From c2bc16817aa0dcd5d4b452661840be976f5d5c65 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Fri, 17 Jun 2022 18:50:00 +0100 Subject: [PATCH] mm/swap: add folio_batch_move_lru() Start converting the LRU from pagevecs to folio_batches. Combine the functionality of pagevec_add_and_need_flush() with pagevec_lru_move_fn() in the new folio_batch_add_and_move(). Convert the lru_rotate pagevec to a folio_batch. Adds 223 bytes total to kernel text, because we're duplicating infrastructure. This will be more than made up for in future patches. Link: https://lkml.kernel.org/r/20220617175020.717127-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton --- mm/swap.c | 78 +++++++++++++++++++++++++++++++++++++++++++++------------------ 1 file changed, 56 insertions(+), 22 deletions(-) diff --git a/mm/swap.c b/mm/swap.c index 034bb24879a3..4265bee41bbd 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -46,10 +46,10 @@ /* How many pages do we try to swap or page in/out together? */ int page_cluster; -/* Protecting only lru_rotate.pvec which requires disabling interrupts */ +/* Protecting only lru_rotate.fbatch which requires disabling interrupts */ struct lru_rotate { local_lock_t lock; - struct pagevec pvec; + struct folio_batch fbatch; }; static DEFINE_PER_CPU(struct lru_rotate, lru_rotate) = { .lock = INIT_LOCAL_LOCK(lock), @@ -214,18 +214,6 @@ static void pagevec_lru_move_fn(struct pagevec *pvec, pagevec_reinit(pvec); } -static void pagevec_move_tail_fn(struct page *page, struct lruvec *lruvec) -{ - struct folio *folio = page_folio(page); - - if (!folio_test_unevictable(folio)) { - lruvec_del_folio(lruvec, folio); - folio_clear_active(folio); - lruvec_add_folio_tail(lruvec, folio); - __count_vm_events(PGROTATED, folio_nr_pages(folio)); - } -} - /* return true if pagevec needs to drain */ static bool pagevec_add_and_need_flush(struct pagevec *pvec, struct page *page) { @@ -238,6 +226,52 @@ static bool pagevec_add_and_need_flush(struct pagevec *pvec, struct page *page) return ret; } +typedef void (*move_fn_t)(struct lruvec *lruvec, struct folio *folio); + +static void folio_batch_move_lru(struct folio_batch *fbatch, move_fn_t move_fn) +{ + int i; + struct lruvec *lruvec = NULL; + unsigned long flags = 0; + + for (i = 0; i < folio_batch_count(fbatch); i++) { + struct folio *folio = fbatch->folios[i]; + + /* block memcg migration while the folio moves between lru */ + if (!folio_test_clear_lru(folio)) + continue; + + lruvec = folio_lruvec_relock_irqsave(folio, lruvec, &flags); + move_fn(lruvec, folio); + + folio_set_lru(folio); + } + + if (lruvec) + unlock_page_lruvec_irqrestore(lruvec, flags); + folios_put(fbatch->folios, folio_batch_count(fbatch)); + folio_batch_init(fbatch); +} + +static void folio_batch_add_and_move(struct folio_batch *fbatch, + struct folio *folio, move_fn_t move_fn) +{ + if (folio_batch_add(fbatch, folio) && !folio_test_large(folio) && + !lru_cache_disabled()) + return; + folio_batch_move_lru(fbatch, move_fn); +} + +static void lru_move_tail_fn(struct lruvec *lruvec, struct folio *folio) +{ + if (!folio_test_unevictable(folio)) { + lruvec_del_folio(lruvec, folio); + folio_clear_active(folio); + lruvec_add_folio_tail(lruvec, folio); + __count_vm_events(PGROTATED, folio_nr_pages(folio)); + } +} + /* * Writeback is about to end against a folio which has been marked for * immediate reclaim. If it still appears to be reclaimable, move it @@ -249,14 +283,13 @@ void folio_rotate_reclaimable(struct folio *folio) { if (!folio_test_locked(folio) && !folio_test_dirty(folio) && !folio_test_unevictable(folio) && folio_test_lru(folio)) { - struct pagevec *pvec; + struct folio_batch *fbatch; unsigned long flags; folio_get(folio); local_lock_irqsave(&lru_rotate.lock, flags); - pvec = this_cpu_ptr(&lru_rotate.pvec); - if (pagevec_add_and_need_flush(pvec, &folio->page)) - pagevec_lru_move_fn(pvec, pagevec_move_tail_fn); + fbatch = this_cpu_ptr(&lru_rotate.fbatch); + folio_batch_add_and_move(fbatch, folio, lru_move_tail_fn); local_unlock_irqrestore(&lru_rotate.lock, flags); } } @@ -595,19 +628,20 @@ static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec) */ void lru_add_drain_cpu(int cpu) { + struct folio_batch *fbatch; struct pagevec *pvec = &per_cpu(lru_pvecs.lru_add, cpu); if (pagevec_count(pvec)) __pagevec_lru_add(pvec); - pvec = &per_cpu(lru_rotate.pvec, cpu); + fbatch = &per_cpu(lru_rotate.fbatch, cpu); /* Disabling interrupts below acts as a compiler barrier. */ - if (data_race(pagevec_count(pvec))) { + if (data_race(folio_batch_count(fbatch))) { unsigned long flags; /* No harm done if a racing interrupt already did this */ local_lock_irqsave(&lru_rotate.lock, flags); - pagevec_lru_move_fn(pvec, pagevec_move_tail_fn); + folio_batch_move_lru(fbatch, lru_move_tail_fn); local_unlock_irqrestore(&lru_rotate.lock, flags); } @@ -824,7 +858,7 @@ static inline void __lru_add_drain_all(bool force_all_cpus) struct work_struct *work = &per_cpu(lru_add_drain_work, cpu); if (pagevec_count(&per_cpu(lru_pvecs.lru_add, cpu)) || - data_race(pagevec_count(&per_cpu(lru_rotate.pvec, cpu))) || + data_race(folio_batch_count(&per_cpu(lru_rotate.fbatch, cpu))) || pagevec_count(&per_cpu(lru_pvecs.lru_deactivate_file, cpu)) || pagevec_count(&per_cpu(lru_pvecs.lru_deactivate, cpu)) || pagevec_count(&per_cpu(lru_pvecs.lru_lazyfree, cpu)) || -- 2.11.0