Merge "cgroup/cpuset: remove circular dependency deadlock" (f64deba8) · Commits · e / devices / android_kernel_fairphone_FP3

include/linux/cpu.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -194,6 +194,7 @@ extern struct bus_type cpu_subsys;
		extern void cpu_hotplug_begin(void);
		extern void cpu_hotplug_done(void);
		extern void get_online_cpus(void);
		extern void cpu_hotplug_mutex_held(void);
		extern void put_online_cpus(void);
		extern void cpu_hotplug_disable(void);
		extern void cpu_hotplug_enable(void);
		@@ -216,6 +217,7 @@ static inline void cpu_hotplug_done(void) {}
		#define cpu_hotplug_enable() do { } while (0)
		#define hotcpu_notifier(fn, pri) do { (void)(fn); } while (0)
		#define __hotcpu_notifier(fn, pri) do { (void)(fn); } while (0)
		#define cpu_hotplug_mutex_held() do { } while (0)
		/* These aren't inline functions due to a GCC bug. */
		#define register_hotcpu_notifier(nb) ({ (void)(nb); 0; })
		#define __register_hotcpu_notifier(nb) ({ (void)(nb); 0; })

kernel/cpu.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -239,6 +239,11 @@ static struct {
		#define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map)
		#define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map)

		void cpu_hotplug_mutex_held(void)
		{
		lockdep_assert_held(&cpu_hotplug.lock);
		}
		EXPORT_SYMBOL(cpu_hotplug_mutex_held);

		void get_online_cpus(void)
		{

kernel/cpuset.c

+19 −14

Original line number	Diff line number	Diff line
		@@ -808,16 +808,15 @@ static int generate_sched_domains(cpumask_var_t **domains,
		* 'cpus' is removed, then call this routine to rebuild the
		* scheduler's dynamic sched domains.
		*
		* Call with cpuset_mutex held. Takes get_online_cpus().
		*/
		static void rebuild_sched_domains_locked(void)
		static void rebuild_sched_domains_unlocked(void)
		{
		struct sched_domain_attr *attr;
		cpumask_var_t *doms;
		int ndoms;

		cpu_hotplug_mutex_held();
		lockdep_assert_held(&cpuset_mutex);
		get_online_cpus();

		/*
		* We have raced with CPU hotplug. Don't do anything to avoid
		@@ -825,27 +824,27 @@ static void rebuild_sched_domains_locked(void)
		* Anyways, hotplug work item will rebuild sched domains.
		*/
		if (!cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask))
		goto out;
		return;

		/* Generate domain masks and attrs */
		ndoms = generate_sched_domains(&doms, &attr);

		/* Have scheduler rebuild the domains */
		partition_sched_domains(ndoms, doms, attr);
		out:
		put_online_cpus();
		}
		#else /* !CONFIG_SMP */
		static void rebuild_sched_domains_locked(void)
		static void rebuild_sched_domains_unlocked(void)
		{
		}
		#endif /* CONFIG_SMP */

		void rebuild_sched_domains(void)
		{
		get_online_cpus();
		mutex_lock(&cpuset_mutex);
		rebuild_sched_domains_locked();
		rebuild_sched_domains_unlocked();
		mutex_unlock(&cpuset_mutex);
		put_online_cpus();
		}

		/**
		@@ -877,7 +876,6 @@ static void update_tasks_cpumask(struct cpuset *cs)
		*
		* On legacy hierachy, effective_cpus will be the same with cpu_allowed.
		*
		* Called with cpuset_mutex held
		*/
		static void update_cpumasks_hier(struct cpuset cs, struct cpumask new_cpus)
		{
		@@ -932,7 +930,7 @@ static void update_cpumasks_hier(struct cpuset cs, struct cpumask new_cpus)
		rcu_read_unlock();

		if (need_rebuild_sched_domains)
		rebuild_sched_domains_locked();
		rebuild_sched_domains_unlocked();
		}

		/**
		@@ -1282,7 +1280,7 @@ static int update_relax_domain_level(struct cpuset *cs, s64 val)
		cs->relax_domain_level = val;
		if (!cpumask_empty(cs->cpus_allowed) &&
		is_sched_load_balance(cs))
		rebuild_sched_domains_locked();
		rebuild_sched_domains_unlocked();
		}

		return 0;
		@@ -1313,7 +1311,6 @@ static void update_tasks_flags(struct cpuset *cs)
		* cs: the cpuset to update
		* turning_on: whether the flag is being set or cleared
		*
		* Call with cpuset_mutex held.
		*/

		static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
		@@ -1348,7 +1345,7 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
		spin_unlock_irq(&callback_lock);

		if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
		rebuild_sched_domains_locked();
		rebuild_sched_domains_unlocked();

		if (spread_flag_changed)
		update_tasks_flags(cs);
		@@ -1616,6 +1613,7 @@ static int cpuset_write_u64(struct cgroup_subsys_state css, struct cftype cft,
		cpuset_filetype_t type = cft->private;
		int retval = 0;

		get_online_cpus();
		mutex_lock(&cpuset_mutex);
		if (!is_cpuset_online(cs)) {
		retval = -ENODEV;
		@@ -1653,6 +1651,7 @@ static int cpuset_write_u64(struct cgroup_subsys_state css, struct cftype cft,
		}
		out_unlock:
		mutex_unlock(&cpuset_mutex);
		put_online_cpus();
		return retval;
		}

		@@ -1663,6 +1662,7 @@ static int cpuset_write_s64(struct cgroup_subsys_state css, struct cftype cft,
		cpuset_filetype_t type = cft->private;
		int retval = -ENODEV;

		get_online_cpus();
		mutex_lock(&cpuset_mutex);
		if (!is_cpuset_online(cs))
		goto out_unlock;
		@@ -1677,6 +1677,7 @@ static int cpuset_write_s64(struct cgroup_subsys_state css, struct cftype cft,
		}
		out_unlock:
		mutex_unlock(&cpuset_mutex);
		put_online_cpus();
		return retval;
		}

		@@ -1715,6 +1716,7 @@ static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
		kernfs_break_active_protection(of->kn);
		flush_work(&cpuset_hotplug_work);

		get_online_cpus();
		mutex_lock(&cpuset_mutex);
		if (!is_cpuset_online(cs))
		goto out_unlock;
		@@ -1740,6 +1742,7 @@ static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
		free_trial_cpuset(trialcs);
		out_unlock:
		mutex_unlock(&cpuset_mutex);
		put_online_cpus();
		kernfs_unbreak_active_protection(of->kn);
		css_put(&cs->css);
		flush_workqueue(cpuset_migrate_mm_wq);
		@@ -2046,13 +2049,14 @@ static int cpuset_css_online(struct cgroup_subsys_state *css)
		/*
		* If the cpuset being removed has its flag 'sched_load_balance'
		* enabled, then simulate turning sched_load_balance off, which
		* will call rebuild_sched_domains_locked().
		* will call rebuild_sched_domains_unlocked().
		*/

		static void cpuset_css_offline(struct cgroup_subsys_state *css)
		{
		struct cpuset *cs = css_cs(css);

		get_online_cpus();
		mutex_lock(&cpuset_mutex);

		if (is_sched_load_balance(cs))
		@@ -2062,6 +2066,7 @@ static void cpuset_css_offline(struct cgroup_subsys_state *css)
		clear_bit(CS_ONLINE, &cs->flags);

		mutex_unlock(&cpuset_mutex);
		put_online_cpus();
		}

		static void cpuset_css_free(struct cgroup_subsys_state *css)