Raise MaxRequestWorkers to 400

Browsing costs two workers rather than one, because the front vhost proxies
to Anubis and Anubis proxies back into this same apache on port 3001. The
Debian default of 150 caps concurrent browsing at 75, which the front door
still reaches in bursts: AH00484 fired 34 times in two weeks outside the
window the hourly restart accounts for.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: hsbt

recipes/apache2.rb

@@ -33,6 +33,17 @@
   to '../conf-available/cgit.conf'
 end
 
+remote_file '/etc/apache2/conf-available/mpm-tuning.conf' do
+  mode  '644'
+  owner 'root'
+  notifies :restart, 'service[apache2]'
+end
+
+link '/etc/apache2/conf-enabled/mpm-tuning.conf' do
+  to '../conf-available/mpm-tuning.conf'
+  notifies :restart, 'service[apache2]'
+end
+
 %w[git svn].each do |subdomain|
   remote_file "/etc/apache2/sites-available/#{subdomain}.ruby-lang.org.conf" do
     mode  '644'

recipes/files/etc/apache2/conf-available/mpm-tuning.conf

@@ -0,0 +1,12 @@
+# Overrides what mods-available/mpm_event.conf sets. That file is a dpkg
+# conffile, so it is left alone and this one wins by being included later.
+#
+# Browsing costs two workers rather than one: the front vhost proxies to Anubis
+# and Anubis proxies back into this same apache on port 3001. Debian's default
+# of 150 therefore caps concurrent browsing at 75, and AH00484 fires on bursts
+# even though steady state is 35 to 55 busy workers. 16 children of 25 threads
+# is the event MPM's own ServerLimit, and costs about 400 MB out of 7 GB.
+<IfModule mpm_event_module>
+	ServerLimit			 16
+	MaxRequestWorkers	400
+</IfModule>