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nixpkgs/modules/tasks/swap.nix
Eelco Dolstra eba8f94069 * jobAttrs -> jobs.
svn path=/nixos/trunk/; revision=17769
2009-10-12 18:09:34 +00:00

99 lines
2.2 KiB
Nix

{ config, pkgs, ... }:
with pkgs.lib;
let
inherit (pkgs) utillinux;
toPath = x: if x.device != null then x.device else "/dev/disk/by-label/${x.label}";
in
{
###### interface
options = {
swapDevices = mkOption {
default = [];
example = [
{ device = "/dev/hda7"; }
{ device = "/var/swapfile"; }
{ label = "bigswap"; }
];
description = ''
The swap devices and swap files. These must have been
initialised using <command>mkswap</command>. Each element
should be an attribute set specifying either the path of the
swap device or file (<literal>device</literal>) or the label
of the swap device (<literal>label</literal>, see
<command>mkswap -L</command>). Using a label is
recommended.
'';
type = types.list types.optionSet;
options = {
device = mkOption {
default = null;
example = "/dev/sda3";
type = types.nullOr types.string;
description = ''
Path of the device.
'';
};
label = mkOption {
default = null;
example = "swap";
type = types.nullOr types.string;
description = "
Label of the device. Can be used instead of <varname>device</varname>.
";
};
};
};
};
###### implementation
config = {
jobs.swap =
{ task = true;
startOn = ["startup" "new-devices"];
script =
''
swapDevices=${toString (map toPath config.swapDevices)}
for device in $swapDevices; do
${utillinux}/sbin/swapon "$device" || true
done
# Remove swap devices not listed in swapDevices.
for used in $(cat /proc/swaps | grep '^/' | sed 's/ .*//'); do
found=
for device in $swapDevices; do
device=$(readlink -f $device)
if test "$used" = "$device"; then found=1; fi
done
if test -z "$found"; then
${utillinux}/sbin/swapoff "$used" || true
fi
done
'';
};
};
}