dt-bindings: arm: tegra: pmc: Remove useless boilerplate descriptions

[thirdparty/linux.git] / mm / list_lru.c

// 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);