system: Add swap flags.

* gnu/system/file-systems.scm (swap-space)[priority, discard?]: Add
them.
* guix/build/syscalls.scm (SWAP_FLAG_PREFER, SWAP_FLAG_PRIO_MASK,
SWAP_FLAG_PRIO_SHIFT, SWAP_FLAG_DISCARD): Add them.
* gnu/build/file-systems.scm (swap-space->flags-bit-mask): Add it.
* gnu/services/base.scm (swap-service-type): Use it.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

1 files changed, 8 insertions, 2 deletions

diff --git a/gnu/system/file-systems.scm b/gnu/system/file-systems.scm
index 027df7e9660..e1d1fb72cca 100644
--- a/gnu/system/file-systems.scm
+++ b/gnu/system/file-systems.scm
@@ -102,7 +102,9 @@
             swap-space
             swap-space?
             swap-space-target
-            swap-space-dependencies))
+            swap-space-dependencies
+            swap-space-priority
+            swap-space-discard?))
 
 ;;; Commentary:
 ;;;
@@ -726,6 +728,10 @@ subvolume name is unknown."))
   this-swap-space
   (target swap-space-target)
   (dependencies swap-space-dependencies
-                (default '())))
+                (default '()))
+  (priority swap-space-priority
+            (default #f))
+  (discard? swap-space-discard?
+           (default #f)))
 
 ;;; file-systems.scm ends here