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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) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2022-06-17 18:50:00 +01:00 committed by akpm
parent e3c4cebf3f
commit c2bc16817a
1 changed files with 56 additions and 22 deletions
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78
mm/swap.c
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@ -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)) ||