diff --git a/kernel/cgroup/freezer.c b/kernel/cgroup/freezer.c index 188d5f2aeb5a..bf1690a167dd 100644 --- a/kernel/cgroup/freezer.c +++ b/kernel/cgroup/freezer.c @@ -8,6 +8,28 @@ #include +/* + * Update CGRP_FROZEN of cgroup.flag + * Return true if flags is updated; false if flags has no change + */ +static bool cgroup_update_frozen_flag(struct cgroup *cgrp, bool frozen) +{ + lockdep_assert_held(&css_set_lock); + + /* Already there? */ + if (test_bit(CGRP_FROZEN, &cgrp->flags) == frozen) + return false; + + if (frozen) + set_bit(CGRP_FROZEN, &cgrp->flags); + else + clear_bit(CGRP_FROZEN, &cgrp->flags); + + cgroup_file_notify(&cgrp->events_file); + TRACE_CGROUP_PATH(notify_frozen, cgrp, frozen); + return true; +} + /* * Propagate the cgroup frozen state upwards by the cgroup tree. */ @@ -24,24 +46,16 @@ static void cgroup_propagate_frozen(struct cgroup *cgrp, bool frozen) while ((cgrp = cgroup_parent(cgrp))) { if (frozen) { cgrp->freezer.nr_frozen_descendants += desc; - if (!test_bit(CGRP_FROZEN, &cgrp->flags) && - test_bit(CGRP_FREEZE, &cgrp->flags) && - cgrp->freezer.nr_frozen_descendants == - cgrp->nr_descendants) { - set_bit(CGRP_FROZEN, &cgrp->flags); - cgroup_file_notify(&cgrp->events_file); - TRACE_CGROUP_PATH(notify_frozen, cgrp, 1); - desc++; - } + if (!test_bit(CGRP_FREEZE, &cgrp->flags) || + (cgrp->freezer.nr_frozen_descendants != + cgrp->nr_descendants)) + continue; } else { cgrp->freezer.nr_frozen_descendants -= desc; - if (test_bit(CGRP_FROZEN, &cgrp->flags)) { - clear_bit(CGRP_FROZEN, &cgrp->flags); - cgroup_file_notify(&cgrp->events_file); - TRACE_CGROUP_PATH(notify_frozen, cgrp, 0); - desc++; - } } + + if (cgroup_update_frozen_flag(cgrp, frozen)) + desc++; } } @@ -53,8 +67,6 @@ void cgroup_update_frozen(struct cgroup *cgrp) { bool frozen; - lockdep_assert_held(&css_set_lock); - /* * If the cgroup has to be frozen (CGRP_FREEZE bit set), * and all tasks are frozen and/or stopped, let's consider @@ -63,24 +75,9 @@ void cgroup_update_frozen(struct cgroup *cgrp) frozen = test_bit(CGRP_FREEZE, &cgrp->flags) && cgrp->freezer.nr_frozen_tasks == __cgroup_task_count(cgrp); - if (frozen) { - /* Already there? */ - if (test_bit(CGRP_FROZEN, &cgrp->flags)) - return; - - set_bit(CGRP_FROZEN, &cgrp->flags); - } else { - /* Already there? */ - if (!test_bit(CGRP_FROZEN, &cgrp->flags)) - return; - - clear_bit(CGRP_FROZEN, &cgrp->flags); - } - cgroup_file_notify(&cgrp->events_file); - TRACE_CGROUP_PATH(notify_frozen, cgrp, frozen); - - /* Update the state of ancestor cgroups. */ - cgroup_propagate_frozen(cgrp, frozen); + /* If flags is updated, update the state of ancestor cgroups. */ + if (cgroup_update_frozen_flag(cgrp, frozen)) + cgroup_propagate_frozen(cgrp, frozen); } /*