On 2019-04-03, John Ogness <john.ogn...@linutronix.de> wrote:
> IMHO it is a bit crazy that userspace RT prio 99 maps to kernel prio
> 0. This leaves a hole at kernel prio 99. Wouldn't it be better just to
> map userspace RT prio 1-99 to kernel prio 99-1?
FWIW, the current mapping:
userspace kernel
--------- ------
rt 1...99 98...0
nice -20...+19 100...139
has been in place since the introduction of Ingo's scalable scheduler:
Author: linus1 <torva...@athlon.transmeta.com>
Date: Sun Dec 16 12:00:00 2001 -0800
v2.5.1.9 -> v2.5.1.10
- Kai Germaschewski: ISDN updates
- Al Viro: start moving buffer cache indexing to "struct
- block_device *"
- Greg KH: USB update
- Russell King: fix up some ARM merge issues
- Ingo Molnar: scalable scheduler
With that commit, the then separate nice and rt_priority task_struct
fields were combined to the new prio field, and thus the mapping was
born.
John Ogness
