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authorTejun Heo <tj@kernel.org>2015-10-15 16:41:51 -0400
committerTejun Heo <tj@kernel.org>2015-10-15 16:41:51 -0400
commit389b9c1bc927c8194a49f5f0c7e069ed0ec79b9e (patch)
tree67c3faae1cd833128a515a19e212bdee4d48b36f /kernel/cgroup.c
parent91486f61f486662c27ef86dd910f875832e3a5de (diff)
downloadop-kernel-dev-389b9c1bc927c8194a49f5f0c7e069ed0ec79b9e.zip
op-kernel-dev-389b9c1bc927c8194a49f5f0c7e069ed0ec79b9e.tar.gz
cgroup: keep css_set and task lists in chronological order
css task iteration will be updated to not leak cgroup internal locking to iterator users. In preparation, update css_set and task lists to be in chronological order. For tasks, as migration path is already using list_splice_tail_init(), only cgroup_enable_task_cg_lists() and cgroup_post_fork() need updating. For css_sets, link_css_set() is the only place which needs to be updated. Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/cgroup.c')
-rw-r--r--kernel/cgroup.c11
1 files changed, 5 insertions, 6 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 61ee85d..5244467 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -914,12 +914,11 @@ static void link_css_set(struct list_head *tmp_links, struct css_set *cset,
link->cset = cset;
link->cgrp = cgrp;
- list_move(&link->cset_link, &cgrp->cset_links);
-
/*
- * Always add links to the tail of the list so that the list
- * is sorted by order of hierarchy creation
+ * Always add links to the tail of the lists so that the lists are
+ * in choronological order.
*/
+ list_move_tail(&link->cset_link, &cgrp->cset_links);
list_add_tail(&link->cgrp_link, &cset->cgrp_links);
if (cgroup_parent(cgrp))
@@ -1780,7 +1779,7 @@ static void cgroup_enable_task_cg_lists(void)
if (!css_set_populated(cset))
css_set_update_populated(cset, true);
- list_add(&p->cg_list, &cset->tasks);
+ list_add_tail(&p->cg_list, &cset->tasks);
get_css_set(cset);
}
spin_unlock_irq(&p->sighand->siglock);
@@ -5480,7 +5479,7 @@ void cgroup_post_fork(struct task_struct *child,
cset = task_css_set(current);
if (list_empty(&child->cg_list)) {
rcu_assign_pointer(child->cgroups, cset);
- list_add(&child->cg_list, &cset->tasks);
+ list_add_tail(&child->cg_list, &cset->tasks);
get_css_set(cset);
}
up_write(&css_set_rwsem);
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