From b88e04237dcfbf1d7c4b7aa6023465f8e4a34f44 Mon Sep 17 00:00:00 2001
From: Tom Hughes <tom@compton.nu>
Date: Thu, 14 Dec 2023 17:43:25 +0000
Subject: [PATCH 1/1] Limit the number of threads used for low zoom renders

---
 cookbooks/tile/recipes/default.rb                   | 5 ++++-
 cookbooks/tile/templates/default/render-lowzoom.erb | 2 +-
 cookbooks/tile/templates/default/update-lowzoom.erb | 2 +-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/cookbooks/tile/recipes/default.rb b/cookbooks/tile/recipes/default.rb
index 40486dac6..4ceba4a18 100644
--- a/cookbooks/tile/recipes/default.rb
+++ b/cookbooks/tile/recipes/default.rb
@@ -282,6 +282,8 @@ end
 
 nodejs_package "carto"
 
+lowzoom_threads = [node.cpu_cores - 1, node[:memory][:total].to_f / 4194304].min.floor
+
 systemd_service "update-lowzoom@" do
   description "Low zoom tile update service for %i layer"
   user "tile"
@@ -312,7 +314,7 @@ node[:tile][:styles].each do |name, details|
     owner "root"
     group "root"
     mode "755"
-    variables :style => name
+    variables :style => name, :threads => lowzoom_threads
   end
 
   service "update-lowzoom@#{name}" do
@@ -606,6 +608,7 @@ template "/usr/local/bin/render-lowzoom" do
   owner "root"
   group "root"
   mode "755"
+  variables :threads => lowzoom_threads
 end
 
 systemd_service "render-lowzoom" do
diff --git a/cookbooks/tile/templates/default/render-lowzoom.erb b/cookbooks/tile/templates/default/render-lowzoom.erb
index 834eecc30..eb3e2e84e 100644
--- a/cookbooks/tile/templates/default/render-lowzoom.erb
+++ b/cookbooks/tile/templates/default/render-lowzoom.erb
@@ -16,7 +16,7 @@ function update_<%= style %>
     --timestamp=${timestamp} \
     --tile-dir=/srv/tile.openstreetmap.org/tiles \
     --socket=/var/run/renderd/renderd.sock \
-    --num-threads=<%= node.cpu_cores - 1 %> \
+    --num-threads=<%= @threads %> \
     --map="<%= style %>" \
     --max-load=<%= node.cpu_cores - 1 %> \
     --min-zoom=0 --max-zoom=12
diff --git a/cookbooks/tile/templates/default/update-lowzoom.erb b/cookbooks/tile/templates/default/update-lowzoom.erb
index 81e138076..0455493d9 100644
--- a/cookbooks/tile/templates/default/update-lowzoom.erb
+++ b/cookbooks/tile/templates/default/update-lowzoom.erb
@@ -12,7 +12,7 @@ function update_tiles
     --timestamp=$(stat -c %Y "/srv/tile.openstreetmap.org/styles/<%= @style %>/project.xml") \
     --tile-dir=/srv/tile.openstreetmap.org/tiles \
     --socket=/var/run/renderd/renderd.sock \
-    --num-threads=<%= node.cpu_cores - 1 %> \
+    --num-threads=<%= @threads %> \
     --map="<%= @style %>" \
     --max-load=<%= node.cpu_cores - 1 %> \
     --min-zoom=0 --max-zoom=12
-- 
2.39.5