From: Muchun Song In a subsequent patch, we'll reparent the LRU folios. The folios that are moved to the appropriate LRU list can undergo reparenting during the move_folios_to_lru() process. Hence, it's incorrect for the caller to hold a lruvec lock. Instead, we should utilize the more general interface of folio_lruvec_relock_irq() to obtain the correct lruvec lock. This patch involves only code refactoring and doesn't introduce any functional changes. Signed-off-by: Muchun Song Acked-by: Johannes Weiner Signed-off-by: Qi Zheng --- mm/vmscan.c | 46 +++++++++++++++++++++------------------------- 1 file changed, 21 insertions(+), 25 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 49e5661746213..354b19f7365d4 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1883,24 +1883,27 @@ static bool too_many_isolated(struct pglist_data *pgdat, int file, /* * move_folios_to_lru() moves folios from private @list to appropriate LRU list. * - * Returns the number of pages moved to the given lruvec. + * Returns the number of pages moved to the appropriate lruvec. + * + * Note: The caller must not hold any lruvec lock. */ -static unsigned int move_folios_to_lru(struct lruvec *lruvec, - struct list_head *list) +static unsigned int move_folios_to_lru(struct list_head *list) { int nr_pages, nr_moved = 0; + struct lruvec *lruvec = NULL; struct folio_batch free_folios; folio_batch_init(&free_folios); while (!list_empty(list)) { struct folio *folio = lru_to_folio(list); + lruvec = folio_lruvec_relock_irq(folio, lruvec); VM_BUG_ON_FOLIO(folio_test_lru(folio), folio); list_del(&folio->lru); if (unlikely(!folio_evictable(folio))) { - spin_unlock_irq(&lruvec->lru_lock); + lruvec_unlock_irq(lruvec); folio_putback_lru(folio); - spin_lock_irq(&lruvec->lru_lock); + lruvec = NULL; continue; } @@ -1922,19 +1925,15 @@ static unsigned int move_folios_to_lru(struct lruvec *lruvec, folio_unqueue_deferred_split(folio); if (folio_batch_add(&free_folios, folio) == 0) { - spin_unlock_irq(&lruvec->lru_lock); + lruvec_unlock_irq(lruvec); mem_cgroup_uncharge_folios(&free_folios); free_unref_folios(&free_folios); - spin_lock_irq(&lruvec->lru_lock); + lruvec = NULL; } continue; } - /* - * All pages were isolated from the same lruvec (and isolation - * inhibits memcg migration). - */ VM_BUG_ON_FOLIO(!folio_matches_lruvec(folio, lruvec), folio); lruvec_add_folio(lruvec, folio); nr_pages = folio_nr_pages(folio); @@ -1943,11 +1942,12 @@ static unsigned int move_folios_to_lru(struct lruvec *lruvec, workingset_age_nonresident(lruvec, nr_pages); } + if (lruvec) + lruvec_unlock_irq(lruvec); + if (free_folios.nr) { - spin_unlock_irq(&lruvec->lru_lock); mem_cgroup_uncharge_folios(&free_folios); free_unref_folios(&free_folios); - spin_lock_irq(&lruvec->lru_lock); } return nr_moved; @@ -2016,8 +2016,7 @@ static unsigned long shrink_inactive_list(unsigned long nr_to_scan, 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); + move_folios_to_lru(&folio_list); mod_lruvec_state(lruvec, PGDEMOTE_KSWAPD + reclaimer_offset(sc), stat.nr_demoted); @@ -2028,6 +2027,7 @@ static unsigned long shrink_inactive_list(unsigned long nr_to_scan, count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed); count_vm_events(PGSTEAL_ANON + file, nr_reclaimed); + spin_lock_irq(&lruvec->lru_lock); lru_note_cost_unlock_irq(lruvec, file, stat.nr_pageout, nr_scanned - nr_reclaimed); @@ -2166,16 +2166,14 @@ static void shrink_active_list(unsigned long nr_to_scan, /* * Move folios back to the lru list. */ - spin_lock_irq(&lruvec->lru_lock); - - nr_activate = move_folios_to_lru(lruvec, &l_active); - nr_deactivate = move_folios_to_lru(lruvec, &l_inactive); + nr_activate = move_folios_to_lru(&l_active); + nr_deactivate = move_folios_to_lru(&l_inactive); count_vm_events(PGDEACTIVATE, nr_deactivate); count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_deactivate); - mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken); + spin_lock_irq(&lruvec->lru_lock); lru_note_cost_unlock_irq(lruvec, file, 0, nr_rotated); trace_mm_vmscan_lru_shrink_active(pgdat->node_id, nr_taken, nr_activate, nr_deactivate, nr_rotated, sc->priority, file); @@ -4736,14 +4734,14 @@ static int evict_folios(unsigned long nr_to_scan, struct lruvec *lruvec, set_mask_bits(&folio->flags.f, LRU_REFS_FLAGS, BIT(PG_active)); } - spin_lock_irq(&lruvec->lru_lock); - - move_folios_to_lru(lruvec, &list); + move_folios_to_lru(&list); walk = current->reclaim_state->mm_walk; if (walk && walk->batched) { walk->lruvec = lruvec; + spin_lock(&lruvec->lru_lock); reset_batch_size(walk); + spin_unlock(&lruvec->lru_lock); } mod_lruvec_state(lruvec, PGDEMOTE_KSWAPD + reclaimer_offset(sc), @@ -4755,8 +4753,6 @@ static int evict_folios(unsigned long nr_to_scan, struct lruvec *lruvec, count_memcg_events(memcg, item, reclaimed); count_vm_events(PGSTEAL_ANON + type, reclaimed); - spin_unlock_irq(&lruvec->lru_lock); - list_splice_init(&clean, &list); if (!list_empty(&list)) { -- 2.20.1