Re: [PATCH 1/3] sched, cgroup: reorganize threadgroup locking

[Tejun Heo]

Hello, Sergey.

On Thu, May 14, 2015 at 10:09:13AM +0900, Sergey Senozhatsky wrote:
> > +static inline void threadgroup_change_begin(struct task_struct *tsk)
> >  {
> > -	down_write(&tsk->signal->group_rwsem);
> > +	might_sleep();
> 
> I think cgroup_threadgroup_change_begin()->down_read() already does
> might_sleep() check.

Sure but it's a layering thing.  threadgroup_change_begin() should be
called from a blockable context whether the hook users actually make
use of it or not.  e.g. We want might_sleep() even when
!CONFIG_CGROUP.

Thanks.

-- 
tejun
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/