Re: [dpdk-stable] [PATCH] mem: balanced allocation of hugepages

[Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>]

On 10/04/2017 08:11, Ilya Maximets wrote:
> On 07.04.2017 18:44, Thomas Monjalon wrote:
>> 2017-04-07 18:14, Ilya Maximets:
>>> Hi All.
>>>
>>> I wanted to ask (just to clarify current status):
>>> Will this patch be included in current release (acked by maintainer)
>>> and then I will upgrade it to hybrid logic or I will just prepare v3
>>> with hybrid logic for 17.08 ?
>> What is your preferred option Ilya?
> I have no strong opinion on this. One thought is that it could be
> nice if someone else could test this functionality with current
> release before enabling it by default in 17.08.
>
> Tomorrow I'm going on vacation. So I'll post rebased version today
> (there are few fuzzes with current master) and you with Sergio may
> decide what to do.
>
> Best regards, Ilya Maximets.
>
>> Sergio?

I would be inclined towards v3 targeting v17.08. IMHO it would be more 
clean this way.

Sergio

>>
>>> On 27.03.2017 17:43, Ilya Maximets wrote:
>>>> On 27.03.2017 16:01, Sergio Gonzalez Monroy wrote:
>>>>> On 09/03/2017 12:57, Ilya Maximets wrote:
>>>>>> On 08.03.2017 16:46, Sergio Gonzalez Monroy wrote:
>>>>>>> Hi Ilya,
>>>>>>>
>>>>>>> I have done similar tests and as you already pointed out, 'numactl --interleave' does not seem to work as expected.
>>>>>>> I have also checked that the issue can be reproduced with quota limit on hugetlbfs mount point.
>>>>>>>
>>>>>>> I would be inclined towards *adding libnuma as dependency* to DPDK to make memory allocation a bit more reliable.
>>>>>>>
>>>>>>> Currently at a high level regarding hugepages per numa node:
>>>>>>> 1) Try to map all free hugepages. The total number of mapped hugepages depends if there were any limits, such as cgroups or quota in mount point.
>>>>>>> 2) Find out numa node of each hugepage.
>>>>>>> 3) Check if we have enough hugepages for requested memory in each numa socket/node.
>>>>>>>
>>>>>>> Using libnuma we could try to allocate hugepages per numa:
>>>>>>> 1) Try to map as many hugepages from numa 0.
>>>>>>> 2) Check if we have enough hugepages for requested memory in numa 0.
>>>>>>> 3) Try to map as many hugepages from numa 1.
>>>>>>> 4) Check if we have enough hugepages for requested memory in numa 1.
>>>>>>>
>>>>>>> This approach would improve failing scenarios caused by limits but It would still not fix issues regarding non-contiguous hugepages (worst case each hugepage is a memseg).
>>>>>>> The non-contiguous hugepages issues are not as critical now that mempools can span over multiple memsegs/hugepages, but it is still a problem for any other library requiring big chunks of memory.
>>>>>>>
>>>>>>> Potentially if we were to add an option such as 'iommu-only' when all devices are bound to vfio-pci, we could have a reliable way to allocate hugepages by just requesting the number of pages from each numa.
>>>>>>>
>>>>>>> Thoughts?
>>>>>> Hi Sergio,
>>>>>>
>>>>>> Thanks for your attention to this.
>>>>>>
>>>>>> For now, as we have some issues with non-contiguous
>>>>>> hugepages, I'm thinking about following hybrid schema:
>>>>>> 1) Allocate essential hugepages:
>>>>>>      1.1) Allocate as many hugepages from numa N to
>>>>>>           only fit requested memory for this numa.
>>>>>>      1.2) repeat 1.1 for all numa nodes.
>>>>>> 2) Try to map all remaining free hugepages in a round-robin
>>>>>>      fashion like in this patch.
>>>>>> 3) Sort pages and choose the most suitable.
>>>>>>
>>>>>> This solution should decrease number of issues connected with
>>>>>> non-contiguous memory.
>>>>> Sorry for late reply, I was hoping for more comments from the community.
>>>>>
>>>>> IMHO this should be default behavior, which means no config option and libnuma as EAL dependency.
>>>>> I think your proposal is good, could you consider implementing such approach on next release?
>>>> Sure, I can implement this for 17.08 release.
>>>>
>>>>>>> On 06/03/2017 09:34, Ilya Maximets wrote:
>>>>>>>> Hi all.
>>>>>>>>
>>>>>>>> So, what about this change?
>>>>>>>>
>>>>>>>> Best regards, Ilya Maximets.
>>>>>>>>
>>>>>>>> On 16.02.2017 16:01, Ilya Maximets wrote:
>>>>>>>>> Currently EAL allocates hugepages one by one not paying
>>>>>>>>> attention from which NUMA node allocation was done.
>>>>>>>>>
>>>>>>>>> Such behaviour leads to allocation failure if number of
>>>>>>>>> available hugepages for application limited by cgroups
>>>>>>>>> or hugetlbfs and memory requested not only from the first
>>>>>>>>> socket.
>>>>>>>>>
>>>>>>>>> Example:
>>>>>>>>>       # 90 x 1GB hugepages availavle in a system
>>>>>>>>>
>>>>>>>>>       cgcreate -g hugetlb:/test
>>>>>>>>>       # Limit to 32GB of hugepages
>>>>>>>>>       cgset -r hugetlb.1GB.limit_in_bytes=34359738368 test
>>>>>>>>>       # Request 4GB from each of 2 sockets
>>>>>>>>>       cgexec -g hugetlb:test testpmd --socket-mem=4096,4096 ...
>>>>>>>>>
>>>>>>>>>       EAL: SIGBUS: Cannot mmap more hugepages of size 1024 MB
>>>>>>>>>       EAL: 32 not 90 hugepages of size 1024 MB allocated
>>>>>>>>>       EAL: Not enough memory available on socket 1!
>>>>>>>>>            Requested: 4096MB, available: 0MB
>>>>>>>>>       PANIC in rte_eal_init():
>>>>>>>>>       Cannot init memory
>>>>>>>>>
>>>>>>>>>       This happens beacause all allocated pages are
>>>>>>>>>       on socket 0.
>>>>>>>>>
>>>>>>>>> Fix this issue by setting mempolicy MPOL_PREFERRED for each
>>>>>>>>> hugepage to one of requested nodes in a round-robin fashion.
>>>>>>>>> In this case all allocated pages will be fairly distributed
>>>>>>>>> between all requested nodes.
>>>>>>>>>
>>>>>>>>> New config option RTE_LIBRTE_EAL_NUMA_AWARE_HUGEPAGES
>>>>>>>>> introduced and disabled by default because of external
>>>>>>>>> dependency from libnuma.
>>>>>>>>>
>>>>>>>>> Cc:<stable@dpdk.org>
>>>>>>>>> Fixes: 77988fc08dc5 ("mem: fix allocating all free hugepages")
>>>>>>>>>
>>>>>>>>> Signed-off-by: Ilya Maximets<i.maximets@samsung.com>
>>>>>>>>> ---
>>>>>>>>>     config/common_base                       |  1 +
>>>>>>>>>     lib/librte_eal/Makefile                  |  4 ++
>>>>>>>>>     lib/librte_eal/linuxapp/eal/eal_memory.c | 66 ++++++++++++++++++++++++++++++++
>>>>>>>>>     mk/rte.app.mk                            |  3 ++
>>>>>>>>>     4 files changed, 74 insertions(+)
>>>>> Acked-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>
>>>> Thanks.
>>>>
>>>> Best regards, Ilya Maximets.
>>>>
>>
>>
>>
>>