docs: net: document neigh gc_interval sysctl

Add entry for the neigh/default/gc_interval sysctl. This sysctl is
unused since kernel v2.6.8.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Gabriel Goller <g.goller@proxmox.com>
Link: https://patch.msgid.link/20260225095822.44050-1-g.goller@proxmox.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index d1eeb5323af00c250423849d648b9d5b205373ec..265158534cda53fb55f3a9f9a000221e4124b9b2 100644 (file)
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -202,6 +202,13 @@ neigh/default/gc_thresh3 - INTEGER
 
        Default: 1024
 
+neigh/default/gc_interval - INTEGER
+       Specifies how often the garbage collector for neighbor entries
+       should run. This value applies to the entire table, not
+       individual entries. Unused since kernel v2.6.8.
+
+       Default: 30 seconds
+
 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