Messages in this thread | | | Subject | Re: [PATCH] cgroups: move cpuset specific checks from generic code to cpuset_can_attach (v2) | From | Mike Galbraith <> | Date | Thu, 26 Nov 2015 16:42:13 -0700 |
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On Thu, 2015-11-26 at 20:32 -0200, Marcelo Tosatti wrote: > Move PF_NO_SETAFFINITY and kthreadd_task checks to cpuset cgroups, > where they belong. This makes it possible to attach PF_NO_SETAFFINITY > tasks to Intel CAT cgroup. > > Reported-by: Luiz Capitulino <lcapitulino@redhat.com> > Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> > Reviewed-by: Chao Peng <chao.p.peng@linux.intel.com> > > v2: "PF_NO_SETAFFINITY check" -> "PF_NO_SETAFFINITY and kthreadd_task > checks" > > diff --git a/kernel/cgroup.c b/kernel/cgroup.c > index f89d929..0603652 100644 > --- a/kernel/cgroup.c > +++ b/kernel/cgroup.c > @@ -2466,16 +2466,6 @@ static ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf, > if (threadgroup) > tsk = tsk->group_leader; > > - /* > - * Workqueue threads may acquire PF_NO_SETAFFINITY and become > - * trapped in a cpuset, or RT worker may be born in a cgroup > - * with no rt_runtime allocated. Just say no. > - */ > - if (tsk == kthreadd_task || (tsk->flags & PF_NO_SETAFFINITY)) { > - ret = -EINVAL; > - goto out_unlock_rcu; > - } > - > get_task_struct(tsk); > rcu_read_unlock(); > > diff --git a/kernel/cpuset.c b/kernel/cpuset.c > index f0acff0..9fff4d6 100644 > --- a/kernel/cpuset.c > +++ b/kernel/cpuset.c > @@ -53,6 +53,7 @@ > #include <linux/time.h> > #include <linux/backing-dev.h> > #include <linux/sort.h> > +#include <linux/kthread.h> > > #include <asm/uaccess.h> > #include <linux/atomic.h> > @@ -1445,6 +1446,17 @@ static int cpuset_can_attach(struct cgroup_subsys_state *css, > goto out_unlock; > > cgroup_taskset_for_each(task, tset) { > + /* > + * Workqueue threads may acquire PF_NO_SETAFFINITY and become > + * trapped in a cpuset, or RT worker may be born in a cgroup > + * with no rt_runtime allocated. Just say no. > + */ > + if (task == kthreadd_task || > + (task->flags & PF_NO_SETAFFINITY)) { > + ret = -EINVAL; > + goto out_unlock; > + } > + > ret = task_can_attach(task, cs->cpus_allowed); > if (ret) > goto out_unlock;
Note the rt_runtime reference in the comment, that wasn't about cpuset. The kthreadd wants to remain immune to all fiddlings methinks.
-Mike
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