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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2013 Red Hat, Inc. and Parallels Inc. All rights reserved.
  * Authors: David Chinner and Glauber Costa
  *
  * Generic LRU infrastructure
  */
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/mm.h>
 #include <linux/list_lru.h>
 #include <linux/slab.h>
 #include <linux/mutex.h>
 #include <linux/memcontrol.h>
 #include "slab.h"
 #include "internal.h"
 
 #ifdef CONFIG_MEMCG_KMEM
 static LIST_HEAD(memcg_list_lrus);
 static DEFINE_MUTEX(list_lrus_mutex);
 
 static inline bool list_lru_memcg_aware(struct list_lru *lru)
 {
     return lru->memcg_aware;
 }
 
 static void list_lru_register(struct list_lru *lru)
 {
     if (!list_lru_memcg_aware(lru))
         return;
 
     mutex_lock(&list_lrus_mutex);
     list_add(&lru->list, &memcg_list_lrus);
     mutex_unlock(&list_lrus_mutex);
 }
 
 static void list_lru_unregister(struct list_lru *lru)
 {
     if (!list_lru_memcg_aware(lru))
         return;
 
     mutex_lock(&list_lrus_mutex);
     list_del(&lru->list);
     mutex_unlock(&list_lrus_mutex);
 }
 
 static int lru_shrinker_id(struct list_lru *lru)
 {
     return lru->shrinker_id;
 }
 
 static inline struct list_lru_one *
 list_lru_from_memcg_idx(struct list_lru *lru, int nid, int idx)
 {
     if (list_lru_memcg_aware(lru) && idx >= 0) {
         struct list_lru_memcg *mlru = xa_load(&lru->xa, idx);
 
         return mlru ? &mlru->node[nid] : NULL;
     }
     return &lru->node[nid].lru;
 }
 
 static inline struct list_lru_one *
 list_lru_from_kmem(struct list_lru *lru, int nid, void *ptr,
            struct mem_cgroup **memcg_ptr)
 {
     struct list_lru_node *nlru = &lru->node[nid];
     struct list_lru_one *l = &nlru->lru;
     struct mem_cgroup *memcg = NULL;
 
     if (!list_lru_memcg_aware(lru))
         goto out;
 
     memcg = mem_cgroup_from_slab_obj(ptr);
     if (!memcg)
         goto out;
 
     l = list_lru_from_memcg_idx(lru, nid, memcg_kmem_id(memcg));
 out:
     if (memcg_ptr)
         *memcg_ptr = memcg;
     return l;
 }
 #else
 static void list_lru_register(struct list_lru *lru)
 {
 }
 
 static void list_lru_unregister(struct list_lru *lru)
 {
 }
 
 static int lru_shrinker_id(struct list_lru *lru)
 {
     return -1;
 }
 
 static inline bool list_lru_memcg_aware(struct list_lru *lru)
 {
     return false;
 }
 
 static inline struct list_lru_one *
 list_lru_from_memcg_idx(struct list_lru *lru, int nid, int idx)
 {
     return &lru->node[nid].lru;
 }
 
 static inline struct list_lru_one *
 list_lru_from_kmem(struct list_lru *lru, int nid, void *ptr,
            struct mem_cgroup **memcg_ptr)
 {
     if (memcg_ptr)
         *memcg_ptr = NULL;
     return &lru->node[nid].lru;
 }
 #endif /* CONFIG_MEMCG_KMEM */
 
 bool list_lru_add(struct list_lru *lru, struct list_head *item)
 {
     int nid = page_to_nid(virt_to_page(item));
     struct list_lru_node *nlru = &lru->node[nid];
     struct mem_cgroup *memcg;
     struct list_lru_one *l;
 
     spin_lock(&nlru->lock);
     if (list_empty(item)) {
         l = list_lru_from_kmem(lru, nid, item, &memcg);
         list_add_tail(item, &l->list);
         /* Set shrinker bit if the first element was added */
         if (!l->nr_items++)
             set_shrinker_bit(memcg, nid,
                      lru_shrinker_id(lru));
         nlru->nr_items++;
         spin_unlock(&nlru->lock);
         return true;
     }
     spin_unlock(&nlru->lock);
     return false;
 }
 EXPORT_SYMBOL_GPL(list_lru_add);
 
 bool list_lru_del(struct list_lru *lru, struct list_head *item)
 {
     int nid = page_to_nid(virt_to_page(item));
     struct list_lru_node *nlru = &lru->node[nid];
     struct list_lru_one *l;
 
     spin_lock(&nlru->lock);
     if (!list_empty(item)) {
         l = list_lru_from_kmem(lru, nid, item, NULL);
         list_del_init(item);
         l->nr_items--;
         nlru->nr_items--;
         spin_unlock(&nlru->lock);
         return true;
     }
     spin_unlock(&nlru->lock);
     return false;
 }
 EXPORT_SYMBOL_GPL(list_lru_del);
 
 void list_lru_isolate(struct list_lru_one *list, struct list_head *item)
 {
     list_del_init(item);
     list->nr_items--;
 }
 EXPORT_SYMBOL_GPL(list_lru_isolate);
 
 void list_lru_isolate_move(struct list_lru_one *list, struct list_head *item,
                struct list_head *head)
 {
     list_move(item, head);
     list->nr_items--;
 }
 EXPORT_SYMBOL_GPL(list_lru_isolate_move);
 
 unsigned long list_lru_count_one(struct list_lru *lru,
                  int nid, struct mem_cgroup *memcg)
 {
     struct list_lru_one *l;
     long count;
 
     rcu_read_lock();
     l = list_lru_from_memcg_idx(lru, nid, memcg_kmem_id(memcg));
     count = l ? READ_ONCE(l->nr_items) : 0;
     rcu_read_unlock();
 
     if (unlikely(count < 0))
         count = 0;
 
     return count;
 }
 EXPORT_SYMBOL_GPL(list_lru_count_one);
 
 unsigned long list_lru_count_node(struct list_lru *lru, int nid)
 {
     struct list_lru_node *nlru;
 
     nlru = &lru->node[nid];
     return nlru->nr_items;
 }
 EXPORT_SYMBOL_GPL(list_lru_count_node);
 
 static unsigned long
 __list_lru_walk_one(struct list_lru *lru, int nid, int memcg_idx,
             list_lru_walk_cb isolate, void *cb_arg,
             unsigned long *nr_to_walk)
 {
     struct list_lru_node *nlru = &lru->node[nid];
     struct list_lru_one *l;
     struct list_head *item, *n;
     unsigned long isolated = 0;
 
 restart:
     l = list_lru_from_memcg_idx(lru, nid, memcg_idx);
     if (!l)
         goto out;
 
     list_for_each_safe(item, n, &l->list) {
         enum lru_status ret;
 
         /*
          * decrement nr_to_walk first so that we don't livelock if we
          * get stuck on large numbers of LRU_RETRY items
          */
         if (!*nr_to_walk)
             break;
         --*nr_to_walk;
 
         ret = isolate(item, l, &nlru->lock, cb_arg);
         switch (ret) {
         case LRU_REMOVED_RETRY:
             assert_spin_locked(&nlru->lock);
             fallthrough;
         case LRU_REMOVED:
             isolated++;
             nlru->nr_items--;
             /*
              * If the lru lock has been dropped, our list
              * traversal is now invalid and so we have to
              * restart from scratch.
              */
             if (ret == LRU_REMOVED_RETRY)
                 goto restart;
             break;
         case LRU_ROTATE:
             list_move_tail(item, &l->list);
             break;
         case LRU_SKIP:
             break;
         case LRU_RETRY:
             /*
              * The lru lock has been dropped, our list traversal is
              * now invalid and so we have to restart from scratch.
              */
             assert_spin_locked(&nlru->lock);
             goto restart;
         default:
             BUG();
         }
     }
 out:
     return isolated;
 }
 
 unsigned long
 list_lru_walk_one(struct list_lru *lru, int nid, struct mem_cgroup *memcg,
           list_lru_walk_cb isolate, void *cb_arg,
           unsigned long *nr_to_walk)
 {
     struct list_lru_node *nlru = &lru->node[nid];
     unsigned long ret;
 
     spin_lock(&nlru->lock);
     ret = __list_lru_walk_one(lru, nid, memcg_kmem_id(memcg), isolate,
                   cb_arg, nr_to_walk);
     spin_unlock(&nlru->lock);
     return ret;
 }
 EXPORT_SYMBOL_GPL(list_lru_walk_one);
 
 unsigned long
 list_lru_walk_one_irq(struct list_lru *lru, int nid, struct mem_cgroup *memcg,
               list_lru_walk_cb isolate, void *cb_arg,
               unsigned long *nr_to_walk)
 {
     struct list_lru_node *nlru = &lru->node[nid];
     unsigned long ret;
 
     spin_lock_irq(&nlru->lock);
     ret = __list_lru_walk_one(lru, nid, memcg_kmem_id(memcg), isolate,
                   cb_arg, nr_to_walk);
     spin_unlock_irq(&nlru->lock);
     return ret;
 }
 
 unsigned long list_lru_walk_node(struct list_lru *lru, int nid,
                  list_lru_walk_cb isolate, void *cb_arg,
                  unsigned long *nr_to_walk)
 {
     long isolated = 0;
 
     isolated += list_lru_walk_one(lru, nid, NULL, isolate, cb_arg,
                       nr_to_walk);
 
 #ifdef CONFIG_MEMCG_KMEM
     if (*nr_to_walk > 0 && list_lru_memcg_aware(lru)) {
         struct list_lru_memcg *mlru;
         unsigned long index;
 
         xa_for_each(&lru->xa, index, mlru) {
             struct list_lru_node *nlru = &lru->node[nid];
 
             spin_lock(&nlru->lock);
             isolated += __list_lru_walk_one(lru, nid, index,
                             isolate, cb_arg,
                             nr_to_walk);
             spin_unlock(&nlru->lock);
 
             if (*nr_to_walk <= 0)
                 break;
         }
     }
 #endif
 
     return isolated;
 }
 EXPORT_SYMBOL_GPL(list_lru_walk_node);
 
 static void init_one_lru(struct list_lru_one *l)
 {
     INIT_LIST_HEAD(&l->list);
     l->nr_items = 0;
 }
 
 #ifdef CONFIG_MEMCG_KMEM
 static struct list_lru_memcg *memcg_init_list_lru_one(gfp_t gfp)
 {
     int nid;
     struct list_lru_memcg *mlru;
 
     mlru = kmalloc(struct_size(mlru, node, nr_node_ids), gfp);
     if (!mlru)
         return NULL;
 
     for_each_node(nid)
         init_one_lru(&mlru->node[nid]);
 
     return mlru;
 }
 
 static void memcg_list_lru_free(struct list_lru *lru, int src_idx)
 {
     struct list_lru_memcg *mlru = xa_erase_irq(&lru->xa, src_idx);
 
     /*
      * The __list_lru_walk_one() can walk the list of this node.
      * We need kvfree_rcu() here. And the walking of the list
      * is under lru->node[nid]->lock, which can serve as a RCU
      * read-side critical section.
      */
     if (mlru)
         kvfree_rcu(mlru, rcu);
 }
 
 static inline void memcg_init_list_lru(struct list_lru *lru, bool memcg_aware)
 {
     if (memcg_aware)
         xa_init_flags(&lru->xa, XA_FLAGS_LOCK_IRQ);
     lru->memcg_aware = memcg_aware;
 }
 
 static void memcg_destroy_list_lru(struct list_lru *lru)
 {
     XA_STATE(xas, &lru->xa, 0);
     struct list_lru_memcg *mlru;
 
     if (!list_lru_memcg_aware(lru))
         return;
 
     xas_lock_irq(&xas);
     xas_for_each(&xas, mlru, ULONG_MAX) {
         kfree(mlru);
         xas_store(&xas, NULL);
     }
     xas_unlock_irq(&xas);
 }
 
 static void memcg_reparent_list_lru_node(struct list_lru *lru, int nid,
                      int src_idx, struct mem_cgroup *dst_memcg)
 {
     struct list_lru_node *nlru = &lru->node[nid];
     int dst_idx = dst_memcg->kmemcg_id;
     struct list_lru_one *src, *dst;
 
     /*
      * Since list_lru_{add,del} may be called under an IRQ-safe lock,
      * we have to use IRQ-safe primitives here to avoid deadlock.
      */
     spin_lock_irq(&nlru->lock);
 
     src = list_lru_from_memcg_idx(lru, nid, src_idx);
     if (!src)
         goto out;
     dst = list_lru_from_memcg_idx(lru, nid, dst_idx);
 
     list_splice_init(&src->list, &dst->list);
 
     if (src->nr_items) {
         dst->nr_items += src->nr_items;
         set_shrinker_bit(dst_memcg, nid, lru_shrinker_id(lru));
         src->nr_items = 0;
     }
 out:
     spin_unlock_irq(&nlru->lock);
 }
 
 static void memcg_reparent_list_lru(struct list_lru *lru,
                     int src_idx, struct mem_cgroup *dst_memcg)
 {
     int i;
 
     for_each_node(i)
         memcg_reparent_list_lru_node(lru, i, src_idx, dst_memcg);
 
     memcg_list_lru_free(lru, src_idx);
 }
 
 void memcg_reparent_list_lrus(struct mem_cgroup *memcg, struct mem_cgroup *parent)
 {
     struct cgroup_subsys_state *css;
     struct list_lru *lru;
     int src_idx = memcg->kmemcg_id;
 
     /*
      * Change kmemcg_id of this cgroup and all its descendants to the
      * parent's id, and then move all entries from this cgroup's list_lrus
      * to ones of the parent.
      *
      * After we have finished, all list_lrus corresponding to this cgroup
      * are guaranteed to remain empty. So we can safely free this cgroup's
      * list lrus in memcg_list_lru_free().
      *
      * Changing ->kmemcg_id to the parent can prevent memcg_list_lru_alloc()
      * from allocating list lrus for this cgroup after memcg_list_lru_free()
      * call.
      */
     rcu_read_lock();
     css_for_each_descendant_pre(css, &memcg->css) {
         struct mem_cgroup *child;
 
         child = mem_cgroup_from_css(css);
         WRITE_ONCE(child->kmemcg_id, parent->kmemcg_id);
     }
     rcu_read_unlock();
 
     mutex_lock(&list_lrus_mutex);
     list_for_each_entry(lru, &memcg_list_lrus, list)
         memcg_reparent_list_lru(lru, src_idx, parent);
     mutex_unlock(&list_lrus_mutex);
 }
 
 static inline bool memcg_list_lru_allocated(struct mem_cgroup *memcg,
                         struct list_lru *lru)
 {
     int idx = memcg->kmemcg_id;
 
     return idx < 0 || xa_load(&lru->xa, idx);
 }
 
 int memcg_list_lru_alloc(struct mem_cgroup *memcg, struct list_lru *lru,
              gfp_t gfp)
 {
     int i;
     unsigned long flags;
     struct list_lru_memcg_table {
         struct list_lru_memcg *mlru;
         struct mem_cgroup *memcg;
     } *table;
     XA_STATE(xas, &lru->xa, 0);
 
     if (!list_lru_memcg_aware(lru) || memcg_list_lru_allocated(memcg, lru))
         return 0;
 
     gfp &= GFP_RECLAIM_MASK;
     table = kmalloc_array(memcg->css.cgroup->level, sizeof(*table), gfp);
     if (!table)
         return -ENOMEM;
 
     /*
      * Because the list_lru can be reparented to the parent cgroup's
      * list_lru, we should make sure that this cgroup and all its
      * ancestors have allocated list_lru_memcg.
      */
     for (i = 0; memcg; memcg = parent_mem_cgroup(memcg), i++) {
         if (memcg_list_lru_allocated(memcg, lru))
             break;
 
         table[i].memcg = memcg;
         table[i].mlru = memcg_init_list_lru_one(gfp);
         if (!table[i].mlru) {
             while (i--)
                 kfree(table[i].mlru);
             kfree(table);
             return -ENOMEM;
         }
     }
 
     xas_lock_irqsave(&xas, flags);
     while (i--) {
         int index = READ_ONCE(table[i].memcg->kmemcg_id);
         struct list_lru_memcg *mlru = table[i].mlru;
 
         xas_set(&xas, index);
 retry:
         if (unlikely(index < 0 || xas_error(&xas) || xas_load(&xas))) {
             kfree(mlru);
         } else {
             xas_store(&xas, mlru);
             if (xas_error(&xas) == -ENOMEM) {
                 xas_unlock_irqrestore(&xas, flags);
                 if (xas_nomem(&xas, gfp))
                     xas_set_err(&xas, 0);
                 xas_lock_irqsave(&xas, flags);
                 /*
                  * The xas lock has been released, this memcg
                  * can be reparented before us. So reload
                  * memcg id. More details see the comments
                  * in memcg_reparent_list_lrus().
                  */
                 index = READ_ONCE(table[i].memcg->kmemcg_id);
                 if (index < 0)
                     xas_set_err(&xas, 0);
                 else if (!xas_error(&xas) && index != xas.xa_index)
                     xas_set(&xas, index);
                 goto retry;
             }
         }
     }
     /* xas_nomem() is used to free memory instead of memory allocation. */
     if (xas.xa_alloc)
         xas_nomem(&xas, gfp);
     xas_unlock_irqrestore(&xas, flags);
     kfree(table);
 
     return xas_error(&xas);
 }
 #else
 static inline void memcg_init_list_lru(struct list_lru *lru, bool memcg_aware)
 {
 }
 
 static void memcg_destroy_list_lru(struct list_lru *lru)
 {
 }
 #endif /* CONFIG_MEMCG_KMEM */
 
 int __list_lru_init(struct list_lru *lru, bool memcg_aware,
             struct lock_class_key *key, struct shrinker *shrinker)
 {
     int i;
 
 #ifdef CONFIG_MEMCG_KMEM
     if (shrinker)
         lru->shrinker_id = shrinker->id;
     else
         lru->shrinker_id = -1;
 #endif
 
     lru->node = kcalloc(nr_node_ids, sizeof(*lru->node), GFP_KERNEL);
     if (!lru->node)
         return -ENOMEM;
 
     for_each_node(i) {
         spin_lock_init(&lru->node[i].lock);
         if (key)
             lockdep_set_class(&lru->node[i].lock, key);
         init_one_lru(&lru->node[i].lru);
     }
 
     memcg_init_list_lru(lru, memcg_aware);
     list_lru_register(lru);
 
     return 0;
 }
 EXPORT_SYMBOL_GPL(__list_lru_init);
 
 void list_lru_destroy(struct list_lru *lru)
 {
     /* Already destroyed or not yet initialized? */
     if (!lru->node)
         return;
 
     list_lru_unregister(lru);
 
     memcg_destroy_list_lru(lru);
     kfree(lru->node);
     lru->node = NULL;
 
 #ifdef CONFIG_MEMCG_KMEM
     lru->shrinker_id = -1;
 #endif
 }
 EXPORT_SYMBOL_GPL(list_lru_destroy);

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