Re: [NUMA] Display and modify the memory policy of a process through /proc/<pid>/numa_policy

[David Singleton <David.Singleton@anu.edu.au>]

Andi Kleen wrote:
>>No it wont. If you know that you are going to start a process that must 
>>run on node 3 and know its going to use 2G but there is only 1G free 
>>then you may want to modify the policy of an existing huge process on 
>>node 3that is still allocating to go to node 2 that just happens to have 
>>free space.
> 
> I think you should leave that to the kernel.
> 

But the kernel doesn't know about these future requirements.
A batch scheduler does.

> 
>>>>A batch scheduler may anticipate memory shortages and redirect memory 
>>>>allocations in order to avoid page migration.
>>>
>>>I think that jobs more belongs to the kernel. After all we don't
>>>want to move half of our VM into your proprietary scheduler.
>>
>>Care to tell me which proprietary scheduler you are talking about? I was 
> 
> 
> That SGI batch scheduler with its incredibly long specification
> list you guys seem to want to mess up all interfaces
> for. If I can download source to it please supply an URL. 

I think SGI are just trying to facilitate users (like us) with our
own schedulers.

> 
> 
>>And you are now going to implement automatic page migration into the 
>>existing scheduler?
> 
> 
> Hmm? You mean the kernel CPU scheduler? Nobody is planning to add
> page migration to that.

Exactly.  Some of us think we can do a half decent job of manually
controlling page migration.  What is the harm in letting us "shoot
ourselves in the foot" trying?

-- 
--------------------------------------------------------------------------
                                     ANU Supercomputer Facility
    David.Singleton@anu.edu.au       and APAC National Facility
    Phone: +61 2 6125 4389           Leonard Huxley Bldg (No. 56)
    Fax:   +61 2 6125 8199           Australian National University
                                     Canberra, ACT, 0200, Australia
--------------------------------------------------------------------------
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"aart@kvack.org"> aart@kvack.org </a>