real SetProcessClass and SetThreadPriority support

[Robert Reif]

Robert Shearman wrote:

> Robert Reif wrote:
>
>> Are there any plans or is anyone working on mapping Windows
>> SetProcessClass and SetThreadPriority support to linux process
>> priorities on kernels that support CAP_SYS_NICE?
>
>
>
> Mapping Win32 thread priority levels to Linux nice levels is fairly 
> trivial, but convincing kernel developers to allow unprivileged 
> user-space programs to control thread priorities is the big problem. 
> The last time a discussion like this came up, we (Wine developers and 
> Cedega developers) requested a way of changing a thread's relative 
> priority within a process (without affecting the overall CPU time the 
> process gets). This should be a good compromise between meeting 
> applications' needs and preventing unprivileged applications from 
> freezing the computer. AFAIK, this hasn't been implemented yet.
>
> Rob
>
Do you need more than CAP_SYS_NICE?

CAP_SYS_NICE gives you:

    * Allow raising priority and setting priority on other (different
      UID) processes
    * Allow use of FIFO and round-robin (realtime) scheduling on own
      processes and setting the scheduling algorithm used by another
      process.

wineserver would need to be a setuid program but it could set 
CAP_SYS_NICE at startup and immediately reduce it's privileges back to 
normal.