From: Gowrishankar M <gomut...@linux.vnet.ibm.com>
In current model, task by task we populate cgroup.
Incase of multi-threaded task, it becomes difficult
as we should first know about list of threads created
and add them one by one in cgroup.
In below patch, when a thread group leader is scanned,
belonging threads are also moved along with it, while
populating cgroup tasks.
Below steps can help to verify the patch:
(1) mount -t cgroup -o cpuset cgroup /cgroup
(2) /bin/mkdir /cgroup/testgroup and cd /cgroup/testgroup
(3) /bin/echo 0 > cpuset.mems
(4) /bin/echo 0 > cpuset.cpus
(5) /bin/echo "<PID of thread group leader>" > tasks (tip: ps -aeL)
(6) cat tasks and check for thread ids.
Signed-off-by: Gowrishankar M <gowrishanka...@linux.vnet.ibm.com>
---
kernel/cgroup.c | 17 ++++++++++-------
1 files changed, 10 insertions(+), 7 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 35eebd5..de7f0cc 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1279,6 +1279,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct
task_struct *tsk)
static int attach_task_by_pid(struct cgroup *cgrp, u64 pid)
{
struct task_struct *tsk;
+ struct task_struct *p;
int ret;
if (pid) {
@@ -1288,21 +1289,23 @@ static int attach_task_by_pid(struct cgroup *cgrp, u64
pid)
rcu_read_unlock();
return -ESRCH;
}
- get_task_struct(tsk);
rcu_read_unlock();
if ((current->euid) && (current->euid != tsk->uid)
&& (current->euid != tsk->suid)) {
- put_task_struct(tsk);
return -EACCES;
}
- } else {
+ } else
tsk = current;
- get_task_struct(tsk);
- }
- ret = cgroup_attach_task(cgrp, tsk);
- put_task_struct(tsk);
+ p = tsk;
+ do {
+ get_task_struct(p);
+ ret = cgroup_attach_task(cgrp, p);
+ put_task_struct(p);
+ if (thread_group_empty(p) && !(has_group_leader_pid(p)))
+ break;
+ } while_each_thread(tsk, p);
return ret;
}
--
1.5.5.1
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