mm: vmscan: remove old flusher wakeup from direct reclaim path (bbef9384) · Commits · 戴 / test

Direct reclaim has been replaced by kswapd reclaim in pretty much all common memory pressure situations, so this code most likely doesn't accomplish the described effect anymore. The previous patch wakes up flushers for all reclaimers when we encounter dirty pages at the tail end of the LRU. Remove the crufty old direct reclaim invocation. Link: http://lkml.kernel.org/r/20170123181641.23938-4-hannes@cmpxchg.org Signed-off-by:

Johannes Weiner <hannes@cmpxchg.org> Acked-by:

Minchan Kim <minchan@kernel.org> Acked-by:

Michal Hocko <mhocko@suse.com> Acked-by:

Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/vmscan.c

+0 −17

Original line number	Diff line number	Diff line
		@@ -2757,8 +2757,6 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
		struct scan_control *sc)
		{
		int initial_priority = sc->priority;
		unsigned long total_scanned = 0;
		unsigned long writeback_threshold;
		retry:
		delayacct_freepages_start();

		@@ -2771,7 +2769,6 @@ retry:
		sc->nr_scanned = 0;
		shrink_zones(zonelist, sc);

		total_scanned += sc->nr_scanned;
		if (sc->nr_reclaimed >= sc->nr_to_reclaim)
		break;

		@@ -2784,20 +2781,6 @@ retry:
		*/
		if (sc->priority < DEF_PRIORITY - 2)
		sc->may_writepage = 1;

		/*
		* Try to write back as many pages as we just scanned. This
		* tends to cause slow streaming writers to write data to the
		* disk smoothly, at the dirtying rate, which is nice. But
		* that's undesirable in laptop mode, where we want lumpy
		* writeout. So in laptop mode, write out the whole world.
		*/
		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_VMSCAN);
		sc->may_writepage = 1;
		}
		} while (--sc->priority >= 0);

		delayacct_freepages_end();

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