Mention dirty expiration as a condition: we need dirty data that is too recent for periodic flushing and not large enough for waking up limit flushing. As per Mel.
Link: http://lkml.kernel.org/r/20170126174739.ga30...@cmpxchg.org Signed-off-by: Johannes Weiner <han...@cmpxchg.org> Cc: Hillf Danton <hillf...@alibaba-inc.com> Cc: Mel Gorman <mgor...@suse.de> Signed-off-by: Andrew Morton <a...@linux-foundation.org> --- mm/vmscan.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 56ea8d24041f..83c92b866afe 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1799,14 +1799,14 @@ 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 doing their job. This can - * happen when memory pressure pushes dirty pages to the end - * of the LRU without the dirty limits being breached. 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. + * 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) { wakeup_flusher_threads(0, WB_REASON_VMSCAN); -- 2.11.0
