diff --git a/mm/vmscan.c b/mm/vmscan.c index 87e4d6a6dc11..ae3bf0a09cdd 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1642,18 +1642,6 @@ static void move_active_pages_to_lru(struct zone *zone, unsigned long pgmoved = 0; struct page *page; - if (buffer_heads_over_limit) { - spin_unlock_irq(&zone->lru_lock); - list_for_each_entry(page, list, lru) { - if (page_has_private(page) && trylock_page(page)) { - if (page_has_private(page)) - try_to_release_page(page, 0); - unlock_page(page); - } - } - spin_lock_irq(&zone->lru_lock); - } - while (!list_empty(list)) { struct lruvec *lruvec; @@ -1735,6 +1723,14 @@ static void shrink_active_list(unsigned long nr_to_scan, continue; } + if (unlikely(buffer_heads_over_limit)) { + if (page_has_private(page) && trylock_page(page)) { + if (page_has_private(page)) + try_to_release_page(page, 0); + unlock_page(page); + } + } + if (page_referenced(page, 0, mz->mem_cgroup, &vm_flags)) { nr_rotated += hpage_nr_pages(page); /* @@ -2238,6 +2234,14 @@ static bool shrink_zones(int priority, struct zonelist *zonelist, unsigned long nr_soft_scanned; bool aborted_reclaim = false; + /* + * If the number of buffer_heads in the machine exceeds the maximum + * allowed level, force direct reclaim to scan the highmem zone as + * highmem pages could be pinning lowmem pages storing buffer_heads + */ + if (buffer_heads_over_limit) + sc->gfp_mask |= __GFP_HIGHMEM; + for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(sc->gfp_mask), sc->nodemask) { if (!populated_zone(zone)) @@ -2727,6 +2731,17 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order, */ age_active_anon(zone, &sc, priority); + /* + * If the number of buffer_heads in the machine + * exceeds the maximum allowed level and this node + * has a highmem zone, force kswapd to reclaim from + * it to relieve lowmem pressure. + */ + if (buffer_heads_over_limit && is_highmem_idx(i)) { + end_zone = i; + break; + } + if (!zone_watermark_ok_safe(zone, order, high_wmark_pages(zone), 0, 0)) { end_zone = i; @@ -2802,7 +2817,8 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order, COMPACT_SKIPPED) testorder = 0; - if (!zone_watermark_ok_safe(zone, testorder, + if ((buffer_heads_over_limit && is_highmem_idx(i)) || + !zone_watermark_ok_safe(zone, order, high_wmark_pages(zone) + balance_gap, end_zone, 0)) { shrink_zone(priority, zone, &sc);