[PATCH RFC 14/15] mm: optimize putback for 0-order reclaim

Konstantin Khlebnikov
2012-02-15T22:58:02Z

At 0-order reclaim all pages are taken from one book,
thus we don't need to recheck and relock page_book on putback.

Maybe it would be better to collect lumpy-isolated pages into
separate list and handle them independently.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
---
mm/vmscan.c | 16 +++++++++++-----
1 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 9a3fb72..9fc814f 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1340,6 +1340,7 @@ static int too_many_isolated(struct zone *zone, int file,
*/
static noinline_for_stack struct book *
putback_inactive_pages(struct book *book,
+ struct scan_control *sc,
struct list_head *page_list)
{
struct zone_reclaim_stat *reclaim_stat = &book->reclaim_stat;
@@ -1364,7 +1365,9 @@ putback_inactive_pages(struct book *book,
lru = page_lru(page);

/* can differ only on lumpy reclaim */
- book = __relock_page_book(book, page);
+ if (sc->order)
+ book = __relock_page_book(book, page);
+
add_page_to_lru_list(book, page, lru);
if (is_active_lru(lru)) {
int file = is_file_lru(lru);
@@ -1560,7 +1563,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct book *book,
__count_vm_events(KSWAPD_STEAL, nr_reclaimed);
__count_zone_vm_events(PGSTEAL, zone, nr_reclaimed);

- book = putback_inactive_pages(book, &page_list);
+ book = putback_inactive_pages(book, sc, &page_list);

__mod_zone_page_state(zone, NR_ISOLATED_ANON, -nr_anon);
__mod_zone_page_state(zone, NR_ISOLATED_FILE, -nr_file);
@@ -1625,6 +1628,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct book *book,

static struct book *
move_active_pages_to_lru(struct book *book,
+ struct scan_control *sc,
struct list_head *list,
struct list_head *pages_to_free,
enum lru_list lru)
@@ -1653,7 +1657,9 @@ move_active_pages_to_lru(struct book *book,
SetPageLRU(page);

/* can differ only on lumpy reclaim */
- book = __relock_page_book(book, page);
+ if (sc->order)
+ book = __relock_page_book(book, page);
+
list_move(&page->lru, &book->pages_lru[lru]);
numpages = hpage_nr_pages(page);
book->pages_count[lru] += numpages;
@@ -1765,9 +1771,9 @@ static void shrink_active_list(unsigned long nr_to_scan,
*/
reclaim_stat->recent_rotated[file] += nr_rotated;

- book = move_active_pages_to_lru(book, &l_active, &l_hold,
+ book = move_active_pages_to_lru(book, sc, &l_active, &l_hold,
LRU_ACTIVE + file * LRU_FILE);
- book = move_active_pages_to_lru(book, &l_inactive, &l_hold,
+ book = move_active_pages_to_lru(book, sc, &l_inactive, &l_hold,
LRU_BASE + file * LRU_FILE);
__mod_zone_page_state(zone, NR_ISOLATED_ANON + file, -nr_taken);
unlock_book_irq(book);