mm: compaction: fix the page state calculation in too_many_isolated
Commit "mm: vmscan: fix the page state calculation in too_many_isolated"
fixed an issue where a number of tasks were blocked in reclaim path
for seconds, because of vmstat_diff not being synced in time.
A similar problem can happen in isolate_migratepages_block, where
similar calculation is performed. This patch fixes that.
Change-Id: Ie74f108ef770da688017b515fe37faea6f384589
Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org>
diff --git a/mm/compaction.c b/mm/compaction.c
index 70e6bec..f002a7f 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -635,20 +635,52 @@
}
/* Similar to reclaim, but different enough that they don't share logic */
-static bool too_many_isolated(struct zone *zone)
+static bool __too_many_isolated(struct zone *zone, int safe)
{
unsigned long active, inactive, isolated;
- inactive = node_page_state(zone->zone_pgdat, NR_INACTIVE_FILE) +
+ if (safe) {
+ inactive = node_page_state_snapshot(zone->zone_pgdat,
+ NR_INACTIVE_FILE) +
+ node_page_state_snapshot(zone->zone_pgdat,
+ NR_INACTIVE_ANON);
+ active = node_page_state_snapshot(zone->zone_pgdat,
+ NR_ACTIVE_FILE) +
+ node_page_state_snapshot(zone->zone_pgdat,
+ NR_ACTIVE_ANON);
+ isolated = node_page_state_snapshot(zone->zone_pgdat,
+ NR_ISOLATED_FILE) +
+ node_page_state_snapshot(zone->zone_pgdat,
+ NR_ISOLATED_ANON);
+ } else {
+ inactive = node_page_state(zone->zone_pgdat, NR_INACTIVE_FILE) +
node_page_state(zone->zone_pgdat, NR_INACTIVE_ANON);
- active = node_page_state(zone->zone_pgdat, NR_ACTIVE_FILE) +
+ active = node_page_state(zone->zone_pgdat, NR_ACTIVE_FILE) +
node_page_state(zone->zone_pgdat, NR_ACTIVE_ANON);
- isolated = node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE) +
+ isolated = node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE) +
node_page_state(zone->zone_pgdat, NR_ISOLATED_ANON);
+ }
return isolated > (inactive + active) / 2;
}
+/* Similar to reclaim, but different enough that they don't share logic */
+static bool too_many_isolated(struct compact_control *cc)
+{
+ /*
+ * __too_many_isolated(safe=0) is fast but inaccurate, because it
+ * doesn't account for the vm_stat_diff[] counters. So if it looks
+ * like too_many_isolated() is about to return true, fall back to the
+ * slower, more accurate zone_page_state_snapshot().
+ */
+ if (unlikely(__too_many_isolated(cc->zone, 0))) {
+ if (cc->mode != MIGRATE_ASYNC)
+ return __too_many_isolated(cc->zone, 1);
+ }
+
+ return false;
+}
+
/**
* isolate_migratepages_block() - isolate all migrate-able pages within
* a single pageblock
@@ -686,7 +718,7 @@
* list by either parallel reclaimers or compaction. If there are,
* delay for some time until fewer pages are isolated
*/
- while (unlikely(too_many_isolated(zone))) {
+ while (unlikely(too_many_isolated(cc))) {
/* async migration should just abort */
if (cc->mode == MIGRATE_ASYNC)
return 0;