Re: [patch v2]numa: add a sysctl to control interleave allocationgranularity from each node

[David Rientjes]

On Wed, 7 Dec 2011, Shaohua Li wrote:

> based on the allocation size, right? I did consider it. It would be easy to
> implement this. Note even without my patch we have the issue if allocation
> from one node is big order and small order from other node. And nobody
> complains the imbalance. This makes me think maybe people didn't care
> about the imbalance too much.
> 

Right, I certainly see what you're trying to do and I support it, however, 
if we're going to add a userspace tunable then I think it would be better 
implemented as a size.  You can still get the functionality that you have 
with your patch (just with a size of 0, the default, making every 
allocation on the next node) but can also interleave on PAGE_SIZE, 
HPAGE_SIZE, etc, increments.  I think it would help for users who are 
concerned about node symmetry for contention on the memory bus and it 
would be a shame if someone needed to add a second tunable for that affect 
if your tunable already has applications using it.
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