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[v2,nf-next,5/7] netfilter: conntrack: resched gc again if eviction rate is high

Message ID 1472039755-14267-6-git-send-email-fw@strlen.de
State Changes Requested
Delegated to: Pablo Neira
Headers show

Commit Message

Florian Westphal Aug. 24, 2016, 11:55 a.m. UTC 
If we evicted a large fraction of the scanned conntrack entries re-schedule
the next gc cycle for immediate execution.

This triggers during tests where load is high, then drops to zero and
many connections will be in TW/CLOSE state with < 30 second timeouts.

Without this change it will take several minutes until conntrack count
comes back to normal.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/nf_conntrack_core.c | 6 ++++++
 1 file changed, 6 insertions(+)
diff mbox

Patch

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index e0a7889..f2133e8 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -938,6 +938,7 @@  static void gc_worker(struct work_struct *work)
 {
 	unsigned int i, goal, buckets = 0, expired_count = 0;
 	unsigned long next_run = GC_INTERVAL;
+	unsigned int ratio, scanned = 0;
 	struct conntrack_gc_work *gc_work;
 
 	gc_work = container_of(work, struct conntrack_gc_work, dwork.work);
@@ -962,6 +963,7 @@  static void gc_worker(struct work_struct *work)
 		hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[i], hnnode) {
 			tmp = nf_ct_tuplehash_to_ctrack(h);
 
+			scanned++;
 			if (nf_ct_is_expired(tmp)) {
 				nf_ct_gc_expired(tmp);
 				expired_count++;
@@ -981,6 +983,10 @@  static void gc_worker(struct work_struct *work)
 	if (gc_work->exiting)
 		return;
 
+	ratio = scanned ? expired_count * 100 / scanned : 0;
+	if (ratio >= 90)
+		next_run = 0;
+
 	gc_work->last_bucket = i;
 	schedule_delayed_work(&gc_work->dwork, next_run);
 }