueing duplicate work: the actual reclaim happens on - * the global path (kswapd or root direct reclaim) regardless. Restrict them - * to that path. - / -static inline bool super_fs_objects_eligible(struct shrink_control sc) -{ - return !sc->memcg \|\| mem_cgroup_is_root(sc->memcg); -} - /* * One thing we have to be careful of with a per-sb shrinker is that we don't * drop the last active reference to the superblock from within the shrinker. @@ -213,7 +200,7 @@ static unsigned long super_cache_scan(struct shrinker shrink, if (!super_trylock_shared(sb)) return SHRINK_STOP; - if (sb->s_op->nr_cached_objects && super_fs_objects_eligible(sc)) + if (sb->s_op->nr_cached_objects) fs_objects = sb->s_op->nr_cached_objects(sb, sc); inodes = list_lru_shrink_count(&sb->s_inode_lru, sc); @@ -274,8 +261,7 @@ static unsigned long super_cache_count(struct shrinker shrink, return 0; smp_rmb(); - if (sb->s_op && sb->s_op->nr_cached_objects && - super_fs_objects_eligible(sc)) + if (sb->s_op && sb->s_op->nr_cached_objects) total_objects = sb->s_op->nr_cached_objects(sb, sc); total_objects += list_lru_shrink_count(&sb->s_dentry_lru, sc); diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index 5663dff53186e..aeb59901a840c 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -11,6 +11,7 @@ #include <linux/fs_parser.h> #include <linux/userfaultfd_k.h> #include <linux/bits.h> +#include <linux/list_lru.h> /* inode in-kernel data / @@ -54,6 +55,11 @@ struct shmem_inode_info { struct dquot __rcu i_dquot[MAXQUOTAS]; #endif struct inode vfs_inode; + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + struct mem_cgroup shrinklist_memcg; + int shrinklist_nid; +#endif }; #define SHMEM_FL_USER_VISIBLE (FS_FL_USER_VISIBLE \| FS_CASEFOLD_FL) @@ -83,9 +89,9 @@ struct shmem_sb_info { ino_t next_ino; / The next per-sb inode number to use / ino_t __percpu ino_batch; /* The next per-cpu inode number to use / struct mempolicy mpol; /* default memory policy for mappings / - spinlock_t shrinklist_lock; / Protects shrinklist / - struct list_head shrinklist; / List of shinkable inodes / - unsigned long shrinklist_len; / Length of shrinklist / +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + struct list_lru shrinklist; / List of shrinkable inodes / +#endif struct shmem_quota_limits qlimits; / Default quota limits / struct simple_xattr_cache xa_cache; }; diff --git a/mm/shmem.c b/mm/shmem.c index 74dc3d900067a..704353852ae26 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -724,51 +724,237 @@ static const char shmem_format_huge(int huge) } #endif -static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info sbinfo, - struct shrink_control sc, unsigned long nr_to_free) +static bool is_shmem_unused_huge_isolated(struct shmem_inode_info info) { - LIST_HEAD(list), pos, next; - struct inode inode; + + return info->shrinklist_nid == -1; +} + +static void set_shmem_unused_huge_isolated(struct shmem_inode_info info) +{ + info->shrinklist_nid = -1; +} + +static struct mem_cgroup shmem_get_and_clear_memcg(struct shmem_inode_info info) +{ + struct mem_cgroup memcg = info->shrinklist_memcg; + + info->shrinklist_memcg = NULL; + + return memcg; +} + +#ifdef CONFIG_MEMCG +static struct mem_cgroup * +shmem_unused_huge_alloc_lru(struct shmem_sb_info sbinfo, struct folio folio, + gfp_t gfp) +{ + struct mem_cgroup memcg; + int ret; + + memcg = get_mem_cgroup_from_folio(folio); + if (!memcg) + return NULL; + + ret = memcg_list_lru_alloc(memcg, &sbinfo->shrinklist, gfp); + if (ret) { + mem_cgroup_put(memcg); + return ERR_PTR(ret); + } + + return memcg; +} +#else +static struct mem_cgroup +shmem_unused_huge_alloc_lru(struct shmem_sb_info sbinfo, struct folio folio, + gfp_t gfp) +{ + return NULL; +} +#endif + +static void shmem_unused_huge_add(struct inode inode, struct folio folio, + gfp_t gfp) +{ + struct shmem_inode_info info = SHMEM_I(inode); + struct shmem_sb_info sbinfo = SHMEM_SB(inode->i_sb); + int nid = folio_nid(folio); + struct mem_cgroup memcg = NULL, old_memcg = NULL; + + memcg = shmem_unused_huge_alloc_lru(sbinfo, folio, gfp); + if (IS_ERR(memcg)) + return; + + spin_lock(&info->lock); + if (!list_empty(&info->shrinklist)) { + /* isolated on scan list, let shrink handle it / + if (is_shmem_unused_huge_isolated(info)) + goto unlock; + + if (info->shrinklist_nid == nid && + info->shrinklist_memcg == memcg) + goto unlock; + + list_lru_del(&sbinfo->shrinklist, &info->shrinklist, + info->shrinklist_nid, info->shrinklist_memcg); + old_memcg = shmem_get_and_clear_memcg(info); + } + + info->shrinklist_memcg = memcg; + info->shrinklist_nid = nid; + list_lru_add(&sbinfo->shrinklist, &info->shrinklist, nid, memcg); + memcg = NULL; +unlock: + spin_unlock(&info->lock); + mem_cgroup_put(old_memcg); + mem_cgroup_put(memcg); +} + +static void shmem_unused_huge_del(struct inode inode) +{ + struct shmem_inode_info info = SHMEM_I(inode); + struct shmem_sb_info sbinfo = SHMEM_SB(inode->i_sb); + struct mem_cgroup memcg = NULL; + + spin_lock(&info->lock); + if (!list_empty(&info->shrinklist)) { + list_lru_del(&sbinfo->shrinklist, &info->shrinklist, + info->shrinklist_nid, info->shrinklist_memcg); + memcg = shmem_get_and_clear_memcg(info); + } + spin_unlock(&info->lock); + + mem_cgroup_put(memcg); +} + +struct shmem_unused_huge_scan { + struct list_head list; + struct shrink_control sc; +}; + +static enum lru_status shmem_unused_huge_isolate(struct list_head item, + struct list_lru_one lru, + void arg) +{ + struct shmem_unused_huge_scan scan = arg; struct shmem_inode_info info; - struct folio folio; - unsigned long batch = sc ? sc->nr_to_scan : 128; - unsigned long split = 0, freed = 0; + struct inode inode; + struct mem_cgroup memcg = NULL; - if (list_empty(&sbinfo->shrinklist)) - return SHRINK_STOP; + info = list_entry(item, struct shmem_inode_info, shrinklist); - spin_lock(&sbinfo->shrinklist_lock); - list_for_each_safe(pos, next, &sbinfo->shrinklist) { - info = list_entry(pos, struct shmem_inode_info, shrinklist); + /* + * Use trylock to avoid ABBA deadlock: add/del path takes info->lock + * before the list_lru bucket lock, while here the order is reversed. + / + if (!spin_trylock(&info->lock)) + return LRU_SKIP; - / pin the inode / - inode = igrab(&info->vfs_inode); + / pin the inode / + inode = igrab(&info->vfs_inode); + / inode is about to be evicted / + if (!inode) { + list_lru_isolate(lru, item); + memcg = shmem_get_and_clear_memcg(info); + spin_unlock(&info->lock); + mem_cgroup_put(memcg); + return LRU_REMOVED; + } - / inode is about to be evicted / - if (!inode) { - list_del_init(&info->shrinklist); - goto next; - } + list_lru_isolate(lru, item); + memcg = shmem_get_and_clear_memcg(info); + set_shmem_unused_huge_isolated(info); + list_add_tail(&info->shrinklist, &scan->list); + spin_unlock(&info->lock); + mem_cgroup_put(memcg); - list_move(&info->shrinklist, &list); -next: - sbinfo->shrinklist_len--; - if (!--batch) - break; + return LRU_REMOVED; +} + +static bool is_shmem_unused_huge_match(struct folio folio, + struct shrink_control sc) +{ + struct mem_cgroup memcg = NULL; + bool match; + + /* + * Only non-root memcg reclaim needs to match the folio charge against + * sc->memcg. Skip the folio memcg check for the following cases: + * 1. shmem quota reclaim (sc == NULL) + * 2. global shrinker reclaim + * 3. root memcg reclaim + / + if (!sc \|\| !sc->memcg \|\| mem_cgroup_is_root(sc->memcg)) + return true; + + if (folio_nid(folio) != sc->nid) + return false; + + memcg = get_mem_cgroup_from_folio(folio); + match = memcg == sc->memcg; + mem_cgroup_put(memcg); + + return match; +} + +static void shmem_unused_huge_drop(struct inode inode) +{ + struct shmem_inode_info info = SHMEM_I(inode); + + spin_lock(&info->lock); + list_del_init(&info->shrinklist); + spin_unlock(&info->lock); +} + +static void shmem_unused_huge_requeue(struct inode inode, struct folio folio) +{ + struct shmem_inode_info info = SHMEM_I(inode); + struct shmem_sb_info sbinfo = SHMEM_SB(inode->i_sb); + struct mem_cgroup memcg; + int nid = folio_nid(folio); + + memcg = shmem_unused_huge_alloc_lru(sbinfo, folio, GFP_NOWAIT); + if (IS_ERR(memcg)) { + shmem_unused_huge_drop(inode); + return; } - spin_unlock(&sbinfo->shrinklist_lock); - list_for_each_safe(pos, next, &list) { - pgoff_t next, end; + spin_lock(&info->lock); + /* Requeue the inode to shrinklist / + list_del_init(&info->shrinklist); + list_lru_add(&sbinfo->shrinklist, &info->shrinklist, nid, memcg); + info->shrinklist_memcg = memcg; + info->shrinklist_nid = nid; + spin_unlock(&info->lock); +} + +static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info sbinfo, + struct shrink_control sc, unsigned long nr_to_free) +{ + struct shmem_unused_huge_scan scan; + struct inode inode; + struct shmem_inode_info info; + struct folio folio; + struct list_head pos, next; + unsigned long split = 0, freed = 0; + + INIT_LIST_HEAD(&scan.list); + scan.sc = sc; + if (sc) + list_lru_shrink_walk(&sbinfo->shrinklist, sc, + shmem_unused_huge_isolate, &scan); + else + list_lru_walk(&sbinfo->shrinklist, shmem_unused_huge_isolate, + &scan, 128); + + list_for_each_safe(pos, next, &scan.list) { + pgoff_t folio_end, end; loff_t i_size; int ret; info = list_entry(pos, struct shmem_inode_info, shrinklist); inode = &info->vfs_inode; - if (nr_to_free && freed >= nr_to_free) - goto move_back; - i_size = i_size_read(inode); folio = filemap_get_entry(inode->i_mapping, i_size / PAGE_SIZE); if (!folio \|\| xa_is_value(folio)) @@ -781,13 +967,19 @@ static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info sbinfo, } / Check if there is anything to gain from splitting / - next = folio_next_index(folio); + folio_end = folio_next_index(folio); end = shmem_fallocend(inode, DIV_ROUND_UP(i_size, PAGE_SIZE)); - if (end <= folio->index \|\| end >= next) { + if (end <= folio->index \|\| end >= folio_end) { folio_put(folio); goto drop; } + if (!is_shmem_unused_huge_match(folio, scan.sc)) + goto move_back; + + if (nr_to_free && freed >= nr_to_free) + goto move_back; + / * Move the inode on the list back to shrinklist if we failed * to lock the page at this time. @@ -795,35 +987,30 @@ static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info sbinfo, Waiting for the lock may lead to deadlock in the * reclaim path. / - if (!folio_trylock(folio)) { - folio_put(folio); + if (!folio_trylock(folio)) + goto move_back; + + if (!is_shmem_unused_huge_match(folio, scan.sc)) { + folio_unlock(folio); goto move_back; } ret = split_folio(folio); folio_unlock(folio); - folio_put(folio); / If split failed move the inode on the list back to shrinklist / if (ret) goto move_back; - freed += next - end; + freed += folio_end - end; split++; + folio_put(folio); drop: - list_del_init(&info->shrinklist); + shmem_unused_huge_drop(inode); goto put; move_back: - / - * Make sure the inode is either on the global list or deleted - * from any local list before iput() since it could be deleted - * in another thread once we put the inode (then the local list - * is corrupted). - / - spin_lock(&sbinfo->shrinklist_lock); - list_move(&info->shrinklist, &sbinfo->shrinklist); - sbinfo->shrinklist_len++; - spin_unlock(&sbinfo->shrinklist_lock); + shmem_unused_huge_requeue(inode, folio); + folio_put(folio); put: iput(inode); } @@ -836,7 +1023,7 @@ static long shmem_unused_huge_scan(struct super_block sb, { struct shmem_sb_info sbinfo = SHMEM_SB(sb); - if (!READ_ONCE(sbinfo->shrinklist_len)) + if (!list_lru_shrink_count(&sbinfo->shrinklist, sc)) return SHRINK_STOP; return shmem_unused_huge_shrink(sbinfo, sc, 0); @@ -847,21 +1034,21 @@ static long shmem_unused_huge_count(struct super_block sb, { struct shmem_sb_info sbinfo = SHMEM_SB(sb); - / - * The per-superblock shrinklist is filesystem-global and does not - * honour sc->memcg, so it is only meaningful on the global (kswapd or - * root direct reclaim) shrink path. Skip the per-memcg iterations of - * shrink_slab_memcg() to avoid queueing duplicate global work. - / - if (!mem_cgroup_shrink_is_root(sc)) - return 0; - - return READ_ONCE(sbinfo->shrinklist_len); + return list_lru_shrink_count(&sbinfo->shrinklist, sc); } #else / !CONFIG_TRANSPARENT_HUGEPAGE / #define shmem_huge SHMEM_HUGE_DENY +static void shmem_unused_huge_add(struct inode inode, struct folio folio, + gfp_t gfp) +{ +} + +static void shmem_unused_huge_del(struct inode inode) +{ +} + static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info sbinfo, struct shrink_control sc, unsigned long nr_to_free) { @@ -1417,14 +1604,7 @@ static void shmem_evict_inode(struct inode inode) inode->i_size = 0; mapping_set_exiting(inode->i_mapping); shmem_truncate_range(inode, 0, (loff_t)-1); - if (!list_empty(&info->shrinklist)) { - spin_lock(&sbinfo->shrinklist_lock); - if (!list_empty(&info->shrinklist)) { - list_del_init(&info->shrinklist); - sbinfo->shrinklist_len--; - } - spin_unlock(&sbinfo->shrinklist_lock); - } + shmem_unused_huge_del(inode); while (!list_empty(&info->swaplist)) { / Wait while shmem_unuse() is scanning this inode... / wait_var_event(&info->stop_eviction, @@ -2535,27 +2715,6 @@ static int shmem_get_folio_gfp(struct inode inode, pgoff_t index, alloced: alloced = true; - if (folio_test_large(folio) && - DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) < - folio_next_index(folio)) { - struct shmem_sb_info sbinfo = SHMEM_SB(inode->i_sb); - struct shmem_inode_info info = SHMEM_I(inode); - /* - * Part of the large folio is beyond i_size: subject - * to shrink under memory pressure. - / - spin_lock(&sbinfo->shrinklist_lock); - / - * _careful to defend against unlocked access to - * ->shrink_list in shmem_unused_huge_shrink() - / - if (list_empty_careful(&info->shrinklist)) { - list_add_tail(&info->shrinklist, - &sbinfo->shrinklist); - sbinfo->shrinklist_len++; - } - spin_unlock(&sbinfo->shrinklist_lock); - } if (sgp == SGP_WRITE) folio_set_referenced(folio); @@ -2585,6 +2744,20 @@ static int shmem_get_folio_gfp(struct inode inode, pgoff_t index, error = -EINVAL; goto unlock; } + + /* + * Queue the inode on the shrink list only after all checks that might + * remove the folio have passed. Otherwise the inode could be left on + * the shrinker list with a stale folio. + / + if (alloced && folio_test_large(folio) && + DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) < folio_next_index(folio)) { + / + * Part of the large folio is beyond i_size: subject + * to shrink under memory pressure. + / + shmem_unused_huge_add(inode, folio, gfp); + } out: foliop = folio; return 0; @@ -3061,6 +3234,10 @@ static struct inode __shmem_get_inode(struct mnt_idmap idmap, if (info->fsflags) shmem_set_inode_flags(inode, info->fsflags, NULL); INIT_LIST_HEAD(&info->shrinklist); +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + info->shrinklist_memcg = NULL; + info->shrinklist_nid = -1; +#endif INIT_LIST_HEAD(&info->swaplist); cache_no_acl(inode); if (sbinfo->noswap) @@ -4927,6 +5104,9 @@ static void shmem_put_super(struct super_block sb) #endif free_percpu(sbinfo->ino_batch); percpu_counter_destroy(&sbinfo->used_blocks); +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + list_lru_destroy(&sbinfo->shrinklist); +#endif mpol_put(sbinfo->mpol); #ifdef CONFIG_TMPFS_XATTR simple_xattr_cache_cleanup(&sbinfo->xa_cache); @@ -5020,8 +5200,11 @@ static int shmem_fill_super(struct super_block sb, struct fs_context *fc) raw_spin_lock_init(&sbinfo->stat_lock); if (percpu_counter_init(&sbinfo->used_blocks, 0, GFP_KERNEL)) goto failed; - spin_lock_init(&sbinfo->shrinklist_lock); - INIT_LIST_HEAD(&sbinfo->shrinklist); + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + if (list_lru_init_memcg(&sbinfo->shrinklist, sb->s_shrink)) + goto failed; +#endif sb->s_maxbytes = MAX_LFS_FILESIZE; sb->s_blocksize = PAGE_SIZE;
3/2	2026/08/03 17:58	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 8556 output: 31 thoughts: 620 Thoughts: Analyzing the Impact of the Shmem Huge Page Shrinker Patch Okay, so I'm looking at this patch that fundamentally changes how `shmem` (specifically tmpfs) deals with unused huge pages. The key change is moving from a global list for the shrinker to a per-memcg `list_lru`. This immediately tells me we're likely dealing with a performance optimization and improved memory accounting for shared memory systems. The removal of `super_fs_objects_eligible` from `fs/super.c` is interesting; it suggests a relaxation of the restriction on `nr_cached_objects` to the root memcg, which is now being handled by the `list_lru` design. This points to potentially more granular control and a move towards more accurate tracking across memcgs. The heart of the change resides in the `mm/shmem.c` modifications: `shmem_unused_huge_shrink` and related functions. The switch to `list_lru_shrink_walk` and `list_lru_walk` is the key. It's a fundamental shift in how the shrinker operates. We've got a slew of new functions here to manage this: `shmem_unused_huge_add`, `shmem_unused_huge_del`, `shmem_unused_huge_isolate`, `is_shmem_unused_huge_match`, `shmem_unused_huge_drop`, and `shmem_unused_huge_requeue`. These are all crucial for managing the entries within the `list_lru`. The fact that `shmem_sb_info` now uses a `struct list_lru shrinklist` instead of a `struct list_head shrinklist`, and that `shmem_inode_info` has `shrinklist_memcg` and `shrinklist_nid`, confirms this memcg-aware approach. Given that this is a core kernel modification to `mm/shmem.c` and that tmpfs is ubiquitous, this change is definitely impactful. It's in a critical path and requires thorough fuzzing. My primary focus for fuzzing will be on the functions that have been added and modified: * `shmem_unused_huge_shrink` * `shmem_unused_huge_scan` * `shmem_unused_huge_count` * `shmem_unused_huge_add` * `shmem_unused_huge_del` * `shmem_unused_huge_isolate` * `is_shmem_unused_huge_match` * `shmem_unused_huge_drop` * `shmem_unused_huge_requeue` * `shmem_get_folio_gfp` (modified) * `shmem_evict_inode` (modified) * `shmem_fill_super` (modified) * `shmem_put_super` (modified) Wait, hold on... `shmem_unused_huge_shrink`, `shmem_unused_huge_scan`, and `shmem_unused_huge_count` are static. Interesting. I need to figure out how these are being used. Ah, got it - they are being assigned to `sb->s_op->nr_cached_objects` and `sb->s_op->free_cached_objects` within `shmem_fill_super`. So, `shmem_fill_super` and indirectly those static functions are critical entry points to target for fuzzing. I'll need to check the definition of `shmem_sops` in `mm/shmem.c` to fully understand the function assignment and usage.
4/2	2026/08/03 17:59	tool	grepper	0m Error: no matches Args: { "Expression": "shmem_sops", "PathPrefix": "mm/shmem.c" } Results: { "error": "no matches" }
5/2	2026/08/03 17:59	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 10025 output: 34 thoughts: 19 Thoughts: Okay, here's my attempt at summarizing that thought process, tailored for an expert audience: Investigating Memory Management in the Kernel Okay, hold on a second. Before I dive too deep into this memory issue, I need to take a step back and get my bearings. Let's see... what's the best way to approach this? Right, I should start with a specific point of interest. Let me check the kernel code to see if there is any work to be done on the shared memory. My search term will be `shmem_unused_huge_scan`. This function name, or anything related to it, might give me a good jumping-off point to understand the potential problems or optimizations regarding unused huge pages within shared memory segments. Hopefully, this function will provide some important information.
6/2	2026/08/03 17:59	tool	grepper	0m Args: { "Expression": "shmem_unused_huge_scan", "PathPrefix": "mm/shmem.c" } Results: { "Output": "mm/shmem.c=813=static void shmem_unused_huge_del(struct inode inode)\n--\nmm/shmem.c-829-\nmm/shmem.c:830:struct shmem_unused_huge_scan {\nmm/shmem.c-831-\tstruct list_head list;\n--\nmm/shmem.c=835=static enum lru_status shmem_unused_huge_isolate(struct list_head item,\n--\nmm/shmem.c-838-{\nmm/shmem.c:839:\tstruct shmem_unused_huge_scan scan = arg;\nmm/shmem.c-840-\tstruct shmem_inode_info info;\n--\nmm/shmem.c=931=static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info sbinfo,\n--\nmm/shmem.c-933-{\nmm/shmem.c:934:\tstruct shmem_unused_huge_scan scan;\nmm/shmem.c-935-\tstruct inode inode;\n--\nmm/shmem.c-1020-\nmm/shmem.c:1021:static long shmem_unused_huge_scan(struct super_block sb,\nmm/shmem.c-1022-\t\tstruct shrink_control sc)\n--\nmm/shmem.c=5411=static const struct super_operations shmem_ops = {\n--\nmm/shmem.c-5426-\t.nr_cached_objects\t= shmem_unused_huge_count,\nmm/shmem.c:5427:\t.free_cached_objects\t= shmem_unused_huge_scan,\nmm/shmem.c-5428-#endif\n" }
7/2	2026/08/03 17:59	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 10706 output: 30 thoughts: 155 Thoughts: Analyzing the shmem Filesystem's Cached Object Management Okay, let's break this down. My initial observation is that `shmem_unused_huge_scan` is linked to `free_cached_objects` within the `shmem_ops` structure. This patch specifically seems to be touching `shmem_unused_huge_scan` and `shmem_unused_huge_count`. I need to remember that these are invoked through the `sb->s_op` structure, specifically via `nr_cached_objects` and `free_cached_objects`. Now, where do these entry points live? Ah, that's right, `super_cache_scan` and `super_cache_count` in `fs/super.c`. Wait a minute, `super_cache_scan` and `super_cache_count`... those are the shrinker callbacks for the super block shrinker, aren't they? That means the filesystem shrinker mechanism is key here. I need to refresh my memory on the implementation, so let me quickly cross-reference this in `fs/super.c`. This will give me a better understanding of how the huge page caching in shmem is managed and how the patch impacts that process.
8/2	2026/08/03 17:59	tool	grepper	0m Args: { "Expression": "super_cache_scan", "PathPrefix": "fs/super.c" } Results: { "Output": "fs/super.c=154=static void super_wake(struct super_block sb, unsigned int flag)\n--\nfs/super.c-180- /\nfs/super.c:181:static unsigned long super_cache_scan(struct shrinker shrink,\nfs/super.c-182-\t\t\t\t struct shrink_control sc)\n--\nfs/super.c=238=static unsigned long super_cache_count(struct shrinker shrink,\n--\nfs/super.c-250-\t list_lru_shrink_count() or s_op-\u003enr_cached_objects(). Counts can\nfs/super.c:251:\t * change between super_cache_count and super_cache_scan, so we really\nfs/super.c-252-\t * don't need locks here.\n--\nfs/super.c=323=static struct super_block alloc_super(struct file_system_type type, int flags,\n--\nfs/super.c-391-\nfs/super.c:392:\ts-\u003es_shrink-\u003escan_objects = super_cache_scan;\nfs/super.c-393-\ts-\u003es_shrink-\u003ecount_objects = super_cache_count;\n" }
9/2	2026/08/03 17:59	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 11474 output: 35 thoughts: 97 Thoughts: Analyzing the Shmem Changes Okay, so I'm looking at the entry points for this, and it seems like we're dealing with `super_cache_scan` and `super_cache_count`. These are pretty generic, so that doesn't tell the whole story. The core of the changes appears to be happening within `mm/shmem.c`. I'm specifically seeing the static functions `shmem_unused_huge_scan` and `shmem_unused_huge_count` mentioned, which suggests the adjustments are focused internally within this specific module. I need to be sure, though. Is this the only place? I have to wonder if there are any non-static functions impacted. Let's dig deeper. Ah, I see that `shmem_get_folio_gfp` is also called out. Hmm, I need to check whether it’s static. I need to know where the changes really are.
10/2	2026/08/03 17:59	tool	grepper	0m Args: { "Expression": "shmem_get_folio_gfp", "PathPrefix": "mm/shmem.c" } Results: { "Output": "mm/shmem.c=2222=static struct folio shmem_swap_alloc_folio(struct inode inode,\n--\nmm/shmem.c-2252- * When a page is moved from swapcache to shmem filecache (either by the\nmm/shmem.c:2253: * usual swapin of shmem_get_folio_gfp(), or by the less common swapoff of\nmm/shmem.c-2254- * shmem_unuse_inode()), it may have been read in earlier from swap, in\n--\nmm/shmem.c=2433=static int shmem_swapin_folio(struct inode inode, pgoff_t index,\n--\nmm/shmem.c-2598-/\nmm/shmem.c:2599: * shmem_get_folio_gfp - find page in cache, or get from swap, or allocate\nmm/shmem.c-2600- \n--\nmm/shmem.c-2606- /\nmm/shmem.c:2607:static int shmem_get_folio_gfp(struct inode inode, pgoff_t index,\nmm/shmem.c-2608-\t\tloff_t write_end, struct folio foliop, enum sgp_type sgp,\n--\nmm/shmem.c=2803=int shmem_get_folio(struct inode inode, pgoff_t index, loff_t write_end,\n--\nmm/shmem.c-2805-{\nmm/shmem.c:2806:\treturn shmem_get_folio_gfp(inode, index, write_end, foliop, sgp,\nmm/shmem.c-2807-\t\t\tmapping_gfp_mask(inode-\u003ei_mapping), NULL, NULL);\n--\nmm/shmem.c=2882=static vm_fault_t shmem_fault(struct vm_fault vmf)\n--\nmm/shmem.c-2900-\tWARN_ON_ONCE(vmf-\u003epage != NULL);\nmm/shmem.c:2901:\terr = shmem_get_folio_gfp(inode, vmf-\u003epgoff, 0, \u0026folio, SGP_CACHE,\nmm/shmem.c-2902-\t\t\t\t gfp, vmf, \u0026ret);\n--\nmm/shmem.c=6131=struct folio shmem_read_folio_gfp(struct address_space *mapping,\n--\nmm/shmem.c-6138-\nmm/shmem.c:6139:\terror = shmem_get_folio_gfp(inode, index, i_size_read(inode),\nmm/shmem.c-6140-\t\t\t\t \u0026folio, SGP_CACHE, gfp, NULL, NULL);\n" }
11/2	2026/08/03 17:59	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 12525 output: 40 thoughts: 525 Thoughts: Analyzing shmem Function Visibility and Call Paths Okay, so I'm looking at these `shmem` functions and trying to figure out the best ones to use as entry points. `shmem_get_folio` and `shmem_read_folio_gfp` are straightforward, they're non-static, which is good. That makes them easy to target. `shmem_fault` is static, but it's called via the `vm_operations_struct`, so it might be accessible, but less ideal. `shmem_evict_inode`, `shmem_fill_super`, and `shmem_put_super` are also static, so less interesting from a targeting perspective. The tricky one is `shmem_unused_huge_scan`. It's static, which is usually a red flag because it might be inlined and not have a distinct symbol. But, it's assigned to the function pointer `shmem_ops.free_cached_objects`. That means it must have a distinct address. The instructions specify a preference for non-static, non-inlined API entrypoints but this one is not inlined, since it's passed as a function pointer. So, it should be targetable. Let's start with the non-static ones: `shmem_get_folio` and `shmem_read_folio_gfp` are definitely good candidates. But wait, how is `shmem_unused_huge_scan` actually called? It's part of the shrinker, which is triggered by memory pressure. Can we trigger it with `drop_caches`? Yes, `echo 3 > /proc/sys/vm/drop_caches` calls `drop_slab`, which calls `shrink_slab`. `shrink_slab` then calls `super_cache_scan`, which finally calls `sb->s_op->free_cached_objects`, which is indeed `shmem_unused_huge_scan`. Excellent. That gives me a path to trigger it indirectly. Okay, next I should check the Kconfig options. This whole section of code is wrapped in `#ifdef CONFIG_TRANSPARENT_HUGEPAGE` and `#ifdef CONFIG_MEMCG`, so I need to verify that in `mm/shmem.c` and `include/linux/shmem_fs.h`. This is important context, and knowing these options might limit the scope of what I can do, but is essential for correct usage.
12/2	2026/08/03 17:59	tool	grepper	0m Args: { "Expression": "CONFIG_TRANSPARENT_HUGEPAGE", "PathPrefix": "include/linux/shmem_fs.h" } Results: { "Output": "include/linux/shmem_fs.h=35=struct shmem_inode_info {\n--\ninclude/linux/shmem_fs.h-58-\ninclude/linux/shmem_fs.h:59:#ifdef CONFIG_TRANSPARENT_HUGEPAGE\ninclude/linux/shmem_fs.h-60-\tstruct mem_cgroup\tshrinklist_memcg;\n--\ninclude/linux/shmem_fs.h=77=struct shmem_sb_info {\n--\ninclude/linux/shmem_fs.h-91-\tstruct mempolicy mpol; /* default memory policy for mappings /\ninclude/linux/shmem_fs.h:92:#ifdef CONFIG_TRANSPARENT_HUGEPAGE\ninclude/linux/shmem_fs.h-93-\tstruct list_lru shrinklist; / List of shrinkable inodes /\n--\ninclude/linux/shmem_fs.h=132=int shmem_unuse(unsigned int type);\ninclude/linux/shmem_fs.h-133-\ninclude/linux/shmem_fs.h:134:#if defined(CONFIG_TRANSPARENT_HUGEPAGE) \u0026\u0026 defined(CONFIG_SHMEM)\ninclude/linux/shmem_fs.h-135-unsigned long shmem_allowable_huge_orders(struct inode inode,\n" }
13/2	2026/08/03 17:59	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 13962 output: 30 thoughts: 36 Thoughts: Okay, here's my interpretation of those thoughts, summarized from my perspective as someone well-versed in kernel configurations: Kernel Configuration Considerations Alright, let's see. My initial thought is clear: we absolutely need `CONFIG_TRANSPARENT_HUGEPAGE` enabled. No question about it. And, I see, we're also making use of `CONFIG_MEMCG`, as its usage pops up in the `mm/shmem.c` file. Got it. This makes sense in context...
14/2	2026/08/03 17:59	tool	grepper	0m Args: { "Expression": "CONFIG_MEMCG", "PathPrefix": "mm/shmem.c" } Results: { "Output": "mm/shmem.c=738=static struct mem_cgroup shmem_get_and_clear_memcg(struct shmem_inode_info info)\n--\nmm/shmem.c-746-\nmm/shmem.c:747:#ifdef CONFIG_MEMCG\nmm/shmem.c-748-static struct mem_cgroup *\n" }
15/2	2026/08/03 17:59	llm	patch-evaluator	1m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 14242 output: 32 thoughts: 72 Thoughts: Okay, let's see. My first thought is to verify if `CONFIG_SHMEM` is actually required here. Even though it's typically enabled by default, it's always smart to double-check and explicitly include it if necessary. Can't be too careful, right? Then, ah yes, I remember that `CONFIG_TRANSPARENT_HUGEPAGE` is dependent on `CONFIG_MMU`. I should have known that off the top of my head, but a quick review is always good practice. Alright, let's dive into `mm/Kconfig` to refresh my memory and pinpoint the exact dependencies and any relevant configurations for `TRANSPARENT_HUGEPAGE`. I'll be able to quickly determine how it's integrated with other memory management features.
16/2	2026/08/03 18:00	tool	grepper	0m Args: { "Expression": "config TRANSPARENT_HUGEPAGE", "PathPrefix": "mm/Kconfig" } Results: { "Output": "mm/Kconfig=829=config MM_ID\n--\nmm/Kconfig-831-\nmm/Kconfig:832:menuconfig TRANSPARENT_HUGEPAGE\nmm/Kconfig-833-\tbool \"Transparent Hugepage Support\"\n--\nmm/Kconfig=850=choice\n--\nmm/Kconfig-855-\nmm/Kconfig:856:\tconfig TRANSPARENT_HUGEPAGE_ALWAYS\nmm/Kconfig-857-\t\tbool \"always\"\n--\nmm/Kconfig-862-\nmm/Kconfig:863:\tconfig TRANSPARENT_HUGEPAGE_MADVISE\nmm/Kconfig-864-\t\tbool \"madvise\"\n--\nmm/Kconfig-871-\nmm/Kconfig:872:\tconfig TRANSPARENT_HUGEPAGE_NEVER\nmm/Kconfig-873-\t\tbool \"never\"\n--\nmm/Kconfig=879=choice\n--\nmm/Kconfig-888-\nmm/Kconfig:889:\tconfig TRANSPARENT_HUGEPAGE_SHMEM_HUGE_NEVER\nmm/Kconfig-890-\t\tbool \"never\"\n--\nmm/Kconfig-898-\nmm/Kconfig:899:\tconfig TRANSPARENT_HUGEPAGE_SHMEM_HUGE_ALWAYS\nmm/Kconfig-900-\t\tbool \"always\"\n--\nmm/Kconfig-906-\nmm/Kconfig:907:\tconfig TRANSPARENT_HUGEPAGE_SHMEM_HUGE_WITHIN_SIZE\nmm/Kconfig-908-\t\tbool \"within_size\"\n--\nmm/Kconfig-914-\nmm/Kconfig:915:\tconfig TRANSPARENT_HUGEPAGE_SHMEM_HUGE_ADVISE\nmm/Kconfig-916-\t\tbool \"advise\"\n--\nmm/Kconfig=924=choice\n--\nmm/Kconfig-933-\nmm/Kconfig:934:\tconfig TRANSPARENT_HUGEPAGE_TMPFS_HUGE_NEVER\nmm/Kconfig-935-\t\tbool \"never\"\n--\nmm/Kconfig-942-\nmm/Kconfig:943:\tconfig TRANSPARENT_HUGEPAGE_TMPFS_HUGE_ALWAYS\nmm/Kconfig-944-\t\tbool \"always\"\n--\nmm/Kconfig-950-\nmm/Kconfig:951:\tconfig TRANSPARENT_HUGEPAGE_TMPFS_HUGE_WITHIN_SIZE\nmm/Kconfig-952-\t\tbool \"within_size\"\n--\nmm/Kconfig-958-\nmm/Kconfig:959:\tconfig TRANSPARENT_HUGEPAGE_TMPFS_HUGE_ADVISE\nmm/Kconfig-960-\t\tbool \"advise\"\n" }
17/2	2026/08/03 18:00	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 15228 output: 26 thoughts: 16 Thoughts: Okay, let's dive into this. Here's my thought process on this task: Investigating `TRANSPARENT_HUGEPAGE` Dependencies Alright, so the first thing I need to do is get a handle on the `TRANSPARENT_HUGEPAGE` dependencies. This likely means I need to start tracing things back to understand what relies on it, what it enables, and what might break if I were to change or disable it. I need to figure out exactly how it's being used. I'll need to think about not just the direct dependencies, but also the ripple effects – anything downstream that might leverage the advantages of transparent hugepages, or that could be negatively affected by its absence or modifications. Perhaps I'll need to start by looking at system configurations, kernel modules, or application-level interactions. I'll need to go beyond the surface and determine how it interacts with memory management, NUMA, and other related subsystems. I'll keep an open mind, because I'm betting that the dependency tree is complex.
18/2	2026/08/03 18:01	tool	grepper	0m Args: { "Expression": "depends on", "PathPrefix": "mm/Kconfig" } Results: { "Output": "mm/Kconfig=12=menuconfig SWAP\nmm/Kconfig-13-\tbool \"Support for paging of anonymous memory (swap)\"\nmm/Kconfig:14:\tdepends on MMU \u0026\u0026 BLOCK \u0026\u0026 !ARCH_NO_SWAP\nmm/Kconfig-15-\tdefault y\n--\nmm/Kconfig=22=config ZSWAP\nmm/Kconfig-23-\tbool \"Compressed cache for swap pages\"\nmm/Kconfig:24:\tdepends on SWAP\nmm/Kconfig-25-\tselect CRYPTO\n--\nmm/Kconfig=35=config ZSWAP_DEFAULT_ON\nmm/Kconfig-36-\tbool \"Enable the compressed cache for swap pages by default\"\nmm/Kconfig:37:\tdepends on ZSWAP\nmm/Kconfig-38-\thelp\n--\nmm/Kconfig=45=config ZSWAP_SHRINKER_DEFAULT_ON\nmm/Kconfig-46-\tbool \"Shrink the zswap pool on memory pressure\"\nmm/Kconfig:47:\tdepends on ZSWAP\nmm/Kconfig-48-\tdefault n\n--\nmm/Kconfig=59=choice\nmm/Kconfig-60-\tprompt \"Default compressor\"\nmm/Kconfig:61:\tdepends on ZSWAP\nmm/Kconfig-62-\tdefault ZSWAP_COMPRESSOR_DEFAULT_LZO\n--\nmm/Kconfig=114=config ZSWAP_COMPRESSOR_DEFAULT\nmm/Kconfig-115- string\nmm/Kconfig:116: depends on ZSWAP\nmm/Kconfig-117- default \"deflate\" if ZSWAP_COMPRESSOR_DEFAULT_DEFLATE\n--\nmm/Kconfig=128=menu \"Zsmalloc allocator options\"\nmm/Kconfig:129:\tdepends on ZSMALLOC\nmm/Kconfig-130-\n--\nmm/Kconfig=168=config KVFREE_RCU_BATCHED\nmm/Kconfig-169-\tdef_bool y\nmm/Kconfig:170:\tdepends on !SLUB_TINY \u0026\u0026 !TINY_RCU\nmm/Kconfig:171:\tdepends on !RCU_STRICT_GRACE_PERIOD\nmm/Kconfig-172-\nmm/Kconfig=173=config SLUB_TINY\nmm/Kconfig-174-\tbool \"Configure for minimal memory footprint\"\nmm/Kconfig:175:\tdepends on EXPERT \u0026\u0026 !COMPILE_TEST\nmm/Kconfig-176-\tselect SLAB_MERGE_DEFAULT\n--\nmm/Kconfig=200=config SLAB_FREELIST_RANDOM\nmm/Kconfig-201-\tbool \"Randomize slab freelist\"\nmm/Kconfig:202:\tdepends on !SLUB_TINY\nmm/Kconfig-203-\thelp\n--\nmm/Kconfig=208=config SLAB_FREELIST_HARDENED\nmm/Kconfig-209-\tbool \"Harden slab freelist metadata\"\nmm/Kconfig:210:\tdepends on !SLUB_TINY\nmm/Kconfig-211-\thelp\n--\nmm/Kconfig=217=config SLAB_BUCKETS\nmm/Kconfig-218-\tbool \"Support allocation from separate kmalloc buckets\"\nmm/Kconfig:219:\tdepends on !SLUB_TINY\nmm/Kconfig-220-\tdefault SLAB_FREELIST_HARDENED\n--\nmm/Kconfig=234=config SLUB_STATS\n--\nmm/Kconfig-236-\tbool \"Enable performance statistics\"\nmm/Kconfig:237:\tdepends on SYSFS \u0026\u0026 !SLUB_TINY\nmm/Kconfig-238-\thelp\n--\nmm/Kconfig=247=config KMALLOC_PARTITION_CACHES\nmm/Kconfig:248:\tdepends on !SLUB_TINY\nmm/Kconfig-249-\tbool \"Partitioned slab caches for normal kmalloc\"\n--\nmm/Kconfig=263=choice\nmm/Kconfig-264-\tprompt \"Partitioned slab cache mode\"\nmm/Kconfig:265:\tdepends on KMALLOC_PARTITION_CACHES\nmm/Kconfig-266-\tdefault KMALLOC_PARTITION_TYPED if CC_HAS_ALLOC_TOKEN\n--\nmm/Kconfig=283=config KMALLOC_PARTITION_TYPED\nmm/Kconfig-284-\tbool \"Type based slab cache selection for normal kmalloc\"\nmm/Kconfig:285:\tdepends on CC_HAS_ALLOC_TOKEN\nmm/Kconfig-286-\thelp\n--\nmm/Kconfig=354=config MMAP_ALLOW_UNINITIALIZED\nmm/Kconfig-355-\tbool \"Allow mmapped anonymous memory to be uninitialized\"\nmm/Kconfig:356:\tdepends on EXPERT \u0026\u0026 !MMU\nmm/Kconfig-357-\tdefault n\n--\nmm/Kconfig=376=config SELECT_MEMORY_MODEL\nmm/Kconfig-377-\tdef_bool y\nmm/Kconfig:378:\tdepends on ARCH_SELECT_MEMORY_MODEL\nmm/Kconfig-379-\nmm/Kconfig=380=choice\nmm/Kconfig-381-\tprompt \"Memory model\"\nmm/Kconfig:382:\tdepends on SELECT_MEMORY_MODEL\nmm/Kconfig-383-\tdefault SPARSEMEM_MANUAL if ARCH_SPARSEMEM_DEFAULT\n--\nmm/Kconfig=391=config FLATMEM_MANUAL\nmm/Kconfig-392-\tbool \"Flat Memory\"\nmm/Kconfig:393:\tdepends on !ARCH_SPARSEMEM_ENABLE \|\| ARCH_FLATMEM_ENABLE\nmm/Kconfig-394-\thelp\n--\nmm/Kconfig=406=config SPARSEMEM_MANUAL\nmm/Kconfig-407-\tbool \"Sparse Memory\"\nmm/Kconfig:408:\tdepends on ARCH_SPARSEMEM_ENABLE\nmm/Kconfig-409-\thelp\n--\nmm/Kconfig=421=config SPARSEMEM\nmm/Kconfig-422-\tdef_bool y\nmm/Kconfig:423:\tdepends on (!SELECT_MEMORY_MODEL \u0026\u0026 ARCH_SPARSEMEM_ENABLE) \|\| SPARSEMEM_MANUAL\nmm/Kconfig-424-\nmm/Kconfig=425=config FLATMEM\nmm/Kconfig-426-\tdef_bool y\nmm/Kconfig:427:\tdepends on !SPARSEMEM \|\| FLATMEM_MANUAL\nmm/Kconfig-428-\n--\nmm/Kconfig=447=config SPARSEMEM_EXTREME\nmm/Kconfig-448-\tdef_bool y\nmm/Kconfig:449:\tdepends on SPARSEMEM \u0026\u0026 !SPARSEMEM_STATIC\nmm/Kconfig-450-\n--\nmm/Kconfig=454=config SPARSEMEM_VMEMMAP\nmm/Kconfig-455-\tdef_bool y\nmm/Kconfig:456:\tdepends on SPARSEMEM \u0026\u0026 SPARSEMEM_VMEMMAP_ENABLE\nmm/Kconfig-457-\thelp\n--\nmm/Kconfig=480=config HAVE_GUP_FAST\nmm/Kconfig:481:\tdepends on MMU\nmm/Kconfig-482-\tbool\n--\nmm/Kconfig=504=config EXCLUSIVE_SYSTEM_RAM\nmm/Kconfig-505-\tdef_bool y\nmm/Kconfig:506:\tdepends on !DEVMEM \|\| STRICT_DEVMEM\nmm/Kconfig-507-\n--\nmm/Kconfig=512=menuconfig MEMORY_HOTPLUG\n--\nmm/Kconfig-514-\tselect MEMORY_ISOLATION\nmm/Kconfig:515:\tdepends on SPARSEMEM_VMEMMAP\nmm/Kconfig:516:\tdepends on ARCH_ENABLE_MEMORY_HOTPLUG\nmm/Kconfig:517:\tdepends on 64BIT\nmm/Kconfig-518-\tselect NUMA_KEEP_MEMINFO if NUMA\n--\nmm/Kconfig=584=config MHP_MEMMAP_ON_MEMORY\nmm/Kconfig-585-\tdef_bool y\nmm/Kconfig:586:\tdepends on ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE\nmm/Kconfig-587-\n--\nmm/Kconfig=590=config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE\n--\nmm/Kconfig-596-# Default to 4 for wider testing, though 8 might be more appropriate.\nmm/Kconfig:597:# ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock.\nmm/Kconfig-598-# PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes.\n--\nmm/Kconfig=604=config SPLIT_PTE_PTLOCKS\nmm/Kconfig-605-\tdef_bool y\nmm/Kconfig:606:\tdepends on MMU\nmm/Kconfig:607:\tdepends on SMP\nmm/Kconfig:608:\tdepends on NR_CPUS \u003e= 4\nmm/Kconfig:609:\tdepends on !ARM \|\| CPU_CACHE_VIPT\nmm/Kconfig:610:\tdepends on !PARISC \|\| PA20\nmm/Kconfig:611:\tdepends on !SPARC32\nmm/Kconfig:612:\tdepends on !UML\nmm/Kconfig-613-\n--\nmm/Kconfig=617=config SPLIT_PMD_PTLOCKS\nmm/Kconfig-618-\tdef_bool y\nmm/Kconfig:619:\tdepends on SPLIT_PTE_PTLOCKS \u0026\u0026 ARCH_ENABLE_SPLIT_PMD_PTLOCK\nmm/Kconfig-620-\n--\nmm/Kconfig=628=config BALLOON_MIGRATION\n--\nmm/Kconfig-630-\tdefault y\nmm/Kconfig:631:\tdepends on MIGRATION \u0026\u0026 BALLOON\nmm/Kconfig-632-\thelp\n--\nmm/Kconfig=640=config COMPACTION\n--\nmm/Kconfig-643-\tselect MIGRATION\nmm/Kconfig:644:\tdepends on MMU\nmm/Kconfig-645-\thelp\n--\nmm/Kconfig=655=config COMPACT_UNEVICTABLE_DEFAULT\nmm/Kconfig-656-\tint\nmm/Kconfig:657:\tdepends on COMPACTION\nmm/Kconfig-658-\tdefault 0 if PREEMPT_RT\n--\nmm/Kconfig=671=config NUMA_MIGRATION\n--\nmm/Kconfig-673-\tdefault y\nmm/Kconfig:674:\tdepends on NUMA \u0026\u0026 MMU\nmm/Kconfig-675-\tselect MIGRATION\n--\nmm/Kconfig=682=config MIGRATION\nmm/Kconfig-683-\tbool\nmm/Kconfig:684:\tdepends on MMU\nmm/Kconfig-685-\n--\nmm/Kconfig=726=config KSM\nmm/Kconfig-727-\tbool \"Enable KSM for page merging\"\nmm/Kconfig:728:\tdepends on MMU\nmm/Kconfig-729-\tselect XXHASH\n--\nmm/Kconfig=741=config DEFAULT_MMAP_MIN_ADDR\nmm/Kconfig-742-\tint \"Low address space to protect from user allocation\"\nmm/Kconfig:743:\tdepends on MMU\nmm/Kconfig-744-\tdefault 4096\n--\nmm/Kconfig=763=config MEMORY_FAILURE\nmm/Kconfig:764:\tdepends on MMU\nmm/Kconfig:765:\tdepends on ARCH_SUPPORTS_MEMORY_FAILURE\nmm/Kconfig-766-\tbool \"Enable recovery from hardware memory errors\"\n--\nmm/Kconfig=774=config HWPOISON_INJECT\nmm/Kconfig-775-\ttristate \"HWPoison pages injector\"\nmm/Kconfig:776:\tdepends on MEMORY_FAILURE \u0026\u0026 DEBUG_KERNEL \u0026\u0026 PROC_FS\nmm/Kconfig-777-\tselect PROC_PAGE_MONITOR\n--\nmm/Kconfig=779=config NOMMU_INITIAL_TRIM_EXCESS\nmm/Kconfig-780-\tint \"Turn on mmap() excess space trimming before booting\"\nmm/Kconfig:781:\tdepends on !MMU\nmm/Kconfig-782-\tdefault 1\n--\nmm/Kconfig=813=config PERSISTENT_HUGE_ZERO_FOLIO\nmm/Kconfig-814-\tbool \"Allocate a PMD sized folio for zeroing\"\nmm/Kconfig:815:\tdepends on TRANSPARENT_HUGEPAGE\nmm/Kconfig-816-\thelp\n--\nmm/Kconfig=832=menuconfig TRANSPARENT_HUGEPAGE\nmm/Kconfig-833-\tbool \"Transparent Hugepage Support\"\nmm/Kconfig:834:\tdepends on HAVE_ARCH_TRANSPARENT_HUGEPAGE \u0026\u0026 !PREEMPT_RT\nmm/Kconfig-835-\tselect COMPACTION\n--\nmm/Kconfig=968=config THP_SWAP\nmm/Kconfig-969-\tdef_bool y\nmm/Kconfig:970:\tdepends on ARCH_WANTS_THP_SWAP \u0026\u0026 SWAP \u0026\u0026 64BIT\nmm/Kconfig-971-\thelp\n--\nmm/Kconfig=1014=config ARCH_SUPPORTS_HUGE_PFNMAP\nmm/Kconfig-1015-\tdef_bool n\nmm/Kconfig:1016:\tdepends on TRANSPARENT_HUGEPAGE\nmm/Kconfig-1017-\nmm/Kconfig=1018=config ARCH_SUPPORTS_PMD_PFNMAP\nmm/Kconfig-1019-\tdef_bool y\nmm/Kconfig:1020:\tdepends on ARCH_SUPPORTS_HUGE_PFNMAP \u0026\u0026 HAVE_ARCH_TRANSPARENT_HUGEPAGE\nmm/Kconfig-1021-\nmm/Kconfig=1022=config ARCH_SUPPORTS_PUD_PFNMAP\nmm/Kconfig-1023-\tdef_bool y\nmm/Kconfig:1024:\tdepends on ARCH_SUPPORTS_HUGE_PFNMAP \u0026\u0026 HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD\nmm/Kconfig-1025-\n--\nmm/Kconfig=1036=config NEED_PER_CPU_KM\nmm/Kconfig:1037:\tdepends on !SMP \|\| !MMU\nmm/Kconfig-1038-\tbool\n--\nmm/Kconfig=1053=config CMA\nmm/Kconfig-1054-\tbool \"Contiguous Memory Allocator\"\nmm/Kconfig:1055:\tdepends on MMU\nmm/Kconfig-1056-\tselect MIGRATION\n--\nmm/Kconfig=1068=config CMA_DEBUGFS\nmm/Kconfig-1069-\tbool \"CMA debugfs interface\"\nmm/Kconfig:1070:\tdepends on CMA \u0026\u0026 DEBUG_FS\nmm/Kconfig-1071-\thelp\n--\nmm/Kconfig=1074=config CMA_SYSFS\nmm/Kconfig-1075-\tbool \"CMA information through sysfs interface\"\nmm/Kconfig:1076:\tdepends on CMA \u0026\u0026 SYSFS\nmm/Kconfig-1077-\thelp\n--\nmm/Kconfig=1081=config CMA_AREAS\nmm/Kconfig-1082-\tint \"Maximum count of the CMA areas\"\nmm/Kconfig:1083:\tdepends on CMA\nmm/Kconfig-1084-\tdefault 20 if NUMA\n--\nmm/Kconfig=1128=config MEM_SOFT_DIRTY\nmm/Kconfig-1129-\tbool \"Track memory changes\"\nmm/Kconfig:1130:\tdepends on CHECKPOINT_RESTORE \u0026\u0026 HAVE_ARCH_SOFT_DIRTY \u0026\u0026 PROC_FS\nmm/Kconfig-1131-\tselect PROC_PAGE_MONITOR\n--\nmm/Kconfig=1143=config STACK_MAX_DEFAULT_SIZE_MB\n--\nmm/Kconfig-1146-\trange 8 2048\nmm/Kconfig:1147:\tdepends on STACK_GROWSUP \u0026\u0026 (!64BIT \|\| COMPAT)\nmm/Kconfig-1148-\thelp\n--\nmm/Kconfig=1155=config DEFERRED_STRUCT_PAGE_INIT\nmm/Kconfig-1156-\tbool \"Defer initialisation of struct pages to kthreads\"\nmm/Kconfig:1157:\tdepends on SPARSEMEM\nmm/Kconfig:1158:\tdepends on !NEED_PER_CPU_KM\nmm/Kconfig:1159:\tdepends on 64BIT\nmm/Kconfig:1160:\tdepends on !KMSAN\nmm/Kconfig-1161-\tselect PADATA\n--\nmm/Kconfig=1179=config IDLE_PAGE_TRACKING\nmm/Kconfig-1180-\tbool \"Enable idle page tracking\"\nmm/Kconfig:1181:\tdepends on SYSFS \u0026\u0026 MMU\nmm/Kconfig-1182-\tselect PAGE_IDLE_FLAG\n--\nmm/Kconfig=1217=config ZONE_DMA32\nmm/Kconfig-1218-\tbool \"Support DMA32 zone\" if ARCH_HAS_ZONE_DMA_SET\nmm/Kconfig:1219:\tdepends on !X86_32\nmm/Kconfig-1220-\tdefault y if ARM64\n--\nmm/Kconfig=1222=config ZONE_DEVICE\nmm/Kconfig-1223-\tbool \"Device memory (pmem, HMM, etc...) hotplug support\"\nmm/Kconfig:1224:\tdepends on MEMORY_HOTREMOVE\nmm/Kconfig-1225-\tselect XARRAY_MULTI\n--\nmm/Kconfig=1244=config HMM_MIRROR\nmm/Kconfig-1245-\tbool\nmm/Kconfig:1246:\tdepends on MMU\nmm/Kconfig-1247-\tselect MMU_NOTIFIER\n--\nmm/Kconfig=1252=config DEVICE_PRIVATE\nmm/Kconfig-1253-\tbool \"Unaddressable device memory (GPU memory, ...)\"\nmm/Kconfig:1254:\tdepends on ZONE_DEVICE\nmm/Kconfig-1255-\tselect GET_FREE_REGION\n--\nmm/Kconfig=1291=config GUP_TEST\nmm/Kconfig-1292-\tbool \"Enable infrastructure for get_user_pages()-related unit tests\"\nmm/Kconfig:1293:\tdepends on DEBUG_FS\nmm/Kconfig-1294-\thelp\n--\nmm/Kconfig=1311=comment \"GUP_TEST needs to have DEBUG_FS enabled\"\nmm/Kconfig:1312:\tdepends on !GUP_TEST \u0026\u0026 !DEBUG_FS\nmm/Kconfig-1313-\n--\nmm/Kconfig=1317=config DMAPOOL_TEST\nmm/Kconfig-1318-\ttristate \"Enable a module to run time tests on dma_pool\"\nmm/Kconfig:1319:\tdepends on HAS_DMA\nmm/Kconfig-1320-\thelp\n--\nmm/Kconfig=1341=config SECRETMEM\n--\nmm/Kconfig-1343-\tbool \"Enable memfd_secret() system call\" if EXPERT\nmm/Kconfig:1344:\tdepends on ARCH_HAS_SET_DIRECT_MAP\nmm/Kconfig-1345-\thelp\n--\nmm/Kconfig=1350=config ANON_VMA_NAME\nmm/Kconfig-1351-\tbool \"Anonymous VMA name support\"\nmm/Kconfig:1352:\tdepends on PROC_FS \u0026\u0026 ADVISE_SYSCALLS \u0026\u0026 MMU\nmm/Kconfig-1353-\n--\nmm/Kconfig=1374=config USERFAULTFD_RWP\nmm/Kconfig-1375-\tdef_bool y\nmm/Kconfig:1376:\tdepends on 64BIT \u0026\u0026 ARCH_HAS_PTE_PROTNONE \u0026\u0026 HAVE_ARCH_USERFAULTFD_WP\nmm/Kconfig-1377-\thelp\n--\nmm/Kconfig=1383=menuconfig USERFAULTFD\nmm/Kconfig-1384-\tbool \"Enable userfaultfd() system call\"\nmm/Kconfig:1385:\tdepends on MMU\nmm/Kconfig-1386-\thelp\n--\nmm/Kconfig=1390=config PTE_MARKER_UFFD_WP\n--\nmm/Kconfig-1392-\tdefault y\nmm/Kconfig:1393:\tdepends on USERFAULTFD \u0026\u0026 HAVE_ARCH_USERFAULTFD_WP\nmm/Kconfig-1394-\n--\nmm/Kconfig=1401=config LRU_GEN\nmm/Kconfig-1402-\tbool \"Multi-Gen LRU\"\nmm/Kconfig:1403:\tdepends on MMU\nmm/Kconfig-1404-\t# make sure folio-\u003eflags has enough spare bits\nmm/Kconfig:1405:\tdepends on 64BIT \|\| !SPARSEMEM \|\| SPARSEMEM_VMEMMAP\nmm/Kconfig-1406-\thelp\n--\nmm/Kconfig=1410=config LRU_GEN_ENABLED\nmm/Kconfig-1411-\tbool \"Enable by default\"\nmm/Kconfig:1412:\tdepends on LRU_GEN\nmm/Kconfig-1413-\thelp\n--\nmm/Kconfig=1416=config LRU_GEN_STATS\nmm/Kconfig-1417-\tbool \"Full stats for debugging\"\nmm/Kconfig:1418:\tdepends on LRU_GEN\nmm/Kconfig-1419-\thelp\n--\nmm/Kconfig=1425=config LRU_GEN_WALKS_MMU\nmm/Kconfig-1426-\tdef_bool y\nmm/Kconfig:1427:\tdepends on LRU_GEN \u0026\u0026 ARCH_HAS_HW_PTE_YOUNG\nmm/Kconfig-1428-# }\n--\nmm/Kconfig=1433=config PER_VMA_LOCK\nmm/Kconfig-1434-\tdef_bool y\nmm/Kconfig:1435:\tdepends on ARCH_SUPPORTS_PER_VMA_LOCK \u0026\u0026 MMU \u0026\u0026 SMP\nmm/Kconfig-1436-\thelp\n--\nmm/Kconfig=1442=config LOCK_MM_AND_FIND_VMA\nmm/Kconfig-1443-\tbool\nmm/Kconfig:1444:\tdepends on !STACK_GROWSUP\nmm/Kconfig-1445-\n--\nmm/Kconfig=1455=config NUMA_EMU\nmm/Kconfig-1456-\tbool \"NUMA emulation\"\nmm/Kconfig:1457:\tdepends on NUMA_MEMBLKS\nmm/Kconfig:1458:\tdepends on X86 \|\| GENERIC_ARCH_NUMA\nmm/Kconfig-1459-\thelp\n--\nmm/Kconfig=1473=config PT_RECLAIM\nmm/Kconfig-1474-\tdef_bool y\nmm/Kconfig:1475:\tdepends on MMU_GATHER_RCU_TABLE_FREE \u0026\u0026 !HAVE_ARCH_TLB_REMOVE_TABLE\nmm/Kconfig-1476-\thelp\n--\nmm/Kconfig=1492=config LAZY_MMU_MODE_KUNIT_TEST\nmm/Kconfig-1493-\ttristate \"KUnit tests for the lazy MMU mode\" if !KUNIT_ALL_TESTS\nmm/Kconfig:1494:\tdepends on ARCH_HAS_LAZY_MMU_MODE\nmm/Kconfig:1495:\tdepends on KUNIT\nmm/Kconfig-1496-\tdefault KUNIT_ALL_TESTS\n" }
19/2	2026/08/03 18:01	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 21587 output: 27 thoughts: 74 Thoughts: Examining THP and MEMCG Configuration Okay, so I'm looking at how `TRANSPARENT_HUGEPAGE` is configured. Right, it looks like its availability is determined by both `HAVE_ARCH_TRANSPARENT_HUGEPAGE` and the absence of `PREEMPT_RT`. Therefore, when documenting these, I should just list `TRANSPARENT_HUGEPAGE` and `MEMCG`. Wait a minute, where is `MEMCG` defined? Ah, right, that's defined in `init/Kconfig`. I should go check that file to confirm.
20/2	2026/08/03 18:01	tool	grepper	0m Args: { "Expression": "config MEMCG", "PathPrefix": "init/Kconfig" } Results: { "Output": "init/Kconfig=1074=config CGROUP_FAVOR_DYNMODS\n--\ninit/Kconfig-1083-\ninit/Kconfig:1084:config MEMCG\ninit/Kconfig-1085-\tbool \"Memory controller\"\n--\ninit/Kconfig-1092-\ninit/Kconfig:1093:config MEMCG_NMI_UNSAFE\ninit/Kconfig-1094-\tbool\n--\ninit/Kconfig-1099-\ninit/Kconfig:1100:config MEMCG_NMI_SAFETY_REQUIRES_ATOMIC\ninit/Kconfig-1101-\tbool\n--\ninit/Kconfig-1106-\ninit/Kconfig:1107:config MEMCG_V1\ninit/Kconfig-1108-\tbool \"Legacy cgroup v1 memory controller\"\n" }
21/2	2026/08/03 18:01	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 22047 output: 27 thoughts: 1105 Thoughts: Focus Function Selection for tmpfs/shmem Memory Management Okay, so I'm zeroing in on the best focus functions for this tmpfs/shmem change, considering `MEMCG` and `TRANSPARENT_HUGEPAGE` are the relevant configurations. First, I ruled out `shmem_get_folio` and `shmem_read_folio_gfp` quickly, despite their API entry point status. `shmem_get_folio` is a hot path; it's called very frequently which could skew the results, which is undesirable. We want a more targeted test. Then, I looked at `shmem_unused_huge_shrink`, but it's static. The instructions specify that we should prefer non-static, non-inlined API entrypoints functions, but static functions are only a problem if inlined by the compiler. If NOT inlined, they have distinct symbols and can be used. `shmem_unused_huge_scan` is static, but is assigned to `shmem_ops.free_cached_objects`, so it’s likely not inlined because it's passed as a function pointer. This makes it promising. And yes, it looks like the modified logic's entry point is exactly in this function, so it's a strong contender. The same holds true for `shmem_unused_huge_count`. I reviewed the other functions, but found that `shmem_evict_inode`, and `shmem_fill_super` are also static, but called indirectly via function pointers or data structures. So, these are also not inlined. The best focus functions, I've concluded, are `shmem_unused_huge_scan` and `shmem_unused_huge_count`. They're the core entry points for the shrinker logic modifications. Finally, I considered including `shmem_get_folio` as it is an entry point, and the allocation path interacts with the shrinklist: ```c if (alloced && folio_test_large(folio) && DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) < folio_next_index(folio)) { /* * Part of the large folio is beyond i_size: subject * to shrink under memory pressure. */ shmem_unused_huge_add(inode, folio, gfp); } ``` However, the allocation of folios to the shrinklist only occurs for huge folios on tmpfs, so it's not a general hot path. The function `shmem_get_folio` itself, however, is called on ALL page faults. While `shmem_get_folio` would hit that allocation path and be relevant, it's a very hot path, so I'll stick with `shmem_unused_huge_scan` and `shmem_unused_huge_count` for now, to ensure specificity. I'll also include `shmem_evict_inode` as it calls `shmem_unused_huge_del`. I just checked that I spelled all the function names correctly... Yes, `shmem_unused_huge_scan` and `shmem_unused_huge_count` it is. The patch also specifies that `CONFIG_TRANSPARENT_HUGEPAGE` and `CONFIG_MEMCG` are used, but `CONFIG_SHMEM` is usually enabled so no need to verify it.
22/2	2026/08/03 18:01	tool	grepper	0m Error: no matches Args: { "Expression": "config SHMEM", "PathPrefix": "mm/Kconfig" } Results: { "error": "no matches" }
23/2	2026/08/03 18:01	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 23944 output: 27 thoughts: 17 Thoughts: Here's my thought process, summarized as you requested: Kconfig Dive for Shared Memory Configuration Okay, so I need to find the configuration options related to shared memory, specifically within the kernel's initialization code. My immediate thought is to start with the `init/Kconfig` file. It's the central repository for kernel configuration options, and `SHMEM` is a pretty specific term that should yield relevant results if I use it as a search term. My aim is to locate the relevant Kconfig symbols to understand how shared memory is configured, controlled and supported. I'll need to figure out what those symbols are so that I can then trace their dependency trees, and understand the implications of different settings. Let's see what `init/Kconfig` reveals...
24/2	2026/08/03 18:01	tool	grepper	0m Args: { "Expression": "config SHMEM", "PathPrefix": "init/Kconfig" } Results: { "Output": "init/Kconfig=1931=config EVENTFD\n--\ninit/Kconfig-1939-\ninit/Kconfig:1940:config SHMEM\ninit/Kconfig-1941-\tbool \"Use full shmem filesystem\" if EXPERT\n" }
25/2	2026/08/03 18:01	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 24227 output: 34 thoughts: 443 Thoughts: My Assessment of the Shared Memory Huge Page Shrinker Patch Okay, so `SHMEM` is definitely enabled by default, according to `init/Kconfig`, which is good news. And with `TRANSPARENT_HUGEPAGE` and `MEMCG` all being enabled too, things are looking promising. Let's dive back into this patch. The core of it seems to be moving the shrinker from a global list to a per-memcg `list_lru`. The way it uses `shmem_unused_huge_shrink` is changing to use `list_lru_shrink_walk` and `list_lru_walk`. There's a whole suite of new functions added: `shmem_unused_huge_add`, `shmem_unused_huge_del`, `shmem_unused_huge_isolate`, `is_shmem_unused_huge_match`, `shmem_unused_huge_drop`, and `shmem_unused_huge_requeue`, which are all part of that new `list_lru` based shrinker implementation. It also appears that `shmem_sb_info` is being modified to use `struct list_lru shrinklist` instead of the old `struct list_head shrinklist`. Similarly, `shmem_inode_info` is now including `shrinklist_memcg` and `shrinklist_nid`. The logic looks functional and should be reachable. This definitely warrants some fuzzing. My focus should be on these symbols: `shmem_unused_huge_scan`, `shmem_unused_huge_count`, `shmem_evict_inode`, and `shmem_fill_super`. Hang on a second... `shmem_evict_inode` and `shmem_fill_super` are also static, but passed as function pointers. Interesting. Are there any non-static functions? Yes, `shmem_get_folio` and `shmem_read_folio_gfp` are non-static. But, I think the most important functions to include will be `shmem_unused_huge_scan` and `shmem_unused_huge_count` since these are the main entry points for the modified shrinker logic. Now, I need to double-check something. Let's make sure that `shmem_unused_huge_scan` isn't defined if `CONFIG_TRANSPARENT_HUGEPAGE` is disabled. That could be a source of confusion.
26/2	2026/08/03 18:01	tool	grepper	0m Args: { "Expression": "shmem_unused_huge_scan", "PathPrefix": "mm/shmem.c" } Results: { "Output": "mm/shmem.c=813=static void shmem_unused_huge_del(struct inode inode)\n--\nmm/shmem.c-829-\nmm/shmem.c:830:struct shmem_unused_huge_scan {\nmm/shmem.c-831-\tstruct list_head list;\n--\nmm/shmem.c=835=static enum lru_status shmem_unused_huge_isolate(struct list_head item,\n--\nmm/shmem.c-838-{\nmm/shmem.c:839:\tstruct shmem_unused_huge_scan scan = arg;\nmm/shmem.c-840-\tstruct shmem_inode_info info;\n--\nmm/shmem.c=931=static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info sbinfo,\n--\nmm/shmem.c-933-{\nmm/shmem.c:934:\tstruct shmem_unused_huge_scan scan;\nmm/shmem.c-935-\tstruct inode inode;\n--\nmm/shmem.c-1020-\nmm/shmem.c:1021:static long shmem_unused_huge_scan(struct super_block sb,\nmm/shmem.c-1022-\t\tstruct shrink_control sc)\n--\nmm/shmem.c=5411=static const struct super_operations shmem_ops = {\n--\nmm/shmem.c-5426-\t.nr_cached_objects\t= shmem_unused_huge_count,\nmm/shmem.c:5427:\t.free_cached_objects\t= shmem_unused_huge_scan,\nmm/shmem.c-5428-#endif\n" }
27/2	2026/08/03 18:01	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 25704 output: 30 thoughts: 48 Thoughts: Okay, let me break this down. Decoding the Compilation Context Hmm, so I've spotted a crucial detail here: that `#endif` right after the assignment to `free_cached_objects`. That immediately makes me think about potential conditional compilation. The fact that it's after the assignment is important, as it suggests the definition or assignment might only be present under specific build configurations. My expert intuition is immediately piqued; I need to understand the implications of any `#ifdef` directives in play. Let me see... I need to check precisely which conditional compilation directives surround the definition of `shmem_ops`, because that's what seems to control whether `free_cached_objects` is assigned to a specific function pointer. The `#ifdef`s are the key. Understanding the preprocessor directives will reveal the different build contexts.
28/2	2026/08/03 18:01	tool	grepper	0m Args: { "Expression": "shmem_ops", "PathPrefix": "mm/shmem.c" } Results: { "Output": "mm/shmem.c=254=static void shmem_inode_unacct_blocks(struct inode inode, long pages)\n--\nmm/shmem.c-266-\nmm/shmem.c:267:static const struct super_operations shmem_ops;\nmm/shmem.c-268-static const struct address_space_operations shmem_aops;\n--\nmm/shmem.c=5125=static int shmem_fill_super(struct super_block sb, struct fs_context *fc)\n--\nmm/shmem.c-5212-\tsb-\u003es_magic = TMPFS_MAGIC;\nmm/shmem.c:5213:\tsb-\u003es_op = \u0026shmem_ops;\nmm/shmem.c-5214-\tsb-\u003es_time_gran = 1;\n--\nmm/shmem.c=5400=static const struct inode_operations shmem_special_inode_operations = {\n--\nmm/shmem.c-5410-\nmm/shmem.c:5411:static const struct super_operations shmem_ops = {\nmm/shmem.c-5412-\t.alloc_inode\t= shmem_alloc_inode,\n" }
29/2	2026/08/03 18:01	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 26281 output: 35 thoughts: 20 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: Diving into `mm/shmem.c` Okay, time to dig into this. I'm going to jump straight to `mm/shmem.c`, specifically around line 5411. I need to get a handle on what's happening at that point in the shared memory implementation. I'm expecting this area to be dealing with allocation, deallocation, or perhaps some sort of metadata management related to shared memory segments. Given my experience, I'm already mentally running through potential scenarios – could be page fault handling, synchronization primitives being used, or interactions with the page cache. Let's see what the code actually reveals. I anticipate the immediate context will provide the key insight.
30/2	2026/08/03 18:01	tool	read-file	0m Args: { "File": "mm/shmem.c", "FirstLine": 5411, "LineCount": 30 } Results: { "Contents": "5411:\tstatic const struct super_operations shmem_ops = {\n5412:\t\t.alloc_inode\t= shmem_alloc_inode,\n5413:\t\t.free_inode\t= shmem_free_in_core_inode,\n5414:\t\t.destroy_inode\t= shmem_destroy_inode,\n5415:\t#ifdef CONFIG_TMPFS\n5416:\t\t.statfs\t\t= shmem_statfs,\n5417:\t\t.show_options\t= shmem_show_options,\n5418:\t#endif\n5419:\t#ifdef CONFIG_TMPFS_QUOTA\n5420:\t\t.get_dquots\t= shmem_get_dquots,\n5421:\t#endif\n5422:\t\t.evict_inode\t= shmem_evict_inode,\n5423:\t\t.drop_inode\t= inode_just_drop,\n5424:\t\t.put_super\t= shmem_put_super,\n5425:\t#ifdef CONFIG_TRANSPARENT_HUGEPAGE\n5426:\t\t.nr_cached_objects\t= shmem_unused_huge_count,\n5427:\t\t.free_cached_objects\t= shmem_unused_huge_scan,\n5428:\t#endif\n5429:\t};\n5430:\t\n5431:\tstatic const struct vm_operations_struct shmem_vm_ops = {\n5432:\t\t.fault\t\t= shmem_fault,\n5433:\t\t.map_pages\t= filemap_map_pages,\n5434:\t#ifdef CONFIG_NUMA\n5435:\t\t.set_policy = shmem_set_policy,\n5436:\t\t.get_policy = shmem_get_policy,\n5437:\t#endif\n5438:\t#ifdef CONFIG_USERFAULTFD\n5439:\t\t.uffd_ops\t= \u0026shmem_uffd_ops,\n5440:\t#endif\n" }
31/2	2026/08/03 18:01	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 27027 output: 35 thoughts: 79 Thoughts: Okay, let's break this down. Unpacking the Transparent Hugepage Configuration Right, so `shmem_unused_huge_count` and `shmem_unused_huge_scan`... I see they're only actually assigned a value when `CONFIG_TRANSPARENT_HUGEPAGE` is enabled. Seems pretty straightforward, as expected. They're part of that transparent hugepage machinery, so that makes sense. But hold on a second... are they even defined when THP is disabled? We need to verify that these symbols aren't somehow polluting the namespace when they shouldn't be. Let me quickly check the `#ifdef` conditions around their declarations. I need to make sure this is all behaving as it should in different configurations. Let's see... a quick check should settle it. Gotta be careful with these preprocessor directives.
32/2	2026/08/03 18:01	tool	read-file	0m Args: { "File": "mm/shmem.c", "FirstLine": 1030, "LineCount": 30 } Results: { "Contents": "1030:\t}\n1031:\t\n1032:\tstatic long shmem_unused_huge_count(struct super_block sb,\n1033:\t\t\tstruct shrink_control sc)\n1034:\t{\n1035:\t\tstruct shmem_sb_info sbinfo = SHMEM_SB(sb);\n1036:\t\n1037:\t\treturn list_lru_shrink_count(\u0026sbinfo-\u003eshrinklist, sc);\n1038:\t}\n1039:\t#else / !CONFIG_TRANSPARENT_HUGEPAGE /\n1040:\t\n1041:\t#define shmem_huge SHMEM_HUGE_DENY\n1042:\t\n1043:\tstatic void shmem_unused_huge_add(struct inode inode, struct folio folio,\n1044:\t\t\t\t\t gfp_t gfp)\n1045:\t{\n1046:\t}\n1047:\t\n1048:\tstatic void shmem_unused_huge_del(struct inode inode)\n1049:\t{\n1050:\t}\n1051:\t\n1052:\tstatic unsigned long shmem_unused_huge_shrink(struct shmem_sb_info sbinfo,\n1053:\t\t\tstruct shrink_control sc, unsigned long nr_to_free)\n1054:\t{\n1055:\t\treturn 0;\n1056:\t}\n1057:\t\n1058:\tstatic unsigned int shmem_huge_global_enabled(struct inode *inode, pgoff_t index,\n1059:\t\t\t\t\t\t loff_t write_end, bool shmem_huge_force,\n" }
33/2	2026/08/03 18:01	llm	patch-evaluator	7m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 27779 output: 34 thoughts: 86 Thoughts: My Analysis of Hugepage Configuration Okay, so it's become clear: if `CONFIG_TRANSPARENT_HUGEPAGE` is disabled, these elements, whatever they are, aren't even defined. That means their very existence hinges on `CONFIG_TRANSPARENT_HUGEPAGE` being enabled. No ambiguity there. It definitively establishes that `CONFIG_TRANSPARENT_HUGEPAGE` is a mandatory prerequisite. Now, I need to shift my focus. My next logical step is to examine `CONFIG_MEMCG` to understand how it interacts with the hugepage configuration in this context. I'll start by digging into `mm/shmem.c` to see what I can find.
34/2	2026/08/03 18:09	tool	read-file	0m Args: { "File": "mm/shmem.c", "FirstLine": 740, "LineCount": 30 } Results: { "Contents": " 740:\t\tstruct mem_cgroup memcg = info-\u003eshrinklist_memcg;\n 741:\t\n 742:\t\tinfo-\u003eshrinklist_memcg = NULL;\n 743:\t\n 744:\t\treturn memcg;\n 745:\t}\n 746:\t\n 747:\t#ifdef CONFIG_MEMCG\n 748:\tstatic struct mem_cgroup \n 749:\tshmem_unused_huge_alloc_lru(struct shmem_sb_info sbinfo, struct folio folio,\n 750:\t\t\t\t gfp_t gfp)\n 751:\t{\n 752:\t\tstruct mem_cgroup memcg;\n 753:\t\tint ret;\n 754:\t\n 755:\t\tmemcg = get_mem_cgroup_from_folio(folio);\n 756:\t\tif (!memcg)\n 757:\t\t\treturn NULL;\n 758:\t\n 759:\t\tret = memcg_list_lru_alloc(memcg, \u0026sbinfo-\u003eshrinklist, gfp);\n 760:\t\tif (ret) {\n 761:\t\t\tmem_cgroup_put(memcg);\n 762:\t\t\treturn ERR_PTR(ret);\n 763:\t\t}\n 764:\t\n 765:\t\treturn memcg;\n 766:\t}\n 767:\t#else\n 768:\tstatic struct mem_cgroup \n 769:\tshmem_unused_huge_alloc_lru(struct shmem_sb_info sbinfo, struct folio folio,\n" }
35/2	2026/08/03 18:09	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 28485 output: 25 thoughts: 177 Thoughts: Analyzing the Dependencies for Testing Memcg-Specific Shrinker Logic Okay, so I'm digging into this patch. It looks like the new shrinker is designed to work on a per-memcg basis. That means `CONFIG_MEMCG` is definitely essential for testing the new functionality, because, if it's disabled, the allocation will return NULL and the code will fall back to a global operation. We wouldn't be able to validate the per-memcg behavior at all without `CONFIG_MEMCG` enabled. Now, I need to check if we need anything else. I'm thinking about `CONFIG_TMPFS`, but that's usually enabled anyway. The real question is whether `CONFIG_SHMEM` is required. I know `shmem_unused_huge_scan` is defined in `mm/shmem.c`. Aha! Now the question is: is `mm/shmem.c` even compiled if `CONFIG_SHMEM` is disabled? I'll need to check the `mm/Makefile` to confirm the dependencies for `mm/shmem.c` compilation. This is the crucial bit. If it's not compiled without `CONFIG_SHMEM`, then that's another prerequisite.
36/2	2026/08/03 18:09	tool	grepper	0m Args: { "Expression": "shmem", "PathPrefix": "mm/Makefile" } Results: { "Output": "mm/Makefile=51=obj-y\t\t\t:= filemap.o mempool.o oom_kill.o fadvise.o \\\n--\nmm/Makefile-53-\t\t\t readahead.o folio.o truncate.o vmscan.o shrinker.o \\\nmm/Makefile:54:\t\t\t shmem.o util.o mmzone.o vmstat.o backing-dev.o \\\nmm/Makefile-55-\t\t\t mm_init.o percpu.o slab_common.o \\\n--\nmm/Makefile=146=obj-$(CONFIG_EXECMEM) += execmem.o\nmm/Makefile:147:obj-$(CONFIG_TMPFS_QUOTA) += shmem_quota.o\nmm/Makefile-148-obj-$(CONFIG_LAZY_MMU_MODE_KUNIT_TEST) += tests/lazy_mmu_mode_kunit.o\n" }
37/2	2026/08/03 18:09	llm	patch-evaluator	1m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 29179 output: 30 thoughts: 61 Thoughts: Investigating the Compilation of `shmem.o` Okay, so `shmem.o` is consistently being compiled, declared as `obj-y`. That's the expected default behavior. But hold on, something seems off. Even when `CONFIG_SHMEM` is disabled, I'm seeing `mm/shmem.c` still being compiled. This seems counterintuitive and I need to verify why. The logical next step is to examine the source code itself, specifically `mm/shmem.c`. I need to search this file for any conditional compilation directives related to `CONFIG_SHMEM`. I need to understand if there is some other mechanism to explain why the shmem file is being included.
38/2	2026/08/03 18:11	tool	grepper	0m Args: { "Expression": "CONFIG_SHMEM", "PathPrefix": "mm/shmem.c" } Results: { "Output": "mm/shmem.c=46=static struct vfsmount shm_mnt __ro_after_init;\nmm/shmem.c-47-\nmm/shmem.c:48:#ifdef CONFIG_SHMEM\nmm/shmem.c-49-/\n--\nmm/shmem.c=5896=__setup(\"thp_shmem=\", setup_thp_shmem);\n--\nmm/shmem.c-5899-\nmm/shmem.c:5900:#else /* !CONFIG_SHMEM /\nmm/shmem.c-5901-\n--\nmm/shmem.c=5969=static inline struct inode shmem_get_inode(struct mnt_idmap idmap,\n--\nmm/shmem.c-5976-\nmm/shmem.c:5977:#endif / CONFIG_SHMEM /\nmm/shmem.c-5978-\n--\nmm/shmem.c=6131=struct folio shmem_read_folio_gfp(struct address_space mapping,\n--\nmm/shmem.c-6133-{\nmm/shmem.c:6134:#ifdef CONFIG_SHMEM\nmm/shmem.c-6135-\tstruct inode inode = mapping-\u003ehost;\n" }
39/2	2026/08/03 18:11	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 29759 output: 34 thoughts: 1026 Thoughts: My Analysis of the TMPFS/SHMEM Shrinker Modification Okay, so I'm looking at this patch and immediately, I see that `CONFIG_SHMEM` is essential for the full tmpfs implementation – a tiny shmem implementation gets used otherwise. That's a given. Beyond that, I need to identify the key configuration symbols and focus functions for fuzzing. Let's see, we've got `TRANSPARENT_HUGEPAGE`, `MEMCG`, and `SHMEM` as the relevant configs. Seems straightforward. Syzkaller will likely handle enabling `TRANSPARENT_HUGEPAGE_ALWAYS` if `TRANSPARENT_HUGEPAGE` is enabled, given the `mm/Kconfig` structure. Now, the important functions... I initially considered `shmem_unused_huge_scan`, `shmem_unused_huge_count`, `shmem_get_folio`, and `shmem_read_folio_gfp`. But, since `shmem_get_folio` and `shmem_read_folio_gfp` are unchanged, the real impact seems to be on `shmem_get_folio_gfp`. I know this is static and potentially inlined, which is something I want to avoid. The instructions are clear – prefer non-static, non-inlined entry points. Therefore, the key entry points for the shrinker logic are `shmem_unused_huge_scan` and `shmem_unused_huge_count`. I've confirmed that `shmem_unused_huge_scan` is a valid symbol in `mm/shmem.c`. Crucially, it's passed as a function pointer, which means it won't be inlined. This makes it an ideal target. `shmem_unused_huge_count` is also relevant. Looking further, `shmem_unused_huge_shrink` is called by these, so `shmem_unused_huge_scan` is the way to go. Next, I noted that `shmem_evict_inode` is modified to call `shmem_unused_huge_del`, and it's also passed as a function pointer through `shmem_ops.evict_inode`. That makes it another excellent focus function as it is not inlined. Finally, `shmem_fill_super` is modified to initialize the `list_lru`, and, like `shmem_evict_inode`, is passed as a function pointer. I'll add this to the list. So, here's my final list of focus symbols: * `shmem_unused_huge_scan` * `shmem_unused_huge_count` * `shmem_evict_inode` * `shmem_fill_super` And the configurations: * `TRANSPARENT_HUGEPAGE` * `MEMCG` * `SHMEM` I've verified the dependencies: `TRANSPARENT_HUGEPAGE` needs `HAVE_ARCH_TRANSPARENT_HUGEPAGE && !PREEMPT_RT`, which is fine, syzkaller will enable that if it can. `MEMCG` and `SHMEM` have no special dependencies. Essentially, this patch is about integrating a per-memcg `list_lru` into the tmpfs/shmem unused huge page shrinker. It affects shrinker entry points, inode eviction, and superblock initialization. This is a crucial area to fuzz, especially when tmpfs is used with huge pages and memory cgroups. The code is reachable in standard environments. This is definitely worth fuzzing. I'll make sure syzkaller targets these functions and configurations.
40/2	2026/08/03 18:11	tool	grepper	0m Args: { "Expression": "config TRANSPARENT_HUGEPAGE_ALWAYS", "PathPrefix": "mm/Kconfig" } Results: { "Output": "mm/Kconfig=850=choice\n--\nmm/Kconfig-855-\nmm/Kconfig:856:\tconfig TRANSPARENT_HUGEPAGE_ALWAYS\nmm/Kconfig-857-\t\tbool \"always\"\n" }
41/2	2026/08/03 18:11	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 31695 output: 40 thoughts: 59 Thoughts: Okay, here's my take on those thoughts, framed as an expert's internal monologue: Considering TMPFS and Huge Pages for Optimal Memory Management Right, so we're talking about a conscious decision point here. It's a choice: do we leverage huge pages for our temporary file systems? The immediate question that jumps to mind is, can we, and if so, how do we do it? I'm thinking specifically about `tmpfs` and huge pages. The performance implications could be significant. Now, which configuration option is most relevant here? Do we need to force this behaviour across the board, or can we do this more surgically? Let's quickly refresh. Do we go with `CONFIG_TRANSPARENT_HUGEPAGE_TMPFS_HUGE_ALWAYS` to guarantee that tmpfs gets to use huge pages, or do we use `CONFIG_TRANSPARENT_HUGEPAGE_SHMEM_HUGE_ALWAYS` to focus on the shared memory side of things? Both options have their implications, depending on the workload and how `tmpfs` is used in this environment. Need to consider the system's memory allocation behaviour.
42/2	2026/08/03 18:11	tool	grepper	0m Args: { "Expression": "config TRANSPARENT_HUGEPAGE_SHMEM_HUGE_ALWAYS", "PathPrefix": "mm/Kconfig" } Results: { "Output": "mm/Kconfig=879=choice\n--\nmm/Kconfig-898-\nmm/Kconfig:899:\tconfig TRANSPARENT_HUGEPAGE_SHMEM_HUGE_ALWAYS\nmm/Kconfig-900-\t\tbool \"always\"\n" }
43/2	2026/08/03 18:11	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 32122 output: 194 thoughts: 56 Thoughts: Okay, here's my take on those thoughts, framed as my own: My Approach to Syzkaller Configuration Right, so Syzkaller's probably going to enable the default set of options soon, which is fine, but I think I'll just go ahead and explicitly specify what I need for this particular round of testing. It'll give me more control and avoid any potential conflicts with those defaults, even if it is a bit more work upfront. Therefore, I'll focus on setting `TRANSPARENT_HUGEPAGE`, because that's crucial for the performance testing I have in mind. I'll also bring in `MEMCG` for isolating the resources being used, and `SHMEM` which I'm pretty sure I'll need for this particular test case. Once those are set up, I'll need to call `set-results`. Hopefully, that'll do what I expect and get the results tracking in the way that I think is best.
44/2	2026/08/03 18:11	tool	set-results	0m Args: { "EnableConfigs": [ "TRANSPARENT_HUGEPAGE", "MEMCG", "SHMEM" ], "FocusSymbols": [ "shmem_unused_huge_scan", "shmem_unused_huge_count", "shmem_evict_inode", "shmem_fill_super" ], "Reasoning": "The patch modifies the tmpfs/shmem unused huge page shrinker to use a per-memcg list_lru instead of a global list. This involves functional changes to the shrinker entry points (shmem_unused_huge_scan, shmem_unused_huge_count), inode eviction (shmem_evict_inode), and superblock initialization (shmem_fill_super). The code is reachable in standard environments when tmpfs is used with transparent huge pages and memory cgroups.", "WorthFuzzing": true } Results: { "EnableConfigs": [ "TRANSPARENT_HUGEPAGE", "MEMCG", "SHMEM" ], "FocusSymbols": [ "shmem_unused_huge_scan", "shmem_unused_huge_count", "shmem_evict_inode", "shmem_fill_super" ], "Reasoning": "The patch modifies the tmpfs/shmem unused huge page shrinker to use a per-memcg list_lru instead of a global list. This involves functional changes to the shrinker entry points (shmem_unused_huge_scan, shmem_unused_huge_count), inode eviction (shmem_evict_inode), and superblock initialization (shmem_fill_super). The code is reachable in standard environments when tmpfs is used with transparent huge pages and memory cgroups.", "WorthFuzzing": true }

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