Re: [PATCH v2] Make transparent hugepages cpuset aware

[David Rientjes <rientjes@google.com>]

On Tue, 11 Jun 2013, Alex Thorlton wrote:

> This patch adds the ability to control THPs on a per cpuset basis.  Please see
> the additions to Documentation/cgroups/cpusets.txt for more information.
> 

What's missing from both this changelog and the documentation you point to 
is why this change is needed.

I can understand how you would want a subset of processes to not use thp 
when it is enabled.  This is typically where MADV_NOHUGEPAGE is used with 
some type of malloc hook.

I don't think we need to do this on a cpuset level, so unfortunately I 
think this needs to be reworked.  Would it make sense to add a per-process 
tunable to always get MADV_NOHUGEPAGE behavior for all of its sbrk() and 
mmap() calls?  Perhaps, but then you would need to justify why it can't be 
done with a malloc hook in userspace.

This seems to just be working around a userspace issue or for a matter of 
convenience, right?

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