linux/kernel/cgroup/freezer.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/cgroup.h>
#include <linux/sched.h>
#include <linux/sched/task.h>
#include <linux/sched/signal.h>

#include "cgroup-internal.h"

#include <trace/events/cgroup.h>

/*
 * Propagate the cgroup frozen state upwards by the cgroup tree.
 */
static void cgroup_propagate_frozen(struct cgroup *cgrp, bool frozen)
{ … }

/*
 * Revisit the cgroup frozen state.
 * Checks if the cgroup is really frozen and perform all state transitions.
 */
void cgroup_update_frozen(struct cgroup *cgrp)
{ … }

/*
 * Increment cgroup's nr_frozen_tasks.
 */
static void cgroup_inc_frozen_cnt(struct cgroup *cgrp)
{ … }

/*
 * Decrement cgroup's nr_frozen_tasks.
 */
static void cgroup_dec_frozen_cnt(struct cgroup *cgrp)
{ … }

/*
 * Enter frozen/stopped state, if not yet there. Update cgroup's counters,
 * and revisit the state of the cgroup, if necessary.
 */
void cgroup_enter_frozen(void)
{ … }

/*
 * Conditionally leave frozen/stopped state. Update cgroup's counters,
 * and revisit the state of the cgroup, if necessary.
 *
 * If always_leave is not set, and the cgroup is freezing,
 * we're racing with the cgroup freezing. In this case, we don't
 * drop the frozen counter to avoid a transient switch to
 * the unfrozen state.
 */
void cgroup_leave_frozen(bool always_leave)
{ … }

/*
 * Freeze or unfreeze the task by setting or clearing the JOBCTL_TRAP_FREEZE
 * jobctl bit.
 */
static void cgroup_freeze_task(struct task_struct *task, bool freeze)
{ … }

/*
 * Freeze or unfreeze all tasks in the given cgroup.
 */
static void cgroup_do_freeze(struct cgroup *cgrp, bool freeze)
{ … }

/*
 * Adjust the task state (freeze or unfreeze) and revisit the state of
 * source and destination cgroups.
 */
void cgroup_freezer_migrate_task(struct task_struct *task,
				 struct cgroup *src, struct cgroup *dst)
{ … }

void cgroup_freeze(struct cgroup *cgrp, bool freeze)
{ … }