1 files changed, 20 insertions, 19 deletions

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 6feb5d370319..4e8083c5e01d 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -85,9 +85,11 @@ static __read_mostly DEFINE_SPINLOCK(nf_conntrack_locks_all_lock);
 static __read_mostly bool nf_conntrack_locks_all;
 
 /* every gc cycle scans at most 1/GC_MAX_BUCKETS_DIV part of table */
-#define GC_MAX_BUCKETS_DIV	64u
-/* upper bound of scan intervals */
-#define GC_INTERVAL_MAX		(2 * HZ)
+#define GC_MAX_BUCKETS_DIV	128u
+/* upper bound of full table scan */
+#define GC_MAX_SCAN_JIFFIES	(16u * HZ)
+/* desired ratio of entries found to be expired */
+#define GC_EVICT_RATIO	50u
 
 static struct conntrack_gc_work conntrack_gc_work;
 
@@ -936,6 +938,7 @@ static noinline int early_drop(struct net *net, unsigned int _hash)
 
 static void gc_worker(struct work_struct *work)
 {
+	unsigned int min_interval = max(HZ / GC_MAX_BUCKETS_DIV, 1u);
 	unsigned int i, goal, buckets = 0, expired_count = 0;
 	struct conntrack_gc_work *gc_work;
 	unsigned int ratio, scanned = 0;
@@ -994,27 +997,25 @@ static void gc_worker(struct work_struct *work)
 	 * 1. Minimize time until we notice a stale entry
 	 * 2. Maximize scan intervals to not waste cycles
 	 *
-	 * Normally, expired_count will be 0, this increases the next_run time
-	 * to priorize 2) above.
+	 * Normally, expire ratio will be close to 0.
 	 *
-	 * As soon as a timed-out entry is found, move towards 1) and increase
-	 * the scan frequency.
-	 * In case we have lots of evictions next scan is done immediately.
+	 * As soon as a sizeable fraction of the entries have expired
+	 * increase scan frequency.
 	 */
 	ratio = scanned ? expired_count * 100 / scanned : 0;
-	if (ratio >= 90) {
-		gc_work->next_gc_run = 0;
-		next_run = 0;
-	} else if (expired_count) {
-		gc_work->next_gc_run /= 2U;
-		next_run = msecs_to_jiffies(1);
+	if (ratio > GC_EVICT_RATIO) {
+		gc_work->next_gc_run = min_interval;
 	} else {
-		if (gc_work->next_gc_run < GC_INTERVAL_MAX)
-			gc_work->next_gc_run += msecs_to_jiffies(1);
+		unsigned int max = GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV;
 
-		next_run = gc_work->next_gc_run;
+		BUILD_BUG_ON((GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV) == 0);
+
+		gc_work->next_gc_run += min_interval;
+		if (gc_work->next_gc_run > max)
+			gc_work->next_gc_run = max;
 	}
 
+	next_run = gc_work->next_gc_run;
 	gc_work->last_bucket = i;
 	queue_delayed_work(system_long_wq, &gc_work->dwork, next_run);
 }
@@ -1022,7 +1023,7 @@ static void gc_worker(struct work_struct *work)
 static void conntrack_gc_work_init(struct conntrack_gc_work *gc_work)
 {
 	INIT_DELAYED_WORK(&gc_work->dwork, gc_worker);
-	gc_work->next_gc_run = GC_INTERVAL_MAX;
+	gc_work->next_gc_run = HZ;
 	gc_work->exiting = false;
 }
 
@@ -1914,7 +1915,7 @@ int nf_conntrack_init_start(void)
 	nf_ct_untracked_status_or(IPS_CONFIRMED | IPS_UNTRACKED);
 
 	conntrack_gc_work_init(&conntrack_gc_work);
-	queue_delayed_work(system_long_wq, &conntrack_gc_work.dwork, GC_INTERVAL_MAX);
+	queue_delayed_work(system_long_wq, &conntrack_gc_work.dwork, HZ);
 
 	return 0;