From 0f0f6ddbb97716de7af9a5bbd4519c0ec4e53b95 Mon Sep 17 00:00:00 2001
From: Erik Arvstedt <erik.arvstedt@gmail.com>
Date: Fri, 21 Aug 2020 22:35:57 +0200
Subject: [PATCH] netns: add comment about undesirable algorithmic complexity
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

We don't want to be Accidentally Quadratic™
---
 modules/netns-isolation.nix | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/modules/netns-isolation.nix b/modules/netns-isolation.nix
index e51d89e..050e183 100644
--- a/modules/netns-isolation.nix
+++ b/modules/netns-isolation.nix
@@ -16,6 +16,12 @@ let
   #   availableNetns.bitcoind = [ "clighting" ];
   #   and
   #   availableNetns.clighting = [ "bitcoind" ];
+  #
+  # FIXME: Although negligible for our purposes, this calculation's runtime
+  # is in the order of (number of connections * number of services),
+  # because attrsets and lists are fully copied on each update with '//' or '++'.
+  # This can only be improved with an update in the nix language.
+  #
   availableNetns = let
     # base = { clightning = [ "bitcoind" ]; ... }
     base = builtins.mapAttrs (n: v: