diff options
Diffstat (limited to 'mm/vmscan.c')
| -rw-r--r-- | mm/vmscan.c | 1418 |
1 files changed, 817 insertions, 601 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 3ef654addd44..f2858cc92c2c 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -56,6 +56,7 @@ #include <linux/khugepaged.h> #include <linux/rculist_nulls.h> #include <linux/random.h> +#include <linux/mmu_notifier.h> #include <asm/tlbflush.h> #include <asm/div64.h> @@ -92,6 +93,11 @@ struct scan_control { unsigned long anon_cost; unsigned long file_cost; +#ifdef CONFIG_MEMCG + /* Swappiness value for proactive reclaim. Always use sc_swappiness()! */ + int *proactive_swappiness; +#endif + /* Can active folios be deactivated as part of reclaim? */ #define DEACTIVATE_ANON 1 #define DEACTIVATE_FILE 2 @@ -128,6 +134,9 @@ struct scan_control { unsigned int memcg_low_reclaim:1; unsigned int memcg_low_skipped:1; + /* Shared cgroup tree walk failed, rescan the whole tree */ + unsigned int memcg_full_walk:1; + unsigned int hibernation_mode:1; /* One of the zones is ready for compaction */ @@ -189,7 +198,7 @@ struct scan_control { #endif /* - * From 0 .. 200. Higher means more swappy. + * From 0 .. MAX_SWAPPINESS. Higher means more swappy. */ int vm_swappiness = 60; @@ -233,6 +242,13 @@ static bool writeback_throttling_sane(struct scan_control *sc) #endif return false; } + +static int sc_swappiness(struct scan_control *sc, struct mem_cgroup *memcg) +{ + if (sc->proactive && sc->proactive_swappiness) + return *sc->proactive_swappiness; + return mem_cgroup_swappiness(memcg); +} #else static bool cgroup_reclaim(struct scan_control *sc) { @@ -248,8 +264,32 @@ static bool writeback_throttling_sane(struct scan_control *sc) { return true; } + +static int sc_swappiness(struct scan_control *sc, struct mem_cgroup *memcg) +{ + return READ_ONCE(vm_swappiness); +} #endif +/* for_each_managed_zone_pgdat - helper macro to iterate over all managed zones in a pgdat up to + * and including the specified highidx + * @zone: The current zone in the iterator + * @pgdat: The pgdat which node_zones are being iterated + * @idx: The index variable + * @highidx: The index of the highest zone to return + * + * This macro iterates through all managed zones up to and including the specified highidx. + * The zone iterator enters an invalid state after macro call and must be reinitialized + * before it can be used again. + */ +#define for_each_managed_zone_pgdat(zone, pgdat, idx, highidx) \ + for ((idx) = 0, (zone) = (pgdat)->node_zones; \ + (idx) <= (highidx); \ + (idx)++, (zone)++) \ + if (!managed_zone(zone)) \ + continue; \ + else + static void set_task_reclaim_state(struct task_struct *task, struct reclaim_state *rs) { @@ -302,16 +342,22 @@ static void flush_reclaim_state(struct scan_control *sc) } } -static bool can_demote(int nid, struct scan_control *sc) +static bool can_demote(int nid, struct scan_control *sc, + struct mem_cgroup *memcg) { + int demotion_nid; + if (!numa_demotion_enabled) return false; if (sc && sc->no_demotion) return false; - if (next_demotion_node(nid) == NUMA_NO_NODE) + + demotion_nid = next_demotion_node(nid); + if (demotion_nid == NUMA_NO_NODE) return false; - return true; + /* If demotion node isn't in the cgroup's mems_allowed, fall back */ + return mem_cgroup_node_allowed(memcg, demotion_nid); } static inline bool can_reclaim_anon_pages(struct mem_cgroup *memcg, @@ -336,7 +382,7 @@ static inline bool can_reclaim_anon_pages(struct mem_cgroup *memcg, * * Can it be reclaimed from this node via demotion? */ - return can_demote(nid, sc); + return can_demote(nid, sc, memcg); } /* @@ -353,7 +399,14 @@ unsigned long zone_reclaimable_pages(struct zone *zone) if (can_reclaim_anon_pages(NULL, zone_to_nid(zone), NULL)) nr += zone_page_state_snapshot(zone, NR_ZONE_INACTIVE_ANON) + zone_page_state_snapshot(zone, NR_ZONE_ACTIVE_ANON); - + /* + * If there are no reclaimable file-backed or anonymous pages, + * ensure zones with sufficient free pages are not skipped. + * This prevents zones like DMA32 from being ignored in reclaim + * scenarios where they can still help alleviate memory pressure. + */ + if (nr == 0) + nr = zone_page_state_snapshot(zone, NR_FREE_PAGES); return nr; } @@ -368,13 +421,9 @@ static unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru, { unsigned long size = 0; int zid; + struct zone *zone; - for (zid = 0; zid <= zone_idx; zid++) { - struct zone *zone = &lruvec_pgdat(lruvec)->node_zones[zid]; - - if (!managed_zone(zone)) - continue; - + for_each_managed_zone_pgdat(zone, lruvec_pgdat(lruvec), zid, zone_idx) { if (!mem_cgroup_disabled()) size += mem_cgroup_get_zone_lru_size(lruvec, lru, zid); else @@ -413,21 +462,26 @@ void drop_slab(void) } while ((freed >> shift++) > 1); } -static int reclaimer_offset(void) +#define CHECK_RECLAIMER_OFFSET(type) \ + do { \ + BUILD_BUG_ON(PGSTEAL_##type - PGSTEAL_KSWAPD != \ + PGDEMOTE_##type - PGDEMOTE_KSWAPD); \ + BUILD_BUG_ON(PGSTEAL_##type - PGSTEAL_KSWAPD != \ + PGSCAN_##type - PGSCAN_KSWAPD); \ + } while (0) + +static int reclaimer_offset(struct scan_control *sc) { - BUILD_BUG_ON(PGSTEAL_DIRECT - PGSTEAL_KSWAPD != - PGDEMOTE_DIRECT - PGDEMOTE_KSWAPD); - BUILD_BUG_ON(PGSTEAL_KHUGEPAGED - PGSTEAL_KSWAPD != - PGDEMOTE_KHUGEPAGED - PGDEMOTE_KSWAPD); - BUILD_BUG_ON(PGSTEAL_DIRECT - PGSTEAL_KSWAPD != - PGSCAN_DIRECT - PGSCAN_KSWAPD); - BUILD_BUG_ON(PGSTEAL_KHUGEPAGED - PGSTEAL_KSWAPD != - PGSCAN_KHUGEPAGED - PGSCAN_KSWAPD); + CHECK_RECLAIMER_OFFSET(DIRECT); + CHECK_RECLAIMER_OFFSET(KHUGEPAGED); + CHECK_RECLAIMER_OFFSET(PROACTIVE); if (current_is_kswapd()) return 0; if (current_is_khugepaged()) return PGSTEAL_KHUGEPAGED - PGSTEAL_KSWAPD; + if (sc->proactive) + return PGSTEAL_PROACTIVE - PGSTEAL_KSWAPD; return PGSTEAL_DIRECT - PGSTEAL_KSWAPD; } @@ -467,7 +521,7 @@ static bool skip_throttle_noprogress(pg_data_t *pgdat) { int reclaimable = 0, write_pending = 0; int i; - + struct zone *zone; /* * If kswapd is disabled, reschedule if necessary but do not * throttle as the system is likely near OOM. @@ -480,12 +534,7 @@ static bool skip_throttle_noprogress(pg_data_t *pgdat) * throttle as throttling will occur when the folios cycle * towards the end of the LRU if still under writeback. */ - for (i = 0; i < MAX_NR_ZONES; i++) { - struct zone *zone = pgdat->node_zones + i; - - if (!managed_zone(zone)) - continue; - + for_each_managed_zone_pgdat(zone, pgdat, i, MAX_NR_ZONES - 1) { reclaimable += zone_reclaimable_pages(zone); write_pending += zone_page_state_snapshot(zone, NR_ZONE_WRITE_PENDING); @@ -605,21 +654,20 @@ typedef enum { /* * pageout is called by shrink_folio_list() for each dirty folio. - * Calls ->writepage(). */ static pageout_t pageout(struct folio *folio, struct address_space *mapping, - struct swap_iocb **plug) + struct swap_iocb **plug, struct list_head *folio_list) { + int (*writeout)(struct folio *, struct writeback_control *); + /* - * If the folio is dirty, only perform writeback if that write - * will be non-blocking. To prevent this allocation from being - * stalled by pagecache activity. But note that there may be - * stalls if we need to run get_block(). We could test - * PagePrivate for that. - * - * If this process is currently in __generic_file_write_iter() against - * this folio's queue, we can perform writeback even if that - * will block. + * We no longer attempt to writeback filesystem folios here, other + * than tmpfs/shmem. That's taken care of in page-writeback. + * If we find a dirty filesystem folio at the end of the LRU list, + * typically that means the filesystem is saturating the storage + * with contiguous writes and telling it to write a folio here + * would only make the situation worse by injecting an element + * of random access. * * If the folio is swapcache, write it back even if that would * block, for some throttling. This happens by accident, because @@ -642,7 +690,11 @@ static pageout_t pageout(struct folio *folio, struct address_space *mapping, } return PAGE_KEEP; } - if (mapping->a_ops->writepage == NULL) + if (shmem_mapping(mapping)) + writeout = shmem_writeout; + else if (folio_test_anon(folio)) + writeout = swap_writeout; + else return PAGE_ACTIVATE; if (folio_clear_dirty_for_io(folio)) { @@ -656,8 +708,16 @@ static pageout_t pageout(struct folio *folio, struct address_space *mapping, .swap_plug = plug, }; + /* + * The large shmem folio can be split if CONFIG_THP_SWAP is + * not enabled or contiguous swap entries are failed to + * allocate. + */ + if (shmem_mapping(mapping) && folio_test_large(folio)) + wbc.list = folio_list; + folio_set_reclaim(folio); - res = mapping->a_ops->writepage(&folio->page, &wbc); + res = writeout(folio, &wbc); if (res < 0) handle_write_error(mapping, folio, res); if (res == AOP_WRITEPAGE_ACTIVATE) { @@ -666,7 +726,7 @@ static pageout_t pageout(struct folio *folio, struct address_space *mapping, } if (!folio_test_writeback(folio)) { - /* synchronous write or broken a_ops? */ + /* synchronous write? */ folio_clear_reclaim(folio); } trace_mm_vmscan_write_folio(folio); @@ -733,7 +793,7 @@ static int __remove_mapping(struct address_space *mapping, struct folio *folio, if (reclaimed && !mapping_exiting(mapping)) shadow = workingset_eviction(folio, target_memcg); __delete_from_swap_cache(folio, swap, shadow); - mem_cgroup_swapout(folio, swap); + memcg1_swapout(folio, swap); xa_unlock_irq(&mapping->i_pages); put_swap_folio(folio, swap); } else { @@ -826,6 +886,31 @@ enum folio_references { FOLIOREF_ACTIVATE, }; +#ifdef CONFIG_LRU_GEN +/* + * Only used on a mapped folio in the eviction (rmap walk) path, where promotion + * needs to be done by taking the folio off the LRU list and then adding it back + * with PG_active set. In contrast, the aging (page table walk) path uses + * folio_update_gen(). + */ +static bool lru_gen_set_refs(struct folio *folio) +{ + /* see the comment on LRU_REFS_FLAGS */ + if (!folio_test_referenced(folio) && !folio_test_workingset(folio)) { + set_mask_bits(&folio->flags, LRU_REFS_MASK, BIT(PG_referenced)); + return false; + } + + set_mask_bits(&folio->flags, LRU_REFS_FLAGS, BIT(PG_workingset)); + return true; +} +#else +static bool lru_gen_set_refs(struct folio *folio) +{ + return false; +} +#endif /* CONFIG_LRU_GEN */ + static enum folio_references folio_check_references(struct folio *folio, struct scan_control *sc) { @@ -834,7 +919,6 @@ static enum folio_references folio_check_references(struct folio *folio, referenced_ptes = folio_referenced(folio, 1, sc->target_mem_cgroup, &vm_flags); - referenced_folio = folio_test_clear_referenced(folio); /* * The supposedly reclaimable folio was found to be in a VM_LOCKED vma. @@ -843,10 +927,24 @@ static enum folio_references folio_check_references(struct folio *folio, if (vm_flags & VM_LOCKED) return FOLIOREF_ACTIVATE; - /* rmap lock contention: rotate */ + /* + * There are two cases to consider. + * 1) Rmap lock contention: rotate. + * 2) Skip the non-shared swapbacked folio mapped solely by + * the exiting or OOM-reaped process. + */ if (referenced_ptes == -1) return FOLIOREF_KEEP; + if (lru_gen_enabled()) { + if (!referenced_ptes) + return FOLIOREF_RECLAIM; + + return lru_gen_set_refs(folio) ? FOLIOREF_ACTIVATE : FOLIOREF_KEEP; + } + + referenced_folio = folio_test_clear_referenced(folio); + if (referenced_ptes) { /* * All mapped folios start out with page table @@ -916,8 +1014,7 @@ static void folio_check_dirty_writeback(struct folio *folio, mapping->a_ops->is_dirty_writeback(folio, dirty, writeback); } -static struct folio *alloc_demote_folio(struct folio *src, - unsigned long private) +struct folio *alloc_migrate_folio(struct folio *src, unsigned long private) { struct folio *dst; nodemask_t *allowed_mask; @@ -967,7 +1064,8 @@ static unsigned int demote_folio_list(struct list_head *demote_folios, .gfp_mask = (GFP_HIGHUSER_MOVABLE & ~__GFP_RECLAIM) | __GFP_NOWARN | __GFP_NOMEMALLOC | GFP_NOWAIT, .nid = target_nid, - .nmask = &allowed_mask + .nmask = &allowed_mask, + .reason = MR_DEMOTION, }; if (list_empty(demote_folios)) @@ -979,13 +1077,10 @@ static unsigned int demote_folio_list(struct list_head *demote_folios, node_get_allowed_targets(pgdat, &allowed_mask); /* Demotion ignores all cpuset and mempolicy settings */ - migrate_pages(demote_folios, alloc_demote_folio, NULL, + migrate_pages(demote_folios, alloc_migrate_folio, NULL, (unsigned long)&mtc, MIGRATE_ASYNC, MR_DEMOTION, &nr_succeeded); - mod_node_page_state(pgdat, PGDEMOTE_KSWAPD + reclaimer_offset(), - nr_succeeded); - return nr_succeeded; } @@ -1010,12 +1105,13 @@ static bool may_enter_fs(struct folio *folio, gfp_t gfp_mask) */ static unsigned int shrink_folio_list(struct list_head *folio_list, struct pglist_data *pgdat, struct scan_control *sc, - struct reclaim_stat *stat, bool ignore_references) + struct reclaim_stat *stat, bool ignore_references, + struct mem_cgroup *memcg) { struct folio_batch free_folios; LIST_HEAD(ret_folios); LIST_HEAD(demote_folios); - unsigned int nr_reclaimed = 0; + unsigned int nr_reclaimed = 0, nr_demoted = 0; unsigned int pgactivate = 0; bool do_demote_pass; struct swap_iocb *plug = NULL; @@ -1023,7 +1119,7 @@ static unsigned int shrink_folio_list(struct list_head *folio_list, folio_batch_init(&free_folios); memset(stat, 0, sizeof(*stat)); cond_resched(); - do_demote_pass = can_demote(pgdat->node_id, sc); + do_demote_pass = can_demote(pgdat->node_id, sc, memcg); retry: while (!list_empty(folio_list)) { @@ -1041,6 +1137,13 @@ retry: if (!folio_trylock(folio)) goto keep; + if (folio_contain_hwpoisoned_page(folio)) { + unmap_poisoned_folio(folio, folio_pfn(folio), false); + folio_unlock(folio); + folio_put(folio); + continue; + } + VM_BUG_ON_FOLIO(folio_test_active(folio), folio); nr_pages = folio_nr_pages(folio); @@ -1054,11 +1157,6 @@ retry: if (!sc->may_unmap && folio_mapped(folio)) goto keep_locked; - /* folio_update_gen() tried to promote this page? */ - if (lru_gen_enabled() && !ignore_references && - folio_mapped(folio) && folio_test_referenced(folio)) - goto keep_locked; - /* * The number of dirty pages determines if a node is marked * reclaim_congested. kswapd will stall and start writing @@ -1202,38 +1300,49 @@ retry: goto keep_locked; if (folio_test_large(folio)) { /* cannot split folio, skip it */ - if (!can_split_folio(folio, NULL)) + if (!can_split_folio(folio, 1, NULL)) goto activate_locked; /* - * Split folios without a PMD map right - * away. Chances are some or all of the - * tail pages can be freed without IO. + * Split partially mapped folios right away. + * We can free the unmapped pages without IO. */ - if (!folio_entire_mapcount(folio) && - split_folio_to_list(folio, - folio_list)) + if (data_race(!list_empty(&folio->_deferred_list) && + folio_test_partially_mapped(folio)) && + split_folio_to_list(folio, folio_list)) goto activate_locked; } - if (!add_to_swap(folio)) { + if (folio_alloc_swap(folio, __GFP_HIGH | __GFP_NOWARN)) { + int __maybe_unused order = folio_order(folio); + if (!folio_test_large(folio)) goto activate_locked_split; /* Fallback to swap normal pages */ - if (split_folio_to_list(folio, - folio_list)) + if (split_folio_to_list(folio, folio_list)) goto activate_locked; #ifdef CONFIG_TRANSPARENT_HUGEPAGE - count_memcg_folio_events(folio, THP_SWPOUT_FALLBACK, 1); - count_vm_event(THP_SWPOUT_FALLBACK); + if (nr_pages >= HPAGE_PMD_NR) { + count_memcg_folio_events(folio, + THP_SWPOUT_FALLBACK, 1); + count_vm_event(THP_SWPOUT_FALLBACK); + } #endif - if (!add_to_swap(folio)) + count_mthp_stat(order, MTHP_STAT_SWPOUT_FALLBACK); + if (folio_alloc_swap(folio, __GFP_HIGH | __GFP_NOWARN)) goto activate_locked_split; } + /* + * Normally the folio will be dirtied in unmap because its + * pte should be dirty. A special case is MADV_FREE page. The + * page's pte could have dirty bit cleared but the folio's + * SwapBacked flag is still set because clearing the dirty bit + * and SwapBacked flag has no lock protected. For such folio, + * unmap will not set dirty bit for it, so folio reclaim will + * not write the folio out. This can cause data corruption when + * the folio is swapped in later. Always setting the dirty flag + * for the folio solves the problem. + */ + folio_mark_dirty(folio); } - } else if (folio_test_swapbacked(folio) && - folio_test_large(folio)) { - /* Split shmem folio */ - if (split_folio_to_list(folio, folio_list)) - goto keep_locked; } /* @@ -1256,6 +1365,20 @@ retry: if (folio_test_pmd_mappable(folio)) flags |= TTU_SPLIT_HUGE_PMD; + /* + * Without TTU_SYNC, try_to_unmap will only begin to + * hold PTL from the first present PTE within a large + * folio. Some initial PTEs might be skipped due to + * races with parallel PTE writes in which PTEs can be + * cleared temporarily before being written new present + * values. This will lead to a large folio is still + * mapped while some subpages have been partially + * unmapped after try_to_unmap; TTU_SYNC helps + * try_to_unmap acquire PTL from the first PTE, + * eliminating the influence of temporary PTE values. + */ + if (folio_test_large(folio)) + flags |= TTU_SYNC; try_to_unmap(folio, flags); if (folio_mapped(folio)) { @@ -1320,12 +1443,25 @@ retry: * starts and then write it out here. */ try_to_unmap_flush_dirty(); - switch (pageout(folio, mapping, &plug)) { + switch (pageout(folio, mapping, &plug, folio_list)) { case PAGE_KEEP: goto keep_locked; case PAGE_ACTIVATE: + /* + * If shmem folio is split when writeback to swap, + * the tail pages will make their own pass through + * this function and be accounted then. + */ + if (nr_pages > 1 && !folio_test_large(folio)) { + sc->nr_scanned -= (nr_pages - 1); + nr_pages = 1; + } goto activate_locked; case PAGE_SUCCESS: + if (nr_pages > 1 && !folio_test_large(folio)) { + sc->nr_scanned -= (nr_pages - 1); + nr_pages = 1; + } stat->nr_pageout += nr_pages; if (folio_test_writeback(folio)) @@ -1419,9 +1555,7 @@ free_it: */ nr_reclaimed += nr_pages; - if (folio_test_large(folio) && - folio_test_large_rmappable(folio)) - folio_undo_large_rmappable(folio); + folio_unqueue_deferred_split(folio); if (folio_batch_add(&free_folios, folio) == 0) { mem_cgroup_uncharge_folios(&free_folios); try_to_unmap_flush(); @@ -1460,7 +1594,9 @@ keep: /* 'folio_list' is always empty here */ /* Migrate folios selected for demotion */ - nr_reclaimed += demote_folio_list(&demote_folios, pgdat); + nr_demoted = demote_folio_list(&demote_folios, pgdat); + nr_reclaimed += nr_demoted; + stat->nr_demoted += nr_demoted; /* Folios that could not be demoted are still in @demote_folios */ if (!list_empty(&demote_folios)) { /* Folios which weren't demoted go back on @folio_list */ @@ -1532,7 +1668,7 @@ unsigned int reclaim_clean_pages_from_list(struct zone *zone, */ noreclaim_flag = memalloc_noreclaim_save(); nr_reclaimed = shrink_folio_list(&clean_folios, zone->zone_pgdat, &sc, - &stat, true); + &stat, true, NULL); memalloc_noreclaim_restore(noreclaim_flag); list_splice(&clean_folios, folio_list); @@ -1569,25 +1705,6 @@ static __always_inline void update_lru_sizes(struct lruvec *lruvec, } -#ifdef CONFIG_CMA -/* - * It is waste of effort to scan and reclaim CMA pages if it is not available - * for current allocation context. Kswapd can not be enrolled as it can not - * distinguish this scenario by using sc->gfp_mask = GFP_KERNEL - */ -static bool skip_cma(struct folio *folio, struct scan_control *sc) -{ - return !current_is_kswapd() && - gfp_migratetype(sc->gfp_mask) != MIGRATE_MOVABLE && - folio_migratetype(folio) == MIGRATE_CMA; -} -#else -static bool skip_cma(struct folio *folio, struct scan_control *sc) -{ - return false; -} -#endif - /* * Isolating page from the lruvec to fill in @dst list by nr_to_scan times. * @@ -1618,12 +1735,11 @@ static unsigned long isolate_lru_folios(unsigned long nr_to_scan, unsigned long nr_taken = 0; unsigned long nr_zone_taken[MAX_NR_ZONES] = { 0 }; unsigned long nr_skipped[MAX_NR_ZONES] = { 0, }; - unsigned long skipped = 0; - unsigned long scan, total_scan, nr_pages; + unsigned long skipped = 0, total_scan = 0, scan = 0; + unsigned long nr_pages; + unsigned long max_nr_skipped = 0; LIST_HEAD(folios_skipped); - total_scan = 0; - scan = 0; while (scan < nr_to_scan && !list_empty(src)) { struct list_head *move_to = src; struct folio *folio; @@ -1634,10 +1750,12 @@ static unsigned long isolate_lru_folios(unsigned long nr_to_scan, nr_pages = folio_nr_pages(folio); total_scan += nr_pages; - if (folio_zonenum(folio) > sc->reclaim_idx || - skip_cma(folio, sc)) { + /* Using max_nr_skipped to prevent hard LOCKUP*/ + if (max_nr_skipped < SWAP_CLUSTER_MAX_SKIPPED && + (folio_zonenum(folio) > sc->reclaim_idx)) { nr_skipped[folio_zonenum(folio)] += nr_pages; move_to = &folios_skipped; + max_nr_skipped++; goto move; } @@ -1828,9 +1946,7 @@ static unsigned int move_folios_to_lru(struct lruvec *lruvec, if (unlikely(folio_put_testzero(folio))) { __folio_clear_lru_flags(folio); - if (folio_test_large(folio) && - folio_test_large_rmappable(folio)) - folio_undo_large_rmappable(folio); + folio_unqueue_deferred_split(folio); if (folio_batch_add(&free_folios, folio) == 0) { spin_unlock_irq(&lruvec->lru_lock); mem_cgroup_uncharge_folios(&free_folios); @@ -1912,10 +2028,10 @@ static unsigned long shrink_inactive_list(unsigned long nr_to_scan, &nr_scanned, sc, lru); __mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, nr_taken); - item = PGSCAN_KSWAPD + reclaimer_offset(); + item = PGSCAN_KSWAPD + reclaimer_offset(sc); if (!cgroup_reclaim(sc)) __count_vm_events(item, nr_scanned); - __count_memcg_events(lruvec_memcg(lruvec), item, nr_scanned); + count_memcg_events(lruvec_memcg(lruvec), item, nr_scanned); __count_vm_events(PGSCAN_ANON + file, nr_scanned); spin_unlock_irq(&lruvec->lru_lock); @@ -1923,16 +2039,19 @@ static unsigned long shrink_inactive_list(unsigned long nr_to_scan, if (nr_taken == 0) return 0; - nr_reclaimed = shrink_folio_list(&folio_list, pgdat, sc, &stat, false); + nr_reclaimed = shrink_folio_list(&folio_list, pgdat, sc, &stat, false, + lruvec_memcg(lruvec)); spin_lock_irq(&lruvec->lru_lock); move_folios_to_lru(lruvec, &folio_list); + __mod_lruvec_state(lruvec, PGDEMOTE_KSWAPD + reclaimer_offset(sc), + stat.nr_demoted); __mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken); - item = PGSTEAL_KSWAPD + reclaimer_offset(); + item = PGSTEAL_KSWAPD + reclaimer_offset(sc); if (!cgroup_reclaim(sc)) __count_vm_events(item, nr_reclaimed); - __count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed); + count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed); __count_vm_events(PGSTEAL_ANON + file, nr_reclaimed); spin_unlock_irq(&lruvec->lru_lock); @@ -2022,7 +2141,7 @@ static void shrink_active_list(unsigned long nr_to_scan, if (!cgroup_reclaim(sc)) __count_vm_events(PGREFILL, nr_scanned); - __count_memcg_events(lruvec_memcg(lruvec), PGREFILL, nr_scanned); + count_memcg_events(lruvec_memcg(lruvec), PGREFILL, nr_scanned); spin_unlock_irq(&lruvec->lru_lock); @@ -2079,7 +2198,7 @@ static void shrink_active_list(unsigned long nr_to_scan, nr_deactivate = move_folios_to_lru(lruvec, &l_inactive); __count_vm_events(PGDEACTIVATE, nr_deactivate); - __count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_deactivate); + count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_deactivate); __mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken); spin_unlock_irq(&lruvec->lru_lock); @@ -2091,10 +2210,9 @@ static void shrink_active_list(unsigned long nr_to_scan, } static unsigned int reclaim_folio_list(struct list_head *folio_list, - struct pglist_data *pgdat, - bool ignore_references) + struct pglist_data *pgdat) { - struct reclaim_stat dummy_stat; + struct reclaim_stat stat; unsigned int nr_reclaimed; struct folio *folio; struct scan_control sc = { @@ -2105,17 +2223,18 @@ static unsigned int reclaim_folio_list(struct list_head *folio_list, .no_demotion = 1, }; - nr_reclaimed = shrink_folio_list(folio_list, pgdat, &sc, &dummy_stat, ignore_references); + nr_reclaimed = shrink_folio_list(folio_list, pgdat, &sc, &stat, true, NULL); while (!list_empty(folio_list)) { folio = lru_to_folio(folio_list); list_del(&folio->lru); folio_putback_lru(folio); } + trace_mm_vmscan_reclaim_pages(pgdat->node_id, sc.nr_scanned, nr_reclaimed, &stat); return nr_reclaimed; } -unsigned long reclaim_pages(struct list_head *folio_list, bool ignore_references) +unsigned long reclaim_pages(struct list_head *folio_list) { int nid; unsigned int nr_reclaimed = 0; @@ -2137,12 +2256,11 @@ unsigned long reclaim_pages(struct list_head *folio_list, bool ignore_references continue; } - nr_reclaimed += reclaim_folio_list(&node_folio_list, NODE_DATA(nid), - ignore_references); + nr_reclaimed += reclaim_folio_list(&node_folio_list, NODE_DATA(nid)); nid = folio_nid(lru_to_folio(folio_list)); } while (!list_empty(folio_list)); - nr_reclaimed += reclaim_folio_list(&node_folio_list, NODE_DATA(nid), ignore_references); + nr_reclaimed += reclaim_folio_list(&node_folio_list, NODE_DATA(nid)); memalloc_noreclaim_restore(noreclaim_flag); @@ -2228,10 +2346,11 @@ static void prepare_scan_control(pg_data_t *pgdat, struct scan_control *sc) target_lruvec = mem_cgroup_lruvec(sc->target_mem_cgroup, pgdat); /* - * Flush the memory cgroup stats, so that we read accurate per-memcg - * lruvec stats for heuristics. + * Flush the memory cgroup stats in rate-limited way as we don't need + * most accurate stats here. We may switch to regular stats flushing + * in the future once it is cheap enough. */ - mem_cgroup_flush_stats(sc->target_mem_cgroup); + mem_cgroup_flush_stats_ratelimited(sc->target_mem_cgroup); /* * Determine the scan balance between anon and file LRUs. @@ -2296,17 +2415,13 @@ static void prepare_scan_control(pg_data_t *pgdat, struct scan_control *sc) unsigned long total_high_wmark = 0; unsigned long free, anon; int z; + struct zone *zone; free = sum_zone_node_page_state(pgdat->node_id, NR_FREE_PAGES); file = node_page_state(pgdat, NR_ACTIVE_FILE) + node_page_state(pgdat, NR_INACTIVE_FILE); - for (z = 0; z < MAX_NR_ZONES; z++) { - struct zone *zone = &pgdat->node_zones[z]; - - if (!managed_zone(zone)) - continue; - + for_each_managed_zone_pgdat(zone, pgdat, z, MAX_NR_ZONES - 1) { total_high_wmark += high_wmark_pages(zone); } @@ -2324,6 +2439,43 @@ static void prepare_scan_control(pg_data_t *pgdat, struct scan_control *sc) } } +static inline void calculate_pressure_balance(struct scan_control *sc, + int swappiness, u64 *fraction, u64 *denominator) +{ + unsigned long anon_cost, file_cost, total_cost; + unsigned long ap, fp; + + /* + * Calculate the pressure balance between anon and file pages. + * + * The amount of pressure we put on each LRU is inversely + * proportional to the cost of reclaiming each list, as + * determined by the share of pages that are refaulting, times + * the relative IO cost of bringing back a swapped out + * anonymous page vs reloading a filesystem page (swappiness). + * + * Although we limit that influence to ensure no list gets + * left behind completely: at least a third of the pressure is + * applied, before swappiness. + * + * With swappiness at 100, anon and file have equal IO cost. + */ + total_cost = sc->anon_cost + sc->file_cost; + anon_cost = total_cost + sc->anon_cost; + file_cost = total_cost + sc->file_cost; + total_cost = anon_cost + file_cost; + + ap = swappiness * (total_cost + 1); + ap /= anon_cost + 1; + + fp = (MAX_SWAPPINESS - swappiness) * (total_cost + 1); + fp /= file_cost + 1; + + fraction[WORKINGSET_ANON] = ap; + fraction[WORKINGSET_FILE] = fp; + *denominator = ap + fp; +} + /* * Determine how aggressively the anon and file LRU lists should be * scanned. @@ -2336,12 +2488,10 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc, { struct pglist_data *pgdat = lruvec_pgdat(lruvec); struct mem_cgroup *memcg = lruvec_memcg(lruvec); - unsigned long anon_cost, file_cost, total_cost; - int swappiness = mem_cgroup_swappiness(memcg); + int swappiness = sc_swappiness(sc, memcg); u64 fraction[ANON_AND_FILE]; u64 denominator = 0; /* gcc */ enum scan_balance scan_balance; - unsigned long ap, fp; enum lru_list lru; /* If we have no swap space, do not bother scanning anon folios. */ @@ -2362,6 +2512,13 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc, goto out; } + /* Proactive reclaim initiated by userspace for anonymous memory only */ + if (swappiness == SWAPPINESS_ANON_ONLY) { + WARN_ON_ONCE(!sc->proactive); + scan_balance = SCAN_ANON; + goto out; + } + /* * Do not apply any pressure balancing cleverness when the * system is close to OOM, scan both anon and file equally @@ -2382,7 +2539,8 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc, /* * If there is enough inactive page cache, we do not reclaim - * anything from the anonymous working right now. + * anything from the anonymous working right now to make sure + * a streaming file access pattern doesn't cause swapping. */ if (sc->cache_trim_mode) { scan_balance = SCAN_FILE; @@ -2390,35 +2548,8 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc, } scan_balance = SCAN_FRACT; - /* - * Calculate the pressure balance between anon and file pages. - * - * The amount of pressure we put on each LRU is inversely - * proportional to the cost of reclaiming each list, as - * determined by the share of pages that are refaulting, times - * the relative IO cost of bringing back a swapped out - * anonymous page vs reloading a filesystem page (swappiness). - * - * Although we limit that influence to ensure no list gets - * left behind completely: at least a third of the pressure is - * applied, before swappiness. - * - * With swappiness at 100, anon and file have equal IO cost. - */ - total_cost = sc->anon_cost + sc->file_cost; - anon_cost = total_cost + sc->anon_cost; - file_cost = total_cost + sc->file_cost; - total_cost = anon_cost + file_cost; - - ap = swappiness * (total_cost + 1); - ap /= anon_cost + 1; + calculate_pressure_balance(sc, swappiness, fraction, &denominator); - fp = (200 - swappiness) * (total_cost + 1); - fp /= file_cost + 1; - - fraction[0] = ap; - fraction[1] = fp; - denominator = ap + fp; out: for_each_evictable_lru(lru) { bool file = is_file_lru(lru); @@ -2532,7 +2663,7 @@ out: * Anonymous LRU management is a waste if there is * ultimately no way to reclaim the memory. */ -static bool can_age_anon_pages(struct pglist_data *pgdat, +static bool can_age_anon_pages(struct lruvec *lruvec, struct scan_control *sc) { /* Aging the anon LRU is valuable if swap is present: */ @@ -2540,7 +2671,8 @@ static bool can_age_anon_pages(struct pglist_data *pgdat, return true; /* Also valuable if anon pages can be demoted: */ - return can_demote(pgdat->node_id, sc); + return can_demote(lruvec_pgdat(lruvec)->node_id, sc, + lruvec_memcg(lruvec)); } #ifdef CONFIG_LRU_GEN @@ -2567,8 +2699,6 @@ static bool should_clear_pmd_young(void) * 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) @@ -2578,11 +2708,21 @@ static bool should_clear_pmd_young(void) READ_ONCE((lruvec)->lrugen.min_seq[LRU_GEN_FILE]), \ } +/* Get the min/max evictable type based on swappiness */ +#define min_type(swappiness) (!(swappiness)) +#define max_type(swappiness) ((swappiness) < SWAPPINESS_ANON_ONLY) + +#define evictable_min_seq(min_seq, swappiness) \ + min((min_seq)[min_type(swappiness)], (min_seq)[max_type(swappiness)]) + #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)++) \ for ((zone) = 0; (zone) < MAX_NR_ZONES; (zone)++) +#define for_each_evictable_type(type, swappiness) \ + for ((type) = min_type(swappiness); (type) <= max_type(swappiness); (type)++) + #define get_memcg_gen(seq) ((seq) % MEMCG_NR_GENS) #define get_memcg_bin(bin) ((bin) % MEMCG_NR_BINS) @@ -2614,11 +2754,11 @@ static int get_swappiness(struct lruvec *lruvec, struct scan_control *sc) if (!sc->may_swap) return 0; - if (!can_demote(pgdat->node_id, sc) && + if (!can_demote(pgdat->node_id, sc, memcg) && mem_cgroup_get_nr_swap_pages(memcg) < MIN_LRU_BATCH) return 0; - return mem_cgroup_swappiness(memcg); + return sc_swappiness(sc, memcg); } static int get_nr_gens(struct lruvec *lruvec, int type) @@ -2628,10 +2768,16 @@ 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_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; + int type; + + for (type = 0; type < ANON_AND_FILE; type++) { + int n = get_nr_gens(lruvec, type); + + if (n < MIN_NR_GENS || n > MAX_NR_GENS) + return false; + } + + return true; } /****************************************************************************** @@ -3032,16 +3178,20 @@ struct ctrl_pos { static void read_ctrl_pos(struct lruvec *lruvec, int type, int tier, int gain, struct ctrl_pos *pos) { + int i; struct lru_gen_folio *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; + pos->refaulted = pos->total = 0; + + for (i = tier % MAX_NR_TIERS; i <= min(tier, MAX_NR_TIERS - 1); i++) { + pos->refaulted += lrugen->avg_refaulted[type][i] + + atomic_long_read(&lrugen->refaulted[hist][type][i]); + pos->total += lrugen->avg_total[type][i] + + lrugen->protected[hist][type][i] + + atomic_long_read(&lrugen->evicted[hist][type][i]); + } } static void reset_ctrl_pos(struct lruvec *lruvec, int type, bool carryover) @@ -3067,17 +3217,15 @@ static void reset_ctrl_pos(struct lruvec *lruvec, int type, bool carryover) WRITE_ONCE(lrugen->avg_refaulted[type][tier], sum / 2); sum = lrugen->avg_total[type][tier] + + lrugen->protected[hist][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); + WRITE_ONCE(lrugen->protected[hist][type][tier], 0); } } } @@ -3103,18 +3251,20 @@ static int folio_update_gen(struct folio *folio, int gen) unsigned long new_flags, old_flags = READ_ONCE(folio->flags); VM_WARN_ON_ONCE(gen >= MAX_NR_GENS); - VM_WARN_ON_ONCE(!rcu_read_lock_held()); + + /* see the comment on LRU_REFS_FLAGS */ + if (!folio_test_referenced(folio) && !folio_test_workingset(folio)) { + set_mask_bits(&folio->flags, LRU_REFS_MASK, BIT(PG_referenced)); + return -1; + } do { /* lru_gen_del_folio() has isolated this page? */ - if (!(old_flags & LRU_GEN_MASK)) { - /* for shrink_folio_list() */ - new_flags = old_flags | BIT(PG_referenced); - continue; - } + if (!(old_flags & LRU_GEN_MASK)) + return -1; - new_flags = old_flags & ~(LRU_GEN_MASK | LRU_REFS_MASK | LRU_REFS_FLAGS); - new_flags |= (gen + 1UL) << LRU_GEN_PGOFF; + new_flags = old_flags & ~(LRU_GEN_MASK | LRU_REFS_FLAGS); + new_flags |= ((gen + 1UL) << LRU_GEN_PGOFF) | BIT(PG_workingset); } while (!try_cmpxchg(&folio->flags, &old_flags, new_flags)); return ((old_flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1; @@ -3138,7 +3288,7 @@ static int folio_inc_gen(struct lruvec *lruvec, struct folio *folio, bool reclai new_gen = (old_gen + 1) % MAX_NR_GENS; - new_flags = old_flags & ~(LRU_GEN_MASK | LRU_REFS_MASK | LRU_REFS_FLAGS); + new_flags = old_flags & ~(LRU_GEN_MASK | LRU_REFS_FLAGS); new_flags |= (new_gen + 1UL) << LRU_GEN_PGOFF; /* for folio_end_writeback() */ if (reclaiming) @@ -3213,7 +3363,7 @@ static int should_skip_vma(unsigned long start, unsigned long end, struct mm_wal return true; if (vma_is_anonymous(vma)) - return !walk->can_swap; + return !walk->swappiness; if (WARN_ON_ONCE(!vma->vm_file || !vma->vm_file->f_mapping)) return true; @@ -3223,7 +3373,10 @@ static int should_skip_vma(unsigned long start, unsigned long end, struct mm_wal return true; if (shmem_mapping(mapping)) - return !walk->can_swap; + return !walk->swappiness; + + if (walk->swappiness > MAX_SWAPPINESS) + return true; /* to exclude special mappings like dax, etc. */ return !mapping->a_ops->read_folio; @@ -3260,7 +3413,8 @@ static bool get_next_vma(unsigned long mask, unsigned long size, struct mm_walk return false; } -static unsigned long get_pte_pfn(pte_t pte, struct vm_area_struct *vma, unsigned long addr) +static unsigned long get_pte_pfn(pte_t pte, struct vm_area_struct *vma, unsigned long addr, + struct pglist_data *pgdat) { unsigned long pfn = pte_pfn(pte); @@ -3272,13 +3426,20 @@ static unsigned long get_pte_pfn(pte_t pte, struct vm_area_struct *vma, unsigned if (WARN_ON_ONCE(pte_devmap(pte) || pte_special(pte))) return -1; + if (!pte_young(pte) && !mm_has_notifiers(vma->vm_mm)) + return -1; + if (WARN_ON_ONCE(!pfn_valid(pfn))) return -1; + if (pfn < pgdat->node_start_pfn || pfn >= pgdat_end_pfn(pgdat)) + return -1; + return pfn; } -static unsigned long get_pmd_pfn(pmd_t pmd, struct vm_area_struct *vma, unsigned long addr) +static unsigned long get_pmd_pfn(pmd_t pmd, struct vm_area_struct *vma, unsigned long addr, + struct pglist_data *pgdat) { unsigned long pfn = pmd_pfn(pmd); @@ -3290,30 +3451,30 @@ static unsigned long get_pmd_pfn(pmd_t pmd, struct vm_area_struct *vma, unsigned if (WARN_ON_ONCE(pmd_devmap(pmd))) return -1; + if (!pmd_young(pmd) && !mm_has_notifiers(vma->vm_mm)) + return -1; + if (WARN_ON_ONCE(!pfn_valid(pfn))) return -1; + if (pfn < pgdat->node_start_pfn || pfn >= pgdat_end_pfn(pgdat)) + return -1; + return pfn; } static struct folio *get_pfn_folio(unsigned long pfn, struct mem_cgroup *memcg, - struct pglist_data *pgdat, bool can_swap) + struct pglist_data *pgdat) { - struct folio *folio; + struct folio *folio = pfn_folio(pfn); - /* try to avoid unnecessary memory loads */ - if (pfn < pgdat->node_start_pfn || pfn >= pgdat_end_pfn(pgdat)) + if (folio_lru_gen(folio) < 0) return NULL; - folio = pfn_folio(pfn); if (folio_nid(folio) != pgdat->node_id) return NULL; - if (folio_memcg_rcu(folio) != memcg) - return NULL; - - /* file VMAs can contain anon pages from COW */ - if (!folio_is_file_lru(folio) && !can_swap) + if (folio_memcg(folio) != memcg) return NULL; return folio; @@ -3327,26 +3488,59 @@ static bool suitable_to_scan(int total, int young) return young * n >= total; } +static void walk_update_folio(struct lru_gen_mm_walk *walk, struct folio *folio, + int new_gen, bool dirty) +{ + int old_gen; + + if (!folio) + return; + + if (dirty && !folio_test_dirty(folio) && + !(folio_test_anon(folio) && folio_test_swapbacked(folio) && + !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); + } else if (lru_gen_set_refs(folio)) { + old_gen = folio_lru_gen(folio); + if (old_gen >= 0 && old_gen != new_gen) + folio_activate(folio); + } +} + static bool walk_pte_range(pmd_t *pmd, unsigned long start, unsigned long end, struct mm_walk *args) { int i; + bool dirty; pte_t *pte; spinlock_t *ptl; unsigned long addr; int total = 0; int young = 0; + struct folio *last = NULL; struct lru_gen_mm_walk *walk = args->private; struct mem_cgroup *memcg = lruvec_memcg(walk->lruvec); struct pglist_data *pgdat = lruvec_pgdat(walk->lruvec); DEFINE_MAX_SEQ(walk->lruvec); - int old_gen, new_gen = lru_gen_from_seq(max_seq); + int gen = lru_gen_from_seq(max_seq); + pmd_t pmdval; - pte = pte_offset_map_nolock(args->mm, pmd, start & PMD_MASK, &ptl); + pte = pte_offset_map_rw_nolock(args->mm, pmd, start & PMD_MASK, &pmdval, &ptl); if (!pte) return false; + if (!spin_trylock(ptl)) { pte_unmap(pte); + return true; + } + + if (unlikely(!pmd_same(pmdval, pmdp_get_lockless(pmd)))) { + pte_unmap_unlock(pte, ptl); return false; } @@ -3360,35 +3554,34 @@ restart: total++; walk->mm_stats[MM_LEAF_TOTAL]++; - pfn = get_pte_pfn(ptent, args->vma, addr); + pfn = get_pte_pfn(ptent, args->vma, addr, pgdat); if (pfn == -1) continue; - if (!pte_young(ptent)) { - walk->mm_stats[MM_LEAF_OLD]++; + folio = get_pfn_folio(pfn, memcg, pgdat); + if (!folio) continue; - } - folio = get_pfn_folio(pfn, memcg, pgdat, walk->can_swap); - if (!folio) + if (!ptep_clear_young_notify(args->vma, addr, pte + i)) continue; - if (!ptep_test_and_clear_young(args->vma, addr, pte + i)) - VM_WARN_ON_ONCE(true); + if (last != folio) { + walk_update_folio(walk, last, gen, dirty); - young++; - walk->mm_stats[MM_LEAF_YOUNG]++; + last = folio; + dirty = false; + } - if (pte_dirty(ptent) && !folio_test_dirty(folio) && - !(folio_test_anon(folio) && folio_test_swapbacked(folio) && - !folio_test_swapcache(folio))) - folio_mark_dirty(folio); + if (pte_dirty(ptent)) + dirty = true; - 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); + young++; + walk->mm_stats[MM_LEAF_YOUNG]++; } + walk_update_folio(walk, last, gen, dirty); + last = NULL; + if (i < PTRS_PER_PTE && get_next_vma(PMD_MASK, PAGE_SIZE, args, &start, &end)) goto restart; @@ -3402,13 +3595,15 @@ static void walk_pmd_range_locked(pud_t *pud, unsigned long addr, struct vm_area struct mm_walk *args, unsigned long *bitmap, unsigned long *first) { int i; + bool dirty; pmd_t *pmd; spinlock_t *ptl; + struct folio *last = NULL; struct lru_gen_mm_walk *walk = args->private; struct mem_cgroup *memcg = lruvec_memcg(walk->lruvec); struct pglist_data *pgdat = lruvec_pgdat(walk->lruvec); DEFINE_MAX_SEQ(walk->lruvec); - int old_gen, new_gen = lru_gen_from_seq(max_seq); + int gen = lru_gen_from_seq(max_seq); VM_WARN_ON_ONCE(pud_leaf(*pud)); @@ -3440,37 +3635,44 @@ static void walk_pmd_range_locked(pud_t *pud, unsigned long addr, struct vm_area /* 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) + if (!pmd_present(pmd[i])) goto next; if (!pmd_trans_huge(pmd[i])) { - if (should_clear_pmd_young()) + if (!walk->force_scan && should_clear_pmd_young() && + !mm_has_notifiers(args->mm)) pmdp_test_and_clear_young(vma, addr, pmd + i); goto next; } - folio = get_pfn_folio(pfn, memcg, pgdat, walk->can_swap); + pfn = get_pmd_pfn(pmd[i], vma, addr, pgdat); + if (pfn == -1) + goto next; + + folio = get_pfn_folio(pfn, memcg, pgdat); if (!folio) goto next; - if (!pmdp_test_and_clear_young(vma, addr, pmd + i)) + if (!pmdp_clear_young_notify(vma, addr, pmd + i)) goto next; - walk->mm_stats[MM_LEAF_YOUNG]++; + if (last != folio) { + walk_update_folio(walk, last, gen, dirty); - if (pmd_dirty(pmd[i]) && !folio_test_dirty(folio) && - !(folio_test_anon(folio) && folio_test_swapbacked(folio) && - !folio_test_swapcache(folio))) - folio_mark_dirty(folio); + last = folio; + dirty = false; + } - 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); + if (pmd_dirty(pmd[i])) + dirty = true; + + walk->mm_stats[MM_LEAF_YOUNG]++; next: i = i > MIN_LRU_BATCH ? 0 : find_next_bit(bitmap, MIN_LRU_BATCH, i) + 1; } while (i <= MIN_LRU_BATCH); + walk_update_folio(walk, last, gen, dirty); + arch_leave_lazy_mmu_mode(); spin_unlock(ptl); done: @@ -3512,27 +3714,18 @@ restart: } if (pmd_trans_huge(val)) { - unsigned long pfn = pmd_pfn(val); struct pglist_data *pgdat = lruvec_pgdat(walk->lruvec); + unsigned long pfn = get_pmd_pfn(val, vma, addr, pgdat); walk->mm_stats[MM_LEAF_TOTAL]++; - if (!pmd_young(val)) { - walk->mm_stats[MM_LEAF_OLD]++; - continue; - } - - /* try to avoid unnecessary memory loads */ - if (pfn < pgdat->node_start_pfn || pfn >= pgdat_end_pfn(pgdat)) - continue; - - walk_pmd_range_locked(pud, addr, vma, args, bitmap, &first); + if (pfn != -1) + walk_pmd_range_locked(pud, addr, vma, args, bitmap, &first); continue; } - walk->mm_stats[MM_NONLEAF_TOTAL]++; - - if (should_clear_pmd_young()) { + if (!walk->force_scan && should_clear_pmd_young() && + !mm_has_notifiers(args->mm)) { if (!pmd_young(val)) continue; @@ -3608,10 +3801,8 @@ static void walk_mm(struct mm_struct *mm, struct lru_gen_mm_walk *walk) .p4d_entry = walk_pud_range, .walk_lock = PGWALK_RDLOCK, }; - int err; struct lruvec *lruvec = walk->lruvec; - struct mem_cgroup *memcg = lruvec_memcg(lruvec); walk->next_addr = FIRST_USER_ADDRESS; @@ -3624,10 +3815,6 @@ static void walk_mm(struct mm_struct *mm, struct lru_gen_mm_walk *walk) if (walk->seq != max_seq) break; - /* folio_update_gen() requires stable folio_memcg() */ - if (!mem_cgroup_trylock_pages(memcg)) - break; - /* the caller might be holding the lock for write */ if (mmap_read_trylock(mm)) { err = walk_page_range(mm, walk->next_addr, ULONG_MAX, &mm_walk_ops, walk); @@ -3635,8 +3822,6 @@ static void walk_mm(struct mm_struct *mm, struct lru_gen_mm_walk *walk) mmap_read_unlock(mm); } - mem_cgroup_unlock_pages(); - if (walk->batched) { spin_lock_irq(&lruvec->lru_lock); reset_batch_size(walk); @@ -3679,22 +3864,30 @@ static void clear_mm_walk(void) kfree(walk); } -static bool inc_min_seq(struct lruvec *lruvec, int type, bool can_swap) +static bool inc_min_seq(struct lruvec *lruvec, int type, int swappiness) { int zone; int remaining = MAX_LRU_BATCH; struct lru_gen_folio *lrugen = &lruvec->lrugen; + int hist = lru_hist_from_seq(lrugen->min_seq[type]); int new_gen, old_gen = lru_gen_from_seq(lrugen->min_seq[type]); - if (type == LRU_GEN_ANON && !can_swap) + /* For file type, skip the check if swappiness is anon only */ + if (type && (swappiness == SWAPPINESS_ANON_ONLY)) + goto done; + + /* For anon type, skip the check if swappiness is zero (file only) */ + if (!type && !swappiness) goto done; - /* prevent cold/hot inversion if force_scan is true */ + /* prevent cold/hot inversion if the type is evictable */ for (zone = 0; zone < MAX_NR_ZONES; zone++) { struct list_head *head = &lrugen->folios[old_gen][type][zone]; while (!list_empty(head)) { struct folio *folio = lru_to_folio(head); + int refs = folio_lru_refs(folio); + bool workingset = folio_test_workingset(folio); VM_WARN_ON_ONCE_FOLIO(folio_test_unevictable(folio), folio); VM_WARN_ON_ONCE_FOLIO(folio_test_active(folio), folio); @@ -3704,6 +3897,15 @@ static bool inc_min_seq(struct lruvec *lruvec, int type, bool can_swap) new_gen = folio_inc_gen(lruvec, folio, false); list_move_tail(&folio->lru, &lrugen->folios[new_gen][type][zone]); + /* don't count the workingset being lazily promoted */ + if (refs + workingset != BIT(LRU_REFS_WIDTH) + 1) { + int tier = lru_tier_from_refs(refs, workingset); + int delta = folio_nr_pages(folio); + + WRITE_ONCE(lrugen->protected[hist][type][tier], + lrugen->protected[hist][type][tier] + delta); + } + if (!--remaining) return false; } @@ -3715,7 +3917,7 @@ done: return true; } -static bool try_to_inc_min_seq(struct lruvec *lruvec, bool can_swap) +static bool try_to_inc_min_seq(struct lruvec *lruvec, int swappiness) { int gen, type, zone; bool success = false; @@ -3725,7 +3927,7 @@ static bool try_to_inc_min_seq(struct lruvec *lruvec, bool can_swap) VM_WARN_ON_ONCE(!seq_is_valid(lruvec)); /* find the oldest populated generation */ - for (type = !can_swap; type < ANON_AND_FILE; type++) { + for_each_evictable_type(type, swappiness) { while (min_seq[type] + MIN_NR_GENS <= lrugen->max_seq) { gen = lru_gen_from_seq(min_seq[type]); @@ -3741,13 +3943,17 @@ next: } /* 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]); + if (swappiness && swappiness <= MAX_SWAPPINESS) { + unsigned long seq = lrugen->max_seq - MIN_NR_GENS; + + if (min_seq[LRU_GEN_ANON] > seq && min_seq[LRU_GEN_FILE] < seq) + min_seq[LRU_GEN_ANON] = seq; + else if (min_seq[LRU_GEN_FILE] > seq && min_seq[LRU_GEN_ANON] < seq) + min_seq[LRU_GEN_FILE] = seq; } - for (type = !can_swap; type < ANON_AND_FILE; type++) { - if (min_seq[type] == lrugen->min_seq[type]) + for_each_evictable_type(type, swappiness) { + if (min_seq[type] <= lrugen->min_seq[type]) continue; reset_ctrl_pos(lruvec, type, true); @@ -3758,8 +3964,7 @@ next: return success; } -static bool inc_max_seq(struct lruvec *lruvec, unsigned long seq, - bool can_swap, bool force_scan) +static bool inc_max_seq(struct lruvec *lruvec, unsigned long seq, int swappiness) { bool success; int prev, next; @@ -3777,13 +3982,11 @@ restart: if (!success) goto unlock; - for (type = ANON_AND_FILE - 1; type >= 0; type--) { + for (type = 0; type < ANON_AND_FILE; type++) { if (get_nr_gens(lruvec, type) != MAX_NR_GENS) continue; - VM_WARN_ON_ONCE(!force_scan && (type == LRU_GEN_FILE || can_swap)); - - if (inc_min_seq(lruvec, type, can_swap)) + if (inc_min_seq(lruvec, type, swappiness)) continue; spin_unlock_irq(&lruvec->lru_lock); @@ -3827,7 +4030,7 @@ unlock: } static bool try_to_inc_max_seq(struct lruvec *lruvec, unsigned long seq, - bool can_swap, bool force_scan) + int swappiness, bool force_scan) { bool success; struct lru_gen_mm_walk *walk; @@ -3838,7 +4041,7 @@ static bool try_to_inc_max_seq(struct lruvec *lruvec, unsigned long seq, VM_WARN_ON_ONCE(seq > READ_ONCE(lrugen->max_seq)); if (!mm_state) - return inc_max_seq(lruvec, seq, can_swap, force_scan); + return inc_max_seq(lruvec, seq, swappiness); /* see the comment in iterate_mm_list() */ if (seq <= READ_ONCE(mm_state->seq)) @@ -3863,7 +4066,7 @@ static bool try_to_inc_max_seq(struct lruvec *lruvec, unsigned long seq, walk->lruvec = lruvec; walk->seq = seq; - walk->can_swap = can_swap; + walk->swappiness = swappiness; walk->force_scan = force_scan; do { @@ -3873,7 +4076,7 @@ static bool try_to_inc_max_seq(struct lruvec *lruvec, unsigned long seq, } while (mm); done: if (success) { - success = inc_max_seq(lruvec, seq, can_swap, force_scan); + success = inc_max_seq(lruvec, seq, swappiness); WARN_ON_ONCE(!success); } @@ -3884,17 +4087,43 @@ done: * working set protection ******************************************************************************/ +static void set_initial_priority(struct pglist_data *pgdat, struct scan_control *sc) +{ + int priority; + unsigned long reclaimable; + + if (sc->priority != DEF_PRIORITY || sc->nr_to_reclaim < MIN_LRU_BATCH) + return; + /* + * Determine the initial priority based on + * (total >> priority) * reclaimed_to_scanned_ratio = nr_to_reclaim, + * where reclaimed_to_scanned_ratio = inactive / total. + */ + reclaimable = node_page_state(pgdat, NR_INACTIVE_FILE); + if (can_reclaim_anon_pages(NULL, pgdat->node_id, sc)) + reclaimable += node_page_state(pgdat, NR_INACTIVE_ANON); + + /* round down reclaimable and round up sc->nr_to_reclaim */ + priority = fls_long(reclaimable) - 1 - fls_long(sc->nr_to_reclaim - 1); + + /* + * The estimation is based on LRU pages only, so cap it to prevent + * overshoots of shrinker objects by large margins. + */ + sc->priority = clamp(priority, DEF_PRIORITY / 2, DEF_PRIORITY); +} + static bool lruvec_is_sizable(struct lruvec *lruvec, struct scan_control *sc) { int gen, type, zone; unsigned long total = 0; - bool can_swap = get_swappiness(lruvec, sc); + int swappiness = 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++) { + for_each_evictable_type(type, swappiness) { unsigned long seq; for (seq = min_seq[type]; seq <= max_seq; seq++) { @@ -3914,22 +4143,20 @@ static bool lruvec_is_reclaimable(struct lruvec *lruvec, struct scan_control *sc { int gen; unsigned long birth; + int swappiness = get_swappiness(lruvec, sc); struct mem_cgroup *memcg = lruvec_memcg(lruvec); DEFINE_MIN_SEQ(lruvec); - /* 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 (time_is_after_jiffies(birth + min_ttl)) + if (mem_cgroup_below_min(NULL, memcg)) return false; if (!lruvec_is_sizable(lruvec, sc)) return false; - mem_cgroup_calculate_protection(NULL, memcg); + gen = lru_gen_from_seq(evictable_min_seq(min_seq, swappiness)); + birth = READ_ONCE(lruvec->lrugen.timestamps[gen]); - return !mem_cgroup_below_min(NULL, memcg); + return time_is_before_jiffies(birth + min_ttl); } /* to protect the working set of the last N jiffies */ @@ -3939,23 +4166,20 @@ static void lru_gen_age_node(struct pglist_data *pgdat, struct scan_control *sc) { struct mem_cgroup *memcg; unsigned long min_ttl = READ_ONCE(lru_gen_min_ttl); + bool reclaimable = !min_ttl; VM_WARN_ON_ONCE(!current_is_kswapd()); - /* check the order to exclude compaction-induced reclaim */ - if (!min_ttl || sc->order || sc->priority == DEF_PRIORITY) - return; + set_initial_priority(pgdat, sc); memcg = mem_cgroup_iter(NULL, NULL, NULL); do { struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat); - if (lruvec_is_reclaimable(lruvec, sc, min_ttl)) { - mem_cgroup_iter_break(NULL, memcg); - return; - } + mem_cgroup_calculate_protection(NULL, memcg); - cond_resched(); + if (!reclaimable) + reclaimable = lruvec_is_reclaimable(lruvec, sc, min_ttl); } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL))); /* @@ -3963,7 +4187,7 @@ static void lru_gen_age_node(struct pglist_data *pgdat, struct scan_control *sc) * younger than min_ttl. However, another possibility is all memcgs are * either too small or below min. */ - if (mutex_trylock(&oom_lock)) { + if (!reclaimable && mutex_trylock(&oom_lock)) { struct oom_control oc = { .gfp_mask = sc->gfp_mask, }; @@ -3985,34 +4209,38 @@ static void lru_gen_age_node(struct pglist_data *pgdat, struct scan_control *sc) * the PTE table to the Bloom filter. This forms a feedback loop between the * eviction and the aging. */ -void lru_gen_look_around(struct page_vma_mapped_walk *pvmw) +bool lru_gen_look_around(struct page_vma_mapped_walk *pvmw) { int i; + bool dirty; unsigned long start; unsigned long end; struct lru_gen_mm_walk *walk; - int young = 0; + struct folio *last = NULL; + int young = 1; pte_t *pte = pvmw->pte; unsigned long addr = pvmw->address; struct vm_area_struct *vma = pvmw->vma; struct folio *folio = pfn_folio(pvmw->pfn); - bool can_swap = !folio_is_file_lru(folio); struct mem_cgroup *memcg = folio_memcg(folio); struct pglist_data *pgdat = folio_pgdat(folio); struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat); struct lru_gen_mm_state *mm_state = get_mm_state(lruvec); DEFINE_MAX_SEQ(lruvec); - int old_gen, new_gen = lru_gen_from_seq(max_seq); + int gen = lru_gen_from_seq(max_seq); lockdep_assert_held(pvmw->ptl); VM_WARN_ON_ONCE_FOLIO(folio_test_lru(folio), folio); + if (!ptep_clear_young_notify(vma, addr, pte)) + return false; + if (spin_is_contended(pvmw->ptl)) - return; + return true; /* exclude special VMAs containing anon pages from COW */ if (vma->vm_flags & VM_SPECIAL) - return; + return true; /* avoid taking the LRU lock under the PTL when possible */ walk = current->reclaim_state ? current->reclaim_state->mm_walk : NULL; @@ -4020,6 +4248,9 @@ void lru_gen_look_around(struct page_vma_mapped_walk *pvmw) start = max(addr & PMD_MASK, vma->vm_start); end = min(addr | ~PMD_MASK, vma->vm_end - 1) + 1; + if (end - start == PAGE_SIZE) + return true; + if (end - start > MIN_LRU_BATCH * PAGE_SIZE) { if (addr - start < MIN_LRU_BATCH * PAGE_SIZE / 2) end = start + MIN_LRU_BATCH * PAGE_SIZE; @@ -4031,10 +4262,6 @@ void lru_gen_look_around(struct page_vma_mapped_walk *pvmw) } } - /* folio_update_gen() requires stable folio_memcg() */ - if (!mem_cgroup_trylock_pages(memcg)) - return; - arch_enter_lazy_mmu_mode(); pte -= (addr - start) / PAGE_SIZE; @@ -4043,48 +4270,39 @@ void lru_gen_look_around(struct page_vma_mapped_walk *pvmw) unsigned long pfn; pte_t ptent = ptep_get(pte + i); - pfn = get_pte_pfn(ptent, vma, addr); + pfn = get_pte_pfn(ptent, vma, addr, pgdat); if (pfn == -1) continue; - if (!pte_young(ptent)) - continue; - - folio = get_pfn_folio(pfn, memcg, pgdat, can_swap); + folio = get_pfn_folio(pfn, memcg, pgdat); if (!folio) continue; - if (!ptep_test_and_clear_young(vma, addr, pte + i)) - VM_WARN_ON_ONCE(true); - - young++; - - if (pte_dirty(ptent) && !folio_test_dirty(folio) && - !(folio_test_anon(folio) && folio_test_swapbacked(folio) && - !folio_test_swapcache(folio))) - folio_mark_dirty(folio); + if (!ptep_clear_young_notify(vma, addr, pte + i)) + continue; - 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); + if (last != folio) { + walk_update_folio(walk, last, gen, dirty); - continue; + last = folio; + dirty = false; } - old_gen = folio_lru_gen(folio); - if (old_gen < 0) - folio_set_referenced(folio); - else if (old_gen != new_gen) - folio_activate(folio); + if (pte_dirty(ptent)) + dirty = true; + + young++; } + walk_update_folio(walk, last, gen, dirty); + arch_leave_lazy_mmu_mode(); - mem_cgroup_unlock_pages(); /* feedback from rmap walkers to page table walkers */ if (mm_state && suitable_to_scan(i, young)) update_bloom_filter(mm_state, max_seq, pvmw->pmd); + + return true; } /****************************************************************************** @@ -4229,12 +4447,14 @@ static bool sort_folio(struct lruvec *lruvec, struct folio *folio, struct scan_c int tier_idx) { bool success; + bool dirty, writeback; 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); + bool workingset = folio_test_workingset(folio); + int tier = lru_tier_from_refs(refs, workingset); struct lru_gen_folio *lrugen = &lruvec->lrugen; VM_WARN_ON_ONCE_FOLIO(gen >= MAX_NR_GENS, folio); @@ -4249,15 +4469,6 @@ static bool sort_folio(struct lruvec *lruvec, struct folio *folio, struct scan_c 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; - } - /* promoted */ if (gen != lru_gen_from_seq(lrugen->min_seq[type])) { list_move(&folio->lru, &lrugen->folios[gen][type][zone]); @@ -4265,27 +4476,37 @@ static bool sort_folio(struct lruvec *lruvec, struct folio *folio, struct scan_c } /* protected */ - if (tier > tier_idx || refs == BIT(LRU_REFS_WIDTH)) { - int hist = lru_hist_from_seq(lrugen->min_seq[type]); - + if (tier > tier_idx || refs + workingset == BIT(LRU_REFS_WIDTH) + 1) { gen = folio_inc_gen(lruvec, folio, false); - list_move_tail(&folio->lru, &lrugen->folios[gen][type][zone]); + list_move(&folio->lru, &lrugen->folios[gen][type][zone]); + + /* don't count the workingset being lazily promoted */ + if (refs + workingset != BIT(LRU_REFS_WIDTH) + 1) { + int hist = lru_hist_from_seq(lrugen->min_seq[type]); - WRITE_ONCE(lrugen->protected[hist][type][tier - 1], - lrugen->protected[hist][type][tier - 1] + delta); + WRITE_ONCE(lrugen->protected[hist][type][tier], + lrugen->protected[hist][type][tier] + delta); + } return true; } /* ineligible */ - if (zone > sc->reclaim_idx || skip_cma(folio, sc)) { + if (!folio_test_lru(folio) || zone > sc->reclaim_idx) { gen = folio_inc_gen(lruvec, folio, false); list_move_tail(&folio->lru, &lrugen->folios[gen][type][zone]); return true; } + dirty = folio_test_dirty(folio); + writeback = folio_test_writeback(folio); + if (type == LRU_GEN_FILE && dirty) { + sc->nr.file_taken += delta; + if (!writeback) + sc->nr.unqueued_dirty += delta; + } + /* waiting for writeback */ - if (folio_test_locked(folio) || folio_test_writeback(folio) || - (type == LRU_GEN_FILE && folio_test_dirty(folio))) { + if (writeback || (type == LRU_GEN_FILE && dirty)) { gen = folio_inc_gen(lruvec, folio, true); list_move(&folio->lru, &lrugen->folios[gen][type][zone]); return true; @@ -4314,13 +4535,12 @@ static bool isolate_folio(struct lruvec *lruvec, struct folio *folio, struct sca return false; } - /* see the comment on MAX_NR_TIERS */ + /* see the comment on LRU_REFS_FLAGS */ if (!folio_test_referenced(folio)) - set_mask_bits(&folio->flags, LRU_REFS_MASK | LRU_REFS_FLAGS, 0); + set_mask_bits(&folio->flags, LRU_REFS_MASK, 0); /* for shrink_folio_list() */ folio_clear_reclaim(folio); - folio_clear_referenced(folio); success = lru_gen_del_folio(lruvec, folio, true); VM_WARN_ON_ONCE_FOLIO(!success, folio); @@ -4390,18 +4610,19 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc, break; } - item = PGSCAN_KSWAPD + reclaimer_offset(); + item = PGSCAN_KSWAPD + reclaimer_offset(sc); 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_memcg_events(memcg, item, isolated); + count_memcg_events(memcg, PGREFILL, sorted); __count_vm_events(PGSCAN_ANON + type, isolated); trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, MAX_LRU_BATCH, scanned, skipped, isolated, type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON); - + if (type == LRU_GEN_FILE) + sc->nr.file_taken += isolated; /* * There might not be eligible folios due to reclaim_idx. Check the * remaining to prevent livelock if it's not making progress. @@ -4415,13 +4636,13 @@ static int get_tier_idx(struct lruvec *lruvec, int type) struct ctrl_pos sp, pv; /* - * To leave a margin for fluctuations, use a larger gain factor (1:2). + * To leave a margin for fluctuations, use a larger gain factor (2:3). * 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); + read_ctrl_pos(lruvec, type, 0, 2, &sp); for (tier = 1; tier < MAX_NR_TIERS; tier++) { - read_ctrl_pos(lruvec, type, tier, 2, &pv); + read_ctrl_pos(lruvec, type, tier, 3, &pv); if (!positive_ctrl_err(&sp, &pv)) break; } @@ -4429,79 +4650,45 @@ static int get_tier_idx(struct lruvec *lruvec, int type) return tier - 1; } -static int get_type_to_scan(struct lruvec *lruvec, int swappiness, int *tier_idx) +static int get_type_to_scan(struct lruvec *lruvec, int swappiness) { - int type, tier; struct ctrl_pos sp, pv; - int gain[ANON_AND_FILE] = { swappiness, 200 - swappiness }; + if (swappiness <= MIN_SWAPPINESS + 1) + return LRU_GEN_FILE; + + if (swappiness >= MAX_SWAPPINESS) + return LRU_GEN_ANON; /* - * 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. + * Compare the sum of all tiers of anon with that of file to determine + * which type to scan. */ - 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, LRU_GEN_ANON, MAX_NR_TIERS, swappiness, &sp); + read_ctrl_pos(lruvec, LRU_GEN_FILE, MAX_NR_TIERS, MAX_SWAPPINESS - swappiness, &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; + return positive_ctrl_err(&sp, &pv); } 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); + int type = get_type_to_scan(lruvec, swappiness); - /* - * Try to make the obvious choice first, and if anon and file are both - * available from the same generation, - * 1. Interpret swappiness 1 as file first and MAX_SWAPPINESS as anon - * first. - * 2. If !__GFP_IO, file first since clean pagecache is more likely to - * exist than clean swapcache. - */ - 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 if (!(sc->gfp_mask & __GFP_IO)) - type = LRU_GEN_FILE; - else - type = get_type_to_scan(lruvec, swappiness, &tier); + for_each_evictable_type(i, swappiness) { + int scanned; + int tier = get_tier_idx(lruvec, type); - for (i = !swappiness; i < ANON_AND_FILE; i++) { - if (tier < 0) - tier = get_tier_idx(lruvec, type); + *type_scanned = type; scanned = scan_folios(lruvec, sc, type, tier, list); if (scanned) - break; + return scanned; type = !type; - tier = -1; } - *type_scanned = type; - - return scanned; + return 0; } static int evict_folios(struct lruvec *lruvec, struct scan_control *sc, int swappiness) @@ -4517,6 +4704,7 @@ static int evict_folios(struct lruvec *lruvec, struct scan_control *sc, int swap struct reclaim_stat stat; struct lru_gen_mm_walk *walk; bool skip_retry = false; + struct lru_gen_folio *lrugen = &lruvec->lrugen; struct mem_cgroup *memcg = lruvec_memcg(lruvec); struct pglist_data *pgdat = lruvec_pgdat(lruvec); @@ -4526,7 +4714,7 @@ static int evict_folios(struct lruvec *lruvec, struct scan_control *sc, int swap scanned += try_to_inc_min_seq(lruvec, swappiness); - if (get_nr_gens(lruvec, !swappiness) == MIN_NR_GENS) + if (evictable_min_seq(lrugen->min_seq, swappiness) + MIN_NR_GENS > lrugen->max_seq) scanned = 0; spin_unlock_irq(&lruvec->lru_lock); @@ -4534,39 +4722,32 @@ static int evict_folios(struct lruvec *lruvec, struct scan_control *sc, int swap if (list_empty(&list)) return scanned; retry: - reclaimed = shrink_folio_list(&list, pgdat, sc, &stat, false); + reclaimed = shrink_folio_list(&list, pgdat, sc, &stat, false, memcg); + sc->nr.unqueued_dirty += stat.nr_unqueued_dirty; sc->nr_reclaimed += reclaimed; trace_mm_vmscan_lru_shrink_inactive(pgdat->node_id, scanned, reclaimed, &stat, sc->priority, type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON); list_for_each_entry_safe_reverse(folio, next, &list, lru) { + DEFINE_MIN_SEQ(lruvec); + if (!folio_evictable(folio)) { list_del(&folio->lru); folio_putback_lru(folio); continue; } - if (folio_test_reclaim(folio) && - (folio_test_dirty(folio) || folio_test_writeback(folio))) { - /* restore LRU_REFS_FLAGS cleared by isolate_folio() */ - if (folio_test_workingset(folio)) - folio_set_referenced(folio); - continue; - } - - if (skip_retry || folio_test_active(folio) || folio_test_referenced(folio) || - folio_mapped(folio) || folio_test_locked(folio) || - folio_test_dirty(folio) || folio_test_writeback(folio)) { - /* don't add rejected folios to the oldest generation */ - set_mask_bits(&folio->flags, LRU_REFS_MASK | LRU_REFS_FLAGS, - BIT(PG_active)); + /* retry folios that may have missed folio_rotate_reclaimable() */ + if (!skip_retry && !folio_test_active(folio) && !folio_mapped(folio) && + !folio_test_dirty(folio) && !folio_test_writeback(folio)) { + list_move(&folio->lru, &clean); continue; } - /* retry folios that may have missed folio_rotate_reclaimable() */ - list_move(&folio->lru, &clean); - sc->nr_scanned -= folio_nr_pages(folio); + /* don't add rejected folios to the oldest generation */ + if (lru_gen_folio_seq(lruvec, folio, false) == min_seq[type]) + set_mask_bits(&folio->flags, LRU_REFS_FLAGS, BIT(PG_active)); } spin_lock_irq(&lruvec->lru_lock); @@ -4579,10 +4760,13 @@ retry: reset_batch_size(walk); } - item = PGSTEAL_KSWAPD + reclaimer_offset(); + __mod_lruvec_state(lruvec, PGDEMOTE_KSWAPD + reclaimer_offset(sc), + stat.nr_demoted); + + item = PGSTEAL_KSWAPD + reclaimer_offset(sc); if (!cgroup_reclaim(sc)) __count_vm_events(item, reclaimed); - __count_memcg_events(memcg, item, reclaimed); + count_memcg_events(memcg, item, reclaimed); __count_vm_events(PGSTEAL_ANON + type, reclaimed); spin_unlock_irq(&lruvec->lru_lock); @@ -4598,63 +4782,32 @@ retry: } static bool should_run_aging(struct lruvec *lruvec, unsigned long max_seq, - bool can_swap, unsigned long *nr_to_scan) + int swappiness, unsigned long *nr_to_scan) { int gen, type, zone; - unsigned long old = 0; - unsigned long young = 0; - unsigned long total = 0; + unsigned long size = 0; struct lru_gen_folio *lrugen = &lruvec->lrugen; 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; + *nr_to_scan = 0; + /* have to run aging, since eviction is not possible anymore */ + if (evictable_min_seq(min_seq, swappiness) + MIN_NR_GENS > max_seq) return true; - } - for (type = !can_swap; type < ANON_AND_FILE; type++) { + for_each_evictable_type(type, swappiness) { 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; } } - *nr_to_scan = 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; + *nr_to_scan = size; + /* better to run aging even though eviction is still possible */ + return evictable_min_seq(min_seq, swappiness) + MIN_NR_GENS == max_seq; } /* @@ -4662,7 +4815,7 @@ static bool should_run_aging(struct lruvec *lruvec, unsigned long max_seq, * 1. Defer try_to_inc_max_seq() to workqueues to reduce latency for memcg * reclaim. */ -static long get_nr_to_scan(struct lruvec *lruvec, struct scan_control *sc, bool can_swap) +static long get_nr_to_scan(struct lruvec *lruvec, struct scan_control *sc, int swappiness) { bool success; unsigned long nr_to_scan; @@ -4672,7 +4825,7 @@ static long get_nr_to_scan(struct lruvec *lruvec, struct scan_control *sc, bool if (mem_cgroup_below_min(sc->target_mem_cgroup, memcg)) return -1; - success = should_run_aging(lruvec, max_seq, can_swap, &nr_to_scan); + success = should_run_aging(lruvec, max_seq, swappiness, &nr_to_scan); /* try to scrape all its memory if this memcg was deleted */ if (nr_to_scan && !mem_cgroup_online(memcg)) @@ -4683,7 +4836,7 @@ static long get_nr_to_scan(struct lruvec *lruvec, struct scan_control *sc, bool return nr_to_scan >> sc->priority; /* stop scanning this lruvec as it's low on cold folios */ - return try_to_inc_max_seq(lruvec, max_seq, can_swap, false) ? -1 : 0; + return try_to_inc_max_seq(lruvec, max_seq, swappiness, false) ? -1 : 0; } static bool should_abort_scan(struct lruvec *lruvec, struct scan_control *sc) @@ -4744,6 +4897,13 @@ static bool try_to_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc) cond_resched(); } + /* + * If too many file cache in the coldest generation can't be evicted + * due to being dirty, wake up the flusher. + */ + if (sc->nr.unqueued_dirty && sc->nr.unqueued_dirty == sc->nr.file_taken) + wakeup_flusher_threads(WB_REASON_VMSCAN); + /* whether this lruvec should be rotated */ return nr_to_scan < 0; } @@ -4756,8 +4916,7 @@ static int shrink_one(struct lruvec *lruvec, struct scan_control *sc) struct mem_cgroup *memcg = lruvec_memcg(lruvec); struct pglist_data *pgdat = lruvec_pgdat(lruvec); - mem_cgroup_calculate_protection(NULL, memcg); - + /* lru_gen_age_node() called mem_cgroup_calculate_protection() */ if (mem_cgroup_below_min(NULL, memcg)) return MEMCG_LRU_YOUNG; @@ -4881,28 +5040,6 @@ static void lru_gen_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc blk_finish_plug(&plug); } -static void set_initial_priority(struct pglist_data *pgdat, struct scan_control *sc) -{ - int priority; - unsigned long reclaimable; - - if (sc->priority != DEF_PRIORITY || sc->nr_to_reclaim < MIN_LRU_BATCH) - return; - /* - * Determine the initial priority based on - * (total >> priority) * reclaimed_to_scanned_ratio = nr_to_reclaim, - * where reclaimed_to_scanned_ratio = inactive / total. - */ - reclaimable = node_page_state(pgdat, NR_INACTIVE_FILE); - if (can_reclaim_anon_pages(NULL, pgdat->node_id, sc)) - reclaimable += node_page_state(pgdat, NR_INACTIVE_ANON); - - /* 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; @@ -4941,8 +5078,8 @@ static void lru_gen_shrink_node(struct pglist_data *pgdat, struct scan_control * blk_finish_plug(&plug); done: - /* kswapd should never fail */ - pgdat->kswapd_failures = 0; + if (sc->nr_reclaimed > reclaimed) + pgdat->kswapd_failures = 0; } /****************************************************************************** @@ -5232,19 +5369,18 @@ static void lru_gen_seq_show_full(struct seq_file *m, struct lruvec *lruvec, for (tier = 0; tier < MAX_NR_TIERS; tier++) { seq_printf(m, " %10d", tier); for (type = 0; type < ANON_AND_FILE; type++) { - const char *s = " "; + const char *s = "xxx"; unsigned long n[3] = {}; if (seq == max_seq) { - s = "RT "; + s = "RTx"; n[0] = READ_ONCE(lrugen->avg_refaulted[type][tier]); n[1] = READ_ONCE(lrugen->avg_total[type][tier]); } else if (seq == min_seq[type] || NR_HIST_GENS > 1) { s = "rep"; n[0] = atomic_long_read(&lrugen->refaulted[hist][type][tier]); n[1] = atomic_long_read(&lrugen->evicted[hist][type][tier]); - if (tier) - n[2] = READ_ONCE(lrugen->protected[hist][type][tier - 1]); + n[2] = READ_ONCE(lrugen->protected[hist][type][tier]); } for (i = 0; i < 3; i++) @@ -5258,14 +5394,14 @@ static void lru_gen_seq_show_full(struct seq_file *m, struct lruvec *lruvec, seq_puts(m, " "); for (i = 0; i < NR_MM_STATS; i++) { - const char *s = " "; + const char *s = "xxxx"; unsigned long n = 0; if (seq == max_seq && NR_HIST_GENS == 1) { - s = "LOYNFA"; + s = "TYFA"; n = READ_ONCE(mm_state->stats[hist][i]); } else if (seq != max_seq && NR_HIST_GENS > 1) { - s = "loynfa"; + s = "tyfa"; n = READ_ONCE(mm_state->stats[hist][i]); } @@ -5299,7 +5435,7 @@ static int lru_gen_seq_show(struct seq_file *m, void *v) seq_printf(m, " node %5d\n", nid); if (!full) - seq = min_seq[LRU_GEN_ANON]; + seq = evictable_min_seq(min_seq, MAX_SWAPPINESS / 2); else if (max_seq >= MAX_NR_GENS) seq = max_seq - MAX_NR_GENS + 1; else @@ -5339,23 +5475,14 @@ static const struct seq_operations lru_gen_seq_ops = { }; static int run_aging(struct lruvec *lruvec, unsigned long seq, - bool can_swap, bool force_scan) + int swappiness, bool force_scan) { DEFINE_MAX_SEQ(lruvec); - DEFINE_MIN_SEQ(lruvec); - - if (seq < max_seq) - return 0; if (seq > max_seq) return -EINVAL; - if (!force_scan && min_seq[!can_swap] + MAX_NR_GENS - 1 <= max_seq) - return -ERANGE; - - try_to_inc_max_seq(lruvec, max_seq, can_swap, force_scan); - - return 0; + return try_to_inc_max_seq(lruvec, max_seq, swappiness, force_scan) ? 0 : -EEXIST; } static int run_eviction(struct lruvec *lruvec, unsigned long seq, struct scan_control *sc, @@ -5371,7 +5498,7 @@ static int run_eviction(struct lruvec *lruvec, unsigned long seq, struct scan_co while (!signal_pending(current)) { DEFINE_MIN_SEQ(lruvec); - if (seq < min_seq[!swappiness]) + if (seq < evictable_min_seq(min_seq, swappiness)) return 0; if (sc->nr_reclaimed >= nr_to_reclaim) @@ -5414,9 +5541,9 @@ static int run_cmd(char cmd, int memcg_id, int nid, unsigned long seq, lruvec = get_lruvec(memcg, nid); - if (swappiness < 0) + if (swappiness < MIN_SWAPPINESS) swappiness = get_swappiness(lruvec, sc); - else if (swappiness > 200) + else if (swappiness > SWAPPINESS_ANON_ONLY) goto done; switch (cmd) { @@ -5473,24 +5600,35 @@ static ssize_t lru_gen_seq_write(struct file *file, const char __user *src, while ((cur = strsep(&next, ",;\n"))) { int n; int end; - char cmd; + char cmd, swap_string[5]; unsigned int memcg_id; unsigned int nid; unsigned long seq; - unsigned int swappiness = -1; + unsigned int swappiness; unsigned long opt = -1; cur = skip_spaces(cur); if (!*cur) continue; - n = sscanf(cur, "%c %u %u %lu %n %u %n %lu %n", &cmd, &memcg_id, &nid, - &seq, &end, &swappiness, &end, &opt, &end); + n = sscanf(cur, "%c %u %u %lu %n %4s %n %lu %n", &cmd, &memcg_id, &nid, + &seq, &end, swap_string, &end, &opt, &end); if (n < 4 || cur[end]) { err = -EINVAL; break; } + if (n == 4) { + swappiness = -1; + } else if (!strcmp("max", swap_string)) { + /* set by userspace for anonymous memory only */ + swappiness = SWAPPINESS_ANON_ONLY; + } else { + err = kstrtouint(swap_string, 0, &swappiness); + if (err) + break; + } + err = run_cmd(cmd, memcg_id, nid, seq, &sc, swappiness, opt); if (err) break; @@ -5750,7 +5888,7 @@ static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc) * Even if we did not try to evict anon pages at all, we want to * rebalance the anon lru active/inactive ratio. */ - if (can_age_anon_pages(lruvec_pgdat(lruvec), sc) && + if (can_age_anon_pages(lruvec, sc) && inactive_is_low(lruvec, LRU_INACTIVE_ANON)) shrink_active_list(SWAP_CLUSTER_MAX, lruvec, sc, LRU_ACTIVE_ANON); @@ -5781,6 +5919,7 @@ static inline bool should_continue_reclaim(struct pglist_data *pgdat, unsigned long pages_for_compaction; unsigned long inactive_lru_pages; int z; + struct zone *zone; /* If not in reclaim/compaction mode, stop */ if (!in_reclaim_compaction(sc)) @@ -5800,17 +5939,16 @@ static inline bool should_continue_reclaim(struct pglist_data *pgdat, return false; /* If compaction would go ahead or the allocation would succeed, stop */ - for (z = 0; z <= sc->reclaim_idx; z++) { - struct zone *zone = &pgdat->node_zones[z]; - if (!managed_zone(zone)) - continue; + for_each_managed_zone_pgdat(zone, pgdat, z, sc->reclaim_idx) { + unsigned long watermark = min_wmark_pages(zone); /* Allocation can already succeed, nothing to do */ - if (zone_watermark_ok(zone, sc->order, min_wmark_pages(zone), + if (zone_watermark_ok(zone, sc->order, watermark, sc->reclaim_idx, 0)) return false; - if (compaction_suitable(zone, sc->order, sc->reclaim_idx)) + if (compaction_suitable(zone, sc->order, watermark, + sc->reclaim_idx)) return false; } @@ -5829,9 +5967,25 @@ static inline bool should_continue_reclaim(struct pglist_data *pgdat, static void shrink_node_memcgs(pg_data_t *pgdat, struct scan_control *sc) { struct mem_cgroup *target_memcg = sc->target_mem_cgroup; + struct mem_cgroup_reclaim_cookie reclaim = { + .pgdat = pgdat, + }; + struct mem_cgroup_reclaim_cookie *partial = &reclaim; struct mem_cgroup *memcg; - memcg = mem_cgroup_iter(target_memcg, NULL, NULL); + /* + * In most cases, direct reclaimers can do partial walks + * through the cgroup tree, using an iterator state that + * persists across invocations. This strikes a balance between + * fairness and allocation latency. + * + * For kswapd, reliable forward progress is more important + * than a quick return to idle. Always do full walks. + */ + if (current_is_kswapd() || sc->memcg_full_walk) + partial = NULL; + + memcg = mem_cgroup_iter(target_memcg, NULL, partial); do { struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat); unsigned long reclaimed; @@ -5881,7 +6035,12 @@ static void shrink_node_memcgs(pg_data_t *pgdat, struct scan_control *sc) sc->nr_scanned - scanned, sc->nr_reclaimed - reclaimed); - } while ((memcg = mem_cgroup_iter(target_memcg, memcg, NULL))); + /* If partial walks are allowed, bail once goal is reached */ + if (partial && sc->nr_reclaimed >= sc->nr_to_reclaim) { + mem_cgroup_iter_break(target_memcg, memcg); + break; + } + } while ((memcg = mem_cgroup_iter(target_memcg, memcg, partial))); } static void shrink_node(pg_data_t *pgdat, struct scan_control *sc) @@ -5891,6 +6050,7 @@ static void shrink_node(pg_data_t *pgdat, struct scan_control *sc) bool reclaimable = false; if (lru_gen_enabled() && root_reclaim(sc)) { + memset(&sc->nr, 0, sizeof(sc->nr)); lru_gen_shrink_node(pgdat, sc); return; } @@ -5941,7 +6101,8 @@ again: set_bit(PGDAT_WRITEBACK, &pgdat->flags); /* Allow kswapd to start writing pages during reclaim.*/ - if (sc->nr.unqueued_dirty == sc->nr.file_taken) + if (sc->nr.unqueued_dirty && + sc->nr.unqueued_dirty == sc->nr.file_taken) set_bit(PGDAT_DIRTY, &pgdat->flags); /* @@ -6014,22 +6175,21 @@ static inline bool compaction_ready(struct zone *zone, struct scan_control *sc) sc->reclaim_idx, 0)) return true; - /* Compaction cannot yet proceed. Do reclaim. */ - if (!compaction_suitable(zone, sc->order, sc->reclaim_idx)) - return false; - /* - * Compaction is already possible, but it takes time to run and there - * are potentially other callers using the pages just freed. So proceed - * with reclaim to make a buffer of free pages available to give - * compaction a reasonable chance of completing and allocating the page. + * Direct reclaim usually targets the min watermark, but compaction + * takes time to run and there are potentially other callers using the + * pages just freed. So target a higher buffer to give compaction a + * reasonable chance of completing and allocating the pages. + * * Note that we won't actually reclaim the whole buffer in one attempt * as the target watermark in should_continue_reclaim() is lower. But if * we are already above the high+gap watermark, don't reclaim at all. */ - watermark = high_wmark_pages(zone) + compact_gap(sc->order); + watermark = high_wmark_pages(zone); + if (compaction_suitable(zone, sc->order, watermark, sc->reclaim_idx)) + return true; - return zone_watermark_ok_safe(zone, 0, watermark, sc->reclaim_idx); + return false; } static void consider_reclaim_throttle(pg_data_t *pgdat, struct scan_control *sc) @@ -6134,9 +6294,9 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc) * and balancing, not for a memcg's limit. */ nr_soft_scanned = 0; - nr_soft_reclaimed = mem_cgroup_soft_limit_reclaim(zone->zone_pgdat, - sc->order, sc->gfp_mask, - &nr_soft_scanned); + nr_soft_reclaimed = memcg1_soft_limit_reclaim(zone->zone_pgdat, + sc->order, sc->gfp_mask, + &nr_soft_scanned); sc->nr_reclaimed += nr_soft_reclaimed; sc->nr_scanned += nr_soft_scanned; /* need some check for avoid more shrink_zone() */ @@ -6255,6 +6415,21 @@ retry: return 1; /* + * In most cases, direct reclaimers can do partial walks + * through the cgroup tree to meet the reclaim goal while + * keeping latency low. Since the iterator state is shared + * among all direct reclaim invocations (to retain fairness + * among cgroups), though, high concurrency can result in + * individual threads not seeing enough cgroups to make + * meaningful forward progress. Avoid false OOMs in this case. + */ + if (!sc->memcg_full_walk) { + sc->priority = initial_priority; + sc->memcg_full_walk = 1; + goto retry; + } + + /* * We make inactive:active ratio decisions based on the node's * composition of memory, but a restrictive reclaim_idx or a * memory.low cgroup setting can exempt large amounts of @@ -6293,11 +6468,7 @@ static bool allow_direct_reclaim(pg_data_t *pgdat) if (pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES) return true; - for (i = 0; i <= ZONE_NORMAL; i++) { - zone = &pgdat->node_zones[i]; - if (!managed_zone(zone)) - continue; - + for_each_managed_zone_pgdat(zone, pgdat, i, ZONE_NORMAL) { if (!zone_reclaimable_pages(zone)) continue; @@ -6499,12 +6670,14 @@ unsigned long mem_cgroup_shrink_node(struct mem_cgroup *memcg, unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg, unsigned long nr_pages, gfp_t gfp_mask, - unsigned int reclaim_options) + unsigned int reclaim_options, + int *swappiness) { unsigned long nr_reclaimed; unsigned int noreclaim_flag; struct scan_control sc = { .nr_to_reclaim = max(nr_pages, SWAP_CLUSTER_MAX), + .proactive_swappiness = swappiness, .gfp_mask = (current_gfp_context(gfp_mask) & GFP_RECLAIM_MASK) | (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK), .reclaim_idx = MAX_NR_ZONES - 1, @@ -6546,10 +6719,10 @@ static void kswapd_age_node(struct pglist_data *pgdat, struct scan_control *sc) return; } - if (!can_age_anon_pages(pgdat, sc)) + lruvec = mem_cgroup_lruvec(NULL, pgdat); + if (!can_age_anon_pages(lruvec, sc)) return; - lruvec = mem_cgroup_lruvec(NULL, pgdat); if (!inactive_is_low(lruvec, LRU_INACTIVE_ANON)) return; @@ -6600,17 +6773,48 @@ static bool pgdat_balanced(pg_data_t *pgdat, int order, int highest_zoneidx) * Check watermarks bottom-up as lower zones are more likely to * meet watermarks. */ - for (i = 0; i <= highest_zoneidx; i++) { - zone = pgdat->node_zones + i; - - if (!managed_zone(zone)) - continue; + for_each_managed_zone_pgdat(zone, pgdat, i, highest_zoneidx) { + enum zone_stat_item item; + unsigned long free_pages; if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) - mark = wmark_pages(zone, WMARK_PROMO); + mark = promo_wmark_pages(zone); else mark = high_wmark_pages(zone); - if (zone_watermark_ok_safe(zone, order, mark, highest_zoneidx)) + + /* + * In defrag_mode, watermarks must be met in whole + * blocks to avoid polluting allocator fallbacks. + * + * However, kswapd usually cannot accomplish this on + * its own and needs kcompactd support. Once it's + * reclaimed a compaction gap, and kswapd_shrink_node + * has dropped order, simply ensure there are enough + * base pages for compaction, wake kcompactd & sleep. + */ + if (defrag_mode && order) + item = NR_FREE_PAGES_BLOCKS; + else + item = NR_FREE_PAGES; + + /* + * When there is a high number of CPUs in the system, + * the cumulative error from the vmstat per-cpu cache + * can blur the line between the watermarks. In that + * case, be safe and get an accurate snapshot. + * + * TODO: NR_FREE_PAGES_BLOCKS moves in steps of + * pageblock_nr_pages, while the vmstat pcp threshold + * is limited to 125. On many configurations that + * counter won't actually be per-cpu cached. But keep + * things simple for now; revisit when somebody cares. + */ + free_pages = zone_page_state(zone, item); + if (zone->percpu_drift_mark && free_pages < zone->percpu_drift_mark) + free_pages = zone_page_state_snapshot(zone, item); + + if (__zone_watermark_ok(zone, order, mark, highest_zoneidx, + 0, free_pages)) return true; } @@ -6686,14 +6890,11 @@ static bool kswapd_shrink_node(pg_data_t *pgdat, { struct zone *zone; int z; + unsigned long nr_reclaimed = sc->nr_reclaimed; /* Reclaim a number of pages proportional to the number of zones */ sc->nr_to_reclaim = 0; - for (z = 0; z <= sc->reclaim_idx; z++) { - zone = pgdat->node_zones + z; - if (!managed_zone(zone)) - continue; - + for_each_managed_zone_pgdat(zone, pgdat, z, sc->reclaim_idx) { sc->nr_to_reclaim += max(high_wmark_pages(zone), SWAP_CLUSTER_MAX); } @@ -6713,7 +6914,8 @@ static bool kswapd_shrink_node(pg_data_t *pgdat, if (sc->order && sc->nr_reclaimed >= compact_gap(sc->order)) sc->order = 0; - return sc->nr_scanned >= sc->nr_to_reclaim; + /* account for progress from mm_account_reclaimed_pages() */ + return max(sc->nr_scanned, sc->nr_reclaimed - nr_reclaimed) >= sc->nr_to_reclaim; } /* Page allocator PCP high watermark is lowered if reclaim is active. */ @@ -6723,12 +6925,7 @@ update_reclaim_active(pg_data_t *pgdat, int highest_zoneidx, bool active) int i; struct zone *zone; - for (i = 0; i <= highest_zoneidx; i++) { - zone = pgdat->node_zones + i; - - if (!managed_zone(zone)) - continue; - + for_each_managed_zone_pgdat(zone, pgdat, i, highest_zoneidx) { if (active) set_bit(ZONE_RECLAIM_ACTIVE, &zone->flags); else @@ -6789,11 +6986,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int highest_zoneidx) * stall or direct reclaim until kswapd is finished. */ nr_boost_reclaim = 0; - for (i = 0; i <= highest_zoneidx; i++) { - zone = pgdat->node_zones + i; - if (!managed_zone(zone)) - continue; - + for_each_managed_zone_pgdat(zone, pgdat, i, highest_zoneidx) { nr_boost_reclaim += zone->watermark_boost; zone_boosts[i] = zone->watermark_boost; } @@ -6883,8 +7076,8 @@ restart: /* Call soft limit reclaim before calling shrink_node. */ sc.nr_scanned = 0; nr_soft_scanned = 0; - nr_soft_reclaimed = mem_cgroup_soft_limit_reclaim(pgdat, sc.order, - sc.gfp_mask, &nr_soft_scanned); + nr_soft_reclaimed = memcg1_soft_limit_reclaim(pgdat, sc.order, + sc.gfp_mask, &nr_soft_scanned); sc.nr_reclaimed += nr_soft_reclaimed; /* @@ -7100,10 +7293,6 @@ static int kswapd(void *p) unsigned int highest_zoneidx = MAX_NR_ZONES - 1; pg_data_t *pgdat = (pg_data_t *)p; struct task_struct *tsk = current; - const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id); - - if (!cpumask_empty(cpumask)) - set_cpus_allowed_ptr(tsk, cpumask); /* * Tell the memory management that we're a "memory allocator", @@ -7272,13 +7461,15 @@ void __meminit kswapd_run(int nid) pgdat_kswapd_lock(pgdat); if (!pgdat->kswapd) { - pgdat->kswapd = kthread_run(kswapd, pgdat, "kswapd%d", nid); + pgdat->kswapd = kthread_create_on_node(kswapd, pgdat, nid, "kswapd%d", nid); if (IS_ERR(pgdat->kswapd)) { /* failure at boot is fatal */ pr_err("Failed to start kswapd on node %d，ret=%ld\n", nid, PTR_ERR(pgdat->kswapd)); BUG_ON(system_state < SYSTEM_RUNNING); pgdat->kswapd = NULL; + } else { + wake_up_process(pgdat->kswapd); } } pgdat_kswapd_unlock(pgdat); @@ -7302,6 +7493,28 @@ void __meminit kswapd_stop(int nid) pgdat_kswapd_unlock(pgdat); } +static const struct ctl_table vmscan_sysctl_table[] = { + { + .procname = "swappiness", + .data = &vm_swappiness, + .maxlen = sizeof(vm_swappiness), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_TWO_HUNDRED, + }, +#ifdef CONFIG_NUMA + { + .procname = "zone_reclaim_mode", + .data = &node_reclaim_mode, + .maxlen = sizeof(node_reclaim_mode), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO, + } +#endif +}; + static int __init kswapd_init(void) { int nid; @@ -7309,6 +7522,7 @@ static int __init kswapd_init(void) swap_setup(); for_each_node_state(nid, N_MEMORY) kswapd_run(nid); + register_sysctl_init("vm", vmscan_sysctl_table); return 0; } @@ -7474,13 +7688,15 @@ int node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned int order) if (node_state(pgdat->node_id, N_CPU) && pgdat->node_id != numa_node_id()) return NODE_RECLAIM_NOSCAN; - if (test_and_set_bit(PGDAT_RECLAIM_LOCKED, &pgdat->flags)) + if (test_and_set_bit_lock(PGDAT_RECLAIM_LOCKED, &pgdat->flags)) return NODE_RECLAIM_NOSCAN; ret = __node_reclaim(pgdat, gfp_mask, order); - clear_bit(PGDAT_RECLAIM_LOCKED, &pgdat->flags); + clear_bit_unlock(PGDAT_RECLAIM_LOCKED, &pgdat->flags); - if (!ret) + if (ret) + count_vm_event(PGSCAN_ZONE_RECLAIM_SUCCESS); + else count_vm_event(PGSCAN_ZONE_RECLAIM_FAILED); return ret; |