[jackhill/guix/guix.git] / gnu / services / linux.scm

;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2020 Maxim Cournoyer <maxim.cournoyer@gmail.com>
;;; Copyright © 2020 Brice Waegeneire <brice@waegenei.re>
;;; Copyright © 2020 Efraim Flashner <efraim@flashner.co.il>
;;; Copyright © 2021 raid5atemyhomework <raid5atemyhomework@protonmail.com>
;;; Copyright © 2021 B. Wilson <elaexuotee@wilsonb.com>
;;; Copyright © 2022 Josselin Poiret <dev@jpoiret.xyz>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.

(define-module (gnu services linux)
  #:use-module (guix diagnostics)
  #:use-module (guix gexp)
  #:use-module (guix records)
  #:use-module (guix modules)
  #:use-module (guix i18n)
  #:use-module (guix ui)
  #:use-module (gnu services)
  #:use-module (gnu services base)
  #:use-module (gnu services shepherd)
  #:use-module (gnu packages linux)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-26)
  #:use-module (srfi srfi-34)
  #:use-module (srfi srfi-35)
  #:use-module (ice-9 match)
  #:export (earlyoom-configuration
            earlyoom-configuration?
            earlyoom-configuration-earlyoom
            earlyoom-configuration-minimum-available-memory
            earlyoom-configuration-minimum-free-swap
            earlyoom-configuration-prefer-regexp
            earlyoom-configuration-avoid-regexp
            earlyoom-configuration-memory-report-interval
            earlyoom-configuration-ignore-positive-oom-score-adj?
            earlyoom-configuration-show-debug-messages?
            earlyoom-configuration-send-notification-command
            earlyoom-service-type

            kernel-module-loader-service-type

            rasdaemon-configuration
            rasdaemon-configuration?
            rasdaemon-configuration-record?
            rasdaemon-service-type

            zram-device-configuration
            zram-device-configuration?
            zram-device-configuration-size
            zram-device-configuration-compression-algorithm
            zram-device-configuration-memory-limit
            zram-device-configuration-priority
            zram-device-service-type))

\f
;;;
;;; Early OOM daemon.
;;;

(define-record-type* <earlyoom-configuration>
  earlyoom-configuration make-earlyoom-configuration
  earlyoom-configuration?
  (earlyoom earlyoom-configuration-earlyoom
            (default earlyoom))
  (minimum-available-memory earlyoom-configuration-minimum-available-memory
                            (default 10)) ; in percent
  (minimum-free-swap earlyoom-configuration-minimum-free-swap
                     (default 10))      ; in percent
  (prefer-regexp earlyoom-configuration-prefer-regexp ; <string>
                 (default #f))
  (avoid-regexp earlyoom-configuration-avoid-regexp  ; <string>
                (default #f))
  (memory-report-interval earlyoom-configuration-memory-report-interval
                          (default 0)) ; in seconds; 0 means disabled
  (ignore-positive-oom-score-adj?
   earlyoom-configuration-ignore-positive-oom-score-adj? (default #f))
  (run-with-higher-priority? earlyoom-configuration-run-with-higher-priority?
                             (default #f))
  (show-debug-messages? earlyoom-configuration-show-debug-messages?
                        (default #f))
  (send-notification-command
   earlyoom-configuration-send-notification-command  ; <string>
   (default #f)))

(define (earlyoom-configuration->command-line-args config)
  "Translate a <earlyoom-configuration> object to its command line arguments
representation."
  (match config
    (($ <earlyoom-configuration> earlyoom minimum-available-memory
                                 minimum-free-swap prefer-regexp avoid-regexp
                                 memory-report-interval
                                 ignore-positive-oom-score-adj?
                                 run-with-higher-priority? show-debug-messages?
                                 send-notification-command)
     `(,(file-append earlyoom "/bin/earlyoom")
       ,@(if minimum-available-memory
             (list "-m" (format #f "~s" minimum-available-memory))
             '())
       ,@(if minimum-free-swap
             (list "-s" (format #f "~s" minimum-free-swap))
             '())
       ,@(if prefer-regexp
             (list "--prefer" prefer-regexp)
             '())
       ,@(if avoid-regexp
             (list "--avoid" avoid-regexp)
             '())
       "-r" ,(format #f "~s" memory-report-interval)
       ,@(if ignore-positive-oom-score-adj?
             (list "-i")
             '())
       ,@(if run-with-higher-priority?
             (list "-p")
             '())
       ,@(if show-debug-messages?
             (list "-d")
             '())
       ,@(if send-notification-command
             (list "-N" send-notification-command)
             '())))))

(define (earlyoom-shepherd-service config)
  (shepherd-service
   (documentation "Run the Early OOM daemon.")
   (provision '(earlyoom))
   (start #~(make-forkexec-constructor
             '#$(earlyoom-configuration->command-line-args config)
             #:log-file "/var/log/earlyoom.log"))
   (stop #~(make-kill-destructor))))

(define earlyoom-service-type
  (service-type
   (name 'earlyoom)
   (default-value (earlyoom-configuration))
   (extensions
    (list (service-extension shepherd-root-service-type
                             (compose list earlyoom-shepherd-service))))
   (description "Run @command{earlyoom}, the Early OOM daemon.")))

\f
;;;
;;; Kernel module loader.
;;;

(define kernel-module-loader-shepherd-service
  (match-lambda
    ((and (? list? kernel-modules) ((? string?) ...))
     (shepherd-service
      (documentation "Load kernel modules.")
      (provision '(kernel-module-loader))
      (requirement '())
      (one-shot? #t)
      (modules `((srfi srfi-1)
                 (srfi srfi-34)
                 (srfi srfi-35)
                 (rnrs io ports)
                 ,@%default-modules))
      (start
       #~(lambda _
           (cond
            ((null? '#$kernel-modules) #t)
            ((file-exists? "/proc/sys/kernel/modprobe")
             (let ((modprobe (call-with-input-file
                                 "/proc/sys/kernel/modprobe" get-line)))
               (guard (c ((message-condition? c)
                          (format (current-error-port) "~a~%"
                                  (condition-message c))
                          #f))
                 (every (lambda (module)
                          (invoke/quiet modprobe "--" module))
                        '#$kernel-modules))))
            (else
             (format (current-error-port) "error: ~a~%"
                     "Kernel is missing loadable module support.")
             #f))))))))

(define kernel-module-loader-service-type
  (service-type
   (name 'kernel-module-loader)
   (description "Load kernel modules.")
   (extensions
    (list (service-extension shepherd-root-service-type
                             (compose list kernel-module-loader-shepherd-service))))
   (compose concatenate)
   (extend append)
   (default-value '())))

\f
;;;
;;; Reliability, Availability, and Serviceability (RAS) daemon
;;;

(define-record-type* <rasdaemon-configuration>
  rasdaemon-configuration make-rasdaemon-configuration
  rasdaemon-configuration?
  (record? rasdaemon-configuration-record? (default #f)))

(define (rasdaemon-configuration->command-line-args config)
  "Translate <rasdaemon-configuration> to its command line arguments
  representation"
  (let ((record? (rasdaemon-configuration-record? config)))
    `(,(file-append rasdaemon "/sbin/rasdaemon")
      "--foreground" ,@(if record? '("--record") '()))))

(define (rasdaemon-activation config)
  (let ((record? (rasdaemon-configuration-record? config))
        (rasdaemon-dir "/var/lib/rasdaemon"))
    (with-imported-modules '((guix build utils))
      #~(if #$record? (mkdir-p #$rasdaemon-dir)))))

(define (rasdaemon-shepherd-service config)
  (shepherd-service
   (documentation "Run rasdaemon")
   (provision '(rasdaemon))
   (requirement '(syslogd))
   (start #~(make-forkexec-constructor
             '#$(rasdaemon-configuration->command-line-args config)))
   (stop #~(make-kill-destructor))))

(define rasdaemon-service-type
  (service-type
   (name 'rasdaemon)
   (default-value (rasdaemon-configuration))
   (extensions
    (list (service-extension shepherd-root-service-type
                             (compose list rasdaemon-shepherd-service))
          (service-extension activation-service-type rasdaemon-activation)))
   (compose concatenate)
   (description "Run @command{rasdaemon}, the RAS monitor")))

\f
;;;
;;; Kernel module loader.
;;;

(define-record-type* <zram-device-configuration>
  zram-device-configuration make-zram-device-configuration
  zram-device-configuration?
  (size                     zram-device-configuration-size
                            (default "1G"))     ; string or integer
  (compression-algorithm    zram-device-configuration-compression-algorithm
                            (default 'lzo))     ; symbol
  (memory-limit             zram-device-configuration-memory-limit
                            (default 0))        ; string or integer
  (priority                 zram-device-configuration-priority
                            (default #f)        ; integer | #f
                            (delayed) ; to avoid printing the deprecation
                                      ; warning multiple times
                            (sanitize warn-zram-priority-change)))

(define-with-syntax-properties
  (warn-zram-priority-change (priority properties))
  (if (eqv? priority -1)
      (begin
        (warning (source-properties->location properties)
                 (G_ "using -1 for zram priority is deprecated~%"))
        (display-hint (G_ "Use #f or leave as default instead (@pxref{Linux \
Services})."))
        #f)
      priority))

(define (zram-device-configuration->udev-string config)
  "Translate a <zram-device-configuration> into a string which can be
placed in a udev rules file."
  (match config
    (($ <zram-device-configuration> size compression-algorithm memory-limit priority)
     (string-append
       "KERNEL==\"zram0\", "
       "ATTR{comp_algorithm}=\"" (symbol->string compression-algorithm) "\" "
       (if (not (or (equal? "0" size)
                    (equal? 0 size)))
         (string-append "ATTR{disksize}=\"" (if (number? size)
                                              (number->string size)
                                              size)
                        "\" ")
         "")
       (if (not (or (equal? "0" memory-limit)
                    (equal? 0 memory-limit)))
         (string-append "ATTR{mem_limit}=\"" (if (number? memory-limit)
                                               (number->string memory-limit)
                                               memory-limit)
                        "\" ")
         "")
       "RUN+=\"/run/current-system/profile/sbin/mkswap /dev/zram0\" "
       "RUN+=\"/run/current-system/profile/sbin/swapon "
       ;; TODO: Revert to simply use 'priority' after removing the deprecation
       ;; warning and the delayed property of the field.
       (let ((priority* (force priority)))
         (if priority*
             (format #f "--priority ~a " priority*)
             ""))
       "/dev/zram0\"\n"))))

(define %zram-device-config
  `("modprobe.d/zram.conf"
    ,(plain-file "zram.conf"
                 "options zram num_devices=1")))

(define (zram-device-udev-rule config)
  (file->udev-rule "99-zram.rules"
                   (plain-file "99-zram.rules"
                               (zram-device-configuration->udev-string config))))

(define zram-device-service-type
  (service-type
    (name 'zram)
    (default-value (zram-device-configuration))
    (extensions
      (list (service-extension kernel-module-loader-service-type
                               (const (list "zram")))
            (service-extension etc-service-type
                               (const (list %zram-device-config)))
            (service-extension udev-service-type
                               (compose list zram-device-udev-rule))))
    (description "Creates a zram swap device.")))
Commit	Line	Data
d3e439e3 MC	1	;;; GNU Guix --- Functional package management for GNU
d3e439e3 MC	2	;;; Copyright © 2020 Maxim Cournoyer <maxim.cournoyer@gmail.com>
044d1478	3	;;; Copyright © 2020 Brice Waegeneire <brice@waegenei.re>
587e0d91	4	;;; Copyright © 2020 Efraim Flashner <efraim@flashner.co.il>
fe7529d7	5	;;; Copyright © 2021 raid5atemyhomework <raid5atemyhomework@protonmail.com>
2c93df3d	6	;;; Copyright © 2021 B. Wilson <elaexuotee@wilsonb.com>
a99015c8	7	;;; Copyright © 2022 Josselin Poiret <dev@jpoiret.xyz>
d3e439e3 MC	8	;;;
	9	;;; This file is part of GNU Guix.
	10	;;;
	11	;;; GNU Guix is free software; you can redistribute it and/or modify it
	12	;;; under the terms of the GNU General Public License as published by
	13	;;; the Free Software Foundation; either version 3 of the License, or (at
	14	;;; your option) any later version.
	15	;;;
	16	;;; GNU Guix is distributed in the hope that it will be useful, but
	17	;;; WITHOUT ANY WARRANTY; without even the implied warranty of
	18	;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	19	;;; GNU General Public License for more details.
	20	;;;
	21	;;; You should have received a copy of the GNU General Public License
	22	;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
	23
	24	(define-module (gnu services linux)
a99015c8	25	#:use-module (guix diagnostics)
d3e439e3 MC	26	#:use-module (guix gexp)
	27	#:use-module (guix records)
	28	#:use-module (guix modules)
a99015c8 JP	29	#:use-module (guix i18n)
a99015c8 JP	30	#:use-module (guix ui)
d3e439e3	31	#:use-module (gnu services)
587e0d91	32	#:use-module (gnu services base)
d3e439e3 MC	33	#:use-module (gnu services shepherd)
	34	#:use-module (gnu packages linux)
	35	#:use-module (srfi srfi-1)
	36	#:use-module (srfi srfi-26)
044d1478 BW	37	#:use-module (srfi srfi-34)
044d1478 BW	38	#:use-module (srfi srfi-35)
d3e439e3 MC	39	#:use-module (ice-9 match)
	40	#:export (earlyoom-configuration
	41	earlyoom-configuration?
	42	earlyoom-configuration-earlyoom
	43	earlyoom-configuration-minimum-available-memory
	44	earlyoom-configuration-minimum-free-swap
	45	earlyoom-configuration-prefer-regexp
	46	earlyoom-configuration-avoid-regexp
	47	earlyoom-configuration-memory-report-interval
	48	earlyoom-configuration-ignore-positive-oom-score-adj?
	49	earlyoom-configuration-show-debug-messages?
	50	earlyoom-configuration-send-notification-command
044d1478 BW	51	earlyoom-service-type
044d1478 BW	52
587e0d91 EF	53	kernel-module-loader-service-type
587e0d91 EF	54
2c93df3d W	55	rasdaemon-configuration
	56	rasdaemon-configuration?
	57	rasdaemon-configuration-record?
	58	rasdaemon-service-type
	59
587e0d91 EF	60	zram-device-configuration
	61	zram-device-configuration?
	62	zram-device-configuration-size
	63	zram-device-configuration-compression-algorithm
	64	zram-device-configuration-memory-limit
	65	zram-device-configuration-priority
	66	zram-device-service-type))
d3e439e3 MC	67
	68	\f
	69	;;;
	70	;;; Early OOM daemon.
	71	;;;
	72
	73	(define-record-type* <earlyoom-configuration>
	74	earlyoom-configuration make-earlyoom-configuration
	75	earlyoom-configuration?
	76	(earlyoom earlyoom-configuration-earlyoom
	77	(default earlyoom))
	78	(minimum-available-memory earlyoom-configuration-minimum-available-memory
	79	(default 10)) ; in percent
	80	(minimum-free-swap earlyoom-configuration-minimum-free-swap
	81	(default 10)) ; in percent
	82	(prefer-regexp earlyoom-configuration-prefer-regexp ; <string>
	83	(default #f))
	84	(avoid-regexp earlyoom-configuration-avoid-regexp ; <string>
	85	(default #f))
	86	(memory-report-interval earlyoom-configuration-memory-report-interval
	87	(default 0)) ; in seconds; 0 means disabled
	88	(ignore-positive-oom-score-adj?
	89	earlyoom-configuration-ignore-positive-oom-score-adj? (default #f))
	90	(run-with-higher-priority? earlyoom-configuration-run-with-higher-priority?
	91	(default #f))
	92	(show-debug-messages? earlyoom-configuration-show-debug-messages?
	93	(default #f))
	94	(send-notification-command
	95	earlyoom-configuration-send-notification-command ; <string>
	96	(default #f)))
	97
	98	(define (earlyoom-configuration->command-line-args config)
	99	"Translate a <earlyoom-configuration> object to its command line arguments
	100	representation."
	101	(match config
	102	(($ <earlyoom-configuration> earlyoom minimum-available-memory
	103	minimum-free-swap prefer-regexp avoid-regexp
	104	memory-report-interval
	105	ignore-positive-oom-score-adj?
	106	run-with-higher-priority? show-debug-messages?
	107	send-notification-command)
	108	`(,(file-append earlyoom "/bin/earlyoom")
	109	,@(if minimum-available-memory
	110	(list "-m" (format #f "~s" minimum-available-memory))
	111	'())
	112	,@(if minimum-free-swap
	113	(list "-s" (format #f "~s" minimum-free-swap))
	114	'())
	115	,@(if prefer-regexp
	116	(list "--prefer" prefer-regexp)
	117	'())
	118	,@(if avoid-regexp
	119	(list "--avoid" avoid-regexp)
	120	'())
	121	"-r" ,(format #f "~s" memory-report-interval)
	122	,@(if ignore-positive-oom-score-adj?
	123	(list "-i")
	124	'())
	125	,@(if run-with-higher-priority?
	126	(list "-p")
	127	'())
	128	,@(if show-debug-messages?
	129	(list "-d")
	130	'())
131	,@(if send-notification-command
132	(list "-N" send-notification-command)
133	'())))))
134
135	(define (earlyoom-shepherd-service config)
136	(shepherd-service
137	(documentation "Run the Early OOM daemon.")
138	(provision '(earlyoom))
139	(start #~(make-forkexec-constructor
140	'#$(earlyoom-configuration->command-line-args config)
141	#:log-file "/var/log/earlyoom.log"))
142	(stop #~(make-kill-destructor))))
143
144	(define earlyoom-service-type
145	(service-type
146	(name 'earlyoom)
147	(default-value (earlyoom-configuration))
148	(extensions
149	(list (service-extension shepherd-root-service-type
150	(compose list earlyoom-shepherd-service))))
151	(description "Run @command{earlyoom}, the Early OOM daemon.")))
044d1478 BW	152
	153	\f
	154	;;;
	155	;;; Kernel module loader.
	156	;;;
	157
	158	(define kernel-module-loader-shepherd-service
	159	(match-lambda
	160	((and (? list? kernel-modules) ((? string?) ...))
3d3185b5 BW	161	(shepherd-service
	162	(documentation "Load kernel modules.")
	163	(provision '(kernel-module-loader))
fe7529d7	164	(requirement '())
3d3185b5 BW	165	(one-shot? #t)
	166	(modules `((srfi srfi-1)
	167	(srfi srfi-34)
	168	(srfi srfi-35)
	169	(rnrs io ports)
	170	,@%default-modules))
	171	(start
	172	#~(lambda _
	173	(cond
	174	((null? '#$kernel-modules) #t)
	175	((file-exists? "/proc/sys/kernel/modprobe")
	176	(let ((modprobe (call-with-input-file
	177	"/proc/sys/kernel/modprobe" get-line)))
	178	(guard (c ((message-condition? c)
	179	(format (current-error-port) "~a~%"
	180	(condition-message c))
	181	#f))
	182	(every (lambda (module)
	183	(invoke/quiet modprobe "--" module))
	184	'#$kernel-modules))))
	185	(else
	186	(format (current-error-port) "error: ~a~%"
	187	"Kernel is missing loadable module support.")
	188	#f))))))))
044d1478 BW	189
	190	(define kernel-module-loader-service-type
	191	(service-type
	192	(name 'kernel-module-loader)
	193	(description "Load kernel modules.")
	194	(extensions
	195	(list (service-extension shepherd-root-service-type
3d3185b5	196	(compose list kernel-module-loader-shepherd-service))))
044d1478 BW	197	(compose concatenate)
	198	(extend append)
	199	(default-value '())))
587e0d91 EF	200
587e0d91 EF	201	\f
2c93df3d W	202	;;;
	203	;;; Reliability, Availability, and Serviceability (RAS) daemon
	204	;;;
	205
	206	(define-record-type* <rasdaemon-configuration>
	207	rasdaemon-configuration make-rasdaemon-configuration
	208	rasdaemon-configuration?
	209	(record? rasdaemon-configuration-record? (default #f)))
	210
	211	(define (rasdaemon-configuration->command-line-args config)
	212	"Translate <rasdaemon-configuration> to its command line arguments
	213	representation"
	214	(let ((record? (rasdaemon-configuration-record? config)))
	215	`(,(file-append rasdaemon "/sbin/rasdaemon")
	216	"--foreground" ,@(if record? '("--record") '()))))
	217
	218	(define (rasdaemon-activation config)
	219	(let ((record? (rasdaemon-configuration-record? config))
	220	(rasdaemon-dir "/var/lib/rasdaemon"))
	221	(with-imported-modules '((guix build utils))
	222	#~(if #$record? (mkdir-p #$rasdaemon-dir)))))
	223
	224	(define (rasdaemon-shepherd-service config)
	225	(shepherd-service
	226	(documentation "Run rasdaemon")
	227	(provision '(rasdaemon))
	228	(requirement '(syslogd))
	229	(start #~(make-forkexec-constructor
	230	'#$(rasdaemon-configuration->command-line-args config)))
	231	(stop #~(make-kill-destructor))))
	232
	233	(define rasdaemon-service-type
	234	(service-type
	235	(name 'rasdaemon)
	236	(default-value (rasdaemon-configuration))
	237	(extensions
	238	(list (service-extension shepherd-root-service-type
	239	(compose list rasdaemon-shepherd-service))
	240	(service-extension activation-service-type rasdaemon-activation)))
	241	(compose concatenate)
	242	(description "Run @command{rasdaemon}, the RAS monitor")))
	243
	244	\f
587e0d91 EF	245	;;;
	246	;;; Kernel module loader.
	247	;;;
	248
	249	(define-record-type* <zram-device-configuration>
	250	zram-device-configuration make-zram-device-configuration
	251	zram-device-configuration?
71992a53	252	(size zram-device-configuration-size
587e0d91 EF	253	(default "1G")) ; string or integer
	254	(compression-algorithm zram-device-configuration-compression-algorithm
	255	(default 'lzo)) ; symbol
	256	(memory-limit zram-device-configuration-memory-limit
	257	(default 0)) ; string or integer
	258	(priority zram-device-configuration-priority
a99015c8 JP	259	(default #f) ; integer \| #f
	260	(delayed) ; to avoid printing the deprecation
	261	; warning multiple times
	262	(sanitize warn-zram-priority-change)))
	263
	264	(define-with-syntax-properties
	265	(warn-zram-priority-change (priority properties))
	266	(if (eqv? priority -1)
	267	(begin
	268	(warning (source-properties->location properties)
	269	(G_ "using -1 for zram priority is deprecated~%"))
	270	(display-hint (G_ "Use #f or leave as default instead (@pxref{Linux \
	271	Services})."))
	272	#f)
	273	priority))
587e0d91 EF	274
	275	(define (zram-device-configuration->udev-string config)
	276	"Translate a <zram-device-configuration> into a string which can be
	277	placed in a udev rules file."
	278	(match config
	279	(($ <zram-device-configuration> size compression-algorithm memory-limit priority)
	280	(string-append
	281	"KERNEL==\"zram0\", "
	282	"ATTR{comp_algorithm}=\"" (symbol->string compression-algorithm) "\" "
	283	(if (not (or (equal? "0" size)
	284	(equal? 0 size)))
	285	(string-append "ATTR{disksize}=\"" (if (number? size)
	286	(number->string size)
	287	size)
	288	"\" ")
	289	"")
	290	(if (not (or (equal? "0" memory-limit)
	291	(equal? 0 memory-limit)))
	292	(string-append "ATTR{mem_limit}=\"" (if (number? memory-limit)
	293	(number->string memory-limit)
	294	memory-limit)
	295	"\" ")
	296	"")
	297	"RUN+=\"/run/current-system/profile/sbin/mkswap /dev/zram0\" "
	298	"RUN+=\"/run/current-system/profile/sbin/swapon "
a99015c8 JP	299	;; TODO: Revert to simply use 'priority' after removing the deprecation
	300	;; warning and the delayed property of the field.
	301	(let ((priority* (force priority)))
	302	(if priority*
	303	(format #f "--priority ~a " priority*)
	304	""))
587e0d91 EF	305	"/dev/zram0\"\n"))))
	306
	307	(define %zram-device-config
	308	`("modprobe.d/zram.conf"
	309	,(plain-file "zram.conf"
	310	"options zram num_devices=1")))
	311
	312	(define (zram-device-udev-rule config)
	313	(file->udev-rule "99-zram.rules"
	314	(plain-file "99-zram.rules"
	315	(zram-device-configuration->udev-string config))))
	316
	317	(define zram-device-service-type
	318	(service-type
	319	(name 'zram)
	320	(default-value (zram-device-configuration))
	321	(extensions
	322	(list (service-extension kernel-module-loader-service-type
	323	(const (list "zram")))
	324	(service-extension etc-service-type
	325	(const (list %zram-device-config)))
	326	(service-extension udev-service-type
	327	(compose list zram-device-udev-rule))))
	328	(description "Creates a zram swap device.")))