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authorTejun Heo <tj@kernel.org>2012-11-09 09:12:30 -0800
committerTejun Heo <tj@kernel.org>2012-11-09 09:12:30 -0800
commit04a4ec32571e88c614b229824afec376d24cc035 (patch)
tree47149b8d0c5673a1e4278ac4f0874296b3d19b10 /kernel/cgroup_freezer.c
parentbcd66c894ac994ef5d6fbbaa9a24506ffaf64fd4 (diff)
downloadlinux-04a4ec32571e88c614b229824afec376d24cc035.tar.bz2
cgroup_freezer: prepare freezer_change_state() for full hierarchy support
* Make freezer_change_state() take bool @freeze instead of enum freezer_state. * Separate out freezer_apply_state() out of freezer_change_state(). This makes freezer_change_state() a rather silly thin wrapper. It will be filled with hierarchy handling later on. This patch doesn't introduce any behavior change. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz>
Diffstat (limited to 'kernel/cgroup_freezer.c')
-rw-r--r--kernel/cgroup_freezer.c48
1 files changed, 30 insertions, 18 deletions
diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
index 975b3d8732f4..2690830e7428 100644
--- a/kernel/cgroup_freezer.c
+++ b/kernel/cgroup_freezer.c
@@ -247,45 +247,57 @@ static void unfreeze_cgroup(struct freezer *freezer)
cgroup_iter_end(cgroup, &it);
}
-static void freezer_change_state(struct freezer *freezer,
- enum freezer_state goal_state)
+/**
+ * freezer_apply_state - apply state change to a single cgroup_freezer
+ * @freezer: freezer to apply state change to
+ * @freeze: whether to freeze or unfreeze
+ */
+static void freezer_apply_state(struct freezer *freezer, bool freeze)
{
/* also synchronizes against task migration, see freezer_attach() */
- spin_lock_irq(&freezer->lock);
+ lockdep_assert_held(&freezer->lock);
- switch (goal_state) {
- case CGROUP_THAWED:
- if (freezer->state != CGROUP_THAWED)
- atomic_dec(&system_freezing_cnt);
- freezer->state = CGROUP_THAWED;
- unfreeze_cgroup(freezer);
- break;
- case CGROUP_FROZEN:
+ if (freeze) {
if (freezer->state == CGROUP_THAWED)
atomic_inc(&system_freezing_cnt);
freezer->state = CGROUP_FREEZING;
freeze_cgroup(freezer);
- break;
- default:
- BUG();
+ } else {
+ if (freezer->state != CGROUP_THAWED)
+ atomic_dec(&system_freezing_cnt);
+ freezer->state = CGROUP_THAWED;
+ unfreeze_cgroup(freezer);
}
+}
+/**
+ * freezer_change_state - change the freezing state of a cgroup_freezer
+ * @freezer: freezer of interest
+ * @freeze: whether to freeze or thaw
+ *
+ * Freeze or thaw @cgroup according to @freeze.
+ */
+static void freezer_change_state(struct freezer *freezer, bool freeze)
+{
+ /* update @freezer */
+ spin_lock_irq(&freezer->lock);
+ freezer_apply_state(freezer, freeze);
spin_unlock_irq(&freezer->lock);
}
static int freezer_write(struct cgroup *cgroup, struct cftype *cft,
const char *buffer)
{
- enum freezer_state goal_state;
+ bool freeze;
if (strcmp(buffer, freezer_state_strs[CGROUP_THAWED]) == 0)
- goal_state = CGROUP_THAWED;
+ freeze = false;
else if (strcmp(buffer, freezer_state_strs[CGROUP_FROZEN]) == 0)
- goal_state = CGROUP_FROZEN;
+ freeze = true;
else
return -EINVAL;
- freezer_change_state(cgroup_freezer(cgroup), goal_state);
+ freezer_change_state(cgroup_freezer(cgroup), freeze);
return 0;
}