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author | Michal Hocko <mhocko@suse.cz> | 2011-11-22 07:44:47 -0800 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-12-09 08:52:27 -0800 |
commit | 953d0c888eda75de7d248017f6dd2e5e254ad0cc (patch) | |
tree | 58017d4edf59b04ec606eafd12e6c6a7f967abd7 /kernel | |
parent | 1c8ca629b774d8dd5fb85baf985f260cfcd68fc8 (diff) | |
download | kernel_samsung_tuna-953d0c888eda75de7d248017f6dd2e5e254ad0cc.zip kernel_samsung_tuna-953d0c888eda75de7d248017f6dd2e5e254ad0cc.tar.gz kernel_samsung_tuna-953d0c888eda75de7d248017f6dd2e5e254ad0cc.tar.bz2 |
cgroup_freezer: fix freezing groups with stopped tasks
commit 884a45d964dd395eda945842afff5e16bcaedf56 upstream.
2d3cbf8b (cgroup_freezer: update_freezer_state() does incorrect state
transitions) removed is_task_frozen_enough and replaced it with a simple
frozen call. This, however, breaks freezing for a group with stopped tasks
because those cannot be frozen and so the group remains in CGROUP_FREEZING
state (update_if_frozen doesn't count stopped tasks) and never reaches
CGROUP_FROZEN.
Let's add is_task_frozen_enough back and use it at the original locations
(update_if_frozen and try_to_freeze_cgroup). Semantically we consider
stopped tasks as frozen enough so we should consider both cases when
testing frozen tasks.
Testcase:
mkdir /dev/freezer
mount -t cgroup -o freezer none /dev/freezer
mkdir /dev/freezer/foo
sleep 1h &
pid=$!
kill -STOP $pid
echo $pid > /dev/freezer/foo/tasks
echo FROZEN > /dev/freezer/foo/freezer.state
while true
do
cat /dev/freezer/foo/freezer.state
[ "`cat /dev/freezer/foo/freezer.state`" = "FROZEN" ] && break
sleep 1
done
echo OK
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Tomasz Buchert <tomasz.buchert@inria.fr>
Cc: Paul Menage <paul@paulmenage.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/cgroup_freezer.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c index e691818..a3f638a 100644 --- a/kernel/cgroup_freezer.c +++ b/kernel/cgroup_freezer.c @@ -153,6 +153,13 @@ static void freezer_destroy(struct cgroup_subsys *ss, kfree(cgroup_freezer(cgroup)); } +/* task is frozen or will freeze immediately when next it gets woken */ +static bool is_task_frozen_enough(struct task_struct *task) +{ + return frozen(task) || + (task_is_stopped_or_traced(task) && freezing(task)); +} + /* * The call to cgroup_lock() in the freezer.state write method prevents * a write to that file racing against an attach, and hence the @@ -231,7 +238,7 @@ static void update_if_frozen(struct cgroup *cgroup, cgroup_iter_start(cgroup, &it); while ((task = cgroup_iter_next(cgroup, &it))) { ntotal++; - if (frozen(task)) + if (is_task_frozen_enough(task)) nfrozen++; } @@ -284,7 +291,7 @@ static int try_to_freeze_cgroup(struct cgroup *cgroup, struct freezer *freezer) while ((task = cgroup_iter_next(cgroup, &it))) { if (!freeze_task(task, true)) continue; - if (frozen(task)) + if (is_task_frozen_enough(task)) continue; if (!freezing(task) && !freezer_should_skip(task)) num_cant_freeze_now++; |