[systemd-devel] [PATCH] Cache aggregated cgroup mask data at the slice level.

[david at davidstrauss.net]

From: David Strauss <david at davidstrauss.net>

---
 src/core/cgroup.c | 20 +++++++++++++++++++-
 src/core/cgroup.h |  2 ++
 src/core/unit.c   |  2 ++
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index 6a6c504..b75ab55 100644
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -345,6 +345,14 @@ static CGroupControllerMask unit_get_cgroup_mask(Unit *u) {
         return cgroup_context_get_mask(c);
 }
 
+void unit_update_parent_slice_mask(Unit *u) {
+        if (UNIT_ISSET(u->slice)) {
+                UNIT_DEREF(u->slice)->cgroup_mask |= unit_get_cgroup_mask(u);
+                log_warning("Setting slice to mask: %x", unit_get_cgroup_mask(u));
+        }
+        log_warning("No slice to update.");
+}
+
 static CGroupControllerMask unit_get_members_mask(Unit *u) {
         CGroupControllerMask mask = 0;
         Unit *m;
@@ -425,12 +433,22 @@ static int unit_realize_cgroup_now(Unit *u) {
 
         assert(u);
 
+        log_warning("unit_realize_cgroup_now");
+
         if (u->in_cgroup_queue) {
                 LIST_REMOVE(cgroup_queue, u->manager->cgroup_queue, u);
                 u->in_cgroup_queue = false;
         }
 
-        mask = unit_get_cgroup_mask(u) | unit_get_members_mask(u) | unit_get_siblings_mask(u);
+        /* If the unit is a member of a slice, the slice will contain
+         * aggregated cgroup mask data for the unit and all siblings. */
+        if (UNIT_ISSET(u->slice)) {
+                mask = UNIT_DEREF(u->slice)->cgroup_mask;
+                log_warning("Using cgroup_mask.");
+        } else {
+                mask = unit_get_cgroup_mask(u) | unit_get_members_mask(u) | unit_get_siblings_mask(u);
+                log_warning("Not using cgroup_mask.");
+        }
         mask &= u->manager->cgroup_supported;
 
         if (u->cgroup_realized &&
diff --git a/src/core/cgroup.h b/src/core/cgroup.h
index 0a079e9..1a24d07 100644
--- a/src/core/cgroup.h
+++ b/src/core/cgroup.h
@@ -113,3 +113,5 @@ int manager_notify_cgroup_empty(Manager *m, const char *group);
 
 const char* cgroup_device_policy_to_string(CGroupDevicePolicy i) _const_;
 CGroupDevicePolicy cgroup_device_policy_from_string(const char *s) _pure_;
+
+void unit_update_parent_slice_mask(Unit *u);
diff --git a/src/core/unit.c b/src/core/unit.c
index e19d281..a018dad 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -981,6 +981,8 @@ int unit_load(Unit *u) {
                                 goto fail;
                 }
 
+                unit_update_parent_slice_mask(u);
+
                 r = unit_add_mount_links(u);
                 if (r < 0)
                         goto fail;
-- 
1.8.3.1