hi: 2011/7/11 Mulyadi Santosa <mulyadi.santosa@xxxxxxxxx>: > Hi... > > On Sun, Jul 10, 2011 at is 17:27, loody <miloody@xxxxxxxxx> wrote: >> Dear all: >> I have some questions about kthread: >> 1. can we change kthread priority through user mode program? > > Theoritically you can, but only if the priority not fixed and/or you > have required capability to do so > >> 2. I found some functions that may be helpful. >> sched_getscheduler >> sched_setscheduler >> >> When I use them in user mode, the return value of sched_setscheduler is fail. > > did you do that as root? anything blocking you doing that withing > SELinux or AppArmor policy? I execute it as root. what is "SELinux or AppArmor policy"? > >> there is a thread talking about this, >> http://www.spinics.net/lists/linux-rt-users/msg06588.html >> What makes me confuse is "these 2 functions is used in user mode or >> kernel mode?" > > AFAIK they are user mode libc functions... I found there are the same export_symbols in kernel. I use them to dynamically change the priority. It works but I found something interesting: 1. if thread use schedule algorithm of SCHED_NORMAL, it cannot change the priority. 2. can we set the priority to any number less than (MAX_USER_RT_PRIO-1)? ( I tried to set the priority as 99, but it fail) 3. can we get the name of thread from task_struct or pid? (I use "cat /proc/338/status", I can see the name of thread. But I look around the task_struct, I cannot find any name information in it.) Thanks for your kind help, _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
