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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-05 08:26:59 +00:00
Revert "cgroup/cpuset: remove circular dependency deadlock"
This reverts commitaa24163b2e
. This and the following commit led to another circular locking scenario and the scenario which is fixed by this commit no longer exists aftere8b3f8db7a
("workqueue/hotplug: simplify workqueue_offline_cpu()") which removes work item flushing from hotplug path. Revert it for now. Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
parent
11db855c3d
commit
bdfbbda90a
1 changed files with 23 additions and 30 deletions
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@ -812,18 +812,6 @@ static int generate_sched_domains(cpumask_var_t **domains,
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return ndoms;
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return ndoms;
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}
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}
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static void cpuset_sched_change_begin(void)
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{
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cpus_read_lock();
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mutex_lock(&cpuset_mutex);
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}
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static void cpuset_sched_change_end(void)
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{
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mutex_unlock(&cpuset_mutex);
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cpus_read_unlock();
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}
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/*
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/*
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* Rebuild scheduler domains.
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* Rebuild scheduler domains.
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*
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*
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@ -833,14 +821,16 @@ static void cpuset_sched_change_end(void)
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* 'cpus' is removed, then call this routine to rebuild the
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* 'cpus' is removed, then call this routine to rebuild the
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* scheduler's dynamic sched domains.
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* scheduler's dynamic sched domains.
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*
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*
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* Call with cpuset_mutex held. Takes get_online_cpus().
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*/
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*/
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static void rebuild_sched_domains_cpuslocked(void)
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static void rebuild_sched_domains_locked(void)
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{
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{
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struct sched_domain_attr *attr;
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struct sched_domain_attr *attr;
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cpumask_var_t *doms;
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cpumask_var_t *doms;
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int ndoms;
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int ndoms;
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lockdep_assert_held(&cpuset_mutex);
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lockdep_assert_held(&cpuset_mutex);
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get_online_cpus();
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/*
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/*
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* We have raced with CPU hotplug. Don't do anything to avoid
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* We have raced with CPU hotplug. Don't do anything to avoid
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@ -848,25 +838,27 @@ static void rebuild_sched_domains_cpuslocked(void)
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* Anyways, hotplug work item will rebuild sched domains.
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* Anyways, hotplug work item will rebuild sched domains.
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*/
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*/
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if (!cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask))
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if (!cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask))
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return;
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goto out;
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/* Generate domain masks and attrs */
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/* Generate domain masks and attrs */
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ndoms = generate_sched_domains(&doms, &attr);
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ndoms = generate_sched_domains(&doms, &attr);
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/* Have scheduler rebuild the domains */
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/* Have scheduler rebuild the domains */
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partition_sched_domains(ndoms, doms, attr);
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partition_sched_domains(ndoms, doms, attr);
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out:
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put_online_cpus();
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}
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}
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#else /* !CONFIG_SMP */
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#else /* !CONFIG_SMP */
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static void rebuild_sched_domains_cpuslocked(void)
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static void rebuild_sched_domains_locked(void)
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{
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{
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}
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}
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#endif /* CONFIG_SMP */
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#endif /* CONFIG_SMP */
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void rebuild_sched_domains(void)
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void rebuild_sched_domains(void)
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{
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{
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cpuset_sched_change_begin();
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mutex_lock(&cpuset_mutex);
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rebuild_sched_domains_cpuslocked();
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rebuild_sched_domains_locked();
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cpuset_sched_change_end();
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mutex_unlock(&cpuset_mutex);
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}
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}
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/**
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/**
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@ -952,7 +944,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct cpumask *new_cpus)
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rcu_read_unlock();
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rcu_read_unlock();
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if (need_rebuild_sched_domains)
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if (need_rebuild_sched_domains)
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rebuild_sched_domains_cpuslocked();
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rebuild_sched_domains_locked();
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}
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}
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/**
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/**
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@ -1284,7 +1276,7 @@ static int update_relax_domain_level(struct cpuset *cs, s64 val)
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cs->relax_domain_level = val;
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cs->relax_domain_level = val;
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if (!cpumask_empty(cs->cpus_allowed) &&
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if (!cpumask_empty(cs->cpus_allowed) &&
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is_sched_load_balance(cs))
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is_sched_load_balance(cs))
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rebuild_sched_domains_cpuslocked();
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rebuild_sched_domains_locked();
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}
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}
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return 0;
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return 0;
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@ -1317,6 +1309,7 @@ static void update_tasks_flags(struct cpuset *cs)
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*
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*
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* Call with cpuset_mutex held.
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* Call with cpuset_mutex held.
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*/
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*/
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static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
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static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
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int turning_on)
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int turning_on)
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{
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{
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@ -1349,7 +1342,7 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
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spin_unlock_irq(&callback_lock);
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spin_unlock_irq(&callback_lock);
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if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
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if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
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rebuild_sched_domains_cpuslocked();
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rebuild_sched_domains_locked();
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if (spread_flag_changed)
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if (spread_flag_changed)
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update_tasks_flags(cs);
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update_tasks_flags(cs);
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@ -1617,7 +1610,7 @@ static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft,
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cpuset_filetype_t type = cft->private;
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cpuset_filetype_t type = cft->private;
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int retval = 0;
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int retval = 0;
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cpuset_sched_change_begin();
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mutex_lock(&cpuset_mutex);
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if (!is_cpuset_online(cs)) {
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if (!is_cpuset_online(cs)) {
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retval = -ENODEV;
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retval = -ENODEV;
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goto out_unlock;
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goto out_unlock;
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@ -1653,7 +1646,7 @@ static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft,
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break;
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break;
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}
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}
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out_unlock:
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out_unlock:
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cpuset_sched_change_end();
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mutex_unlock(&cpuset_mutex);
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return retval;
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return retval;
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}
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}
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@ -1664,7 +1657,7 @@ static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft,
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cpuset_filetype_t type = cft->private;
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cpuset_filetype_t type = cft->private;
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int retval = -ENODEV;
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int retval = -ENODEV;
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cpuset_sched_change_begin();
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mutex_lock(&cpuset_mutex);
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if (!is_cpuset_online(cs))
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if (!is_cpuset_online(cs))
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goto out_unlock;
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goto out_unlock;
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@ -1677,7 +1670,7 @@ static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft,
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break;
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break;
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}
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}
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out_unlock:
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out_unlock:
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cpuset_sched_change_end();
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mutex_unlock(&cpuset_mutex);
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return retval;
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return retval;
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}
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}
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@ -1716,7 +1709,7 @@ static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
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kernfs_break_active_protection(of->kn);
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kernfs_break_active_protection(of->kn);
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flush_work(&cpuset_hotplug_work);
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flush_work(&cpuset_hotplug_work);
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cpuset_sched_change_begin();
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mutex_lock(&cpuset_mutex);
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if (!is_cpuset_online(cs))
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if (!is_cpuset_online(cs))
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goto out_unlock;
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goto out_unlock;
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@ -1740,7 +1733,7 @@ static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
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free_trial_cpuset(trialcs);
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free_trial_cpuset(trialcs);
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out_unlock:
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out_unlock:
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cpuset_sched_change_end();
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mutex_unlock(&cpuset_mutex);
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kernfs_unbreak_active_protection(of->kn);
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kernfs_unbreak_active_protection(of->kn);
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css_put(&cs->css);
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css_put(&cs->css);
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flush_workqueue(cpuset_migrate_mm_wq);
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flush_workqueue(cpuset_migrate_mm_wq);
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@ -2041,14 +2034,14 @@ static int cpuset_css_online(struct cgroup_subsys_state *css)
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/*
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/*
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* If the cpuset being removed has its flag 'sched_load_balance'
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* If the cpuset being removed has its flag 'sched_load_balance'
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* enabled, then simulate turning sched_load_balance off, which
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* enabled, then simulate turning sched_load_balance off, which
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* will call rebuild_sched_domains_cpuslocked().
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* will call rebuild_sched_domains_locked().
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*/
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*/
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static void cpuset_css_offline(struct cgroup_subsys_state *css)
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static void cpuset_css_offline(struct cgroup_subsys_state *css)
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{
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{
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struct cpuset *cs = css_cs(css);
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struct cpuset *cs = css_cs(css);
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cpuset_sched_change_begin();
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mutex_lock(&cpuset_mutex);
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if (is_sched_load_balance(cs))
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if (is_sched_load_balance(cs))
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update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
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update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
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@ -2056,7 +2049,7 @@ static void cpuset_css_offline(struct cgroup_subsys_state *css)
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cpuset_dec();
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cpuset_dec();
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clear_bit(CS_ONLINE, &cs->flags);
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clear_bit(CS_ONLINE, &cs->flags);
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cpuset_sched_change_end();
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mutex_unlock(&cpuset_mutex);
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}
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}
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static void cpuset_css_free(struct cgroup_subsys_state *css)
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static void cpuset_css_free(struct cgroup_subsys_state *css)
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