The new priority structure for 2.5.x kernels is described as : /* * Priority of a process goes from 0..MAX_PRIO-1, valid RT * priority is 0..MAX_RT_PRIO-1, and SCHED_NORMAL tasks are * in the range MAX_RT_PRIO..MAX_PRIO-1. Priority values * are inverted: lower p->prio value means higher priority. * * The MAX_RT_USER_PRIO value allows the actual maximum * RT priority to be separate from the value exported to * user-space. This allows kernel threads to set their * priority to a value higher than any user task. Note: * MAX_RT_PRIO must not be smaller than MAX_USER_RT_PRIO. */ #define MAX_USER_RT_PRIO 100 #define MAX_RT_PRIO MAX_USER_RT_PRIO #define MAX_PRIO (MAX_RT_PRIO + 40) Since a lower priority value means a higher priority, I don't see how the separation between MAX_RT_PRIO and MAX_USER_RT_PRIO can allow a kernel thread to have a higher value. It would seem that there needs to be a MIN_USER_RT_PRIO that has to be greater than or equal to 0. This would prevent user RT tasks from getting priority values that were less than a minimum, and kernel threads could get priorities from 0 to MIN_USER_RT_PRIO - 1. Please help me out with my astray reasoning. -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
