diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index b08556d9cc1f..9ac2a148bf48 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -336,7 +336,7 @@ static struct cpuset top_cpuset = { * guidelines for accessing subsystem state in kernel/cgroup.c */ -static DEFINE_MUTEX(cpuset_mutex); +DEFINE_STATIC_PERCPU_RWSEM(cpuset_rwsem); static DEFINE_SPINLOCK(callback_lock); static struct workqueue_struct *cpuset_migrate_mm_wq; @@ -928,7 +928,7 @@ static void rebuild_root_domains(void) struct cpuset *cs = NULL; struct cgroup_subsys_state *pos_css; - lockdep_assert_held(&cpuset_mutex); + percpu_rwsem_assert_held(&cpuset_rwsem); lockdep_assert_cpus_held(); lockdep_assert_held(&sched_domains_mutex); @@ -986,7 +986,8 @@ static void rebuild_sched_domains_locked(void) cpumask_var_t *doms; int ndoms; - lockdep_assert_held(&cpuset_mutex); + lockdep_assert_cpus_held(); + percpu_rwsem_assert_held(&cpuset_rwsem); /* * We have raced with CPU hotplug. Don't do anything to avoid @@ -1016,9 +1017,9 @@ static void rebuild_sched_domains_locked(void) void rebuild_sched_domains(void) { get_online_cpus(); - mutex_lock(&cpuset_mutex); + percpu_down_write(&cpuset_rwsem); rebuild_sched_domains_locked(); - mutex_unlock(&cpuset_mutex); + percpu_up_write(&cpuset_rwsem); put_online_cpus(); } @@ -1137,7 +1138,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, int deleting; /* Moving cpus from subparts_cpus to effective_cpus */ bool part_error = false; /* Partition error? */ - lockdep_assert_held(&cpuset_mutex); + percpu_rwsem_assert_held(&cpuset_rwsem); /* * The parent must be a partition root. @@ -2127,7 +2128,7 @@ static int cpuset_can_attach(struct cgroup_taskset *tset) cpuset_attach_old_cs = task_cs(cgroup_taskset_first(tset, &css)); cs = css_cs(css); - mutex_lock(&cpuset_mutex); + percpu_down_write(&cpuset_rwsem); /* allow moving tasks into an empty cpuset if on default hierarchy */ ret = -ENOSPC; @@ -2151,7 +2152,7 @@ static int cpuset_can_attach(struct cgroup_taskset *tset) cs->attach_in_progress++; ret = 0; out_unlock: - mutex_unlock(&cpuset_mutex); + percpu_up_write(&cpuset_rwsem); return ret; } @@ -2161,9 +2162,9 @@ static void cpuset_cancel_attach(struct cgroup_taskset *tset) cgroup_taskset_first(tset, &css); - mutex_lock(&cpuset_mutex); + percpu_down_write(&cpuset_rwsem); css_cs(css)->attach_in_progress--; - mutex_unlock(&cpuset_mutex); + percpu_up_write(&cpuset_rwsem); } /* @@ -2186,7 +2187,7 @@ static void cpuset_attach(struct cgroup_taskset *tset) cgroup_taskset_first(tset, &css); cs = css_cs(css); - mutex_lock(&cpuset_mutex); + percpu_down_write(&cpuset_rwsem); /* prepare for attach */ if (cs == &top_cpuset) @@ -2240,7 +2241,7 @@ static void cpuset_attach(struct cgroup_taskset *tset) if (!cs->attach_in_progress) wake_up(&cpuset_attach_wq); - mutex_unlock(&cpuset_mutex); + percpu_up_write(&cpuset_rwsem); } /* The various types of files and directories in a cpuset file system */ @@ -2272,7 +2273,7 @@ static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft, int retval = 0; get_online_cpus(); - mutex_lock(&cpuset_mutex); + percpu_down_write(&cpuset_rwsem); if (!is_cpuset_online(cs)) { retval = -ENODEV; goto out_unlock; @@ -2308,7 +2309,7 @@ static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft, break; } out_unlock: - mutex_unlock(&cpuset_mutex); + percpu_up_write(&cpuset_rwsem); put_online_cpus(); return retval; } @@ -2321,7 +2322,7 @@ static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft, int retval = -ENODEV; get_online_cpus(); - mutex_lock(&cpuset_mutex); + percpu_down_write(&cpuset_rwsem); if (!is_cpuset_online(cs)) goto out_unlock; @@ -2334,7 +2335,7 @@ static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft, break; } out_unlock: - mutex_unlock(&cpuset_mutex); + percpu_up_write(&cpuset_rwsem); put_online_cpus(); return retval; } @@ -2375,7 +2376,7 @@ static ssize_t cpuset_write_resmask(struct kernfs_open_file *of, flush_work(&cpuset_hotplug_work); get_online_cpus(); - mutex_lock(&cpuset_mutex); + percpu_down_write(&cpuset_rwsem); if (!is_cpuset_online(cs)) goto out_unlock; @@ -2399,7 +2400,7 @@ static ssize_t cpuset_write_resmask(struct kernfs_open_file *of, free_cpuset(trialcs); out_unlock: - mutex_unlock(&cpuset_mutex); + percpu_up_write(&cpuset_rwsem); put_online_cpus(); kernfs_unbreak_active_protection(of->kn); css_put(&cs->css); @@ -2532,13 +2533,13 @@ static ssize_t sched_partition_write(struct kernfs_open_file *of, char *buf, css_get(&cs->css); get_online_cpus(); - mutex_lock(&cpuset_mutex); + percpu_down_write(&cpuset_rwsem); if (!is_cpuset_online(cs)) goto out_unlock; retval = update_prstate(cs, val); out_unlock: - mutex_unlock(&cpuset_mutex); + percpu_up_write(&cpuset_rwsem); put_online_cpus(); css_put(&cs->css); return retval ?: nbytes; @@ -2746,7 +2747,7 @@ static int cpuset_css_online(struct cgroup_subsys_state *css) return 0; get_online_cpus(); - mutex_lock(&cpuset_mutex); + percpu_down_write(&cpuset_rwsem); set_bit(CS_ONLINE, &cs->flags); if (is_spread_page(parent)) @@ -2798,7 +2799,7 @@ static int cpuset_css_online(struct cgroup_subsys_state *css) cpumask_copy(cs->effective_cpus, parent->cpus_allowed); spin_unlock_irq(&callback_lock); out_unlock: - mutex_unlock(&cpuset_mutex); + percpu_up_write(&cpuset_rwsem); put_online_cpus(); return 0; } @@ -2819,7 +2820,7 @@ static void cpuset_css_offline(struct cgroup_subsys_state *css) struct cpuset *cs = css_cs(css); get_online_cpus(); - mutex_lock(&cpuset_mutex); + percpu_down_write(&cpuset_rwsem); if (is_partition_root(cs)) update_prstate(cs, 0); @@ -2838,7 +2839,7 @@ static void cpuset_css_offline(struct cgroup_subsys_state *css) cpuset_dec(); clear_bit(CS_ONLINE, &cs->flags); - mutex_unlock(&cpuset_mutex); + percpu_up_write(&cpuset_rwsem); put_online_cpus(); } @@ -2851,7 +2852,7 @@ static void cpuset_css_free(struct cgroup_subsys_state *css) static void cpuset_bind(struct cgroup_subsys_state *root_css) { - mutex_lock(&cpuset_mutex); + percpu_down_write(&cpuset_rwsem); spin_lock_irq(&callback_lock); if (is_in_v2_mode()) { @@ -2864,7 +2865,7 @@ static void cpuset_bind(struct cgroup_subsys_state *root_css) } spin_unlock_irq(&callback_lock); - mutex_unlock(&cpuset_mutex); + percpu_up_write(&cpuset_rwsem); } /* @@ -2906,6 +2907,8 @@ struct cgroup_subsys cpuset_cgrp_subsys = { int __init cpuset_init(void) { + BUG_ON(percpu_init_rwsem(&cpuset_rwsem)); + BUG_ON(!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL)); BUG_ON(!alloc_cpumask_var(&top_cpuset.effective_cpus, GFP_KERNEL)); BUG_ON(!zalloc_cpumask_var(&top_cpuset.subparts_cpus, GFP_KERNEL)); @@ -2979,7 +2982,7 @@ hotplug_update_tasks_legacy(struct cpuset *cs, is_empty = cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed); - mutex_unlock(&cpuset_mutex); + percpu_up_write(&cpuset_rwsem); /* * Move tasks to the nearest ancestor with execution resources, @@ -2989,7 +2992,7 @@ hotplug_update_tasks_legacy(struct cpuset *cs, if (is_empty) remove_tasks_in_empty_cpuset(cs); - mutex_lock(&cpuset_mutex); + percpu_down_write(&cpuset_rwsem); } static void @@ -3039,14 +3042,14 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp) retry: wait_event(cpuset_attach_wq, cs->attach_in_progress == 0); - mutex_lock(&cpuset_mutex); + percpu_down_write(&cpuset_rwsem); /* * We have raced with task attaching. We wait until attaching * is finished, so we won't attach a task to an empty cpuset. */ if (cs->attach_in_progress) { - mutex_unlock(&cpuset_mutex); + percpu_up_write(&cpuset_rwsem); goto retry; } @@ -3114,7 +3117,7 @@ update_tasks: hotplug_update_tasks_legacy(cs, &new_cpus, &new_mems, cpus_updated, mems_updated); - mutex_unlock(&cpuset_mutex); + percpu_up_write(&cpuset_rwsem); } /** @@ -3144,7 +3147,7 @@ void cpuset_hotplug_workfn(struct work_struct *work) if (on_dfl && !alloc_cpumasks(NULL, &tmp)) ptmp = &tmp; - mutex_lock(&cpuset_mutex); + percpu_down_write(&cpuset_rwsem); /* fetch the available cpus/mems and find out which changed how */ cpumask_copy(&new_cpus, cpu_active_mask); @@ -3194,7 +3197,7 @@ void cpuset_hotplug_workfn(struct work_struct *work) update_tasks_nodemask(&top_cpuset); } - mutex_unlock(&cpuset_mutex); + percpu_up_write(&cpuset_rwsem); /* if cpus or mems changed, we need to propagate to descendants */ if (cpus_updated || mems_updated) {