Re: Linux Kernel Patch; setpriority

[Chris Wright <chris@wirex.com>]

* Stephen Baker (stbaker@cisco.com) wrote:
> 
> This patch will allow a process or thread to changes it's priority 
> dynamically based on it's capabilities.  In our case we wanted to use 
> threads with Linux.  To have true priorities we need root to use 
> SCHED_FIFO or SCHED_RR; in many case root access is not allowed but we 
> still wanted priorities.  So we started using setpriority to change a 
> threads priority.  Now we used nice values from 19 to 0 which did not 
> require root access.  In some cases a thread need to raise it's nice 
> level and this would fail.  I also saw a note man renice(8) that said 
> this bug exists.

hmm, SUS v3 seems to disagree.

"Only a process with appropriate privileges can lower its nice value."

and with this patch setpriority(2) is now inconsistent with nice(2)
(albeit i don't know how much longer that interface will persist in arch
independent portion of the kernel based on the comments surrounding it).

-chris