Commit c2bc1681 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

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: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent e3c4cebf

mm/swap.c

+56 −22
Original line number Diff line number Diff line
@@ -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)) ||