With node-lru, the locking is based on the pgdat. As Minchan pointed out, there is an opportunity to reduce LRU lock release/acquire in check_move_unevictable_pages by only changing lock on a pgdat change.
Signed-off-by: Mel Gorman <[email protected]> --- mm/vmscan.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 45344acf52ba..a6f31617a08c 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3775,24 +3775,24 @@ int page_evictable(struct page *page) void check_move_unevictable_pages(struct page **pages, int nr_pages) { struct lruvec *lruvec; - struct zone *zone = NULL; + struct pglist_data *pgdat = NULL; int pgscanned = 0; int pgrescued = 0; int i; for (i = 0; i < nr_pages; i++) { struct page *page = pages[i]; - struct zone *pagezone; + struct pglist_data *pagepgdat = page_pgdat(page); pgscanned++; - pagezone = page_zone(page); - if (pagezone != zone) { - if (zone) - spin_unlock_irq(zone_lru_lock(zone)); - zone = pagezone; - spin_lock_irq(zone_lru_lock(zone)); + pagepgdat = page_pgdat(page); + if (pagepgdat != pgdat) { + if (pgdat) + spin_unlock_irq(&pgdat->lru_lock); + pgdat = pagepgdat; + spin_lock_irq(&pgdat->lru_lock); } - lruvec = mem_cgroup_page_lruvec(page, zone->zone_pgdat); + lruvec = mem_cgroup_page_lruvec(page, pgdat); if (!PageLRU(page) || !PageUnevictable(page)) continue; @@ -3808,10 +3808,10 @@ void check_move_unevictable_pages(struct page **pages, int nr_pages) } } - if (zone) { + if (pgdat) { __count_vm_events(UNEVICTABLE_PGRESCUED, pgrescued); __count_vm_events(UNEVICTABLE_PGSCANNED, pgscanned); - spin_unlock_irq(zone_lru_lock(zone)); + spin_unlock_irq(&pgdat->lru_lock); } } #endif /* CONFIG_SHMEM */ -- 2.6.4
