diff options
Diffstat (limited to 'mm/vmscan.c')
| -rw-r--r-- | mm/vmscan.c | 62 |
1 files changed, 33 insertions, 29 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 5f80d018bffa..4898daf074cf 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -695,7 +695,9 @@ static unsigned long shrink_page_list(struct list_head *page_list, struct zone *zone, struct scan_control *sc, enum ttu_flags ttu_flags, + unsigned long *ret_nr_dirty, unsigned long *ret_nr_unqueued_dirty, + unsigned long *ret_nr_congested, unsigned long *ret_nr_writeback, unsigned long *ret_nr_immediate, bool force_reclaim) @@ -1017,20 +1019,13 @@ keep: VM_BUG_ON(PageLRU(page) || PageUnevictable(page)); } - /* - * Tag a zone as congested if all the dirty pages encountered were - * backed by a congested BDI. In this case, reclaimers should just - * back off and wait for congestion to clear because further reclaim - * will encounter the same problem - */ - if (nr_dirty && nr_dirty == nr_congested && global_reclaim(sc)) - zone_set_flag(zone, ZONE_CONGESTED); - free_hot_cold_page_list(&free_pages, 1); list_splice(&ret_pages, page_list); count_vm_events(PGACTIVATE, pgactivate); mem_cgroup_uncharge_end(); + *ret_nr_dirty += nr_dirty; + *ret_nr_congested += nr_congested; *ret_nr_unqueued_dirty += nr_unqueued_dirty; *ret_nr_writeback += nr_writeback; *ret_nr_immediate += nr_immediate; @@ -1045,7 +1040,7 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone, .priority = DEF_PRIORITY, .may_unmap = 1, }; - unsigned long ret, dummy1, dummy2, dummy3; + unsigned long ret, dummy1, dummy2, dummy3, dummy4, dummy5; struct page *page, *next; LIST_HEAD(clean_pages); @@ -1057,8 +1052,8 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone, } ret = shrink_page_list(&clean_pages, zone, &sc, - TTU_UNMAP|TTU_IGNORE_ACCESS, - &dummy1, &dummy2, &dummy3, true); + TTU_UNMAP|TTU_IGNORE_ACCESS, + &dummy1, &dummy2, &dummy3, &dummy4, &dummy5, true); list_splice(&clean_pages, page_list); __mod_zone_page_state(zone, NR_ISOLATED_FILE, -ret); return ret; @@ -1352,6 +1347,8 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, unsigned long nr_scanned; unsigned long nr_reclaimed = 0; unsigned long nr_taken; + unsigned long nr_dirty = 0; + unsigned long nr_congested = 0; unsigned long nr_unqueued_dirty = 0; unsigned long nr_writeback = 0; unsigned long nr_immediate = 0; @@ -1396,8 +1393,9 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, return 0; nr_reclaimed = shrink_page_list(&page_list, zone, sc, TTU_UNMAP, - &nr_unqueued_dirty, &nr_writeback, &nr_immediate, - false); + &nr_dirty, &nr_unqueued_dirty, &nr_congested, + &nr_writeback, &nr_immediate, + false); spin_lock_irq(&zone->lru_lock); @@ -1431,7 +1429,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, * same way balance_dirty_pages() manages. * * This scales the number of dirty pages that must be under writeback - * before throttling depending on priority. It is a simple backoff + * before a zone gets flagged ZONE_WRITEBACK. It is a simple backoff * function that has the most effect in the range DEF_PRIORITY to * DEF_PRIORITY-2 which is the priority reclaim is considered to be * in trouble and reclaim is considered to be in trouble. @@ -1442,12 +1440,14 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, * ... * DEF_PRIORITY-6 For SWAP_CLUSTER_MAX isolated pages, throttle if any * isolated page is PageWriteback + * + * Once a zone is flagged ZONE_WRITEBACK, kswapd will count the number + * of pages under pages flagged for immediate reclaim and stall if any + * are encountered in the nr_immediate check below. */ if (nr_writeback && nr_writeback >= - (nr_taken >> (DEF_PRIORITY - sc->priority))) { + (nr_taken >> (DEF_PRIORITY - sc->priority))) zone_set_flag(zone, ZONE_WRITEBACK); - wait_iff_congested(zone, BLK_RW_ASYNC, HZ/10); - } /* * memcg will stall in page writeback so only consider forcibly @@ -1455,6 +1455,13 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, */ if (global_reclaim(sc)) { /* + * Tag a zone as congested if all the dirty pages scanned were + * backed by a congested BDI and wait_iff_congested will stall. + */ + if (nr_dirty && nr_dirty == nr_congested) + zone_set_flag(zone, ZONE_CONGESTED); + + /* * If dirty pages are scanned that are not queued for IO, it * implies that flushers are not keeping up. In this case, flag * the zone ZONE_TAIL_LRU_DIRTY and kswapd will start writing @@ -1474,6 +1481,14 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, congestion_wait(BLK_RW_ASYNC, HZ/10); } + /* + * Stall direct reclaim for IO completions if underlying BDIs or zone + * is congested. Allow kswapd to continue until it starts encountering + * unqueued dirty pages or cycling through the LRU too quickly. + */ + if (!sc->hibernation_mode && !current_is_kswapd()) + wait_iff_congested(zone, BLK_RW_ASYNC, HZ/10); + trace_mm_vmscan_lru_shrink_inactive(zone->zone_pgdat->node_id, zone_idx(zone), nr_scanned, nr_reclaimed, @@ -2374,17 +2389,6 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, WB_REASON_TRY_TO_FREE_PAGES); sc->may_writepage = 1; } - - /* Take a nap, wait for some writeback to complete */ - if (!sc->hibernation_mode && sc->nr_scanned && - sc->priority < DEF_PRIORITY - 2) { - struct zone *preferred_zone; - - first_zones_zonelist(zonelist, gfp_zone(sc->gfp_mask), - &cpuset_current_mems_allowed, - &preferred_zone); - wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/10); - } } while (--sc->priority >= 0); out: |