[PATCH] netfilter: conntrack: fix nf_conntrack_expect_max default value in documentation

[PATCH] netfilter: conntrack: fix nf_conntrack_expect_max default value in documentation

[Shaojie Sun]

The documentation for nf_conntrack_expect_max incorrectly states that the
default value is nf_conntrack_buckets / 256. However, the code in
nf_conntrack_expect_init() shows:

    nf_ct_expect_hsize = nf_conntrack_htable_size / 256;
    nf_ct_expect_max = nf_ct_expect_hsize * 4;

This means the default value is actually nf_conntrack_buckets / 64
(i.e. 4 times the hash table size, which defaults to
nf_conntrack_buckets / 256).

Fix the documentation to reflect the correct default value and add
explanation of the calculation.

Signed-off-by: Shaojie Sun <sunshaojie@kylinos.cn>
---
 Documentation/networking/nf_conntrack-sysctl.rst | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Documentation/networking/nf_conntrack-sysctl.rst b/Documentation/networking/nf_conntrack-sysctl.rst
index 35f889259fcd..77521253fe22 100644
--- a/Documentation/networking/nf_conntrack-sysctl.rst
+++ b/Documentation/networking/nf_conntrack-sysctl.rst
@@ -44,7 +44,8 @@ nf_conntrack_events - BOOLEAN
 
 nf_conntrack_expect_max - INTEGER
 	Maximum size of expectation table.  Default value is
-	nf_conntrack_buckets / 256. Minimum is 1.
+	nf_conntrack_buckets / 64 (i.e. 4 times the hash table size,
+	which defaults to nf_conntrack_buckets / 256). Minimum is 1.
 
 nf_conntrack_frag6_high_thresh - INTEGER
 	default 262144
-- 
2.50.1

Re: [PATCH] netfilter: conntrack: fix nf_conntrack_expect_max default value in documentation

[Pablo Neira Ayuso]

On Thu, Aug 20, 2026 at 08:57:18PM +0800, Shaojie Sun wrote:
> The documentation for nf_conntrack_expect_max incorrectly states that the
> default value is nf_conntrack_buckets / 256. However, the code in
> nf_conntrack_expect_init() shows:
> 
>     nf_ct_expect_hsize = nf_conntrack_htable_size / 256;
>     nf_ct_expect_max = nf_ct_expect_hsize * 4;
> 
> This means the default value is actually nf_conntrack_buckets / 64
> (i.e. 4 times the hash table size, which defaults to
> nf_conntrack_buckets / 256).
> 
> Fix the documentation to reflect the correct default value and add
> explanation of the calculation.
> 
> Signed-off-by: Shaojie Sun <sunshaojie@kylinos.cn>
> ---
>  Documentation/networking/nf_conntrack-sysctl.rst | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/networking/nf_conntrack-sysctl.rst b/Documentation/networking/nf_conntrack-sysctl.rst
> index 35f889259fcd..77521253fe22 100644
> --- a/Documentation/networking/nf_conntrack-sysctl.rst
> +++ b/Documentation/networking/nf_conntrack-sysctl.rst
> @@ -44,7 +44,8 @@ nf_conntrack_events - BOOLEAN
>  
>  nf_conntrack_expect_max - INTEGER
>  	Maximum size of expectation table.  Default value is
> -	nf_conntrack_buckets / 256. Minimum is 1.
> +	nf_conntrack_buckets / 64 (i.e. 4 times the hash table size,
> +	which defaults to nf_conntrack_buckets / 256). Minimum is 1.

I'd suggest to remove the parens explaination here.

>  
>  nf_conntrack_frag6_high_thresh - INTEGER
>  	default 262144
> -- 
> 2.50.1
>