[PATCH 04/14] cgroup: move check_for_release() invocation

From: Tejun Heo
Date: Fri Oct 09 2015 - 23:31:06 EST


To trigger release agent when the last task leaves the cgroup,
check_for_release() is called from put_css_set_locked(); however,
css_set being unlinked is being decoupled from task leaving the cgroup
and the correct condition to test is cgroup->nr_populated dropping to
zero which check_for_release() is already updated to test.

This patch moves check_for_release() invocation from
put_css_set_locked() to cgroup_update_populated().

Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
---
kernel/cgroup.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 435aa68..855313d 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -623,6 +623,7 @@ static void cgroup_update_populated(struct cgroup *cgrp, bool populated)
if (!trigger)
break;

+ check_for_release(cgrp);
cgroup_file_notify(&cgrp->events_file);

cgrp = cgroup_parent(cgrp);
@@ -686,15 +687,8 @@ static void put_css_set_locked(struct css_set *cset)
css_set_count--;

list_for_each_entry_safe(link, tmp_link, &cset->cgrp_links, cgrp_link) {
- struct cgroup *cgrp = link->cgrp;
-
list_del(&link->cset_link);
list_del(&link->cgrp_link);
-
- /* @cgrp can't go away while we're holding css_set_rwsem */
- if (list_empty(&cgrp->cset_links))
- check_for_release(cgrp);
-
kfree(link);
}

--
2.4.3

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