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mm/swap: convert lru_add to a folio_batch 

When adding folios to the LRU for the first time, the LRU flag will
already be clear, so skip the test-and-clear part of moving from one
LRU to another.

Removes 285 bytes from kernel text, mostly due to removing
__pagevec_lru_add().

Link: https://lkml.kernel.org/r/20220617175020.717127-5-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 18:50:02 +01:00 committed by akpm
parent 7d80dd096f
commit 70dea5346e
1 changed files with 26 additions and 49 deletions
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75
mm/swap.c
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@ -61,7 +61,7 @@ static DEFINE_PER_CPU(struct lru_rotate, lru_rotate) = {
*/
struct lru_pvecs {
local_lock_t lock;
struct pagevec lru_add;
struct folio_batch lru_add;
struct pagevec lru_deactivate_file;
struct pagevec lru_deactivate;
struct pagevec lru_lazyfree;
@ -228,14 +228,13 @@ static bool pagevec_add_and_need_flush(struct pagevec *pvec, struct page *page)
typedef void (*move_fn_t)(struct lruvec *lruvec, struct folio *folio);
static void __pagevec_lru_add_fn(struct folio *folio, struct lruvec *lruvec)
static void lru_add_fn(struct lruvec *lruvec, struct folio *folio)
{
int was_unevictable = folio_test_clear_unevictable(folio);
long nr_pages = folio_nr_pages(folio);
VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
folio_set_lru(folio);
/*
* Is an smp_mb__after_atomic() still required here, before
* folio_evictable() tests PageMlocked, to rule out the possibility
@ -269,28 +268,6 @@ static void __pagevec_lru_add_fn(struct folio *folio, struct lruvec *lruvec)
trace_mm_lru_insertion(folio);
}
/*
* Add the passed pages to the LRU, then drop the caller's refcount
* on them. Reinitialises the caller's pagevec.
*/
static void __pagevec_lru_add(struct pagevec *pvec)
{
int i;
struct lruvec *lruvec = NULL;
unsigned long flags = 0;
for (i = 0; i < pagevec_count(pvec); i++) {
struct folio *folio = page_folio(pvec->pages[i]);
lruvec = folio_lruvec_relock_irqsave(folio, lruvec, &flags);
__pagevec_lru_add_fn(folio, lruvec);
}
if (lruvec)
unlock_page_lruvec_irqrestore(lruvec, flags);
release_pages(pvec->pages, pvec->nr);
pagevec_reinit(pvec);
}
static void folio_batch_move_lru(struct folio_batch *fbatch, move_fn_t move_fn)
{
int i;
@ -301,7 +278,7 @@ static void folio_batch_move_lru(struct folio_batch *fbatch, move_fn_t move_fn)
struct folio *folio = fbatch->folios[i];
/* block memcg migration while the folio moves between lru */
if (!folio_test_clear_lru(folio))
if (move_fn != lru_add_fn && !folio_test_clear_lru(folio))
continue;
lruvec = folio_lruvec_relock_irqsave(folio, lruvec, &flags);
@ -473,26 +450,26 @@ static void folio_activate(struct folio *folio)
static void __lru_cache_activate_folio(struct folio *folio)
{
struct pagevec *pvec;
struct folio_batch *fbatch;
int i;
local_lock(&lru_pvecs.lock);
pvec = this_cpu_ptr(&lru_pvecs.lru_add);
fbatch = this_cpu_ptr(&lru_pvecs.lru_add);
/*
* Search backwards on the optimistic assumption that the page being
* activated has just been added to this pagevec. Note that only
* the local pagevec is examined as a !PageLRU page could be in the
* Search backwards on the optimistic assumption that the folio being
* activated has just been added to this batch. Note that only
* the local batch is examined as a !LRU folio could be in the
* process of being released, reclaimed, migrated or on a remote
* pagevec that is currently being drained. Furthermore, marking
* a remote pagevec's page PageActive potentially hits a race where
* a page is marked PageActive just after it is added to the inactive
* batch that is currently being drained. Furthermore, marking
* a remote batch's folio active potentially hits a race where
* a folio is marked active just after it is added to the inactive
* list causing accounting errors and BUG_ON checks to trigger.
*/
for (i = pagevec_count(pvec) - 1; i >= 0; i--) {
struct page *pagevec_page = pvec->pages[i];
for (i = folio_batch_count(fbatch) - 1; i >= 0; i--) {
struct folio *batch_folio = fbatch->folios[i];
if (pagevec_page == &folio->page) {
if (batch_folio == folio) {
folio_set_active(folio);
break;
}
@ -551,16 +528,16 @@ EXPORT_SYMBOL(folio_mark_accessed);
*/
void folio_add_lru(struct folio *folio)
{
struct pagevec *pvec;
struct folio_batch *fbatch;
VM_BUG_ON_FOLIO(folio_test_active(folio) && folio_test_unevictable(folio), folio);
VM_BUG_ON_FOLIO(folio_test_active(folio) &&
folio_test_unevictable(folio), folio);
VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
folio_get(folio);
local_lock(&lru_pvecs.lock);
pvec = this_cpu_ptr(&lru_pvecs.lru_add);
if (pagevec_add_and_need_flush(pvec, &folio->page))
__pagevec_lru_add(pvec);
fbatch = this_cpu_ptr(&lru_pvecs.lru_add);
folio_batch_add_and_move(fbatch, folio, lru_add_fn);
local_unlock(&lru_pvecs.lock);
}
EXPORT_SYMBOL(folio_add_lru);
@ -691,11 +668,11 @@ 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);
struct folio_batch *fbatch = &per_cpu(lru_pvecs.lru_add, cpu);
struct pagevec *pvec;
if (pagevec_count(pvec))
__pagevec_lru_add(pvec);
if (folio_batch_count(fbatch))
folio_batch_move_lru(fbatch, lru_add_fn);
fbatch = &per_cpu(lru_rotate.fbatch, cpu);
/* Disabling interrupts below acts as a compiler barrier. */
@ -920,7 +897,7 @@ static inline void __lru_add_drain_all(bool force_all_cpus)
for_each_online_cpu(cpu) {
struct work_struct *work = &per_cpu(lru_add_drain_work, cpu);
if (pagevec_count(&per_cpu(lru_pvecs.lru_add, cpu)) ||
if (folio_batch_count(&per_cpu(lru_pvecs.lru_add, 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)) ||
@ -1084,8 +1061,8 @@ EXPORT_SYMBOL(release_pages);
* OK from a correctness point of view but is inefficient - those pages may be
* cache-warm and we want to give them back to the page allocator ASAP.
*
* So __pagevec_release() will drain those queues here. __pagevec_lru_add()
* and __pagevec_lru_add_active() call release_pages() directly to avoid
* So __pagevec_release() will drain those queues here.
* folio_batch_move_lru() calls folios_put() directly to avoid
* mutual recursion.
*/
void __pagevec_release(struct pagevec *pvec)