Subject: Re: [PATCH net-next] docs: net: document neigh gc_interval and gc_stale_time sysctls

From: Jakub Kicinski <[email-masked]>
Date: Fri, 20 Feb 2026 16:43:44 -0800

On Thu, 19 Feb 2026 17:21:58 +0100 Gabriel Goller wrote:
> +neigh/default/gc_interval - INTEGER
> +	How often the garbage collector for neighbor entries should run. This
> +	value applies to the entire table, not individual entries.
> +
> +	Default: 30 seconds

AI suggests that this value is not actually currently used
in our implementation. I can't find any use either, TBH.
It's read and can be written but it's seemingly not used for anything.

> +neigh/default/gc_stale_time - INTEGER
> +	Determines how long a neighbor entry can remain unused before it is
> +	considered stale and eligible for garbage collection. Entries that have
> +	not been used for longer than this time will be removed by the garbage
> +	collector, unless they have active references, are marked as PERMANENT,
> +	or carry the NTF_EXT_LEARNED or NTF_EXT_VALIDATED flag.
> +
> +	Default: 60 seconds

AI adds:

  Important caveat: This check is only reached when total_entries >= gc_thresh1
  (line 1000-1001). Below that threshold, the periodic GC skips the scan
  entirely.

If true I think we should mention that ?
-- 
pw-bot: cr