From 9a48669f1e9d83422781f6f175c3be8bce80cd26 Mon Sep 17 00:00:00 2001
From: Joey Hess <joey@kodama.kitenet.net>
Date: Tue, 11 Nov 2008 15:40:04 -0500
Subject: [PATCH] avoid multiple ikiwiki cgi processes piling up, eating all
memory, and thrashing
Fixed by making the cgi wrapper wait on a cgilock.
If you had to set apache's MaxClients low to avoid ikiwiki thrashing
your server, you can now turn it up to a high value.
The downside to this is that a cgi call that doesn't need to call lockwiki
will be serialised by this so only one can run at a time. (For example,
do=search.) There are few such calls, and all of them call loadindex,
so each still eats gobs of memory, so serialising them still seems ok.
---
IkiWiki/Wrapper.pm | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/IkiWiki/Wrapper.pm b/IkiWiki/Wrapper.pm
index 99237d3b5..d7d7f65b8 100644
--- a/IkiWiki/Wrapper.pm
+++ b/IkiWiki/Wrapper.pm
@@ -44,6 +44,7 @@ EOF
}
my $check_commit_hook="";
+ my $pre_exec="";
if ($config{post_commit}) {
# Optimise checking !commit_hook_enabled() ,
# so that ikiwiki does not have to be started if the
@@ -67,6 +68,19 @@ EOF
}
EOF
}
+ elsif ($config{cgi}) {
+ # Avoid more than one ikiwiki cgi running at a time by
+ # taking a cgi lock. Since ikiwiki uses several MB of
+ # memory, a pile up of processes could cause thrashing
+ # otherwise.
+ $pre_exec=<<"EOF";
+ {
+ int fd=open("$config{wikistatedir}/cgilock", O_CREAT | O_RDWR);
+ if (fd != -1)
+ flock(fd, LOCK_EX);
+ }
+EOF
+ }
$Data::Dumper::Indent=0; # no newlines
my $configstring=Data::Dumper->Dump([\%config], ['*config']);
@@ -122,6 +136,7 @@ $envsave
exit(1);
}
+$pre_exec
execl("$this", "$this", NULL);
perror("exec $this");
exit(1);
--
2.39.5