From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Subject: mm, vmscan: release/reacquire lru_lock on pgdat change 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. [mgorman@xxxxxxxxxxxxxxxxxxx: remove double initialisation] Link: http://lkml.kernel.org/r/20160719074835.GC10438@xxxxxxxxxxxxxxxxxxx Link: http://lkml.kernel.org/r/1468853426-12858-3-git-send-email-mgorman@xxxxxxxxxxxxxxxxxxx Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/vmscan.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) diff -puN mm/vmscan.c~mm-vmscan-release-reacquire-lru_lock-on-pgdat-change mm/vmscan.c --- a/mm/vmscan.c~mm-vmscan-release-reacquire-lru_lock-on-pgdat-change +++ a/mm/vmscan.c @@ -3774,24 +3774,23 @@ 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)); + 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; @@ -3807,10 +3806,10 @@ void check_move_unevictable_pages(struct } } - 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 */ _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
