sched/walt: Accounting for number of irqs pending on each core

[firefly-linux-kernel-4.4.55.git] / kernel / cgroup.c

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index f0bc36879e1d9b05da5e342d4b923ada480a1cf6..f53e61f95b5500cfad27527956f3ea971dd42411 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2776,9 +2776,10 @@ static ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf,
                                    size_t nbytes, loff_t off, bool threadgroup)
 {
        struct task_struct *tsk;
+       struct cgroup_subsys *ss;
        struct cgroup *cgrp;
        pid_t pid;
-       int ret;
+       int ssid, ret;
 
        if (kstrtoint(strstrip(buf), 0, &pid) || pid < 0)
                return -EINVAL;
@@ -2826,8 +2827,10 @@ out_unlock_rcu:
        rcu_read_unlock();
 out_unlock_threadgroup:
        percpu_up_write(&cgroup_threadgroup_rwsem);
+       for_each_subsys(ss, ssid)
+               if (ss->post_attach)
+                       ss->post_attach();
        cgroup_kn_unlock(of->kn);
-       cpuset_post_attach_flush();
        return ret ?: nbytes;
 }
 
@@ -4744,14 +4747,15 @@ static void css_free_work_fn(struct work_struct *work)
 
        if (ss) {
                /* css free path */
+               struct cgroup_subsys_state *parent = css->parent;
                int id = css->id;
 
-               if (css->parent)
-                       css_put(css->parent);
-
                ss->css_free(css);
                cgroup_idr_remove(&ss->css_idr, id);
                cgroup_put(cgrp);
+
+               if (parent)
+                       css_put(parent);
        } else {
                /* cgroup free path */
                atomic_dec(&cgrp->root->nr_cgrps);
@@ -4844,6 +4848,7 @@ static void init_and_link_css(struct cgroup_subsys_state *css,
        memset(css, 0, sizeof(*css));
        css->cgroup = cgrp;
        css->ss = ss;
+       css->id = -1;
        INIT_LIST_HEAD(&css->sibling);
        INIT_LIST_HEAD(&css->children);
        css->serial_nr = css_serial_nr_next++;
@@ -5375,6 +5380,12 @@ int __init cgroup_init(void)
        BUG_ON(cgroup_init_cftypes(NULL, cgroup_dfl_base_files));
        BUG_ON(cgroup_init_cftypes(NULL, cgroup_legacy_base_files));
 
+       /*
+        * The latency of the synchronize_sched() is too high for cgroups,
+        * avoid it at the cost of forcing all readers into the slow path.
+        */
+       rcu_sync_enter_start(&cgroup_threadgroup_rwsem.rss);
+
        mutex_lock(&cgroup_mutex);
 
        /* Add init_css_set to the hash table */