diff options
Diffstat (limited to 'mm/vmscan.c')
| -rw-r--r-- | mm/vmscan.c | 1073 |
1 files changed, 685 insertions, 388 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 5b7b8d4f5297..9c1c5e8b24b8 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -55,6 +55,8 @@ #include <linux/ctype.h> #include <linux/debugfs.h> #include <linux/khugepaged.h> +#include <linux/rculist_nulls.h> +#include <linux/random.h> #include <asm/tlbflush.h> #include <asm/div64.h> @@ -135,12 +137,6 @@ struct scan_control { /* Always discard instead of demoting to lower tier memory */ unsigned int no_demotion:1; -#ifdef CONFIG_LRU_GEN - /* help kswapd make better choices among multiple memcgs */ - unsigned int memcgs_need_aging:1; - unsigned long last_reclaimed; -#endif - /* Allocation order */ s8 order; @@ -449,6 +445,11 @@ static bool cgroup_reclaim(struct scan_control *sc) return sc->target_mem_cgroup; } +static bool global_reclaim(struct scan_control *sc) +{ + return !sc->target_mem_cgroup || mem_cgroup_is_root(sc->target_mem_cgroup); +} + /** * writeback_throttling_sane - is the usual dirty throttling mechanism available? * @sc: scan_control in question @@ -499,6 +500,11 @@ static bool cgroup_reclaim(struct scan_control *sc) return false; } +static bool global_reclaim(struct scan_control *sc) +{ + return true; +} + static bool writeback_throttling_sane(struct scan_control *sc) { return true; @@ -909,7 +915,7 @@ static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid, } /* Call non-slab shrinkers even though kmem is disabled */ - if (!memcg_kmem_enabled() && + if (!memcg_kmem_online() && !(shrinker->flags & SHRINKER_NONSLAB)) continue; @@ -1924,7 +1930,7 @@ retry: !test_bit(PGDAT_DIRTY, &pgdat->flags))) { /* * Immediately reclaim when written back. - * Similar in principle to deactivate_page() + * Similar in principle to folio_deactivate() * except we already have the folio isolated * and know it's dirty */ @@ -2331,12 +2337,12 @@ move: * (2) The lru_lock must not be held. * (3) Interrupts must be enabled. * - * Return: 0 if the folio was removed from an LRU list. - * -EBUSY if the folio was not on an LRU list. + * Return: true if the folio was removed from an LRU list. + * false if the folio was not on an LRU list. */ -int folio_isolate_lru(struct folio *folio) +bool folio_isolate_lru(struct folio *folio) { - int ret = -EBUSY; + bool ret = false; VM_BUG_ON_FOLIO(!folio_ref_count(folio), folio); @@ -2347,7 +2353,7 @@ int folio_isolate_lru(struct folio *folio) lruvec = folio_lruvec_lock_irq(folio); lruvec_del_folio(lruvec, folio); unlock_page_lruvec_irq(lruvec); - ret = 0; + ret = true; } return ret; @@ -3180,6 +3186,9 @@ DEFINE_STATIC_KEY_ARRAY_FALSE(lru_gen_caps, NR_LRU_GEN_CAPS); for ((type) = 0; (type) < ANON_AND_FILE; (type)++) \ for ((zone) = 0; (zone) < MAX_NR_ZONES; (zone)++) +#define get_memcg_gen(seq) ((seq) % MEMCG_NR_GENS) +#define get_memcg_bin(bin) ((bin) % MEMCG_NR_BINS) + static struct lruvec *get_lruvec(struct mem_cgroup *memcg, int nid) { struct pglist_data *pgdat = NODE_DATA(nid); @@ -3205,6 +3214,9 @@ 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 (!sc->may_swap) + return 0; + if (!can_demote(pgdat->node_id, sc) && mem_cgroup_get_nr_swap_pages(memcg) < MIN_LRU_BATCH) return 0; @@ -3219,13 +3231,105 @@ static int get_nr_gens(struct lruvec *lruvec, int type) static bool __maybe_unused seq_is_valid(struct lruvec *lruvec) { - /* see the comment on lru_gen_struct */ + /* see the comment on lru_gen_folio */ 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; } /****************************************************************************** + * Bloom filters + ******************************************************************************/ + +/* + * Bloom filters with m=1<<15, k=2 and the false positive rates of ~1/5 when + * n=10,000 and ~1/2 when n=20,000, where, conventionally, m is the number of + * bits in a bitmap, k is the number of hash functions and n is the number of + * inserted items. + * + * Page table walkers use one of the two filters to reduce their search space. + * To get rid of non-leaf entries that no longer have enough leaf entries, the + * aging uses the double-buffering technique to flip to the other filter each + * time it produces a new generation. For non-leaf entries that have enough + * leaf entries, the aging carries them over to the next generation in + * walk_pmd_range(); the eviction also report them when walking the rmap + * in lru_gen_look_around(). + * + * For future optimizations: + * 1. It's not necessary to keep both filters all the time. The spare one can be + * freed after the RCU grace period and reallocated if needed again. + * 2. And when reallocating, it's worth scaling its size according to the number + * of inserted entries in the other filter, to reduce the memory overhead on + * small systems and false positives on large systems. + * 3. Jenkins' hash function is an alternative to Knuth's. + */ +#define BLOOM_FILTER_SHIFT 15 + +static inline int filter_gen_from_seq(unsigned long seq) +{ + return seq % NR_BLOOM_FILTERS; +} + +static void get_item_key(void *item, int *key) +{ + u32 hash = hash_ptr(item, BLOOM_FILTER_SHIFT * 2); + + BUILD_BUG_ON(BLOOM_FILTER_SHIFT * 2 > BITS_PER_TYPE(u32)); + + key[0] = hash & (BIT(BLOOM_FILTER_SHIFT) - 1); + key[1] = hash >> BLOOM_FILTER_SHIFT; +} + +static bool test_bloom_filter(struct lruvec *lruvec, unsigned long seq, void *item) +{ + int key[2]; + unsigned long *filter; + int gen = filter_gen_from_seq(seq); + + filter = READ_ONCE(lruvec->mm_state.filters[gen]); + if (!filter) + return true; + + get_item_key(item, key); + + return test_bit(key[0], filter) && test_bit(key[1], filter); +} + +static void update_bloom_filter(struct lruvec *lruvec, unsigned long seq, void *item) +{ + int key[2]; + unsigned long *filter; + int gen = filter_gen_from_seq(seq); + + filter = READ_ONCE(lruvec->mm_state.filters[gen]); + if (!filter) + return; + + get_item_key(item, key); + + if (!test_bit(key[0], filter)) + set_bit(key[0], filter); + if (!test_bit(key[1], filter)) + set_bit(key[1], filter); +} + +static void reset_bloom_filter(struct lruvec *lruvec, unsigned long seq) +{ + unsigned long *filter; + int gen = filter_gen_from_seq(seq); + + filter = lruvec->mm_state.filters[gen]; + if (filter) { + bitmap_clear(filter, 0, BIT(BLOOM_FILTER_SHIFT)); + return; + } + + filter = bitmap_zalloc(BIT(BLOOM_FILTER_SHIFT), + __GFP_HIGH | __GFP_NOMEMALLOC | __GFP_NOWARN); + WRITE_ONCE(lruvec->mm_state.filters[gen], filter); +} + +/****************************************************************************** * mm_struct list ******************************************************************************/ @@ -3344,94 +3448,6 @@ void lru_gen_migrate_mm(struct mm_struct *mm) } #endif -/* - * Bloom filters with m=1<<15, k=2 and the false positive rates of ~1/5 when - * n=10,000 and ~1/2 when n=20,000, where, conventionally, m is the number of - * bits in a bitmap, k is the number of hash functions and n is the number of - * inserted items. - * - * Page table walkers use one of the two filters to reduce their search space. - * To get rid of non-leaf entries that no longer have enough leaf entries, the - * aging uses the double-buffering technique to flip to the other filter each - * time it produces a new generation. For non-leaf entries that have enough - * leaf entries, the aging carries them over to the next generation in - * walk_pmd_range(); the eviction also report them when walking the rmap - * in lru_gen_look_around(). - * - * For future optimizations: - * 1. It's not necessary to keep both filters all the time. The spare one can be - * freed after the RCU grace period and reallocated if needed again. - * 2. And when reallocating, it's worth scaling its size according to the number - * of inserted entries in the other filter, to reduce the memory overhead on - * small systems and false positives on large systems. - * 3. Jenkins' hash function is an alternative to Knuth's. - */ -#define BLOOM_FILTER_SHIFT 15 - -static inline int filter_gen_from_seq(unsigned long seq) -{ - return seq % NR_BLOOM_FILTERS; -} - -static void get_item_key(void *item, int *key) -{ - u32 hash = hash_ptr(item, BLOOM_FILTER_SHIFT * 2); - - BUILD_BUG_ON(BLOOM_FILTER_SHIFT * 2 > BITS_PER_TYPE(u32)); - - key[0] = hash & (BIT(BLOOM_FILTER_SHIFT) - 1); - key[1] = hash >> BLOOM_FILTER_SHIFT; -} - -static void reset_bloom_filter(struct lruvec *lruvec, unsigned long seq) -{ - unsigned long *filter; - int gen = filter_gen_from_seq(seq); - - filter = lruvec->mm_state.filters[gen]; - if (filter) { - bitmap_clear(filter, 0, BIT(BLOOM_FILTER_SHIFT)); - return; - } - - filter = bitmap_zalloc(BIT(BLOOM_FILTER_SHIFT), - __GFP_HIGH | __GFP_NOMEMALLOC | __GFP_NOWARN); - WRITE_ONCE(lruvec->mm_state.filters[gen], filter); -} - -static void update_bloom_filter(struct lruvec *lruvec, unsigned long seq, void *item) -{ - int key[2]; - unsigned long *filter; - int gen = filter_gen_from_seq(seq); - - filter = READ_ONCE(lruvec->mm_state.filters[gen]); - if (!filter) - return; - - get_item_key(item, key); - - if (!test_bit(key[0], filter)) - set_bit(key[0], filter); - if (!test_bit(key[1], filter)) - set_bit(key[1], filter); -} - -static bool test_bloom_filter(struct lruvec *lruvec, unsigned long seq, void *item) -{ - int key[2]; - unsigned long *filter; - int gen = filter_gen_from_seq(seq); - - filter = READ_ONCE(lruvec->mm_state.filters[gen]); - if (!filter) - return true; - - get_item_key(item, key); - - return test_bit(key[0], filter) && test_bit(key[1], filter); -} - static void reset_mm_stats(struct lruvec *lruvec, struct lru_gen_mm_walk *walk, bool last) { int i; @@ -3619,7 +3635,7 @@ struct ctrl_pos { 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; + struct lru_gen_folio *lrugen = &lruvec->lrugen; int hist = lru_hist_from_seq(lrugen->min_seq[type]); pos->refaulted = lrugen->avg_refaulted[type][tier] + @@ -3634,7 +3650,7 @@ static void read_ctrl_pos(struct lruvec *lruvec, int type, int tier, int gain, static void reset_ctrl_pos(struct lruvec *lruvec, int type, bool carryover) { int hist, tier; - struct lru_gen_struct *lrugen = &lruvec->lrugen; + struct lru_gen_folio *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; @@ -3711,7 +3727,7 @@ static int folio_update_gen(struct folio *folio, int gen) 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; + struct lru_gen_folio *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); @@ -3756,7 +3772,7 @@ static void update_batch_size(struct lru_gen_mm_walk *walk, struct folio *folio, static void reset_batch_size(struct lruvec *lruvec, struct lru_gen_mm_walk *walk) { int gen, type, zone; - struct lru_gen_struct *lrugen = &lruvec->lrugen; + struct lru_gen_folio *lrugen = &lruvec->lrugen; walk->batched = 0; @@ -3789,7 +3805,10 @@ static int should_skip_vma(unsigned long start, unsigned long end, struct mm_wal if (is_vm_hugetlb_page(vma)) return true; - if (vma->vm_flags & (VM_LOCKED | VM_SPECIAL | VM_SEQ_READ | VM_RAND_READ)) + if (!vma_has_recency(vma)) + return true; + + if (vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) return true; if (vma == get_gate_vma(vma->vm_mm)) @@ -3984,8 +4003,8 @@ restart: } #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG) -static void walk_pmd_range_locked(pud_t *pud, unsigned long next, struct vm_area_struct *vma, - struct mm_walk *args, unsigned long *bitmap, unsigned long *start) +static void walk_pmd_range_locked(pud_t *pud, unsigned long addr, struct vm_area_struct *vma, + struct mm_walk *args, unsigned long *bitmap, unsigned long *first) { int i; pmd_t *pmd; @@ -3998,18 +4017,19 @@ static void walk_pmd_range_locked(pud_t *pud, unsigned long next, struct vm_area VM_WARN_ON_ONCE(pud_leaf(*pud)); /* try to batch at most 1+MIN_LRU_BATCH+1 entries */ - if (*start == -1) { - *start = next; + if (*first == -1) { + *first = addr; + bitmap_zero(bitmap, MIN_LRU_BATCH); return; } - i = next == -1 ? 0 : pmd_index(next) - pmd_index(*start); + i = addr == -1 ? 0 : pmd_index(addr) - pmd_index(*first); if (i && i <= MIN_LRU_BATCH) { __set_bit(i - 1, bitmap); return; } - pmd = pmd_offset(pud, *start); + pmd = pmd_offset(pud, *first); ptl = pmd_lockptr(args->mm, pmd); if (!spin_trylock(ptl)) @@ -4020,15 +4040,16 @@ static void walk_pmd_range_locked(pud_t *pud, unsigned long next, struct vm_area do { unsigned long pfn; struct folio *folio; - unsigned long addr = i ? (*start & PMD_MASK) + i * PMD_SIZE : *start; + + /* don't round down the first address */ + addr = i ? (*first & PMD_MASK) + i * PMD_SIZE : *first; pfn = get_pmd_pfn(pmd[i], vma, addr); if (pfn == -1) goto next; if (!pmd_trans_huge(pmd[i])) { - if (arch_has_hw_nonleaf_pmd_young() && - get_cap(LRU_GEN_NONLEAF_YOUNG)) + if (arch_has_hw_nonleaf_pmd_young() && get_cap(LRU_GEN_NONLEAF_YOUNG)) pmdp_test_and_clear_young(vma, addr, pmd + i); goto next; } @@ -4057,12 +4078,11 @@ next: arch_leave_lazy_mmu_mode(); spin_unlock(ptl); done: - *start = -1; - bitmap_zero(bitmap, MIN_LRU_BATCH); + *first = -1; } #else -static void walk_pmd_range_locked(pud_t *pud, unsigned long next, struct vm_area_struct *vma, - struct mm_walk *args, unsigned long *bitmap, unsigned long *start) +static void walk_pmd_range_locked(pud_t *pud, unsigned long addr, struct vm_area_struct *vma, + struct mm_walk *args, unsigned long *bitmap, unsigned long *first) { } #endif @@ -4075,9 +4095,9 @@ static void walk_pmd_range(pud_t *pud, unsigned long start, unsigned long end, unsigned long next; unsigned long addr; struct vm_area_struct *vma; - unsigned long pos = -1; + unsigned long bitmap[BITS_TO_LONGS(MIN_LRU_BATCH)]; + unsigned long first = -1; struct lru_gen_mm_walk *walk = args->private; - unsigned long bitmap[BITS_TO_LONGS(MIN_LRU_BATCH)] = {}; VM_WARN_ON_ONCE(pud_leaf(*pud)); @@ -4116,18 +4136,17 @@ restart: if (pfn < pgdat->node_start_pfn || pfn >= pgdat_end_pfn(pgdat)) continue; - walk_pmd_range_locked(pud, addr, vma, args, bitmap, &pos); + walk_pmd_range_locked(pud, addr, vma, args, bitmap, &first); continue; } #endif walk->mm_stats[MM_NONLEAF_TOTAL]++; - if (arch_has_hw_nonleaf_pmd_young() && - get_cap(LRU_GEN_NONLEAF_YOUNG)) { + if (arch_has_hw_nonleaf_pmd_young() && get_cap(LRU_GEN_NONLEAF_YOUNG)) { if (!pmd_young(val)) continue; - walk_pmd_range_locked(pud, addr, vma, args, bitmap, &pos); + walk_pmd_range_locked(pud, addr, vma, args, bitmap, &first); } if (!walk->force_scan && !test_bloom_filter(walk->lruvec, walk->max_seq, pmd + i)) @@ -4144,7 +4163,7 @@ restart: update_bloom_filter(walk->lruvec, walk->max_seq + 1, pmd + i); } - walk_pmd_range_locked(pud, -1, vma, args, bitmap, &pos); + walk_pmd_range_locked(pud, -1, vma, args, bitmap, &first); if (i < PTRS_PER_PMD && get_next_vma(PUD_MASK, PMD_SIZE, args, &start, &end)) goto restart; @@ -4234,7 +4253,7 @@ static void walk_mm(struct lruvec *lruvec, struct mm_struct *mm, struct lru_gen_ } while (err == -EAGAIN); } -static struct lru_gen_mm_walk *set_mm_walk(struct pglist_data *pgdat) +static struct lru_gen_mm_walk *set_mm_walk(struct pglist_data *pgdat, bool force_alloc) { struct lru_gen_mm_walk *walk = current->reclaim_state->mm_walk; @@ -4242,7 +4261,7 @@ static struct lru_gen_mm_walk *set_mm_walk(struct pglist_data *pgdat) VM_WARN_ON_ONCE(walk); walk = &pgdat->mm_walk; - } else if (!pgdat && !walk) { + } else if (!walk && force_alloc) { VM_WARN_ON_ONCE(current_is_kswapd()); walk = kzalloc(sizeof(*walk), __GFP_HIGH | __GFP_NOMEMALLOC | __GFP_NOWARN); @@ -4270,7 +4289,7 @@ static bool inc_min_seq(struct lruvec *lruvec, int type, bool can_swap) { int zone; int remaining = MAX_LRU_BATCH; - struct lru_gen_struct *lrugen = &lruvec->lrugen; + struct lru_gen_folio *lrugen = &lruvec->lrugen; int new_gen, old_gen = lru_gen_from_seq(lrugen->min_seq[type]); if (type == LRU_GEN_ANON && !can_swap) @@ -4278,7 +4297,7 @@ static bool inc_min_seq(struct lruvec *lruvec, int type, bool can_swap) /* prevent cold/hot inversion if force_scan is true */ for (zone = 0; zone < MAX_NR_ZONES; zone++) { - struct list_head *head = &lrugen->lists[old_gen][type][zone]; + struct list_head *head = &lrugen->folios[old_gen][type][zone]; while (!list_empty(head)) { struct folio *folio = lru_to_folio(head); @@ -4289,7 +4308,7 @@ static bool inc_min_seq(struct lruvec *lruvec, int type, bool can_swap) VM_WARN_ON_ONCE_FOLIO(folio_zonenum(folio) != zone, folio); new_gen = folio_inc_gen(lruvec, folio, false); - list_move_tail(&folio->lru, &lrugen->lists[new_gen][type][zone]); + list_move_tail(&folio->lru, &lrugen->folios[new_gen][type][zone]); if (!--remaining) return false; @@ -4306,7 +4325,7 @@ 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; + struct lru_gen_folio *lrugen = &lruvec->lrugen; DEFINE_MIN_SEQ(lruvec); VM_WARN_ON_ONCE(!seq_is_valid(lruvec)); @@ -4317,7 +4336,7 @@ static bool try_to_inc_min_seq(struct lruvec *lruvec, bool can_swap) gen = lru_gen_from_seq(min_seq[type]); for (zone = 0; zone < MAX_NR_ZONES; zone++) { - if (!list_empty(&lrugen->lists[gen][type][zone])) + if (!list_empty(&lrugen->folios[gen][type][zone])) goto next; } @@ -4327,7 +4346,7 @@ next: ; } - /* see the comment on lru_gen_struct */ + /* see the comment on lru_gen_folio */ 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]); @@ -4349,7 +4368,7 @@ static void inc_max_seq(struct lruvec *lruvec, bool can_swap, bool force_scan) { int prev, next; int type, zone; - struct lru_gen_struct *lrugen = &lruvec->lrugen; + struct lru_gen_folio *lrugen = &lruvec->lrugen; spin_lock_irq(&lruvec->lru_lock); @@ -4407,7 +4426,7 @@ static bool try_to_inc_max_seq(struct lruvec *lruvec, unsigned long max_seq, bool success; struct lru_gen_mm_walk *walk; struct mm_struct *mm = NULL; - struct lru_gen_struct *lrugen = &lruvec->lrugen; + struct lru_gen_folio *lrugen = &lruvec->lrugen; VM_WARN_ON_ONCE(max_seq > READ_ONCE(lrugen->max_seq)); @@ -4423,12 +4442,12 @@ static bool try_to_inc_max_seq(struct lruvec *lruvec, unsigned long max_seq, * handful of PTEs. Spreading the work out over a period of time usually * is less efficient, but it avoids bursty page faults. */ - if (!force_scan && !(arch_has_hw_pte_young() && get_cap(LRU_GEN_MM_WALK))) { + if (!arch_has_hw_pte_young() || !get_cap(LRU_GEN_MM_WALK)) { success = iterate_mm_list_nowalk(lruvec, max_seq); goto done; } - walk = set_mm_walk(NULL); + walk = set_mm_walk(NULL, true); if (!walk) { success = iterate_mm_list_nowalk(lruvec, max_seq); goto done; @@ -4451,8 +4470,7 @@ done: if (sc->priority <= DEF_PRIORITY - 2) wait_event_killable(lruvec->mm_state.wait, max_seq < READ_ONCE(lrugen->max_seq)); - - return max_seq < READ_ONCE(lrugen->max_seq); + return false; } VM_WARN_ON_ONCE(max_seq != READ_ONCE(lrugen->max_seq)); @@ -4465,97 +4483,56 @@ done: return true; } -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) +/****************************************************************************** + * working set protection + ******************************************************************************/ + +static bool lruvec_is_sizable(struct lruvec *lruvec, struct scan_control *sc) { int gen, type, zone; - unsigned long old = 0; - unsigned long young = 0; unsigned long total = 0; - struct lru_gen_struct *lrugen = &lruvec->lrugen; + bool can_swap = get_swappiness(lruvec, sc); + struct lru_gen_folio *lrugen = &lruvec->lrugen; struct mem_cgroup *memcg = lruvec_memcg(lruvec); + DEFINE_MAX_SEQ(lruvec); + DEFINE_MIN_SEQ(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; + total += max(READ_ONCE(lrugen->nr_pages[gen][type][zone]), 0L); } } - /* 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; + /* whether the size is big enough to be helpful */ + return mem_cgroup_online(memcg) ? (total >> sc->priority) : total; } -static bool age_lruvec(struct lruvec *lruvec, struct scan_control *sc, unsigned long min_ttl) +static bool lruvec_is_reclaimable(struct lruvec *lruvec, struct scan_control *sc, + unsigned long min_ttl) { - bool need_aging; - unsigned long nr_to_scan; - int swappiness = get_swappiness(lruvec, sc); + int gen; + unsigned long birth; 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); + /* see the comment on lru_gen_folio */ + gen = lru_gen_from_seq(min_seq[LRU_GEN_FILE]); + birth = READ_ONCE(lruvec->lrugen.timestamps[gen]); - if (mem_cgroup_below_min(NULL, memcg)) + if (time_is_after_jiffies(birth + min_ttl)) return false; - need_aging = should_run_aging(lruvec, max_seq, min_seq, sc, swappiness, &nr_to_scan); - - if (min_ttl) { - int gen = lru_gen_from_seq(min_seq[LRU_GEN_FILE]); - unsigned long birth = READ_ONCE(lruvec->lrugen.timestamps[gen]); - - if (time_is_after_jiffies(birth + min_ttl)) - return false; - - /* the size is likely too small to be helpful */ - if (!nr_to_scan && sc->priority != DEF_PRIORITY) - return false; - } + if (!lruvec_is_sizable(lruvec, sc)) + return false; - if (need_aging) - try_to_inc_max_seq(lruvec, max_seq, sc, swappiness, false); + mem_cgroup_calculate_protection(NULL, memcg); - return true; + return !mem_cgroup_below_min(NULL, memcg); } /* to protect the working set of the last N jiffies */ @@ -4564,46 +4541,30 @@ static unsigned long lru_gen_min_ttl __read_mostly; static void lru_gen_age_node(struct pglist_data *pgdat, struct scan_control *sc) { struct mem_cgroup *memcg; - bool success = false; unsigned long min_ttl = READ_ONCE(lru_gen_min_ttl); VM_WARN_ON_ONCE(!current_is_kswapd()); - sc->last_reclaimed = sc->nr_reclaimed; - - /* - * To reduce the chance of going into the aging path, which can be - * costly, optimistically skip it if the flag below was cleared in the - * eviction path. This improves the overall performance when multiple - * memcgs are available. - */ - if (!sc->memcgs_need_aging) { - sc->memcgs_need_aging = true; + /* check the order to exclude compaction-induced reclaim */ + if (!min_ttl || sc->order || sc->priority == DEF_PRIORITY) return; - } - - set_mm_walk(pgdat); memcg = mem_cgroup_iter(NULL, NULL, NULL); do { struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat); - if (age_lruvec(lruvec, sc, min_ttl)) - success = true; + if (lruvec_is_reclaimable(lruvec, sc, min_ttl)) { + mem_cgroup_iter_break(NULL, memcg); + return; + } cond_resched(); } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL))); - clear_mm_walk(); - - /* check the order to exclude compaction-induced reclaim */ - if (success || !min_ttl || sc->order) - return; - /* * The main goal is to OOM kill if every generation from all memcgs is * younger than min_ttl. However, another possibility is all memcgs are - * either below min or empty. + * either too small or below min. */ if (mutex_trylock(&oom_lock)) { struct oom_control oc = { @@ -4616,6 +4577,10 @@ static void lru_gen_age_node(struct pglist_data *pgdat, struct scan_control *sc) } } +/****************************************************************************** + * rmap/PT walk feedback + ******************************************************************************/ + /* * This function exploits spatial locality when shrink_folio_list() walks the * rmap. It scans the adjacent PTEs of a young PTE and promotes hot pages. If @@ -4626,13 +4591,12 @@ static void lru_gen_age_node(struct pglist_data *pgdat, struct scan_control *sc) void lru_gen_look_around(struct page_vma_mapped_walk *pvmw) { int i; - pte_t *pte; unsigned long start; unsigned long end; - unsigned long addr; struct lru_gen_mm_walk *walk; int young = 0; - unsigned long bitmap[BITS_TO_LONGS(MIN_LRU_BATCH)] = {}; + pte_t *pte = pvmw->pte; + unsigned long addr = pvmw->address; struct folio *folio = pfn_folio(pvmw->pfn); struct mem_cgroup *memcg = folio_memcg(folio); struct pglist_data *pgdat = folio_pgdat(folio); @@ -4649,25 +4613,28 @@ void lru_gen_look_around(struct page_vma_mapped_walk *pvmw) /* avoid taking the LRU lock under the PTL when possible */ walk = current->reclaim_state ? current->reclaim_state->mm_walk : NULL; - start = max(pvmw->address & PMD_MASK, pvmw->vma->vm_start); - end = min(pvmw->address | ~PMD_MASK, pvmw->vma->vm_end - 1) + 1; + start = max(addr & PMD_MASK, pvmw->vma->vm_start); + end = min(addr | ~PMD_MASK, pvmw->vma->vm_end - 1) + 1; if (end - start > MIN_LRU_BATCH * PAGE_SIZE) { - if (pvmw->address - start < MIN_LRU_BATCH * PAGE_SIZE / 2) + if (addr - start < MIN_LRU_BATCH * PAGE_SIZE / 2) end = start + MIN_LRU_BATCH * PAGE_SIZE; - else if (end - pvmw->address < MIN_LRU_BATCH * PAGE_SIZE / 2) + else if (end - addr < MIN_LRU_BATCH * PAGE_SIZE / 2) start = end - MIN_LRU_BATCH * PAGE_SIZE; else { - start = pvmw->address - MIN_LRU_BATCH * PAGE_SIZE / 2; - end = pvmw->address + MIN_LRU_BATCH * PAGE_SIZE / 2; + start = addr - MIN_LRU_BATCH * PAGE_SIZE / 2; + end = addr + MIN_LRU_BATCH * PAGE_SIZE / 2; } } - pte = pvmw->pte - (pvmw->address - start) / PAGE_SIZE; + /* folio_update_gen() requires stable folio_memcg() */ + if (!mem_cgroup_trylock_pages(memcg)) + return; - rcu_read_lock(); arch_enter_lazy_mmu_mode(); + pte -= (addr - start) / PAGE_SIZE; + for (i = 0, addr = start; addr != end; i++, addr += PAGE_SIZE) { unsigned long pfn; @@ -4692,58 +4659,171 @@ void lru_gen_look_around(struct page_vma_mapped_walk *pvmw) !folio_test_swapcache(folio))) folio_mark_dirty(folio); + if (walk) { + old_gen = folio_update_gen(folio, new_gen); + if (old_gen >= 0 && old_gen != new_gen) + update_batch_size(walk, folio, old_gen, new_gen); + + continue; + } + old_gen = folio_lru_gen(folio); if (old_gen < 0) folio_set_referenced(folio); else if (old_gen != new_gen) - __set_bit(i, bitmap); + folio_activate(folio); } arch_leave_lazy_mmu_mode(); - rcu_read_unlock(); + mem_cgroup_unlock_pages(); /* feedback from rmap walkers to page table walkers */ if (suitable_to_scan(i, young)) update_bloom_filter(lruvec, max_seq, pvmw->pmd); +} - if (!walk && bitmap_weight(bitmap, MIN_LRU_BATCH) < PAGEVEC_SIZE) { - for_each_set_bit(i, bitmap, MIN_LRU_BATCH) { - folio = pfn_folio(pte_pfn(pte[i])); - folio_activate(folio); - } - return; +/****************************************************************************** + * memcg LRU + ******************************************************************************/ + +/* see the comment on MEMCG_NR_GENS */ +enum { + MEMCG_LRU_NOP, + MEMCG_LRU_HEAD, + MEMCG_LRU_TAIL, + MEMCG_LRU_OLD, + MEMCG_LRU_YOUNG, +}; + +#ifdef CONFIG_MEMCG + +static int lru_gen_memcg_seg(struct lruvec *lruvec) +{ + return READ_ONCE(lruvec->lrugen.seg); +} + +static void lru_gen_rotate_memcg(struct lruvec *lruvec, int op) +{ + int seg; + int old, new; + int bin = get_random_u32_below(MEMCG_NR_BINS); + struct pglist_data *pgdat = lruvec_pgdat(lruvec); + + spin_lock(&pgdat->memcg_lru.lock); + + VM_WARN_ON_ONCE(hlist_nulls_unhashed(&lruvec->lrugen.list)); + + seg = 0; + new = old = lruvec->lrugen.gen; + + /* see the comment on MEMCG_NR_GENS */ + if (op == MEMCG_LRU_HEAD) + seg = MEMCG_LRU_HEAD; + else if (op == MEMCG_LRU_TAIL) + seg = MEMCG_LRU_TAIL; + else if (op == MEMCG_LRU_OLD) + new = get_memcg_gen(pgdat->memcg_lru.seq); + else if (op == MEMCG_LRU_YOUNG) + new = get_memcg_gen(pgdat->memcg_lru.seq + 1); + else + VM_WARN_ON_ONCE(true); + + hlist_nulls_del_rcu(&lruvec->lrugen.list); + + if (op == MEMCG_LRU_HEAD || op == MEMCG_LRU_OLD) + hlist_nulls_add_head_rcu(&lruvec->lrugen.list, &pgdat->memcg_lru.fifo[new][bin]); + else + hlist_nulls_add_tail_rcu(&lruvec->lrugen.list, &pgdat->memcg_lru.fifo[new][bin]); + + pgdat->memcg_lru.nr_memcgs[old]--; + pgdat->memcg_lru.nr_memcgs[new]++; + + lruvec->lrugen.gen = new; + WRITE_ONCE(lruvec->lrugen.seg, seg); + + if (!pgdat->memcg_lru.nr_memcgs[old] && old == get_memcg_gen(pgdat->memcg_lru.seq)) + WRITE_ONCE(pgdat->memcg_lru.seq, pgdat->memcg_lru.seq + 1); + + spin_unlock(&pgdat->memcg_lru.lock); +} + +void lru_gen_online_memcg(struct mem_cgroup *memcg) +{ + int gen; + int nid; + int bin = get_random_u32_below(MEMCG_NR_BINS); + + for_each_node(nid) { + struct pglist_data *pgdat = NODE_DATA(nid); + struct lruvec *lruvec = get_lruvec(memcg, nid); + + spin_lock(&pgdat->memcg_lru.lock); + + VM_WARN_ON_ONCE(!hlist_nulls_unhashed(&lruvec->lrugen.list)); + + gen = get_memcg_gen(pgdat->memcg_lru.seq); + + hlist_nulls_add_tail_rcu(&lruvec->lrugen.list, &pgdat->memcg_lru.fifo[gen][bin]); + pgdat->memcg_lru.nr_memcgs[gen]++; + + lruvec->lrugen.gen = gen; + + spin_unlock(&pgdat->memcg_lru.lock); } +} - /* folio_update_gen() requires stable folio_memcg() */ - if (!mem_cgroup_trylock_pages(memcg)) - return; +void lru_gen_offline_memcg(struct mem_cgroup *memcg) +{ + int nid; - if (!walk) { - spin_lock_irq(&lruvec->lru_lock); - new_gen = lru_gen_from_seq(lruvec->lrugen.max_seq); + for_each_node(nid) { + struct lruvec *lruvec = get_lruvec(memcg, nid); + + lru_gen_rotate_memcg(lruvec, MEMCG_LRU_OLD); } +} - for_each_set_bit(i, bitmap, MIN_LRU_BATCH) { - folio = pfn_folio(pte_pfn(pte[i])); - if (folio_memcg_rcu(folio) != memcg) - continue; +void lru_gen_release_memcg(struct mem_cgroup *memcg) +{ + int gen; + int nid; - old_gen = folio_update_gen(folio, new_gen); - if (old_gen < 0 || old_gen == new_gen) - continue; + for_each_node(nid) { + struct pglist_data *pgdat = NODE_DATA(nid); + struct lruvec *lruvec = get_lruvec(memcg, nid); - if (walk) - update_batch_size(walk, folio, old_gen, new_gen); - else - lru_gen_update_size(lruvec, folio, old_gen, new_gen); + spin_lock(&pgdat->memcg_lru.lock); + + VM_WARN_ON_ONCE(hlist_nulls_unhashed(&lruvec->lrugen.list)); + + gen = lruvec->lrugen.gen; + + hlist_nulls_del_rcu(&lruvec->lrugen.list); + pgdat->memcg_lru.nr_memcgs[gen]--; + + if (!pgdat->memcg_lru.nr_memcgs[gen] && gen == get_memcg_gen(pgdat->memcg_lru.seq)) + WRITE_ONCE(pgdat->memcg_lru.seq, pgdat->memcg_lru.seq + 1); + + spin_unlock(&pgdat->memcg_lru.lock); } +} - if (!walk) - spin_unlock_irq(&lruvec->lru_lock); +void lru_gen_soft_reclaim(struct lruvec *lruvec) +{ + /* see the comment on MEMCG_NR_GENS */ + if (lru_gen_memcg_seg(lruvec) != MEMCG_LRU_HEAD) + lru_gen_rotate_memcg(lruvec, MEMCG_LRU_HEAD); +} - mem_cgroup_unlock_pages(); +#else /* !CONFIG_MEMCG */ + +static int lru_gen_memcg_seg(struct lruvec *lruvec) +{ + return 0; } +#endif + /****************************************************************************** * the eviction ******************************************************************************/ @@ -4757,7 +4837,7 @@ static bool sort_folio(struct lruvec *lruvec, struct folio *folio, int tier_idx) 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; + struct lru_gen_folio *lrugen = &lruvec->lrugen; VM_WARN_ON_ONCE_FOLIO(gen >= MAX_NR_GENS, folio); @@ -4782,7 +4862,7 @@ static bool sort_folio(struct lruvec *lruvec, struct folio *folio, int tier_idx) /* promoted */ if (gen != lru_gen_from_seq(lrugen->min_seq[type])) { - list_move(&folio->lru, &lrugen->lists[gen][type][zone]); + list_move(&folio->lru, &lrugen->folios[gen][type][zone]); return true; } @@ -4791,7 +4871,7 @@ static bool sort_folio(struct lruvec *lruvec, struct folio *folio, int 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]); + list_move_tail(&folio->lru, &lrugen->folios[gen][type][zone]); WRITE_ONCE(lrugen->protected[hist][type][tier - 1], lrugen->protected[hist][type][tier - 1] + delta); @@ -4803,7 +4883,7 @@ static bool sort_folio(struct lruvec *lruvec, struct folio *folio, int tier_idx) 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]); + list_move(&folio->lru, &lrugen->folios[gen][type][zone]); return true; } @@ -4814,12 +4894,8 @@ static bool isolate_folio(struct lruvec *lruvec, struct folio *folio, struct sca { bool success; - /* unmapping inhibited */ - if (!sc->may_unmap && folio_mapped(folio)) - return false; - /* swapping inhibited */ - if (!(sc->may_writepage && (sc->gfp_mask & __GFP_IO)) && + if (!(sc->gfp_mask & __GFP_IO) && (folio_test_dirty(folio) || (folio_test_anon(folio) && !folio_test_swapcache(folio)))) return false; @@ -4857,7 +4933,7 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc, int scanned = 0; int isolated = 0; int remaining = MAX_LRU_BATCH; - struct lru_gen_struct *lrugen = &lruvec->lrugen; + struct lru_gen_folio *lrugen = &lruvec->lrugen; struct mem_cgroup *memcg = lruvec_memcg(lruvec); VM_WARN_ON_ONCE(!list_empty(list)); @@ -4870,7 +4946,7 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc, for (zone = sc->reclaim_idx; zone >= 0; zone--) { LIST_HEAD(moved); int skipped = 0; - struct list_head *head = &lrugen->lists[gen][type][zone]; + struct list_head *head = &lrugen->folios[gen][type][zone]; while (!list_empty(head)) { struct folio *folio = lru_to_folio(head); @@ -4916,9 +4992,8 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc, __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. + * There might not be eligible folios due to reclaim_idx. Check the + * remaining to prevent livelock if it's not making progress. */ return isolated || !remaining ? scanned : 0; } @@ -5013,8 +5088,7 @@ static int isolate_folios(struct lruvec *lruvec, struct scan_control *sc, int sw return scanned; } -static int evict_folios(struct lruvec *lruvec, struct scan_control *sc, int swappiness, - bool *need_swapping) +static int evict_folios(struct lruvec *lruvec, struct scan_control *sc, int swappiness) { int type; int scanned; @@ -5103,153 +5177,348 @@ retry: goto retry; } - if (need_swapping && type == LRU_GEN_ANON) - *need_swapping = true; - return scanned; } +static bool should_run_aging(struct lruvec *lruvec, unsigned long max_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_folio *lrugen = &lruvec->lrugen; + struct mem_cgroup *memcg = lruvec_memcg(lruvec); + DEFINE_MIN_SEQ(lruvec); + + /* whether this lruvec is completely out of cold folios */ + if (min_seq[!can_swap] + MIN_NR_GENS > max_seq) { + *nr_to_scan = 0; + return true; + } + + 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 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; +} + /* * For future optimizations: * 1. Defer try_to_inc_max_seq() to workqueues to reduce latency for memcg * reclaim. */ -static unsigned long get_nr_to_scan(struct lruvec *lruvec, struct scan_control *sc, - bool can_swap, bool *need_aging) +static long get_nr_to_scan(struct lruvec *lruvec, struct scan_control *sc, bool can_swap) { 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(sc->target_mem_cgroup, memcg) || - (mem_cgroup_below_low(sc->target_mem_cgroup, memcg) && - !sc->memcg_low_reclaim)) + if (mem_cgroup_below_min(sc->target_mem_cgroup, memcg)) return 0; - *need_aging = should_run_aging(lruvec, max_seq, min_seq, sc, can_swap, &nr_to_scan); - if (!*need_aging) + if (!should_run_aging(lruvec, max_seq, sc, can_swap, &nr_to_scan)) return nr_to_scan; /* skip the aging path at the default priority */ if (sc->priority == DEF_PRIORITY) - goto done; + return nr_to_scan; - /* leave the work to lru_gen_age_node() */ - if (current_is_kswapd()) - return 0; + /* skip this lruvec as it's low on cold folios */ + return try_to_inc_max_seq(lruvec, max_seq, sc, can_swap, false) ? -1 : 0; +} - if (try_to_inc_max_seq(lruvec, max_seq, sc, can_swap, false)) - return nr_to_scan; -done: - return min_seq[!can_swap] + MIN_NR_GENS <= max_seq ? nr_to_scan : 0; +static unsigned long get_nr_to_reclaim(struct scan_control *sc) +{ + /* don't abort memcg reclaim to ensure fairness */ + if (!global_reclaim(sc)) + return -1; + + return max(sc->nr_to_reclaim, compact_gap(sc->order)); } -static bool should_abort_scan(struct lruvec *lruvec, unsigned long seq, - struct scan_control *sc, bool need_swapping) +static bool try_to_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc) { - int i; - DEFINE_MAX_SEQ(lruvec); + long nr_to_scan; + unsigned long scanned = 0; + unsigned long nr_to_reclaim = get_nr_to_reclaim(sc); + int swappiness = get_swappiness(lruvec, sc); - if (!current_is_kswapd()) { - /* age each memcg at most once to ensure fairness */ - if (max_seq - seq > 1) - return true; + /* clean file folios are more likely to exist */ + if (swappiness && !(sc->gfp_mask & __GFP_IO)) + swappiness = 1; - /* over-swapping can increase allocation latency */ - if (sc->nr_reclaimed >= sc->nr_to_reclaim && need_swapping) - return true; + while (true) { + int delta; - /* give this thread a chance to exit and free its memory */ - if (fatal_signal_pending(current)) { - sc->nr_reclaimed += MIN_LRU_BATCH; - return true; - } + nr_to_scan = get_nr_to_scan(lruvec, sc, swappiness); + if (nr_to_scan <= 0) + break; - if (cgroup_reclaim(sc)) - return false; - } else if (sc->nr_reclaimed - sc->last_reclaimed < sc->nr_to_reclaim) - return false; + delta = evict_folios(lruvec, sc, swappiness); + if (!delta) + break; - /* keep scanning at low priorities to ensure fairness */ - if (sc->priority > DEF_PRIORITY - 2) - return false; + scanned += delta; + if (scanned >= nr_to_scan) + break; - /* - * A minimum amount of work was done under global memory pressure. For - * kswapd, it may be overshooting. For direct reclaim, the allocation - * may succeed if all suitable zones are somewhat safe. In either case, - * it's better to stop now, and restart later if necessary. - */ - for (i = 0; i <= sc->reclaim_idx; i++) { - unsigned long wmark; - struct zone *zone = lruvec_pgdat(lruvec)->node_zones + i; + if (sc->nr_reclaimed >= nr_to_reclaim) + break; - if (!managed_zone(zone)) + cond_resched(); + } + + /* whether try_to_inc_max_seq() was successful */ + return nr_to_scan < 0; +} + +static int shrink_one(struct lruvec *lruvec, struct scan_control *sc) +{ + bool success; + unsigned long scanned = sc->nr_scanned; + unsigned long reclaimed = sc->nr_reclaimed; + int seg = lru_gen_memcg_seg(lruvec); + struct mem_cgroup *memcg = lruvec_memcg(lruvec); + struct pglist_data *pgdat = lruvec_pgdat(lruvec); + + /* see the comment on MEMCG_NR_GENS */ + if (!lruvec_is_sizable(lruvec, sc)) + return seg != MEMCG_LRU_TAIL ? MEMCG_LRU_TAIL : MEMCG_LRU_YOUNG; + + mem_cgroup_calculate_protection(NULL, memcg); + + if (mem_cgroup_below_min(NULL, memcg)) + return MEMCG_LRU_YOUNG; + + if (mem_cgroup_below_low(NULL, memcg)) { + /* see the comment on MEMCG_NR_GENS */ + if (seg != MEMCG_LRU_TAIL) + return MEMCG_LRU_TAIL; + + memcg_memory_event(memcg, MEMCG_LOW); + } + + success = try_to_shrink_lruvec(lruvec, sc); + + shrink_slab(sc->gfp_mask, pgdat->node_id, memcg, sc->priority); + + if (!sc->proactive) + vmpressure(sc->gfp_mask, memcg, false, sc->nr_scanned - scanned, + sc->nr_reclaimed - reclaimed); + + sc->nr_reclaimed += current->reclaim_state->reclaimed_slab; + current->reclaim_state->reclaimed_slab = 0; + + return success ? MEMCG_LRU_YOUNG : 0; +} + +#ifdef CONFIG_MEMCG + +static void shrink_many(struct pglist_data *pgdat, struct scan_control *sc) +{ + int op; + int gen; + int bin; + int first_bin; + struct lruvec *lruvec; + struct lru_gen_folio *lrugen; + struct mem_cgroup *memcg; + const struct hlist_nulls_node *pos; + unsigned long nr_to_reclaim = get_nr_to_reclaim(sc); + + bin = first_bin = get_random_u32_below(MEMCG_NR_BINS); +restart: + op = 0; + memcg = NULL; + gen = get_memcg_gen(READ_ONCE(pgdat->memcg_lru.seq)); + + rcu_read_lock(); + + hlist_nulls_for_each_entry_rcu(lrugen, pos, &pgdat->memcg_lru.fifo[gen][bin], list) { + if (op) + lru_gen_rotate_memcg(lruvec, op); + + mem_cgroup_put(memcg); + + lruvec = container_of(lrugen, struct lruvec, lrugen); + memcg = lruvec_memcg(lruvec); + + if (!mem_cgroup_tryget(memcg)) { + op = 0; + memcg = NULL; continue; + } - wmark = current_is_kswapd() ? high_wmark_pages(zone) : low_wmark_pages(zone); - if (wmark > zone_page_state(zone, NR_FREE_PAGES)) - return false; + rcu_read_unlock(); + + op = shrink_one(lruvec, sc); + + rcu_read_lock(); + + if (sc->nr_reclaimed >= nr_to_reclaim) + break; } - sc->nr_reclaimed += MIN_LRU_BATCH; + rcu_read_unlock(); - return true; + if (op) + lru_gen_rotate_memcg(lruvec, op); + + mem_cgroup_put(memcg); + + if (sc->nr_reclaimed >= nr_to_reclaim) + return; + + /* restart if raced with lru_gen_rotate_memcg() */ + if (gen != get_nulls_value(pos)) + goto restart; + + /* try the rest of the bins of the current generation */ + bin = get_memcg_bin(bin + 1); + if (bin != first_bin) + goto restart; } static void lru_gen_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc) { struct blk_plug plug; - bool need_aging = false; - bool need_swapping = false; - unsigned long scanned = 0; - unsigned long reclaimed = sc->nr_reclaimed; - DEFINE_MAX_SEQ(lruvec); + + VM_WARN_ON_ONCE(global_reclaim(sc)); + VM_WARN_ON_ONCE(!sc->may_writepage || !sc->may_unmap); lru_add_drain(); blk_start_plug(&plug); - set_mm_walk(lruvec_pgdat(lruvec)); + set_mm_walk(NULL, sc->proactive); - while (true) { - int delta; - int swappiness; - unsigned long nr_to_scan; + if (try_to_shrink_lruvec(lruvec, sc)) + lru_gen_rotate_memcg(lruvec, MEMCG_LRU_YOUNG); - if (sc->may_swap) - swappiness = get_swappiness(lruvec, sc); - else if (!cgroup_reclaim(sc) && get_swappiness(lruvec, sc)) - swappiness = 1; - else - swappiness = 0; + clear_mm_walk(); - nr_to_scan = get_nr_to_scan(lruvec, sc, swappiness, &need_aging); - if (!nr_to_scan) - goto done; + blk_finish_plug(&plug); +} - delta = evict_folios(lruvec, sc, swappiness, &need_swapping); - if (!delta) - goto done; +#else /* !CONFIG_MEMCG */ - scanned += delta; - if (scanned >= nr_to_scan) - break; +static void shrink_many(struct pglist_data *pgdat, struct scan_control *sc) +{ + BUILD_BUG(); +} - if (should_abort_scan(lruvec, max_seq, sc, need_swapping)) - break; +static void lru_gen_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc) +{ + BUILD_BUG(); +} - cond_resched(); - } +#endif + +static void set_initial_priority(struct pglist_data *pgdat, struct scan_control *sc) +{ + int priority; + unsigned long reclaimable; + struct lruvec *lruvec = mem_cgroup_lruvec(NULL, pgdat); + + if (sc->priority != DEF_PRIORITY || sc->nr_to_reclaim < MIN_LRU_BATCH) + return; + /* + * Determine the initial priority based on ((total / MEMCG_NR_GENS) >> + * priority) * reclaimed_to_scanned_ratio = nr_to_reclaim, where the + * estimated reclaimed_to_scanned_ratio = inactive / total. + */ + reclaimable = node_page_state(pgdat, NR_INACTIVE_FILE); + if (get_swappiness(lruvec, sc)) + reclaimable += node_page_state(pgdat, NR_INACTIVE_ANON); + + reclaimable /= MEMCG_NR_GENS; + + /* round down reclaimable and round up sc->nr_to_reclaim */ + priority = fls_long(reclaimable) - 1 - fls_long(sc->nr_to_reclaim - 1); + + sc->priority = clamp(priority, 0, DEF_PRIORITY); +} + +static void lru_gen_shrink_node(struct pglist_data *pgdat, struct scan_control *sc) +{ + struct blk_plug plug; + unsigned long reclaimed = sc->nr_reclaimed; + + VM_WARN_ON_ONCE(!global_reclaim(sc)); + + /* + * Unmapped clean folios are already prioritized. Scanning for more of + * them is likely futile and can cause high reclaim latency when there + * is a large number of memcgs. + */ + if (!sc->may_writepage || !sc->may_unmap) + goto done; + + lru_add_drain(); + + blk_start_plug(&plug); + + set_mm_walk(pgdat, sc->proactive); + + set_initial_priority(pgdat, sc); + + if (current_is_kswapd()) + sc->nr_reclaimed = 0; + + if (mem_cgroup_disabled()) + shrink_one(&pgdat->__lruvec, sc); + else + shrink_many(pgdat, sc); + + if (current_is_kswapd()) + sc->nr_reclaimed += reclaimed; - /* see the comment in lru_gen_age_node() */ - if (sc->nr_reclaimed - reclaimed >= MIN_LRU_BATCH && !need_aging) - sc->memcgs_need_aging = false; -done: clear_mm_walk(); blk_finish_plug(&plug); +done: + /* kswapd should never fail */ + pgdat->kswapd_failures = 0; } /****************************************************************************** @@ -5258,7 +5527,7 @@ done: static bool __maybe_unused state_is_valid(struct lruvec *lruvec) { - struct lru_gen_struct *lrugen = &lruvec->lrugen; + struct lru_gen_folio *lrugen = &lruvec->lrugen; if (lrugen->enabled) { enum lru_list lru; @@ -5271,7 +5540,7 @@ static bool __maybe_unused state_is_valid(struct lruvec *lruvec) int gen, type, zone; for_each_gen_type_zone(gen, type, zone) { - if (!list_empty(&lrugen->lists[gen][type][zone])) + if (!list_empty(&lrugen->folios[gen][type][zone])) return false; } } @@ -5316,7 +5585,7 @@ static bool drain_evictable(struct lruvec *lruvec) int remaining = MAX_LRU_BATCH; for_each_gen_type_zone(gen, type, zone) { - struct list_head *head = &lruvec->lrugen.lists[gen][type][zone]; + struct list_head *head = &lruvec->lrugen.folios[gen][type][zone]; while (!list_empty(head)) { bool success; @@ -5537,7 +5806,7 @@ static void lru_gen_seq_show_full(struct seq_file *m, struct lruvec *lruvec, int i; int type, tier; int hist = lru_hist_from_seq(seq); - struct lru_gen_struct *lrugen = &lruvec->lrugen; + struct lru_gen_folio *lrugen = &lruvec->lrugen; for (tier = 0; tier < MAX_NR_TIERS; tier++) { seq_printf(m, " %10d", tier); @@ -5587,7 +5856,7 @@ static int lru_gen_seq_show(struct seq_file *m, void *v) unsigned long seq; bool full = !debugfs_real_fops(m->file)->write; struct lruvec *lruvec = v; - struct lru_gen_struct *lrugen = &lruvec->lrugen; + struct lru_gen_folio *lrugen = &lruvec->lrugen; int nid = lruvec_pgdat(lruvec)->node_id; struct mem_cgroup *memcg = lruvec_memcg(lruvec); DEFINE_MAX_SEQ(lruvec); @@ -5684,7 +5953,7 @@ static int run_eviction(struct lruvec *lruvec, unsigned long seq, struct scan_co if (sc->nr_reclaimed >= nr_to_reclaim) return 0; - if (!evict_folios(lruvec, sc, swappiness, NULL)) + if (!evict_folios(lruvec, sc, swappiness)) return 0; cond_resched(); @@ -5705,11 +5974,11 @@ static int run_cmd(char cmd, int memcg_id, int nid, unsigned long seq, if (!mem_cgroup_disabled()) { rcu_read_lock(); + memcg = mem_cgroup_from_id(memcg_id); -#ifdef CONFIG_MEMCG - if (memcg && !css_tryget(&memcg->css)) + if (!mem_cgroup_tryget(memcg)) memcg = NULL; -#endif + rcu_read_unlock(); if (!memcg) @@ -5769,7 +6038,7 @@ static ssize_t lru_gen_seq_write(struct file *file, const char __user *src, set_task_reclaim_state(current, &sc.reclaim_state); flags = memalloc_noreclaim_save(); blk_start_plug(&plug); - if (!set_mm_walk(NULL)) { + if (!set_mm_walk(NULL, true)) { err = -ENOMEM; goto done; } @@ -5841,7 +6110,7 @@ void lru_gen_init_lruvec(struct lruvec *lruvec) { int i; int gen, type, zone; - struct lru_gen_struct *lrugen = &lruvec->lrugen; + struct lru_gen_folio *lrugen = &lruvec->lrugen; lrugen->max_seq = MIN_NR_GENS + 1; lrugen->enabled = lru_gen_enabled(); @@ -5850,13 +6119,26 @@ void lru_gen_init_lruvec(struct lruvec *lruvec) lrugen->timestamps[i] = jiffies; for_each_gen_type_zone(gen, type, zone) - INIT_LIST_HEAD(&lrugen->lists[gen][type][zone]); + INIT_LIST_HEAD(&lrugen->folios[gen][type][zone]); lruvec->mm_state.seq = MIN_NR_GENS; init_waitqueue_head(&lruvec->mm_state.wait); } #ifdef CONFIG_MEMCG + +void lru_gen_init_pgdat(struct pglist_data *pgdat) +{ + int i, j; + + spin_lock_init(&pgdat->memcg_lru.lock); + + for (i = 0; i < MEMCG_NR_GENS; i++) { + for (j = 0; j < MEMCG_NR_BINS; j++) + INIT_HLIST_NULLS_HEAD(&pgdat->memcg_lru.fifo[i][j], i); + } +} + void lru_gen_init_memcg(struct mem_cgroup *memcg) { INIT_LIST_HEAD(&memcg->mm_list.fifo); @@ -5868,19 +6150,25 @@ void lru_gen_exit_memcg(struct mem_cgroup *memcg) int i; int nid; + VM_WARN_ON_ONCE(!list_empty(&memcg->mm_list.fifo)); + for_each_node(nid) { struct lruvec *lruvec = get_lruvec(memcg, nid); + VM_WARN_ON_ONCE(lruvec->mm_state.nr_walkers); VM_WARN_ON_ONCE(memchr_inv(lruvec->lrugen.nr_pages, 0, sizeof(lruvec->lrugen.nr_pages))); + lruvec->lrugen.list.next = LIST_POISON1; + for (i = 0; i < NR_BLOOM_FILTERS; i++) { bitmap_free(lruvec->mm_state.filters[i]); lruvec->mm_state.filters[i] = NULL; } } } -#endif + +#endif /* CONFIG_MEMCG */ static int __init init_lru_gen(void) { @@ -5907,6 +6195,10 @@ static void lru_gen_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc { } +static void lru_gen_shrink_node(struct pglist_data *pgdat, struct scan_control *sc) +{ +} + #endif /* CONFIG_LRU_GEN */ static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc) @@ -5920,7 +6212,7 @@ static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc) bool proportional_reclaim; struct blk_plug plug; - if (lru_gen_enabled()) { + if (lru_gen_enabled() && !global_reclaim(sc)) { lru_gen_shrink_lruvec(lruvec, sc); return; } @@ -6163,6 +6455,11 @@ static void shrink_node(pg_data_t *pgdat, struct scan_control *sc) struct lruvec *target_lruvec; bool reclaimable = false; + if (lru_gen_enabled() && global_reclaim(sc)) { + lru_gen_shrink_node(pgdat, sc); + return; + } + target_lruvec = mem_cgroup_lruvec(sc->target_mem_cgroup, pgdat); again: |