On Mon, Apr 02, 2012 at 08:22:14AM +0400, Alexander Nikiforov wrote:
I think it should be part of task counter css, not core.
CC list updated.
> @@ -4558,6 +4594,22 @@ void cgroup_fork(struct task_struct *child)
> child->cgroups = current->cgroups;
> get_css_set(child->cgroups);
> INIT_LIST_HEAD(&child->cg_list);
> +
> + struct cgroupfs_root *root;
> +
> + /* send event to the userspace */
> + mutex_lock(&cgroup_mutex);
> + for_each_active_root(root) {
> + struct cgroup *cgrp;
> + struct fe_eventfd_list *ev;
> +
> + cgrp = task_cgroup_from_root(child, root);
> +
> + list_for_each_entry(ev, &cgrp->fe_notify, list) {
> + eventfd_signal(ev->eventfd, 1);
> + }
> + }
> + mutex_unlock(&cgroup_mutex);
> }
How does it affect performance?
>
> /**
> @@ -4653,6 +4705,7 @@ void cgroup_exit(struct task_struct *tsk, int run_callbacks)
> {
> struct css_set *cg;
> int i;
> + struct cgroupfs_root *root;
>
> /*
> * Unlink from the css_set task list if necessary.
> @@ -4666,6 +4719,20 @@ void cgroup_exit(struct task_struct *tsk, int run_callbacks)
> write_unlock(&css_set_lock);
> }
>
> + /* send event to the userspace */
> + mutex_lock(&cgroup_mutex);
> + for_each_active_root(root) {
> + struct cgroup *cgrp;
> + struct fe_eventfd_list *ev;
> +
> + cgrp = task_cgroup_from_root(tsk, root);
> +
> + list_for_each_entry(ev, &cgrp->fe_notify, list) {
> + eventfd_signal(ev->eventfd, 1);
> + }
> + }
> + mutex_unlock(&cgroup_mutex);
> +
I think it's racy. You need to notify userspace after reassigning the
task, not before.
> /* Reassign the task to the init_css_set. */
> task_lock(tsk);
> cg = tsk->cgroups;
--
Kirill A. Shutemov
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