diff options
| -rw-r--r-- | include/linux/writeback.h | 2 | ||||
| -rw-r--r-- | include/trace/events/writeback.h | 2 | ||||
| -rw-r--r-- | mm/vmscan.c | 18 |
3 files changed, 15 insertions, 7 deletions
diff --git a/include/linux/writeback.h b/include/linux/writeback.h index 5527d910ba3d..a3c0cbd7c888 100644 --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -46,7 +46,7 @@ enum writeback_sync_modes { */ enum wb_reason { WB_REASON_BACKGROUND, - WB_REASON_TRY_TO_FREE_PAGES, + WB_REASON_VMSCAN, WB_REASON_SYNC, WB_REASON_PERIODIC, WB_REASON_LAPTOP_TIMER, diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h index 2ccd9ccbf9ef..7bd8783a590f 100644 --- a/include/trace/events/writeback.h +++ b/include/trace/events/writeback.h @@ -31,7 +31,7 @@ #define WB_WORK_REASON \ EM( WB_REASON_BACKGROUND, "background") \ - EM( WB_REASON_TRY_TO_FREE_PAGES, "try_to_free_pages") \ + EM( WB_REASON_VMSCAN, "vmscan") \ EM( WB_REASON_SYNC, "sync") \ EM( WB_REASON_PERIODIC, "periodic") \ EM( WB_REASON_LAPTOP_TIMER, "laptop_timer") \ diff --git a/mm/vmscan.c b/mm/vmscan.c index 0d05f7f3b532..83c92b866afe 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1798,12 +1798,20 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, /* * If dirty pages are scanned that are not queued for IO, it - * implies that flushers are not keeping up. In this case, flag - * the pgdat PGDAT_DIRTY and kswapd will start writing pages from - * reclaim context. + * implies that flushers are not doing their job. This can + * happen when memory pressure pushes dirty pages to the end of + * the LRU before the dirty limits are breached and the dirty + * data has expired. It can also happen when the proportion of + * dirty pages grows not through writes but through memory + * pressure reclaiming all the clean cache. And in some cases, + * the flushers simply cannot keep up with the allocation + * rate. Nudge the flusher threads in case they are asleep, but + * also allow kswapd to start writing pages during reclaim. */ - if (stat.nr_unqueued_dirty == nr_taken) + if (stat.nr_unqueued_dirty == nr_taken) { + wakeup_flusher_threads(0, WB_REASON_VMSCAN); set_bit(PGDAT_DIRTY, &pgdat->flags); + } /* * If kswapd scans pages marked marked for immediate @@ -2787,7 +2795,7 @@ retry: writeback_threshold = sc->nr_to_reclaim + sc->nr_to_reclaim / 2; if (total_scanned > writeback_threshold) { wakeup_flusher_threads(laptop_mode ? 0 : total_scanned, - WB_REASON_TRY_TO_FREE_PAGES); + WB_REASON_VMSCAN); sc->may_writepage = 1; } } while (--sc->priority >= 0); |