* Upstart job to start swapping to the devices or files listed in the

swapDevices option.

svn path=/nixos/trunk/; revision=7448

configuration/options.nix

@@ -14,7 +14,7 @@
     description = "
       Whether to find the root device automatically by searching for a
       device with the right label.  If this option is off, then a root
-      file system must be specified using <option>filesystems</option>.
+      file system must be specified using <option>fileSystems</option>.
     ";
   }
 
@@ -141,7 +141,8 @@
 
   
   {
-    name = ["filesystems"];
+    name = ["fileSystems"];
+    default = [];
     example = [
       { mountPoint = "/";
         device = "/dev/hda1";
@@ -155,11 +156,12 @@
     ];
     description = "
       The file systems to be mounted.  It must include an entry for
-      the root directory (<literal>mountPoint = \"/\"</literal>).
-      Each entry in the list is an attribute set with the following
-      fields: <literal>mountPoint</literal>,
-      <literal>device</literal>, <literal>filesystem</literal> (a file
-      system type recognised by <command>mount</command>; defaults to
+      the root directory (<literal>mountPoint = \"/\"</literal>) if
+      <literal>boot.autoDetectRootDevice</literal> is not set.  Each
+      entry in the list is an attribute set with the following fields:
+      <literal>mountPoint</literal>, <literal>device</literal>,
+      <literal>filesystem</literal> (a file system type recognised by
+      <command>mount</command>; defaults to
       <literal>\"auto\"</literal>), <literal>autoMount</literal> (a
       boolean indicating whether the file system is mounted
       automatically; defaults to <literal>true</literal>) and
@@ -170,6 +172,17 @@
   }
 
 
+  {
+    name = ["swapDevices"];
+    default = [];
+    example = ["/dev/hda7" "/dev/hdb3" "/var/swapfile"];
+    description = "
+      The swap devices and swap files.  These must have been
+      initialised using <command>mkswap</command>.
+    ";
+  }
+
+
   {
     name = ["services" "extraJobs"];
     default = [];

configuration/system.nix

@@ -76,7 +76,7 @@ rec {
     rootDevice =
       (pkgs.library.findSingle (fs: fs.mountPoint == "/")
         (abort "No root mount point declared.")
-        (config.get ["filesystems"])).device;
+        (config.get ["fileSystems"])).device;
     rootLabel = config.get ["boot" "rootLabel"];
     inherit stage2Init;
     modulesDir = modulesClosure;

configuration/upstart.nix

@@ -31,6 +31,12 @@ import ../upstart-jobs/gather.nix {
       inherit (pkgs) kernel module_init_tools;
     })
       
+    # Swapping.
+    (import ../upstart-jobs/swap.nix {
+      inherit (pkgs) utillinux;
+      swapDevices = config.get ["swapDevices"];
+    })
+
     # Network interfaces.
     (import ../upstart-jobs/network-interfaces.nix {
       inherit (pkgs) nettools kernel module_init_tools;

instances/examples/basic.nix

@@ -5,11 +5,13 @@
     grubDevice = "/dev/hda";
   };
 
-  filesystems = [
+  fileSystems = [
     { mountPoint = "/";
       device = "/dev/hda1";
     }
   ];
+
+  swapDevices = ["/dev/hdb1"];
   
   services = {
     sshd = {

upstart-jobs/swap.nix

@@ -0,0 +1,29 @@
+{utillinux, swapDevices}:
+
+{
+  name = "swap";
+  
+  job = "
+start on startup
+
+script
+    for device in ${toString swapDevices}; do
+        # !!! Check whether we are already swapping to $device.
+        ${utillinux}/sbin/swapon \"$device\" || true
+    done
+
+    # Remove swap devices not listed in swapDevices.
+    for used in $(cat /proc/swaps | grep '^/' | sed 's/ .*//'); do
+        found=
+        for device in ${toString swapDevices}; do
+            if test \"$used\" = \"$device\"; then found=1; fi
+        done
+        if test -z \"$found\"; then
+            ${utillinux}/sbin/swapoff \"$used\" || true
+        fi
+    done
+    
+end script
+  ";
+
+}