Hi Kirill, thanks for your reply
On 04/02/2012 02:29 PM, Kirill A. Shutemov wrote:
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.
Maybe, I need time to think about your suggestion.
@@ -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?
One cycle with active roots, one inside task_cgroup_from_root() through
cg_links and through events. I don't think what this is significant,
maybe I wrong.
/**
@@ -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.
You are right.
/* Reassign the task to the init_css_set. */
task_lock(tsk);
cg = tsk->cgroups;
--
Best regards,
Alex Nikiforov,
Mobile SW, Advanced Software Group,
Moscow R&D center, Samsung Electronics
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