On Fri, Jul 02, 2010 at 11:06:37PM +0200, Oleg Nesterov wrote: > On 07/02, Peter Zijlstra wrote: > > > > On Fri, 2010-07-02 at 11:01 -0700, Sridhar Samudrala wrote: > > > > > > Does it (Tejun's kthread_clone() patch) also inherit the > > > cgroup of the caller? > > > > Of course, its a simple do_fork() which inherits everything just as you > > would expect from a similar sys_clone()/sys_fork() call. > > Yes. And I'm afraid it can inherit more than we want. IIUC, this is called > from ioctl(), right? > > Then the new thread becomes the natural child of the caller, and it shares > ->mm with the parent. And files, dup_fd() without CLONE_FS. > > Signals. Say, if you send SIGKILL to this new thread, it can't sleep in > TASK_INTERRUPTIBLE or KILLABLE after that. And this SIGKILL can be sent > just because the parent gets SIGQUIT or abother coredumpable signal. > Or the new thread can recieve SIGSTOP via ^Z. > > Perhaps this is OK, I do not know. Just to remind that kernel_thread() > is merely clone(CLONE_VM). > > Oleg. Right. Doing this might break things like flush. The signal and exit behaviour needs to be examined carefully. I am also unsure whether using such threads might be more expensive than inheriting kthreadd. -- MST -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
