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>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 222d540..134381a 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -194,6 +194,24 @@
}
#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;