if (folio_test_swapcache(folio)) {
swp_entry_t swap = folio_swap_entry(folio);
- mem_cgroup_swapout(folio, swap);
+
+ /* get a shadow entry before mem_cgroup_swapout() clears folio_memcg() */
if (reclaimed && !mapping_exiting(mapping))
shadow = workingset_eviction(folio, target_memcg);
+ mem_cgroup_swapout(folio, swap);
__delete_from_swap_cache(folio, swap, shadow);
xa_unlock_irq(&mapping->i_pages);
put_swap_page(&folio->page, swap);
unsigned long file;
struct lruvec *target_lruvec;
+ if (lru_gen_enabled())
+ return;
+
target_lruvec = mem_cgroup_lruvec(sc->target_mem_cgroup, pgdat);
/*
* shorthand helpers
******************************************************************************/
+#define LRU_REFS_FLAGS (BIT(PG_referenced) | BIT(PG_workingset))
+
+#define DEFINE_MAX_SEQ(lruvec) \
+ unsigned long max_seq = READ_ONCE((lruvec)->lrugen.max_seq)
+
+#define DEFINE_MIN_SEQ(lruvec) \
+ unsigned long min_seq[ANON_AND_FILE] = { \
+ READ_ONCE((lruvec)->lrugen.min_seq[LRU_GEN_ANON]), \
+ READ_ONCE((lruvec)->lrugen.min_seq[LRU_GEN_FILE]), \
+ }
+
#define for_each_gen_type_zone(gen, type, zone) \
for ((gen) = 0; (gen) < MAX_NR_GENS; (gen)++) \
for ((type) = 0; (type) < ANON_AND_FILE; (type)++) \
return pgdat ? &pgdat->__lruvec : NULL;
}
+static int get_swappiness(struct lruvec *lruvec, struct scan_control *sc)
+{
+ struct mem_cgroup *memcg = lruvec_memcg(lruvec);
+ struct pglist_data *pgdat = lruvec_pgdat(lruvec);
+
+ if (!can_demote(pgdat->node_id, sc) &&
+ mem_cgroup_get_nr_swap_pages(memcg) < MIN_LRU_BATCH)
+ return 0;
+
+ return mem_cgroup_swappiness(memcg);
+}
+
+static int get_nr_gens(struct lruvec *lruvec, int type)
+{
+ return lruvec->lrugen.max_seq - lruvec->lrugen.min_seq[type] + 1;
+}
+
+static bool __maybe_unused seq_is_valid(struct lruvec *lruvec)
+{
+ /* see the comment on lru_gen_struct */
+ return get_nr_gens(lruvec, LRU_GEN_FILE) >= MIN_NR_GENS &&
+ get_nr_gens(lruvec, LRU_GEN_FILE) <= get_nr_gens(lruvec, LRU_GEN_ANON) &&
+ get_nr_gens(lruvec, LRU_GEN_ANON) <= MAX_NR_GENS;
+}
+
+/******************************************************************************
+ * refault feedback loop
+ ******************************************************************************/
+
+/*
+ * A feedback loop based on Proportional-Integral-Derivative (PID) controller.
+ *
+ * The P term is refaulted/(evicted+protected) from a tier in the generation
+ * currently being evicted; the I term is the exponential moving average of the
+ * P term over the generations previously evicted, using the smoothing factor
+ * 1/2; the D term isn't supported.
+ *
+ * The setpoint (SP) is always the first tier of one type; the process variable
+ * (PV) is either any tier of the other type or any other tier of the same
+ * type.
+ *
+ * The error is the difference between the SP and the PV; the correction is to
+ * turn off protection when SP>PV or turn on protection when SP<PV.
+ *
+ * For future optimizations:
+ * 1. The D term may discount the other two terms over time so that long-lived
+ * generations can resist stale information.
+ */
+struct ctrl_pos {
+ unsigned long refaulted;
+ unsigned long total;
+ int gain;
+};
+
+static void read_ctrl_pos(struct lruvec *lruvec, int type, int tier, int gain,
+ struct ctrl_pos *pos)
+{
+ struct lru_gen_struct *lrugen = &lruvec->lrugen;
+ int hist = lru_hist_from_seq(lrugen->min_seq[type]);
+
+ pos->refaulted = lrugen->avg_refaulted[type][tier] +
+ atomic_long_read(&lrugen->refaulted[hist][type][tier]);
+ pos->total = lrugen->avg_total[type][tier] +
+ atomic_long_read(&lrugen->evicted[hist][type][tier]);
+ if (tier)
+ pos->total += lrugen->protected[hist][type][tier - 1];
+ pos->gain = gain;
+}
+
+static void reset_ctrl_pos(struct lruvec *lruvec, int type, bool carryover)
+{
+ int hist, tier;
+ struct lru_gen_struct *lrugen = &lruvec->lrugen;
+ bool clear = carryover ? NR_HIST_GENS == 1 : NR_HIST_GENS > 1;
+ unsigned long seq = carryover ? lrugen->min_seq[type] : lrugen->max_seq + 1;
+
+ lockdep_assert_held(&lruvec->lru_lock);
+
+ if (!carryover && !clear)
+ return;
+
+ hist = lru_hist_from_seq(seq);
+
+ for (tier = 0; tier < MAX_NR_TIERS; tier++) {
+ if (carryover) {
+ unsigned long sum;
+
+ sum = lrugen->avg_refaulted[type][tier] +
+ atomic_long_read(&lrugen->refaulted[hist][type][tier]);
+ WRITE_ONCE(lrugen->avg_refaulted[type][tier], sum / 2);
+
+ sum = lrugen->avg_total[type][tier] +
+ atomic_long_read(&lrugen->evicted[hist][type][tier]);
+ if (tier)
+ sum += lrugen->protected[hist][type][tier - 1];
+ WRITE_ONCE(lrugen->avg_total[type][tier], sum / 2);
+ }
+
+ if (clear) {
+ atomic_long_set(&lrugen->refaulted[hist][type][tier], 0);
+ atomic_long_set(&lrugen->evicted[hist][type][tier], 0);
+ if (tier)
+ WRITE_ONCE(lrugen->protected[hist][type][tier - 1], 0);
+ }
+ }
+}
+
+static bool positive_ctrl_err(struct ctrl_pos *sp, struct ctrl_pos *pv)
+{
+ /*
+ * Return true if the PV has a limited number of refaults or a lower
+ * refaulted/total than the SP.
+ */
+ return pv->refaulted < MIN_LRU_BATCH ||
+ pv->refaulted * (sp->total + MIN_LRU_BATCH) * sp->gain <=
+ (sp->refaulted + 1) * pv->total * pv->gain;
+}
+
+/******************************************************************************
+ * the aging
+ ******************************************************************************/
+
+/* protect pages accessed multiple times through file descriptors */
+static int folio_inc_gen(struct lruvec *lruvec, struct folio *folio, bool reclaiming)
+{
+ int type = folio_is_file_lru(folio);
+ struct lru_gen_struct *lrugen = &lruvec->lrugen;
+ int new_gen, old_gen = lru_gen_from_seq(lrugen->min_seq[type]);
+ unsigned long new_flags, old_flags = READ_ONCE(folio->flags);
+
+ VM_WARN_ON_ONCE_FOLIO(!(old_flags & LRU_GEN_MASK), folio);
+
+ do {
+ new_gen = (old_gen + 1) % MAX_NR_GENS;
+
+ new_flags = old_flags & ~(LRU_GEN_MASK | LRU_REFS_MASK | LRU_REFS_FLAGS);
+ new_flags |= (new_gen + 1UL) << LRU_GEN_PGOFF;
+ /* for folio_end_writeback() */
+ if (reclaiming)
+ new_flags |= BIT(PG_reclaim);
+ } while (!try_cmpxchg(&folio->flags, &old_flags, new_flags));
+
+ lru_gen_update_size(lruvec, folio, old_gen, new_gen);
+
+ return new_gen;
+}
+
+static void inc_min_seq(struct lruvec *lruvec, int type)
+{
+ struct lru_gen_struct *lrugen = &lruvec->lrugen;
+
+ reset_ctrl_pos(lruvec, type, true);
+ WRITE_ONCE(lrugen->min_seq[type], lrugen->min_seq[type] + 1);
+}
+
+static bool try_to_inc_min_seq(struct lruvec *lruvec, bool can_swap)
+{
+ int gen, type, zone;
+ bool success = false;
+ struct lru_gen_struct *lrugen = &lruvec->lrugen;
+ DEFINE_MIN_SEQ(lruvec);
+
+ VM_WARN_ON_ONCE(!seq_is_valid(lruvec));
+
+ /* find the oldest populated generation */
+ for (type = !can_swap; type < ANON_AND_FILE; type++) {
+ while (min_seq[type] + MIN_NR_GENS <= lrugen->max_seq) {
+ gen = lru_gen_from_seq(min_seq[type]);
+
+ for (zone = 0; zone < MAX_NR_ZONES; zone++) {
+ if (!list_empty(&lrugen->lists[gen][type][zone]))
+ goto next;
+ }
+
+ min_seq[type]++;
+ }
+next:
+ ;
+ }
+
+ /* see the comment on lru_gen_struct */
+ if (can_swap) {
+ min_seq[LRU_GEN_ANON] = min(min_seq[LRU_GEN_ANON], min_seq[LRU_GEN_FILE]);
+ min_seq[LRU_GEN_FILE] = max(min_seq[LRU_GEN_ANON], lrugen->min_seq[LRU_GEN_FILE]);
+ }
+
+ for (type = !can_swap; type < ANON_AND_FILE; type++) {
+ if (min_seq[type] == lrugen->min_seq[type])
+ continue;
+
+ reset_ctrl_pos(lruvec, type, true);
+ WRITE_ONCE(lrugen->min_seq[type], min_seq[type]);
+ success = true;
+ }
+
+ return success;
+}
+
+static void inc_max_seq(struct lruvec *lruvec, unsigned long max_seq, bool can_swap)
+{
+ int prev, next;
+ int type, zone;
+ struct lru_gen_struct *lrugen = &lruvec->lrugen;
+
+ spin_lock_irq(&lruvec->lru_lock);
+
+ VM_WARN_ON_ONCE(!seq_is_valid(lruvec));
+
+ if (max_seq != lrugen->max_seq)
+ goto unlock;
+
+ for (type = ANON_AND_FILE - 1; type >= 0; type--) {
+ if (get_nr_gens(lruvec, type) != MAX_NR_GENS)
+ continue;
+
+ VM_WARN_ON_ONCE(type == LRU_GEN_FILE || can_swap);
+
+ inc_min_seq(lruvec, type);
+ }
+
+ /*
+ * Update the active/inactive LRU sizes for compatibility. Both sides of
+ * the current max_seq need to be covered, since max_seq+1 can overlap
+ * with min_seq[LRU_GEN_ANON] if swapping is constrained. And if they do
+ * overlap, cold/hot inversion happens.
+ */
+ prev = lru_gen_from_seq(lrugen->max_seq - 1);
+ next = lru_gen_from_seq(lrugen->max_seq + 1);
+
+ for (type = 0; type < ANON_AND_FILE; type++) {
+ for (zone = 0; zone < MAX_NR_ZONES; zone++) {
+ enum lru_list lru = type * LRU_INACTIVE_FILE;
+ long delta = lrugen->nr_pages[prev][type][zone] -
+ lrugen->nr_pages[next][type][zone];
+
+ if (!delta)
+ continue;
+
+ __update_lru_size(lruvec, lru, zone, delta);
+ __update_lru_size(lruvec, lru + LRU_ACTIVE, zone, -delta);
+ }
+ }
+
+ for (type = 0; type < ANON_AND_FILE; type++)
+ reset_ctrl_pos(lruvec, type, false);
+
+ /* make sure preceding modifications appear */
+ smp_store_release(&lrugen->max_seq, lrugen->max_seq + 1);
+unlock:
+ spin_unlock_irq(&lruvec->lru_lock);
+}
+
+static bool should_run_aging(struct lruvec *lruvec, unsigned long max_seq, unsigned long *min_seq,
+ struct scan_control *sc, bool can_swap, unsigned long *nr_to_scan)
+{
+ int gen, type, zone;
+ unsigned long old = 0;
+ unsigned long young = 0;
+ unsigned long total = 0;
+ struct lru_gen_struct *lrugen = &lruvec->lrugen;
+ struct mem_cgroup *memcg = lruvec_memcg(lruvec);
+
+ for (type = !can_swap; type < ANON_AND_FILE; type++) {
+ unsigned long seq;
+
+ for (seq = min_seq[type]; seq <= max_seq; seq++) {
+ unsigned long size = 0;
+
+ gen = lru_gen_from_seq(seq);
+
+ for (zone = 0; zone < MAX_NR_ZONES; zone++)
+ size += max(READ_ONCE(lrugen->nr_pages[gen][type][zone]), 0L);
+
+ total += size;
+ if (seq == max_seq)
+ young += size;
+ else if (seq + MIN_NR_GENS == max_seq)
+ old += size;
+ }
+ }
+
+ /* try to scrape all its memory if this memcg was deleted */
+ *nr_to_scan = mem_cgroup_online(memcg) ? (total >> sc->priority) : total;
+
+ /*
+ * The aging tries to be lazy to reduce the overhead, while the eviction
+ * stalls when the number of generations reaches MIN_NR_GENS. Hence, the
+ * ideal number of generations is MIN_NR_GENS+1.
+ */
+ if (min_seq[!can_swap] + MIN_NR_GENS > max_seq)
+ return true;
+ if (min_seq[!can_swap] + MIN_NR_GENS < max_seq)
+ return false;
+
+ /*
+ * It's also ideal to spread pages out evenly, i.e., 1/(MIN_NR_GENS+1)
+ * of the total number of pages for each generation. A reasonable range
+ * for this average portion is [1/MIN_NR_GENS, 1/(MIN_NR_GENS+2)]. The
+ * aging cares about the upper bound of hot pages, while the eviction
+ * cares about the lower bound of cold pages.
+ */
+ if (young * MIN_NR_GENS > total)
+ return true;
+ if (old * (MIN_NR_GENS + 2) < total)
+ return true;
+
+ return false;
+}
+
+static void age_lruvec(struct lruvec *lruvec, struct scan_control *sc)
+{
+ bool need_aging;
+ unsigned long nr_to_scan;
+ int swappiness = get_swappiness(lruvec, sc);
+ struct mem_cgroup *memcg = lruvec_memcg(lruvec);
+ DEFINE_MAX_SEQ(lruvec);
+ DEFINE_MIN_SEQ(lruvec);
+
+ VM_WARN_ON_ONCE(sc->memcg_low_reclaim);
+
+ mem_cgroup_calculate_protection(NULL, memcg);
+
+ if (mem_cgroup_below_min(memcg))
+ return;
+
+ need_aging = should_run_aging(lruvec, max_seq, min_seq, sc, swappiness, &nr_to_scan);
+ if (need_aging)
+ inc_max_seq(lruvec, max_seq, swappiness);
+}
+
+static void lru_gen_age_node(struct pglist_data *pgdat, struct scan_control *sc)
+{
+ struct mem_cgroup *memcg;
+
+ VM_WARN_ON_ONCE(!current_is_kswapd());
+
+ memcg = mem_cgroup_iter(NULL, NULL, NULL);
+ do {
+ struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
+
+ age_lruvec(lruvec, sc);
+
+ cond_resched();
+ } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)));
+}
+
+/******************************************************************************
+ * the eviction
+ ******************************************************************************/
+
+static bool sort_folio(struct lruvec *lruvec, struct folio *folio, int tier_idx)
+{
+ bool success;
+ int gen = folio_lru_gen(folio);
+ int type = folio_is_file_lru(folio);
+ int zone = folio_zonenum(folio);
+ int delta = folio_nr_pages(folio);
+ int refs = folio_lru_refs(folio);
+ int tier = lru_tier_from_refs(refs);
+ struct lru_gen_struct *lrugen = &lruvec->lrugen;
+
+ VM_WARN_ON_ONCE_FOLIO(gen >= MAX_NR_GENS, folio);
+
+ /* unevictable */
+ if (!folio_evictable(folio)) {
+ success = lru_gen_del_folio(lruvec, folio, true);
+ VM_WARN_ON_ONCE_FOLIO(!success, folio);
+ folio_set_unevictable(folio);
+ lruvec_add_folio(lruvec, folio);
+ __count_vm_events(UNEVICTABLE_PGCULLED, delta);
+ return true;
+ }
+
+ /* dirty lazyfree */
+ if (type == LRU_GEN_FILE && folio_test_anon(folio) && folio_test_dirty(folio)) {
+ success = lru_gen_del_folio(lruvec, folio, true);
+ VM_WARN_ON_ONCE_FOLIO(!success, folio);
+ folio_set_swapbacked(folio);
+ lruvec_add_folio_tail(lruvec, folio);
+ return true;
+ }
+
+ /* protected */
+ if (tier > tier_idx) {
+ int hist = lru_hist_from_seq(lrugen->min_seq[type]);
+
+ gen = folio_inc_gen(lruvec, folio, false);
+ list_move_tail(&folio->lru, &lrugen->lists[gen][type][zone]);
+
+ WRITE_ONCE(lrugen->protected[hist][type][tier - 1],
+ lrugen->protected[hist][type][tier - 1] + delta);
+ __mod_lruvec_state(lruvec, WORKINGSET_ACTIVATE_BASE + type, delta);
+ return true;
+ }
+
+ /* waiting for writeback */
+ if (folio_test_locked(folio) || folio_test_writeback(folio) ||
+ (type == LRU_GEN_FILE && folio_test_dirty(folio))) {
+ gen = folio_inc_gen(lruvec, folio, true);
+ list_move(&folio->lru, &lrugen->lists[gen][type][zone]);
+ return true;
+ }
+
+ return false;
+}
+
+static bool isolate_folio(struct lruvec *lruvec, struct folio *folio, struct scan_control *sc)
+{
+ bool success;
+
+ /* unmapping inhibited */
+ if (!sc->may_unmap && folio_mapped(folio))
+ return false;
+
+ /* swapping inhibited */
+ if (!(sc->may_writepage && (sc->gfp_mask & __GFP_IO)) &&
+ (folio_test_dirty(folio) ||
+ (folio_test_anon(folio) && !folio_test_swapcache(folio))))
+ return false;
+
+ /* raced with release_pages() */
+ if (!folio_try_get(folio))
+ return false;
+
+ /* raced with another isolation */
+ if (!folio_test_clear_lru(folio)) {
+ folio_put(folio);
+ return false;
+ }
+
+ /* see the comment on MAX_NR_TIERS */
+ if (!folio_test_referenced(folio))
+ set_mask_bits(&folio->flags, LRU_REFS_MASK | LRU_REFS_FLAGS, 0);
+
+ /* for shrink_page_list() */
+ folio_clear_reclaim(folio);
+ folio_clear_referenced(folio);
+
+ success = lru_gen_del_folio(lruvec, folio, true);
+ VM_WARN_ON_ONCE_FOLIO(!success, folio);
+
+ return true;
+}
+
+static int scan_folios(struct lruvec *lruvec, struct scan_control *sc,
+ int type, int tier, struct list_head *list)
+{
+ int gen, zone;
+ enum vm_event_item item;
+ int sorted = 0;
+ int scanned = 0;
+ int isolated = 0;
+ int remaining = MAX_LRU_BATCH;
+ struct lru_gen_struct *lrugen = &lruvec->lrugen;
+ struct mem_cgroup *memcg = lruvec_memcg(lruvec);
+
+ VM_WARN_ON_ONCE(!list_empty(list));
+
+ if (get_nr_gens(lruvec, type) == MIN_NR_GENS)
+ return 0;
+
+ gen = lru_gen_from_seq(lrugen->min_seq[type]);
+
+ for (zone = sc->reclaim_idx; zone >= 0; zone--) {
+ LIST_HEAD(moved);
+ int skipped = 0;
+ struct list_head *head = &lrugen->lists[gen][type][zone];
+
+ while (!list_empty(head)) {
+ struct folio *folio = lru_to_folio(head);
+ int delta = folio_nr_pages(folio);
+
+ VM_WARN_ON_ONCE_FOLIO(folio_test_unevictable(folio), folio);
+ VM_WARN_ON_ONCE_FOLIO(folio_test_active(folio), folio);
+ VM_WARN_ON_ONCE_FOLIO(folio_is_file_lru(folio) != type, folio);
+ VM_WARN_ON_ONCE_FOLIO(folio_zonenum(folio) != zone, folio);
+
+ scanned += delta;
+
+ if (sort_folio(lruvec, folio, tier))
+ sorted += delta;
+ else if (isolate_folio(lruvec, folio, sc)) {
+ list_add(&folio->lru, list);
+ isolated += delta;
+ } else {
+ list_move(&folio->lru, &moved);
+ skipped += delta;
+ }
+
+ if (!--remaining || max(isolated, skipped) >= MIN_LRU_BATCH)
+ break;
+ }
+
+ if (skipped) {
+ list_splice(&moved, head);
+ __count_zid_vm_events(PGSCAN_SKIP, zone, skipped);
+ }
+
+ if (!remaining || isolated >= MIN_LRU_BATCH)
+ break;
+ }
+
+ item = current_is_kswapd() ? PGSCAN_KSWAPD : PGSCAN_DIRECT;
+ if (!cgroup_reclaim(sc)) {
+ __count_vm_events(item, isolated);
+ __count_vm_events(PGREFILL, sorted);
+ }
+ __count_memcg_events(memcg, item, isolated);
+ __count_memcg_events(memcg, PGREFILL, sorted);
+ __count_vm_events(PGSCAN_ANON + type, isolated);
+
+ /*
+ * There might not be eligible pages due to reclaim_idx, may_unmap and
+ * may_writepage. Check the remaining to prevent livelock if it's not
+ * making progress.
+ */
+ return isolated || !remaining ? scanned : 0;
+}
+
+static int get_tier_idx(struct lruvec *lruvec, int type)
+{
+ int tier;
+ struct ctrl_pos sp, pv;
+
+ /*
+ * To leave a margin for fluctuations, use a larger gain factor (1:2).
+ * This value is chosen because any other tier would have at least twice
+ * as many refaults as the first tier.
+ */
+ read_ctrl_pos(lruvec, type, 0, 1, &sp);
+ for (tier = 1; tier < MAX_NR_TIERS; tier++) {
+ read_ctrl_pos(lruvec, type, tier, 2, &pv);
+ if (!positive_ctrl_err(&sp, &pv))
+ break;
+ }
+
+ return tier - 1;
+}
+
+static int get_type_to_scan(struct lruvec *lruvec, int swappiness, int *tier_idx)
+{
+ int type, tier;
+ struct ctrl_pos sp, pv;
+ int gain[ANON_AND_FILE] = { swappiness, 200 - swappiness };
+
+ /*
+ * Compare the first tier of anon with that of file to determine which
+ * type to scan. Also need to compare other tiers of the selected type
+ * with the first tier of the other type to determine the last tier (of
+ * the selected type) to evict.
+ */
+ read_ctrl_pos(lruvec, LRU_GEN_ANON, 0, gain[LRU_GEN_ANON], &sp);
+ read_ctrl_pos(lruvec, LRU_GEN_FILE, 0, gain[LRU_GEN_FILE], &pv);
+ type = positive_ctrl_err(&sp, &pv);
+
+ read_ctrl_pos(lruvec, !type, 0, gain[!type], &sp);
+ for (tier = 1; tier < MAX_NR_TIERS; tier++) {
+ read_ctrl_pos(lruvec, type, tier, gain[type], &pv);
+ if (!positive_ctrl_err(&sp, &pv))
+ break;
+ }
+
+ *tier_idx = tier - 1;
+
+ return type;
+}
+
+static int isolate_folios(struct lruvec *lruvec, struct scan_control *sc, int swappiness,
+ int *type_scanned, struct list_head *list)
+{
+ int i;
+ int type;
+ int scanned;
+ int tier = -1;
+ DEFINE_MIN_SEQ(lruvec);
+
+ /*
+ * Try to make the obvious choice first. When anon and file are both
+ * available from the same generation, interpret swappiness 1 as file
+ * first and 200 as anon first.
+ */
+ if (!swappiness)
+ type = LRU_GEN_FILE;
+ else if (min_seq[LRU_GEN_ANON] < min_seq[LRU_GEN_FILE])
+ type = LRU_GEN_ANON;
+ else if (swappiness == 1)
+ type = LRU_GEN_FILE;
+ else if (swappiness == 200)
+ type = LRU_GEN_ANON;
+ else
+ type = get_type_to_scan(lruvec, swappiness, &tier);
+
+ for (i = !swappiness; i < ANON_AND_FILE; i++) {
+ if (tier < 0)
+ tier = get_tier_idx(lruvec, type);
+
+ scanned = scan_folios(lruvec, sc, type, tier, list);
+ if (scanned)
+ break;
+
+ type = !type;
+ tier = -1;
+ }
+
+ *type_scanned = type;
+
+ return scanned;
+}
+
+static int evict_folios(struct lruvec *lruvec, struct scan_control *sc, int swappiness)
+{
+ int type;
+ int scanned;
+ int reclaimed;
+ LIST_HEAD(list);
+ struct folio *folio;
+ enum vm_event_item item;
+ struct reclaim_stat stat;
+ struct mem_cgroup *memcg = lruvec_memcg(lruvec);
+ struct pglist_data *pgdat = lruvec_pgdat(lruvec);
+
+ spin_lock_irq(&lruvec->lru_lock);
+
+ scanned = isolate_folios(lruvec, sc, swappiness, &type, &list);
+
+ scanned += try_to_inc_min_seq(lruvec, swappiness);
+
+ if (get_nr_gens(lruvec, !swappiness) == MIN_NR_GENS)
+ scanned = 0;
+
+ spin_unlock_irq(&lruvec->lru_lock);
+
+ if (list_empty(&list))
+ return scanned;
+
+ reclaimed = shrink_page_list(&list, pgdat, sc, &stat, false);
+
+ list_for_each_entry(folio, &list, lru) {
+ /* restore LRU_REFS_FLAGS cleared by isolate_folio() */
+ if (folio_test_workingset(folio))
+ folio_set_referenced(folio);
+
+ /* don't add rejected pages to the oldest generation */
+ if (folio_test_reclaim(folio) &&
+ (folio_test_dirty(folio) || folio_test_writeback(folio)))
+ folio_clear_active(folio);
+ else
+ folio_set_active(folio);
+ }
+
+ spin_lock_irq(&lruvec->lru_lock);
+
+ move_pages_to_lru(lruvec, &list);
+
+ item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT;
+ if (!cgroup_reclaim(sc))
+ __count_vm_events(item, reclaimed);
+ __count_memcg_events(memcg, item, reclaimed);
+ __count_vm_events(PGSTEAL_ANON + type, reclaimed);
+
+ spin_unlock_irq(&lruvec->lru_lock);
+
+ mem_cgroup_uncharge_list(&list);
+ free_unref_page_list(&list);
+
+ sc->nr_reclaimed += reclaimed;
+
+ return scanned;
+}
+
+static unsigned long get_nr_to_scan(struct lruvec *lruvec, struct scan_control *sc,
+ bool can_swap)
+{
+ bool need_aging;
+ unsigned long nr_to_scan;
+ struct mem_cgroup *memcg = lruvec_memcg(lruvec);
+ DEFINE_MAX_SEQ(lruvec);
+ DEFINE_MIN_SEQ(lruvec);
+
+ if (mem_cgroup_below_min(memcg) ||
+ (mem_cgroup_below_low(memcg) && !sc->memcg_low_reclaim))
+ return 0;
+
+ need_aging = should_run_aging(lruvec, max_seq, min_seq, sc, can_swap, &nr_to_scan);
+ if (!need_aging)
+ return nr_to_scan;
+
+ /* skip the aging path at the default priority */
+ if (sc->priority == DEF_PRIORITY)
+ goto done;
+
+ /* leave the work to lru_gen_age_node() */
+ if (current_is_kswapd())
+ return 0;
+
+ inc_max_seq(lruvec, max_seq, can_swap);
+done:
+ return min_seq[!can_swap] + MIN_NR_GENS <= max_seq ? nr_to_scan : 0;
+}
+
+static void lru_gen_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc)
+{
+ struct blk_plug plug;
+ unsigned long scanned = 0;
+
+ lru_add_drain();
+
+ blk_start_plug(&plug);
+
+ while (true) {
+ int delta;
+ int swappiness;
+ unsigned long nr_to_scan;
+
+ if (sc->may_swap)
+ swappiness = get_swappiness(lruvec, sc);
+ else if (!cgroup_reclaim(sc) && get_swappiness(lruvec, sc))
+ swappiness = 1;
+ else
+ swappiness = 0;
+
+ nr_to_scan = get_nr_to_scan(lruvec, sc, swappiness);
+ if (!nr_to_scan)
+ break;
+
+ delta = evict_folios(lruvec, sc, swappiness);
+ if (!delta)
+ break;
+
+ scanned += delta;
+ if (scanned >= nr_to_scan)
+ break;
+
+ cond_resched();
+ }
+
+ blk_finish_plug(&plug);
+}
+
/******************************************************************************
* initialization
******************************************************************************/
};
late_initcall(init_lru_gen);
+#else /* !CONFIG_LRU_GEN */
+
+static void lru_gen_age_node(struct pglist_data *pgdat, struct scan_control *sc)
+{
+}
+
+static void lru_gen_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc)
+{
+}
+
#endif /* CONFIG_LRU_GEN */
static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc)
struct blk_plug plug;
bool scan_adjusted;
+ if (lru_gen_enabled()) {
+ lru_gen_shrink_lruvec(lruvec, sc);
+ return;
+ }
+
get_scan_count(lruvec, sc, nr);
/* Record the original scan target for proportional adjustments later */
struct lruvec *target_lruvec;
unsigned long refaults;
+ if (lru_gen_enabled())
+ return;
+
target_lruvec = mem_cgroup_lruvec(target_memcg, pgdat);
refaults = lruvec_page_state(target_lruvec, WORKINGSET_ACTIVATE_ANON);
target_lruvec->refaults[WORKINGSET_ANON] = refaults;
}
#endif
-static void age_active_anon(struct pglist_data *pgdat,
- struct scan_control *sc)
+static void kswapd_age_node(struct pglist_data *pgdat, struct scan_control *sc)
{
struct mem_cgroup *memcg;
struct lruvec *lruvec;
+ if (lru_gen_enabled()) {
+ lru_gen_age_node(pgdat, sc);
+ return;
+ }
+
if (!can_age_anon_pages(pgdat, sc))
return;
sc.may_swap = !nr_boost_reclaim;
/*
- * Do some background aging of the anon list, to give
- * pages a chance to be referenced before reclaiming. All
- * pages are rotated regardless of classzone as this is
- * about consistent aging.
+ * Do some background aging, to give pages a chance to be
+ * referenced before reclaiming. All pages are rotated
+ * regardless of classzone as this is about consistent aging.
*/
- age_active_anon(pgdat, &sc);
+ kswapd_age_node(pgdat, &sc);
/*
* If we're getting trouble reclaiming, start doing writepage
projects / kernel.git / commitdiff