NEWS

@@ -159,9 +159,11 @@ CHANGES WITH 247 in spe:
           to the service.
 
         * Timer units gained a new FixedRandomDelay= boolean setting. If
-          enabled, the random delay configured with RandomizedDelaySec= is
-          selected in a way that is stable on a given system (though still
-          different for different units).
+          enabled the random delay configured with RandomizedDelaySec= is
+          hashed from the unit name, system identity, and execution context, so
+          that always the same offset is used for the same unit on the same
+          system run in the same context, in a way that is stable across system
+          reboots.
 
         * Socket units gained a new setting Timestamping= that takes "us", "ns"
           or "off". This controls the SO_TIMESTAMP/SO_TIMESTAMPNS socket

man/systemd.special.xml

@@ -1179,60 +1179,6 @@
         </varlistentry>
       </variablelist>
     </refsect2>
-
-    <refsect2>
-      <title>Special User Slice Units</title>
-
-      <para>There are four <literal>.slice</literal> units which form the basis of the user hierarchy for
-      assignment of resources for user applications and services. See
-      <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>7</manvolnum></citerefentry>
-      for details about slice units and the documentation about
-      <ulink url="https://systemd.io/DESKTOP_ENVIRONMENTS">Desktop Environments</ulink>
-      for further information.</para>
-
-      <variablelist>
-        <varlistentry>
-          <term><filename>-.slice</filename></term>
-          <listitem>
-            <para>The root slice is the root of the user's slice hierarchy.
-            It usually does not contain units directly, but may be used to set defaults for the whole tree.</para>
-          </listitem>
-        </varlistentry>
-
-        <varlistentry>
-          <term><filename>app.slice</filename></term>
-          <listitem>
-            <para>By default, all user services and applications managed by
-            <command>systemd</command> are found in this slice.
-            All interactively launched applications like web browsers and text editors
-            as well as non-critical services should be placed into this slice.</para>
-          </listitem>
-        </varlistentry>
-
-        <varlistentry>
-          <term><filename>session.slice</filename></term>
-          <listitem>
-            <para>All essential services and applications required for the
-            session should use this slice.
-            These are services that either cannot be restarted easily
-            or where latency issues may affect the interactivity of the system and applications.
-            This includes the display server, screen readers and other services such as DBus or XDG portals.
-            Such services should be configured to be part of this slice by
-            adding <varname>Slice=session.slice</varname> to their unit files.</para>
-          </listitem>
-        </varlistentry>
-
-        <varlistentry>
-          <term><filename>background.slice</filename></term>
-          <listitem>
-            <para>All services running low-priority background tasks should use this slice.
-            This permits resources to be preferentially assigned to the other slices.
-            Examples include non-interactive tasks like file indexing or backup operations
-            where latency is not important.</para>
-          </listitem>
-        </varlistentry>
-      </variablelist>
-    </refsect2>
   </refsect1>
 
   <refsect1>

man/systemd.timer.xml

@@ -240,41 +240,44 @@
       <varlistentry>
         <term><varname>RandomizedDelaySec=</varname></term>
 
-        <listitem><para>Delay the timer by a randomly selected, evenly distributed amount of time between 0
-        and the specified time value. Defaults to 0, indicating that no randomized delay shall be applied.
-        Each timer unit will determine this delay randomly before each iteration, and the delay will simply
-        be added on top of the next determined elapsing time, unless modified with
-        <varname>FixedRandomDelay=</varname>, see below.</para>
-
-        <para>This setting is useful to stretch dispatching of similarly configured timer events over a
-        certain time interval, to prevent them from firing all at the same time, possibly resulting in
-        resource congestion.</para>
-
-        <para>Note the relation to <varname>AccuracySec=</varname> above: the latter allows the service
-        manager to coalesce timer events within a specified time range in order to minimize wakeups, while
-        this setting does the opposite: it stretches timer events over an interval, to make it unlikely that
-        they fire simultaneously. If <varname>RandomizedDelaySec=</varname> and
-        <varname>AccuracySec=</varname> are used in conjunction, first the randomized delay is added, and
-        then the result is possibly further shifted to coalesce it with other timer events happening on the
-        system. As mentioned above <varname>AccuracySec=</varname> defaults to 1 minute and
-        <varname>RandomizedDelaySec=</varname> to 0, thus encouraging coalescing of timer events. In order to
-        optimally stretch timer events over a certain range of time, set
-        <varname>AccuracySec=1us</varname> and <varname>RandomizedDelaySec=</varname> to some higher value.
-        </para></listitem>
+        <listitem><para>Delay the timer by a randomly selected, evenly
+        distributed amount of time between 0 and the specified time
+        value. Defaults to 0, indicating that no randomized delay
+        shall be applied. Each timer unit will determine this delay
+        randomly before each iteration, and the delay will simply be
+        added on top of the next determined elapsing time. This is
+        useful to stretch dispatching of similarly configured timer
+        events over a certain amount time, to avoid that they all fire
+        at the same time, possibly resulting in resource
+        congestion. Note the relation to
+        <varname>AccuracySec=</varname> above: the latter allows the
+        service manager to coalesce timer events within a specified
+        time range in order to minimize wakeups, the former does the
+        opposite: it stretches timer events over a time range, to make
+        it unlikely that they fire simultaneously. If
+        <varname>RandomizedDelaySec=</varname> and
+        <varname>AccuracySec=</varname> are used in conjunction, first
+        the randomized delay is added, and then the result is
+        possibly further shifted to coalesce it with other timer
+        events happening on the system. As mentioned above
+        <varname>AccuracySec=</varname> defaults to 1min and
+        <varname>RandomizedDelaySec=</varname> to 0, thus encouraging
+        coalescing of timer events. In order to optimally stretch
+        timer events over a certain range of time, make sure to set
+        <varname>RandomizedDelaySec=</varname> to a higher value, and
+        <varname>AccuracySec=1us</varname>.</para></listitem>
       </varlistentry>
 
       <varlistentry>
         <term><varname>FixedRandomDelay=</varname></term>
 
-        <listitem><para>Takes a boolean argument. When enabled, the randomized offset specified by
-        <varname>RandomizedDelaySec=</varname> is reused for all firings of the same timer. For a given timer
-        unit, the offset depends on the machine ID, user identifier and timer name, which means that it is
-        stable between restarts of the manager. This effectively creates a fixed offset for an individual
-        timer, reducing the jitter in firings of this timer, while still avoiding firing at the same time as
-        other similarly configured timers.</para>
-
-        <para>This setting has no effect if <varname>RandomizedDelaySec=</varname> is set to 0. Defaults to
-        <option>false</option>.</para></listitem>
+        <listitem><para>Takes a boolean argument. If true, some amount of time between 0 and
+        <varname>RandomizedDelaySec=</varname> is chosen and added as the delay for each timer iteration. As this
+        delay will not be recalculated on each run, this effectively creates a fixed offset for each iteration.
+        The distribution between 0 and <varname>RandomizedDelaySec=</varname> is deterministic and based on
+        a combination of the machine ID, whether the timer is run by the user/system manager, the service manager's
+        user ID, and the timer's unit name. Has no effect if
+        <varname>RandomizedDelaySec=</varname> is set to 0. Defaults to <option>false</option>.</para></listitem>
       </varlistentry>
 
       <varlistentry>

src/basic/special.h

@@ -107,8 +107,3 @@
 
 /* The root directory. */
 #define SPECIAL_ROOT_MOUNT "-.mount"
-
-/* Special slices valid for the user instance */
-#define SPECIAL_SESSION_SLICE "session.slice"
-#define SPECIAL_APP_SLICE "app.slice"
-#define SPECIAL_BACKGROUND_SLICE "background.slice"

src/core/mount.c

@@ -412,9 +412,8 @@ static int mount_add_quota_dependencies(Mount *m) {
         return 0;
 }
 
-static bool mount_is_extrinsic(Unit *u) {
+static bool mount_is_extrinsic(Mount *m) {
         MountParameters *p;
-        Mount *m = MOUNT(u);
         assert(m);
 
         /* Returns true for all units that are "magic" and should be excluded from the usual
@@ -423,7 +422,10 @@ static bool mount_is_extrinsic(Unit *u) {
          * ourselves but it's fine if the user operates on them with us. */
 
         /* We only automatically manage mounts if we are in system mode */
-        if (MANAGER_IS_USER(u->manager))
+        if (!MANAGER_IS_SYSTEM(UNIT(m)->manager))
+                return true;
+
+        if (UNIT(m)->perpetual) /* All perpetual units never change state */
                 return true;
 
         p = get_mount_parameters(m);
@@ -491,7 +493,7 @@ static int mount_add_default_dependencies(Mount *m) {
          * guaranteed to stay mounted the whole time, since our system is on it.  Also, don't
          * bother with anything mounted below virtual file systems, it's also going to be virtual,
          * and hence not worth the effort. */
-        if (mount_is_extrinsic(UNIT(m)))
+        if (mount_is_extrinsic(m))
                 return 0;
 
         p = get_mount_parameters(m);
@@ -788,7 +790,7 @@ static void mount_dump(Unit *u, FILE *f, const char *prefix) {
                 prefix, p ? strna(p->options) : "n/a",
                 prefix, yes_no(m->from_proc_self_mountinfo),
                 prefix, yes_no(m->from_fragment),
-                prefix, yes_no(mount_is_extrinsic(u)),
+                prefix, yes_no(mount_is_extrinsic(m)),
                 prefix, m->directory_mode,
                 prefix, yes_no(m->sloppy_options),
                 prefix, yes_no(m->lazy_unmount),
@@ -2159,7 +2161,6 @@ const UnitVTable mount_vtable = {
         .will_restart = unit_will_restart_default,
 
         .may_gc = mount_may_gc,
-        .is_extrinsic = mount_is_extrinsic,
 
         .sigchld_event = mount_sigchld_event,
 

src/core/swap.c

@@ -56,35 +56,6 @@ static bool SWAP_STATE_WITH_PROCESS(SwapState state) {
                       SWAP_CLEANING);
 }
 
-_pure_ static UnitActiveState swap_active_state(Unit *u) {
-        assert(u);
-
-        return state_translation_table[SWAP(u)->state];
-}
-
-_pure_ static const char *swap_sub_state_to_string(Unit *u) {
-        assert(u);
-
-        return swap_state_to_string(SWAP(u)->state);
-}
-
-_pure_ static bool swap_may_gc(Unit *u) {
-        Swap *s = SWAP(u);
-
-        assert(s);
-
-        if (s->from_proc_swaps)
-                return false;
-
-        return true;
-}
-
-_pure_ static bool swap_is_extrinsic(Unit *u) {
-        assert(SWAP(u));
-
-        return MANAGER_IS_USER(u->manager);
-}
-
 static void swap_unset_proc_swaps(Swap *s) {
         assert(s);
 
@@ -639,15 +610,13 @@ static void swap_dump(Unit *u, FILE *f, const char *prefix) {
                 "%sClean Result: %s\n"
                 "%sWhat: %s\n"
                 "%sFrom /proc/swaps: %s\n"
-                "%sFrom fragment: %s\n"
-                "%sExtrinsic: %s\n",
+                "%sFrom fragment: %s\n",
                 prefix, swap_state_to_string(s->state),
                 prefix, swap_result_to_string(s->result),
                 prefix, swap_result_to_string(s->clean_result),
                 prefix, s->what,
                 prefix, yes_no(s->from_proc_swaps),
-                prefix, yes_no(s->from_fragment),
-                prefix, yes_no(swap_is_extrinsic(u)));
+                prefix, yes_no(s->from_fragment));
 
         if (s->devnode)
                 fprintf(f, "%sDevice Node: %s\n", prefix, s->devnode);
@@ -1059,6 +1028,29 @@ static int swap_deserialize_item(Unit *u, const char *key, const char *value, FD
         return 0;
 }
 
+_pure_ static UnitActiveState swap_active_state(Unit *u) {
+        assert(u);
+
+        return state_translation_table[SWAP(u)->state];
+}
+
+_pure_ static const char *swap_sub_state_to_string(Unit *u) {
+        assert(u);
+
+        return swap_state_to_string(SWAP(u)->state);
+}
+
+_pure_ static bool swap_may_gc(Unit *u) {
+        Swap *s = SWAP(u);
+
+        assert(s);
+
+        if (s->from_proc_swaps)
+                return false;
+
+        return true;
+}
+
 static void swap_sigchld_event(Unit *u, pid_t pid, int code, int status) {
         Swap *s = SWAP(u);
         SwapResult f;
@@ -1657,7 +1649,6 @@ const UnitVTable swap_vtable = {
         .will_restart = unit_will_restart_default,
 
         .may_gc = swap_may_gc,
-        .is_extrinsic = swap_is_extrinsic,
 
         .sigchld_event = swap_sigchld_event,
 

src/core/unit.c

@@ -1988,10 +1988,6 @@ int unit_stop(Unit *u) {
 bool unit_can_stop(Unit *u) {
         assert(u);
 
-        /* Note: if we return true here, it does not mean that the unit may be successfully stopped.
-         * Extrinsic units follow external state and they may stop following external state changes
-         * (hence we return true here), but an attempt to do this through the manager will fail. */
-
         if (!unit_type_supported(u->type))
                 return false;
 
@@ -3349,17 +3345,12 @@ int unit_set_default_slice(Unit *u) {
                 if (MANAGER_IS_SYSTEM(u->manager))
                         slice_name = strjoina("system-", escaped, ".slice");
                 else
-                        slice_name = strjoina("app-", escaped, ".slice");
-
-        } else if (unit_is_extrinsic(u))
-                /* Keep all extrinsic units (e.g. perpetual units and swap and mount units in user mode) in
-                 * the root slice. They don't really belong in one of the subslices. */
-                slice_name = SPECIAL_ROOT_SLICE;
-
-        else if (MANAGER_IS_SYSTEM(u->manager))
-                slice_name = SPECIAL_SYSTEM_SLICE;
-        else
-                slice_name = SPECIAL_APP_SLICE;
+                        slice_name = strjoina(escaped, ".slice");
+        } else
+                slice_name =
+                        MANAGER_IS_SYSTEM(u->manager) && !unit_has_name(u, SPECIAL_INIT_SCOPE)
+                        ? SPECIAL_SYSTEM_SLICE
+                        : SPECIAL_ROOT_SLICE;
 
         r = manager_load_unit(u->manager, slice_name, NULL, NULL, &slice);
         if (r < 0)

src/core/unit.h

@@ -531,9 +531,6 @@ typedef struct UnitVTable {
          * even though nothing references it and it isn't active in any way. */
         bool (*may_gc)(Unit *u);
 
-        /* Return true when the unit is not controlled by the manager (e.g. extrinsic mounts). */
-        bool (*is_extrinsic)(Unit *u);
-
         /* When the unit is not running and no job for it queued we shall release its runtime resources */
         void (*release_resources)(Unit *u);
 
@@ -687,11 +684,6 @@ int unit_set_description(Unit *u, const char *description);
 
 bool unit_may_gc(Unit *u);
 
-static inline bool unit_is_extrinsic(Unit *u) {
-        return u->perpetual ||
-                (UNIT_VTABLE(u)->is_extrinsic && UNIT_VTABLE(u)->is_extrinsic(u));
-}
-
 void unit_add_to_load_queue(Unit *u);
 void unit_add_to_dbus_queue(Unit *u);
 void unit_add_to_cleanup_queue(Unit *u);

src/systemd/meson.build

@@ -68,7 +68,7 @@ endif
 
 foreach header : _systemd_headers + _not_installed_headers + ['../libudev/libudev.h']
         foreach opt : opts
-                name = ''.join(['cc-', header.split('/')[-1], '_'] + opt)
+                name = ''.join(['cc-', header.split('/')[-1], ':'] + opt)
                 if want_tests != 'false'
                         test(name,
                              check_compilation_sh,

units/user/app.slice

@@ -1,12 +0,0 @@
-#  SPDX-License-Identifier: LGPL-2.1+
-#
-#  This file is part of systemd.
-#
-#  systemd is free software; you can redistribute it and/or modify it
-#  under the terms of the GNU Lesser General Public License as published by
-#  the Free Software Foundation; either version 2.1 of the License, or
-#  (at your option) any later version.
-
-[Unit]
-Description=User Application Slice
-Documentation=man:systemd.special(7)

units/user/background.slice

@@ -1,12 +0,0 @@
-#  SPDX-License-Identifier: LGPL-2.1+
-#
-#  This file is part of systemd.
-#
-#  systemd is free software; you can redistribute it and/or modify it
-#  under the terms of the GNU Lesser General Public License as published by
-#  the Free Software Foundation; either version 2.1 of the License, or
-#  (at your option) any later version.
-
-[Unit]
-Description=User Background Tasks Slice
-Documentation=man:systemd.special(7)

units/user/meson.build

@@ -1,8 +1,6 @@
 # SPDX-License-Identifier: LGPL-2.1-or-later
 
 units = [
-        'app.slice',
-        'background.slice',
         'basic.target',
         'bluetooth.target',
         'default.target',
@@ -11,7 +9,6 @@ units = [
         'graphical-session.target',
         'paths.target',
         'printer.target',
-        'session.slice',
         'shutdown.target',
         'smartcard.target',
         'sockets.target',

units/user/session.slice

@@ -1,12 +0,0 @@
-#  SPDX-License-Identifier: LGPL-2.1+
-#
-#  This file is part of systemd.
-#
-#  systemd is free software; you can redistribute it and/or modify it
-#  under the terms of the GNU Lesser General Public License as published by
-#  the Free Software Foundation; either version 2.1 of the License, or
-#  (at your option) any later version.
-
-[Unit]
-Description=User Core Session Slice
-Documentation=man:systemd.special(7)

units/user/systemd-exit.service

@@ -14,7 +14,3 @@ DefaultDependencies=no
 Requires=shutdown.target
 After=shutdown.target
 SuccessAction=exit-force
-
-[Service]
-# Place into the root slice to not keep another slice unit alive
-Slice=-.slice

units/user/systemd-tmpfiles-clean.service

@@ -19,4 +19,3 @@ Type=oneshot
 ExecStart=systemd-tmpfiles --user --clean
 SuccessExitStatus=DATAERR
 IOSchedulingClass=idle
-Slice=background.slice