X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Fcore%2Fcgroup.c;h=f0420ebc0944a5f60b64f9e851b142dfcaf82d3c;hb=e954c9cfa687065244adebaa15314082ba6d7ec2;hp=6a6c5049b39df1377b571baa2d9e51e0fe80c8b4;hpb=f3669545238702f8ffee7b743ca4347b785b558a;p=elogind.git

diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index 6a6c5049b..f0420ebc0 100644
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -335,7 +335,7 @@ CGroupControllerMask cgroup_context_get_mask(CGroupContext *c) {
         return mask;
 }
 
-static CGroupControllerMask unit_get_cgroup_mask(Unit *u) {
+CGroupControllerMask unit_get_cgroup_mask(Unit *u) {
         CGroupContext *c;
 
         c = unit_get_cgroup_context(u);
@@ -345,54 +345,127 @@ static CGroupControllerMask unit_get_cgroup_mask(Unit *u) {
         return cgroup_context_get_mask(c);
 }
 
-static CGroupControllerMask unit_get_members_mask(Unit *u) {
-        CGroupControllerMask mask = 0;
-        Unit *m;
-        Iterator i;
-
+CGroupControllerMask unit_get_members_mask(Unit *u) {
         assert(u);
 
-        SET_FOREACH(m, u->dependencies[UNIT_BEFORE], i) {
+        if (u->cgroup_members_mask_valid)
+                return u->cgroup_members_mask;
 
-                if (UNIT_DEREF(m->slice) != u)
-                        continue;
+        u->cgroup_members_mask = 0;
+
+        if (u->type == UNIT_SLICE) {
+                Unit *member;
+                Iterator i;
 
-                mask |= unit_get_cgroup_mask(m) | unit_get_members_mask(m);
+                SET_FOREACH(member, u->dependencies[UNIT_BEFORE], i) {
+
+                        if (member == u)
+                                continue;
+
+                         if (UNIT_DEREF(member->slice) != u)
+                                continue;
+
+                        u->cgroup_members_mask |=
+                                unit_get_cgroup_mask(member) |
+                                unit_get_members_mask(member);
+                }
         }
 
-        return mask;
+        u->cgroup_members_mask_valid = true;
+        return u->cgroup_members_mask;
 }
 
-static CGroupControllerMask unit_get_siblings_mask(Unit *u) {
+CGroupControllerMask unit_get_siblings_mask(Unit *u) {
+        CGroupControllerMask m;
+
         assert(u);
 
-        if (!UNIT_ISSET(u->slice))
-                return 0;
+        if (UNIT_ISSET(u->slice))
+                m = unit_get_members_mask(UNIT_DEREF(u->slice));
+        else
+                m = unit_get_cgroup_mask(u) | unit_get_members_mask(u);
 
         /* Sibling propagation is only relevant for weight-based
          * controllers, so let's mask out everything else */
-        return unit_get_members_mask(UNIT_DEREF(u->slice)) &
-                (CGROUP_CPU|CGROUP_BLKIO|CGROUP_CPUACCT);
+        return m & (CGROUP_CPU|CGROUP_BLKIO|CGROUP_CPUACCT);
+}
+
+CGroupControllerMask unit_get_target_mask(Unit *u) {
+        CGroupControllerMask mask;
+
+        mask = unit_get_cgroup_mask(u) | unit_get_members_mask(u) | unit_get_siblings_mask(u);
+        mask &= u->manager->cgroup_supported;
+
+        return mask;
+}
+
+/* Recurse from a unit up through its containing slices, propagating
+ * mask bits upward. A unit is also member of itself. */
+void unit_update_cgroup_members_masks(Unit *u) {
+        CGroupControllerMask m;
+        bool more;
+
+        assert(u);
+
+        /* Calculate subtree mask */
+        m = unit_get_cgroup_mask(u) | unit_get_members_mask(u);
+
+        /* See if anything changed from the previous invocation. If
+         * not, we're done. */
+        if (u->cgroup_subtree_mask_valid && m == u->cgroup_subtree_mask)
+                return;
+
+        more =
+                u->cgroup_subtree_mask_valid &&
+                ((m & ~u->cgroup_subtree_mask) != 0) &&
+                ((~m & u->cgroup_subtree_mask) == 0);
+
+        u->cgroup_subtree_mask = m;
+        u->cgroup_subtree_mask_valid = true;
+
+        if (UNIT_ISSET(u->slice)) {
+                Unit *s = UNIT_DEREF(u->slice);
+
+                if (more)
+                        /* There's more set now than before. We
+                         * propagate the new mask to the parent's mask
+                         * (not caring if it actually was valid or
+                         * not). */
+
+                        s->cgroup_members_mask |= m;
+
+                else
+                        /* There's less set now than before (or we
+                         * don't know), we need to recalculate
+                         * everything, so let's invalidate the
+                         * parent's members mask */
+
+                        s->cgroup_members_mask_valid = false;
+
+                /* And now make sure that this change also hits our
+                 * grandparents */
+                unit_update_cgroup_members_masks(s);
+        }
 }
 
 static int unit_create_cgroups(Unit *u, CGroupControllerMask mask) {
-        char *path = NULL;
+        _cleanup_free_ char *path;
+        bool was_in_hash = false;
         int r;
-        bool is_in_hash = false;
 
         assert(u);
 
         path = unit_default_cgroup_path(u);
         if (!path)
-                return -ENOMEM;
+                return log_oom();
 
         r = hashmap_put(u->manager->cgroup_unit, path, u);
         if (r == 0)
-                is_in_hash = true;
-
-        if (r < 0) {
-                log_error("cgroup %s exists already: %s", path, strerror(-r));
-                free(path);
+                was_in_hash = true;
+        else if (r < 0) {
+                log_error(r == -EEXIST ?
+                          "cgroup %s exists already: %s" : "hashmap_put failed for %s: %s",
+                          path, strerror(-r));
                 return r;
         }
 
@@ -405,23 +478,38 @@ static int unit_create_cgroups(Unit *u, CGroupControllerMask mask) {
         if (u->cgroup_path) {
                 r = cg_migrate_everywhere(u->manager->cgroup_supported, u->cgroup_path, path);
                 if (r < 0)
-                        log_error("Failed to migrate cgroup %s: %s", path, strerror(-r));
+                        log_error("Failed to migrate cgroup from %s to %s: %s",
+                                  u->cgroup_path, path, strerror(-r));
         }
 
-        if (!is_in_hash) {
-                /* And remember the new data */
+        if (!was_in_hash) {
+                /* Remember the new data */
                 free(u->cgroup_path);
                 u->cgroup_path = path;
+                path = NULL;
         }
 
         u->cgroup_realized = true;
-        u->cgroup_mask = mask;
+        u->cgroup_realized_mask = mask;
 
         return 0;
 }
 
+static bool unit_has_mask_realized(Unit *u, CGroupControllerMask mask) {
+        assert(u);
+
+        return u->cgroup_realized && u->cgroup_realized_mask == mask;
+}
+
+/* Check if necessary controllers and attributes for a unit are in place.
+ *
+ * If so, do nothing.
+ * If not, create paths, move processes over, and set attributes.
+ *
+ * Returns 0 on success and < 0 on failure. */
 static int unit_realize_cgroup_now(Unit *u) {
         CGroupControllerMask mask;
+        int r;
 
         assert(u);
 
@@ -430,19 +518,27 @@ static int unit_realize_cgroup_now(Unit *u) {
                 u->in_cgroup_queue = false;
         }
 
-        mask = unit_get_cgroup_mask(u) | unit_get_members_mask(u) | unit_get_siblings_mask(u);
-        mask &= u->manager->cgroup_supported;
+        mask = unit_get_target_mask(u);
 
-        if (u->cgroup_realized &&
-            u->cgroup_mask == mask)
+        if (unit_has_mask_realized(u, mask))
                 return 0;
 
         /* First, realize parents */
-        if (UNIT_ISSET(u->slice))
-                unit_realize_cgroup_now(UNIT_DEREF(u->slice));
+        if (UNIT_ISSET(u->slice)) {
+                r = unit_realize_cgroup_now(UNIT_DEREF(u->slice));
+                if (r < 0)
+                        return r;
+        }
 
         /* And then do the real work */
-        return unit_create_cgroups(u, mask);
+        r = unit_create_cgroups(u, mask);
+        if (r < 0)
+                return r;
+
+        /* Finally, apply the necessary attributes. */
+        cgroup_context_apply(unit_get_cgroup_context(u), mask, u->cgroup_path);
+
+        return 0;
 }
 
 static void unit_add_to_cgroup_queue(Unit *u) {
@@ -457,12 +553,14 @@ static void unit_add_to_cgroup_queue(Unit *u) {
 unsigned manager_dispatch_cgroup_queue(Manager *m) {
         Unit *i;
         unsigned n = 0;
+        int r;
 
         while ((i = m->cgroup_queue)) {
                 assert(i->in_cgroup_queue);
 
-                if (unit_realize_cgroup_now(i) >= 0)
-                        cgroup_context_apply(unit_get_cgroup_context(i), i->cgroup_mask, i->cgroup_path);
+                r = unit_realize_cgroup_now(i);
+                if (r < 0)
+                        log_warning("Failed to realize cgroups for queued unit %s: %s", i->id, strerror(-r));
 
                 n++;
         }
@@ -485,9 +583,22 @@ static void unit_queue_siblings(Unit *u) {
                         if (m == u)
                                 continue;
 
+                        /* Skip units that have a dependency on the slice
+                         * but aren't actually in it. */
                         if (UNIT_DEREF(m->slice) != slice)
                                 continue;
 
+                        /* No point in doing cgroup application for units
+                         * without active processes. */
+                        if (UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(m)))
+                                continue;
+
+                        /* If the unit doesn't need any new controllers
+                         * and has current ones realized, it doesn't need
+                         * any changes. */
+                        if (unit_has_mask_realized(m, unit_get_target_mask(m)))
+                                continue;
+
                         unit_add_to_cgroup_queue(m);
                 }
 
@@ -497,7 +608,6 @@ static void unit_queue_siblings(Unit *u) {
 
 int unit_realize_cgroup(Unit *u) {
         CGroupContext *c;
-        int r;
 
         assert(u);
 
@@ -519,14 +629,8 @@ int unit_realize_cgroup(Unit *u) {
         /* Add all sibling slices to the cgroup queue. */
         unit_queue_siblings(u);
 
-        /* And realize this one now */
-        r = unit_realize_cgroup_now(u);
-
-        /* And apply the values */
-        if (r >= 0)
-                cgroup_context_apply(c, u->cgroup_mask, u->cgroup_path);
-
-        return r;
+        /* And realize this one now (and apply the values) */
+        return unit_realize_cgroup_now(u);
 }
 
 void unit_destroy_cgroup(Unit *u) {
@@ -546,7 +650,7 @@ void unit_destroy_cgroup(Unit *u) {
         free(u->cgroup_path);
         u->cgroup_path = NULL;
         u->cgroup_realized = false;
-        u->cgroup_mask = 0;
+        u->cgroup_realized_mask = 0;
 
 }