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authorMel Gorman <mgorman@techsingularity.net>2016-07-28 15:47:31 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-28 16:07:41 -0700
commit5a1c84b404a7176b8b36e2a0041b6f0adb3151a3 (patch)
treeff98e242c5d4d3a24ca49f6ddc707028aeb938f9 /mm/vmscan.c
parentbb4cc2bea6df7854d629bff114ca03237cc718d6 (diff)
downloadlinux-5a1c84b404a7176b8b36e2a0041b6f0adb3151a3.tar.gz
mm: remove reclaim and compaction retry approximations
If per-zone LRU accounting is available then there is no point
approximating whether reclaim and compaction should retry based on pgdat
statistics.  This is effectively a revert of "mm, vmstat: remove zone
and node double accounting by approximating retries" with the difference
that inactive/active stats are still available.  This preserves the
history of why the approximation was retried and why it had to be
reverted to handle OOM kills on 32-bit systems.

Link: http://lkml.kernel.org/r/1469110261-7365-4-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmscan.c')
-rw-r--r--mm/vmscan.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 222d5403dd4b..134381a20099 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -194,6 +194,24 @@ static bool sane_reclaim(struct scan_control *sc)
 }
 #endif
 
+/*
+ * This misses isolated pages which are not accounted for to save counters.
+ * As the data only determines if reclaim or compaction continues, it is
+ * not expected that isolated pages will be a dominating factor.
+ */
+unsigned long zone_reclaimable_pages(struct zone *zone)
+{
+	unsigned long nr;
+
+	nr = zone_page_state_snapshot(zone, NR_ZONE_INACTIVE_FILE) +
+		zone_page_state_snapshot(zone, NR_ZONE_ACTIVE_FILE);
+	if (get_nr_swap_pages() > 0)
+		nr += zone_page_state_snapshot(zone, NR_ZONE_INACTIVE_ANON) +
+			zone_page_state_snapshot(zone, NR_ZONE_ACTIVE_ANON);
+
+	return nr;
+}
+
 unsigned long pgdat_reclaimable_pages(struct pglist_data *pgdat)
 {
 	unsigned long nr;