On 05/12, Rafael J. Wysocki wrote: > > ... user space tasks that call deamonize() can also be frozen prematurely. > We didn't take this possibility into consideration before, which was obviously > wrong.
No, no, sorry for the confusion. User space tasks never call deamonize(). Kernel threads call daemonize, because when we are doing kernel_thread() on behalf of user-space task, the new kernel thread (child) shares its ->mm with the caller (parent). So it is considered as "is_user_space()" until it does daemonize(). Definitely, is_user_space() should have another name. When a user space task exits, it does exit_mm() and becomes "a kernel thread" from the freezer POV. In its current from, freezer can do nothing with this. The exiting task won't call try_to_freeze() after that, so try_to_freeze_tasks() will wait until it dissapears (actually, until it calls exit_notify(), note the ->exit_state check in freezeable()). I do not think we can improve things if exit_mm() clears TIF_FREEZING. We should clear TIF_FREEZING when we set PF_NOFREEZE, I think. This was discussed before iirc, but I forgot the result. Oleg. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
