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From: Byonggon Chun <byonggonchun@gmail.com>
To: users@dpdk.org
Subject: [dpdk-users] Should ''shmget" not be used to consume hugepages in DPDK?
Date: Fri, 20 Dec 2019 01:23:50 +0900	[thread overview]
Message-ID: <CACh8f0M_W9NvAgqp-vc-KR57hXO6=tYeWbfqQNG+NytYxp6AsQ@mail.gmail.com> (raw)

Hi all.
I'm Kubernetes contributors and I'm working to make container isolation of
hugepages that allows us to set hugepages limit per container cgroup.
(At this point, limits are set on pod level cgroup even though we asked
hugepages as the container level resource)

I tore down testPMD and some parts of DPDK lib and I got a question after i
found there is no usage of "shmget" in DPDK.

My question is that Should "shmget" not be used to consume hugepages in
DPDK?
And here is following questions:
1) If we don't have to use "shmget", Why? Does it affect performance?
2) If I use "shmget" to get hugepages, should I call "mlock" syscall for it?

For more details, as I know there are three ways to consume hugepages in
kubernetes.
1) shmget with SHM_HUGETLB
2) mmap with hugetlbs filebacking
3) mmap with MAP_ANONYMOUS | MAP_HUGETLB

And I found that testPMD calls mlock syscall when it maps an anonymous
hugepages or external allocated hugepages.
https://github.com/DPDK/dpdk/blob/924e55fb340623f03fdf2ff7fbcfd78819d1db25/app/test-pmd/testpmd.c#L896
https://github.com/DPDK/dpdk/blob/924e55fb340623f03fdf2ff7fbcfd78819d1db25/app/test-pmd/testpmd.c#L916

Thanks.

             reply	other threads:[~2019-12-19 16:24 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-19 16:23 Byonggon Chun [this message]
2019-12-19 21:06 ` Stephen Hemminger
2019-12-20 12:42   ` Byonggon Chun
2019-12-22 15:33     ` Byonggon Chun
2020-02-06 13:53       ` [dpdk-users] [dpdk-dev] " Burakov, Anatoly

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