Messages in this thread | | | Date | Sat, 16 Jun 2012 13:26:51 -0700 (PDT) | From | David Rientjes <> | Subject | Re: [PATCH -V6 07/14] memcg: Add HugeTLB extension |
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On Fri, 15 Jun 2012, Aditya Kali wrote:
> Based on the usecase at Google, I see a definite value in including > hugepage usage in memory.usage_in_bytes as well and having a single > limit for memory usage for the job. Our jobs wants to specify only one > (total) memory limit (including slab usage, and other kernel memory > usage, hugepages, etc.). > > The hugepage/smallpage requirements of the job vary during its > lifetime. Having two different limits means less flexibility for jobs > as they now have to specify their limit as (max_hugepage, > max_smallpage) instead of max(hugepage + smallpage). Two limits > complicates the API for the users and requires them to over-specify > the resources. >
If a large number of hugepages, for example, are allocated on the command line because there's a lower success rate of dynamic allocation due to fragmentation, with your suggestion it would no longer allow the admin to restrict the use of those hugepages to only a particular set of tasks. Consider especially 1GB hugepagez on x86, your suggestion would treat a single 1GB hugepage which cannot be freed after boot exactly the same as using 1GB of memory which is obviously not the desired behavior of any hugetlb controller.
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