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

From: David Singleton <David.Singleton_at_anu.edu.au>
Date: 2005-07-16 10:00:11
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?

-- 
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Received on Fri Jul 15 20:00:51 2005

This archive was generated by hypermail 2.1.8 : 2005-08-02 09:20:40 EST