Author: eelco
Date: Thu Nov 24 18:28:45 2011
New Revision: 30551
URL: https://nixos.org/websvn/nix/?rev=30551&sc=1
Log:
* Add a module for managing cgroups.
Added:
nixos/trunk/modules/services/system/cgroups.nix
Modified:
nixos/trunk/modules/module-list.nix
nixos/trunk/modules/system/activation/activation-script.nix
Modified: nixos/trunk/modules/module-list.nix
==============================================================================
--- nixos/trunk/modules/module-list.nix Thu Nov 24 18:14:28 2011 (r30550)
+++ nixos/trunk/modules/module-list.nix Thu Nov 24 18:28:45 2011 (r30551)
@@ -146,6 +146,7 @@
./services/scheduling/fcron.nix
./services/security/tor.nix
./services/security/torsocks.nix
+ ./services/system/cgroups.nix
./services/system/dbus.nix
./services/system/kerberos.nix
./services/system/nscd.nix
Added: nixos/trunk/modules/services/system/cgroups.nix
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ nixos/trunk/modules/services/system/cgroups.nix Thu Nov 24 18:28:45
2011 (r30551)
@@ -0,0 +1,140 @@
+{ config, pkgs, ... }:
+
+with pkgs.lib;
+
+let
+
+ cfg = config.services.cgroups;
+
+ cgconfigConf = pkgs.writeText "cgconfig.conf" cfg.groups;
+
+ cgrulesConf = pkgs.writeText "cgrules.conf" cfg.rules;
+
+in
+
+{
+
+ ###### interface
+
+ options = {
+
+ services.cgroups.enable = mkOption {
+ type = types.bool;
+ default = false;
+ description = ''
+ Whether to enable support for control groups, a Linux kernel
+ feature for resource management. It allows you to assign
+ processes to groups that share certain resource limits (e.g.,
+ CPU or memory). The <command>cgrulesengd</command> daemon
+ automatically assigns processes to the right cgroup depending
+ on the rules defined in
+ <option>services.cgroups.rules</option>.
+ '';
+ };
+
+ services.cgroups.groups = mkOption {
+ type = types.string;
+ default =
+ ''
+ mount {
+ cpu = /dev/cgroup/cpu;
+ }
+ '';
+ example =
+ ''
+ mount {
+ cpu = /dev/cgroup/cpu;
+ cpuacct = /dev/cgroup/cpuacct;
+ }
+
+ # Create a "www" cgroup with a lower share of the CPU (the
+ # default is 1024).
+ group www {
+ cpu {
+ cpu.shares = "500";
+ }
+ }
+ '';
+ description = ''
+ The contents of the <filename>cgconfig.conf</filename>
+ configuration file, which defines the cgroups.
+ '';
+ };
+
+ services.cgroups.rules = mkOption {
+ type = types.string;
+ default = "";
+ example =
+ ''
+ # All processes executed by the "wwwrun" uid should be
+ # assigned to the "www" CPU cgroup.
+ wwwrun cpu www
+ '';
+ description = ''
+ The contents of the <filename>cgrules.conf</filename>
+ configuration file, which determines to which cgroups
+ processes should be assigned by the
+ <command>cgrulesengd</command> daemon.
+ '';
+ };
+
+ };
+
+
+ ###### implementation
+
+ config = mkIf cfg.enable {
+
+ environment.systemPackages = [ pkgs.libcgroup ];
+
+ environment.etc =
+ [ { source = cgconfigConf;
+ target = "cgconfig.conf";
+ }
+ { source = cgrulesConf;
+ target = "cgrules.conf";
+ }
+ ];
+
+ jobs.cgroups =
+ { startOn = "startup";
+
+ description = "Control groups daemon";
+
+ path = [ pkgs.libcgroup pkgs.procps ];
+
+ preStart =
+ ''
+ # The daemon requires the userspace<->kernelspace netlink
+ # connector.
+ ${config.system.sbin.modprobe}/sbin/modprobe cn || true
+
+ cgclear || true
+
+ # Mount the cgroup hierarchies. Note: we refer to the
+ # store path of cgconfig.conf here to ensure that the job
+ # gets reloaded if the configuration changes.
+ cgconfigparser -l ${cgconfigConf}
+
+ # Move existing processes to the right cgroup.
+ cgclassify --cancel-sticky $(ps --no-headers -eL o tid) || true
+
+ # Force a restart if the rules change:
+ # ${cgrulesConf}
+ '';
+
+ # Run the daemon that moves new processes to the right cgroup.
+ exec = "cgrulesengd";
+
+ daemonType = "fork";
+
+ postStop =
+ ''
+ cgclear
+ '';
+ };
+
+
+ };
+
+}
Modified: nixos/trunk/modules/system/activation/activation-script.nix
==============================================================================
--- nixos/trunk/modules/system/activation/activation-script.nix Thu Nov 24
18:14:28 2011 (r30550)
+++ nixos/trunk/modules/system/activation/activation-script.nix Thu Nov 24
18:28:45 2011 (r30551)
@@ -129,14 +129,6 @@
mkdir -p /media
'';
- system.activationScripts.cgroups =
- ''
- if ! ${pkgs.sysvtools}/bin/mountpoint -q /dev/cgroup; then
- mkdir -p /dev/cgroup
- ${pkgs.utillinux}/bin/mount -t cgroup -o
freezer,cpuacct,cpu,cpuset none /dev/cgroup
- fi
- '';
-
};
}
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