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Revert "Revert "cgroup/cpuset: Convert cpuset_mutex to percpu_rwsem""

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This reverts commit 18695a1200.

CPU Pause causes major merge conflicts with the 5.11 scheduler changes
(migrate-disable specifically), so lets revert Pause temporarily as it
is not needed urgently in android-mainline.

Signed-off-by: Quentin Perret <qperret@google.com>
Change-Id: I467f4e74565711ec376cd5e3df9ab1731bbc0af5
This commit is contained in:
Quentin Perret
2020-12-15 17:54:40 +00:00
parent 3c252ab080
commit 34ef9324f3
1 changed files with 36 additions and 33 deletions
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kernel/cgroup/cpuset.c
+36 -33
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@@ -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) {