Commit "3611badc1baa" (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,
similar calculation is performed. This patch fixes that.
Signed-off-by: Vinayak Menon <vinmenon@xxxxxxxxxxxxxx>
---
mm/compaction.c | 32 +++++++++++++++++++++++++++-----
1 file changed, 27 insertions(+), 5 deletions(-)
diff --git a/mm/compaction.c b/mm/compaction.c
index 546e571..2d9730d 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -537,21 +537,43 @@ static void acct_isolated(struct zone *zone, struct compact_control *cc)
mod_zone_page_state(zone, NR_ISOLATED_FILE, count[1]);
}
-/* 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 = zone_page_state(zone, NR_INACTIVE_FILE) +
+ if (safe) {
+ inactive = zone_page_state_snapshot(zone, NR_INACTIVE_FILE) +
+ zone_page_state_snapshot(zone, NR_INACTIVE_ANON);
+ active = zone_page_state_snapshot(zone, NR_ACTIVE_FILE) +
+ zone_page_state_snapshot(zone, NR_ACTIVE_ANON);
+ isolated = zone_page_state_snapshot(zone, NR_ISOLATED_FILE) +
+ zone_page_state_snapshot(zone, NR_ISOLATED_ANON);
+ } else {
+ inactive = zone_page_state(zone, NR_INACTIVE_FILE) +
zone_page_state(zone, NR_INACTIVE_ANON);
- active = zone_page_state(zone, NR_ACTIVE_FILE) +
+ active = zone_page_state(zone, NR_ACTIVE_FILE) +
zone_page_state(zone, NR_ACTIVE_ANON);
- isolated = zone_page_state(zone, NR_ISOLATED_FILE) +
+ isolated = zone_page_state(zone, NR_ISOLATED_FILE) +
zone_page_state(zone, 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 zone *zone)
+{
+ /*
+ * __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(zone, 0)))
+ return __too_many_isolated(zone, 1);
+ return 0;
+}
+
/**
* isolate_migratepages_block() - isolate all migrate-able pages within
* a single pageblock
--
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