vmscan: throttle direct reclaim when too many pages are isolated already (35cd7815) · Commits · 戴 / test

When way too many processes go into direct reclaim, it is possible for all of the pages to be taken off the LRU. One result of this is that the next process in the page reclaim code thinks there are no reclaimable pages left and triggers an out of memory kill. One solution to this problem is to never let so many processes into the page reclaim path that the entire LRU is emptied. Limiting the system to only having half of each inactive list isolated for reclaim should be safe. Signed-off-by:

Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by:

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

Linus Torvalds <torvalds@linux-foundation.org>

mm/vmscan.c

+33 −0

Original line number	Diff line number	Diff line
		@@ -1033,6 +1033,31 @@ int isolate_lru_page(struct page *page)
		return ret;
		}

		/*
		* Are there way too many processes in the direct reclaim path already?
		*/
		static int too_many_isolated(struct zone *zone, int file,
		struct scan_control *sc)
		{
		unsigned long inactive, isolated;

		if (current_is_kswapd())
		return 0;

		if (!scanning_global_lru(sc))
		return 0;

		if (file) {
		inactive = zone_page_state(zone, NR_INACTIVE_FILE);
		isolated = zone_page_state(zone, NR_ISOLATED_FILE);
		} else {
		inactive = zone_page_state(zone, NR_INACTIVE_ANON);
		isolated = zone_page_state(zone, NR_ISOLATED_ANON);
		}

		return isolated > inactive;
		}

		/*
		* shrink_inactive_list() is a helper for shrink_zone(). It returns the number
		* of reclaimed pages
		@@ -1048,6 +1073,14 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,
		struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
		int lumpy_reclaim = 0;

		while (unlikely(too_many_isolated(zone, file, sc))) {
		congestion_wait(WRITE, HZ/10);

		/* We are about to die and free our memory. Return now. */
		if (fatal_signal_pending(current))
		return SWAP_CLUSTER_MAX;
		}

		/*
		* If we need a large contiguous chunk of memory, or have
		* trouble getting a small set of contiguous pages, we

Admin message