openwrt/target/linux/generic/hack-5.10/661-kernel-ct-size-the-hashtable-more-adequately.patch
Vincent Pelletier 15fbb91666 kernel: scale nf_conntrack_max more reasonably
Use the kernel's built-in formula for computing this value.
The value applied by OpenWRT's sysctl configuration file does not scale
with the available memory, under-using hardware capabilities.
Also, that formula also influences net.netfilter.nf_conntrack_buckets,
which should improve conntrack performance in average (fewer connections
per hashtable bucket).

Backport upstream commit for its effect on the number of connections per
hashtable bucket.

Apply a hack patch to set the RAM size divisor to a more reasonable value (2048,
down from 16384) for our use case, a typical router handling several thousands
of connections.

Signed-off-by: Vincent Pelletier <plr.vincent@gmail.com>
Signed-off-by: Rui Salvaterra <rsalvaterra@gmail.com>
2022-04-01 13:23:41 +01:00

26 lines
1006 B
Diff

From 804fbb3f2ec9283f7b778e057a68bfff440a0be6 Mon Sep 17 00:00:00 2001
From: Rui Salvaterra <rsalvaterra@gmail.com>
Date: Wed, 30 Mar 2022 22:51:55 +0100
Subject: [PATCH] kernel: ct: size the hashtable more adequately
To set the default size of the connection tracking hash table, a divider of
16384 becomes inadequate for a router handling lots of connections. Divide by
2048 instead, making the default size scale better with the available RAM.
Signed-off-by: Rui Salvaterra <rsalvaterra@gmail.com>
---
net/netfilter/nf_conntrack_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -2576,7 +2576,7 @@ int nf_conntrack_init_start(void)
if (!nf_conntrack_htable_size) {
nf_conntrack_htable_size
- = (((nr_pages << PAGE_SHIFT) / 16384)
+ = (((nr_pages << PAGE_SHIFT) / 2048)
/ sizeof(struct hlist_head));
if (BITS_PER_LONG >= 64 &&
nr_pages > (4 * (1024 * 1024 * 1024 / PAGE_SIZE)))