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authorDavid Strauss <david@davidstrauss.net>2013-11-11 19:03:31 +1000
committerDavid Strauss <david@davidstrauss.net>2013-11-22 11:22:47 +1000
commit6414b7c981378a6eef480f6806d7cbfc98ca22a1 (patch)
tree52e636340ce65e8e5d69ad7e8dd8b4f2ec310e72 /src/core/cgroup.c
parent52c7f2b2d58394c791ea0c6cf706082fd418f5bc (diff)
cgroups: Cache controller masks and optimize queues.
Diffstat (limited to 'src/core/cgroup.c')
-rw-r--r--src/core/cgroup.c94
1 files changed, 66 insertions, 28 deletions
diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index 1a8fd3728f..c2b1b7d38d 100644
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -346,21 +346,8 @@ static CGroupControllerMask unit_get_cgroup_mask(Unit *u) {
}
static CGroupControllerMask unit_get_members_mask(Unit *u) {
- CGroupControllerMask mask = 0;
- Unit *m;
- Iterator i;
-
assert(u);
-
- SET_FOREACH(m, u->dependencies[UNIT_BEFORE], i) {
-
- if (UNIT_DEREF(m->slice) != u)
- continue;
-
- mask |= unit_get_cgroup_mask(m) | unit_get_members_mask(m);
- }
-
- return mask;
+ return u->cgroup_members_mask;
}
static CGroupControllerMask unit_get_siblings_mask(Unit *u) {
@@ -375,6 +362,26 @@ static CGroupControllerMask unit_get_siblings_mask(Unit *u) {
(CGROUP_CPU|CGROUP_BLKIO|CGROUP_CPUACCT);
}
+static 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_member_masks(Unit *u) {
+ u->cgroup_members_mask |= unit_get_cgroup_mask(u);
+ if (UNIT_ISSET(u->slice)) {
+ Unit *s = UNIT_DEREF(u->slice);
+ s->cgroup_members_mask |= u->cgroup_members_mask;
+ unit_update_member_masks(s);
+ }
+}
+
static int unit_create_cgroups(Unit *u, CGroupControllerMask mask) {
_cleanup_free_ char *path;
int r;
@@ -422,8 +429,19 @@ static int unit_create_cgroups(Unit *u, CGroupControllerMask mask) {
return 0;
}
+static bool unit_has_mask_realized(Unit *u, CGroupControllerMask mask) {
+ return u->cgroup_realized && u->cgroup_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);
@@ -432,19 +450,28 @@ 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)
+ /* TODO: Consider skipping this check. It may be redundant. */
+ 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) {
@@ -459,12 +486,14 @@ 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++;
}
@@ -487,9 +516,22 @@ 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);
}
@@ -521,13 +563,9 @@ int unit_realize_cgroup(Unit *u) {
/* Add all sibling slices to the cgroup queue. */
unit_queue_siblings(u);
- /* And realize this one now */
+ /* And realize this one now (and apply the values) */
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;
}