From 54a91c5eae72181cc7aadf618c152e18ac336b5e Mon Sep 17 00:00:00 2001

From: Lennart Poettering <lennart@poettering.net>

Date: Thu, 3 Nov 2011 19:42:53 +0100

Subject: [PATCH] cgroup: immediately remove all cgroups which run empty

Some controllers have scaling problems when many empty cgroups exist.

Hence, as soon as we get a notification that a cgroup is empty, delete

it. This is also nice to keep the systemd-cgls output short.

(cherry picked from commit 353fa6a21aab96b0b82ab40cc22b08b1fb0bf652)

---

 src/cgroup.c |   12 +++++++++---

 1 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/cgroup.c b/src/cgroup.c

index be837c3..4bbb54f 100644

--- a/src/cgroup.c

+++ b/src/cgroup.c

@@ -363,7 +363,8 @@ int cgroup_notify_empty(Manager *m, const char *group) {

         assert(m);

         assert(group);

-        if (!(l = hashmap_get(m->cgroup_bondings, group)))

+        l = hashmap_get(m->cgroup_bondings, group);

+        if (!l)

                 return 0;

         LIST_FOREACH(by_path, b, l) {

@@ -372,7 +373,8 @@ int cgroup_notify_empty(Manager *m, const char *group) {

                 if (!b->unit)

                         continue;

-                if ((t = cgroup_bonding_is_empty_list(b)) < 0) {

+                t = cgroup_bonding_is_empty_list(b);

+                if (t < 0) {

                         /* If we don't know, we don't know */

                         if (t != -EAGAIN)

@@ -381,9 +383,13 @@ int cgroup_notify_empty(Manager *m, const char *group) {

                         continue;

                 }

-                if (t > 0)

+                if (t > 0) {

+                        /* If it is empty, let's delete it */

+                        cgroup_bonding_trim_list(b->unit->meta.cgroup_bondings, true);

+

                         if (UNIT_VTABLE(b->unit)->cgroup_notify_empty)

                                 UNIT_VTABLE(b->unit)->cgroup_notify_empty(b->unit);

+                }

         }

         return 0;