diff options
Diffstat (limited to 'kernel/cgroup/cgroup.c')
-rw-r--r-- | kernel/cgroup/cgroup.c | 241 |
1 files changed, 225 insertions, 16 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 3f2b4bde0f9c..217cec4e22c6 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -593,6 +593,39 @@ static void cgroup_get_live(struct cgroup *cgrp) css_get(&cgrp->self); } +/** + * __cgroup_task_count - count the number of tasks in a cgroup. The caller + * is responsible for taking the css_set_lock. + * @cgrp: the cgroup in question + */ +int __cgroup_task_count(const struct cgroup *cgrp) +{ + int count = 0; + struct cgrp_cset_link *link; + + lockdep_assert_held(&css_set_lock); + + list_for_each_entry(link, &cgrp->cset_links, cset_link) + count += link->cset->nr_tasks; + + return count; +} + +/** + * cgroup_task_count - count the number of tasks in a cgroup. + * @cgrp: the cgroup in question + */ +int cgroup_task_count(const struct cgroup *cgrp) +{ + int count; + + spin_lock_irq(&css_set_lock); + count = __cgroup_task_count(cgrp); + spin_unlock_irq(&css_set_lock); + + return count; +} + struct cgroup_subsys_state *of_css(struct kernfs_open_file *of) { struct cgroup *cgrp = of->kn->parent->priv; @@ -783,6 +816,8 @@ static void cgroup_update_populated(struct cgroup *cgrp, bool populated) break; cgroup1_check_for_release(cgrp); + TRACE_CGROUP_PATH(notify_populated, cgrp, + cgroup_is_populated(cgrp)); cgroup_file_notify(&cgrp->events_file); child = cgrp; @@ -2402,8 +2437,15 @@ static int cgroup_migrate_execute(struct cgroup_mgctx *mgctx) get_css_set(to_cset); to_cset->nr_tasks++; css_set_move_task(task, from_cset, to_cset, true); - put_css_set_locked(from_cset); from_cset->nr_tasks--; + /* + * If the source or destination cgroup is frozen, + * the task might require to change its state. + */ + cgroup_freezer_migrate_task(task, from_cset->dfl_cgrp, + to_cset->dfl_cgrp); + put_css_set_locked(from_cset); + } } spin_unlock_irq(&css_set_lock); @@ -2602,7 +2644,7 @@ int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx) dst_cset = find_css_set(src_cset, src_cset->mg_dst_cgrp); if (!dst_cset) - goto err; + return -ENOMEM; WARN_ON_ONCE(src_cset->mg_dst_cset || dst_cset->mg_dst_cset); @@ -2634,9 +2676,6 @@ int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx) } return 0; -err: - cgroup_migrate_finish(mgctx); - return -ENOMEM; } /** @@ -3447,8 +3486,11 @@ static ssize_t cgroup_max_depth_write(struct kernfs_open_file *of, static int cgroup_events_show(struct seq_file *seq, void *v) { - seq_printf(seq, "populated %d\n", - cgroup_is_populated(seq_css(seq)->cgroup)); + struct cgroup *cgrp = seq_css(seq)->cgroup; + + seq_printf(seq, "populated %d\n", cgroup_is_populated(cgrp)); + seq_printf(seq, "frozen %d\n", test_bit(CGRP_FROZEN, &cgrp->flags)); + return 0; } @@ -3498,17 +3540,118 @@ static int cpu_stat_show(struct seq_file *seq, void *v) #ifdef CONFIG_PSI static int cgroup_io_pressure_show(struct seq_file *seq, void *v) { - return psi_show(seq, &seq_css(seq)->cgroup->psi, PSI_IO); + struct cgroup *cgroup = seq_css(seq)->cgroup; + struct psi_group *psi = cgroup->id == 1 ? &psi_system : &cgroup->psi; + + return psi_show(seq, psi, PSI_IO); } static int cgroup_memory_pressure_show(struct seq_file *seq, void *v) { - return psi_show(seq, &seq_css(seq)->cgroup->psi, PSI_MEM); + struct cgroup *cgroup = seq_css(seq)->cgroup; + struct psi_group *psi = cgroup->id == 1 ? &psi_system : &cgroup->psi; + + return psi_show(seq, psi, PSI_MEM); } static int cgroup_cpu_pressure_show(struct seq_file *seq, void *v) { - return psi_show(seq, &seq_css(seq)->cgroup->psi, PSI_CPU); + struct cgroup *cgroup = seq_css(seq)->cgroup; + struct psi_group *psi = cgroup->id == 1 ? &psi_system : &cgroup->psi; + + return psi_show(seq, psi, PSI_CPU); +} + +static ssize_t cgroup_pressure_write(struct kernfs_open_file *of, char *buf, + size_t nbytes, enum psi_res res) +{ + struct psi_trigger *new; + struct cgroup *cgrp; + + cgrp = cgroup_kn_lock_live(of->kn, false); + if (!cgrp) + return -ENODEV; + + cgroup_get(cgrp); + cgroup_kn_unlock(of->kn); + + new = psi_trigger_create(&cgrp->psi, buf, nbytes, res); + if (IS_ERR(new)) { + cgroup_put(cgrp); + return PTR_ERR(new); + } + + psi_trigger_replace(&of->priv, new); + + cgroup_put(cgrp); + + return nbytes; +} + +static ssize_t cgroup_io_pressure_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, + loff_t off) +{ + return cgroup_pressure_write(of, buf, nbytes, PSI_IO); +} + +static ssize_t cgroup_memory_pressure_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, + loff_t off) +{ + return cgroup_pressure_write(of, buf, nbytes, PSI_MEM); +} + +static ssize_t cgroup_cpu_pressure_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, + loff_t off) +{ + return cgroup_pressure_write(of, buf, nbytes, PSI_CPU); +} + +static __poll_t cgroup_pressure_poll(struct kernfs_open_file *of, + poll_table *pt) +{ + return psi_trigger_poll(&of->priv, of->file, pt); +} + +static void cgroup_pressure_release(struct kernfs_open_file *of) +{ + psi_trigger_replace(&of->priv, NULL); +} +#endif /* CONFIG_PSI */ + +static int cgroup_freeze_show(struct seq_file *seq, void *v) +{ + struct cgroup *cgrp = seq_css(seq)->cgroup; + + seq_printf(seq, "%d\n", cgrp->freezer.freeze); + + return 0; +} + +static ssize_t cgroup_freeze_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct cgroup *cgrp; + ssize_t ret; + int freeze; + + ret = kstrtoint(strstrip(buf), 0, &freeze); + if (ret) + return ret; + + if (freeze < 0 || freeze > 1) + return -ERANGE; + + cgrp = cgroup_kn_lock_live(of->kn, false); + if (!cgrp) + return -ENOENT; + + cgroup_freeze(cgrp, freeze); + + cgroup_kn_unlock(of->kn); + + return nbytes; } -#endif static int cgroup_file_open(struct kernfs_open_file *of) { @@ -4654,6 +4797,12 @@ static struct cftype cgroup_base_files[] = { .seq_show = cgroup_stat_show, }, { + .name = "cgroup.freeze", + .flags = CFTYPE_NOT_ON_ROOT, + .seq_show = cgroup_freeze_show, + .write = cgroup_freeze_write, + }, + { .name = "cpu.stat", .flags = CFTYPE_NOT_ON_ROOT, .seq_show = cpu_stat_show, @@ -4661,20 +4810,26 @@ static struct cftype cgroup_base_files[] = { #ifdef CONFIG_PSI { .name = "io.pressure", - .flags = CFTYPE_NOT_ON_ROOT, .seq_show = cgroup_io_pressure_show, + .write = cgroup_io_pressure_write, + .poll = cgroup_pressure_poll, + .release = cgroup_pressure_release, }, { .name = "memory.pressure", - .flags = CFTYPE_NOT_ON_ROOT, .seq_show = cgroup_memory_pressure_show, + .write = cgroup_memory_pressure_write, + .poll = cgroup_pressure_poll, + .release = cgroup_pressure_release, }, { .name = "cpu.pressure", - .flags = CFTYPE_NOT_ON_ROOT, .seq_show = cgroup_cpu_pressure_show, + .write = cgroup_cpu_pressure_write, + .poll = cgroup_pressure_poll, + .release = cgroup_pressure_release, }, -#endif +#endif /* CONFIG_PSI */ { } /* terminate */ }; @@ -4781,9 +4936,11 @@ static void css_release_work_fn(struct work_struct *work) if (cgroup_on_dfl(cgrp)) cgroup_rstat_flush(cgrp); + spin_lock_irq(&css_set_lock); for (tcgrp = cgroup_parent(cgrp); tcgrp; tcgrp = cgroup_parent(tcgrp)) tcgrp->nr_dying_descendants--; + spin_unlock_irq(&css_set_lock); cgroup_idr_remove(&cgrp->root->cgroup_idr, cgrp->id); cgrp->id = -1; @@ -5001,12 +5158,31 @@ static struct cgroup *cgroup_create(struct cgroup *parent) if (ret) goto out_psi_free; + /* + * New cgroup inherits effective freeze counter, and + * if the parent has to be frozen, the child has too. + */ + cgrp->freezer.e_freeze = parent->freezer.e_freeze; + if (cgrp->freezer.e_freeze) + set_bit(CGRP_FROZEN, &cgrp->flags); + + spin_lock_irq(&css_set_lock); for (tcgrp = cgrp; tcgrp; tcgrp = cgroup_parent(tcgrp)) { cgrp->ancestor_ids[tcgrp->level] = tcgrp->id; - if (tcgrp != cgrp) + if (tcgrp != cgrp) { tcgrp->nr_descendants++; + + /* + * If the new cgroup is frozen, all ancestor cgroups + * get a new frozen descendant, but their state can't + * change because of this. + */ + if (cgrp->freezer.e_freeze) + tcgrp->freezer.nr_frozen_descendants++; + } } + spin_unlock_irq(&css_set_lock); if (notify_on_release(parent)) set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); @@ -5291,10 +5467,18 @@ static int cgroup_destroy_locked(struct cgroup *cgrp) if (parent && cgroup_is_threaded(cgrp)) parent->nr_threaded_children--; + spin_lock_irq(&css_set_lock); for (tcgrp = cgroup_parent(cgrp); tcgrp; tcgrp = cgroup_parent(tcgrp)) { tcgrp->nr_descendants--; tcgrp->nr_dying_descendants++; + /* + * If the dying cgroup is frozen, decrease frozen descendants + * counters of ancestor cgroups. + */ + if (test_bit(CGRP_FROZEN, &cgrp->flags)) + tcgrp->freezer.nr_frozen_descendants--; } + spin_unlock_irq(&css_set_lock); cgroup1_check_for_release(parent); @@ -5746,6 +5930,26 @@ void cgroup_post_fork(struct task_struct *child) cset->nr_tasks++; css_set_move_task(child, NULL, cset, false); } + + /* + * If the cgroup has to be frozen, the new task has too. + * Let's set the JOBCTL_TRAP_FREEZE jobctl bit to get + * the task into the frozen state. + */ + if (unlikely(cgroup_task_freeze(child))) { + spin_lock(&child->sighand->siglock); + WARN_ON_ONCE(child->frozen); + child->jobctl |= JOBCTL_TRAP_FREEZE; + spin_unlock(&child->sighand->siglock); + + /* + * Calling cgroup_update_frozen() isn't required here, + * because it will be called anyway a bit later + * from do_freezer_trap(). So we avoid cgroup's + * transient switch from the frozen state and back. + */ + } + spin_unlock_irq(&css_set_lock); } @@ -5794,6 +5998,11 @@ void cgroup_exit(struct task_struct *tsk) spin_lock_irq(&css_set_lock); css_set_move_task(tsk, cset, NULL, false); cset->nr_tasks--; + + WARN_ON_ONCE(cgroup_task_frozen(tsk)); + if (unlikely(cgroup_task_freeze(tsk))) + cgroup_update_frozen(task_dfl_cgroup(tsk)); + spin_unlock_irq(&css_set_lock); } else { get_css_set(cset); |