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author | Tejun Heo <tj@kernel.org> | 2012-11-09 18:12:30 +0100 |
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committer | Tejun Heo <tj@kernel.org> | 2012-11-09 18:12:30 +0100 |
commit | 04a4ec32571e88c614b229824afec376d24cc035 (patch) | |
tree | 47149b8d0c5673a1e4278ac4f0874296b3d19b10 /kernel | |
parent | cgroup_freezer: trivial cleanups (diff) | |
download | linux-04a4ec32571e88c614b229824afec376d24cc035.tar.xz linux-04a4ec32571e88c614b229824afec376d24cc035.zip |
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')
-rw-r--r-- | kernel/cgroup_freezer.c | 48 |
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; } |