Re: [dpdk-users] Unable to setup hugepages

[Thomas Monjalon <thomas@monjalon.net>]

31/05/2021 17:35, Gabriel Danjon:
> Hello,
> 
> After successfully installed the DPDK 20.11 on my Centos 8-Stream 
> (minimal), I am trying to configure the hugepages but encounters a lot 
> of difficulties.

There's some confusing info below.
Let's forget all the details and focus on simple things:
	1/ use dpdk-hugepages.py
	2/ choose one page size (2M or 1G)
	3/ check which node requires memory with lstopo
	4/ don't be confused with warnings about unused page size



> I am trying to reserve 4 hugepages of 1GB.
> 
> 
> Here the steps I have done following the documentation 
> (https://doc.dpdk.org/guides-20.11/linux_gsg/sys_reqs.html):
> 
> Additional information about meminfo :
> 
> cat /proc/meminfo
> MemTotal:       32619404 kB
> MemFree:        27331024 kB
> MemAvailable:   27415524 kB
> Buffers:            4220 kB
> Cached:           328628 kB
> SwapCached:            0 kB
> Active:           194828 kB
> Inactive:         210156 kB
> Active(anon):       1744 kB
> Inactive(anon):    83384 kB
> Active(file):     193084 kB
> Inactive(file):   126772 kB
> Unevictable:           0 kB
> Mlocked:               0 kB
> SwapTotal:      16474108 kB
> SwapFree:       16474108 kB
> Dirty:                 0 kB
> Writeback:             0 kB
> AnonPages:         72136 kB
> Mapped:            84016 kB
> Shmem:             12992 kB
> KReclaimable:     211956 kB
> Slab:             372852 kB
> SReclaimable:     211956 kB
> SUnreclaim:       160896 kB
> KernelStack:        9120 kB
> PageTables:         6852 kB
> NFS_Unstable:          0 kB
> Bounce:                0 kB
> WritebackTmp:          0 kB
> CommitLimit:    30686656 kB
> Committed_AS:     270424 kB
> VmallocTotal:   34359738367 kB
> VmallocUsed:           0 kB
> VmallocChunk:          0 kB
> Percpu:            28416 kB
> HardwareCorrupted:     0 kB
> AnonHugePages:     10240 kB
> ShmemHugePages:        0 kB
> ShmemPmdMapped:        0 kB
> FileHugePages:         0 kB
> FilePmdMapped:         0 kB
> HugePages_Total:       0
> HugePages_Free:        0
> HugePages_Rsvd:        0
> HugePages_Surp:        0
> Hugepagesize:    1048576 kB
> Hugetlb:         4194304 kB
> DirectMap4k:      225272 kB
> DirectMap2M:     4919296 kB
> DirectMap1G:    30408704 kB
> 
> 1 Step follow documentation
> 
> bash -c 'echo 2048 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages'
> 
> As we're working on a NUMA machine we do this too. (We even do the 
> previous step because without it, it provides more errors)
> 
> bash -c 'echo 2048 > 
> /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages' && \
> bash -c 'echo 2048 > 
> /sys/devices/system/node/node1/hugepages/hugepages-2048kB/nr_hugepages'
> 
> mkdir /mnt/huge
> mount -t hugetlbfs pagesize=1GB /mnt/huge
> 
> bash -c 'echo nodev /mnt/huge hugetlbfs pagesize=1GB 0 0 >> /etc/fstab'
> 
> So here the result of my meminfo (cat /proc/meminfo | grep Huge) :
> 
> AnonHugePages:     10240 kB
> ShmemHugePages:        0 kB
> FileHugePages:         0 kB
> HugePages_Total:       0
> HugePages_Free:        0
> HugePages_Rsvd:        0
> HugePages_Surp:        0
> Hugepagesize:    1048576 kB
> Hugetlb:         4194304 kB
> 
> It looks strange that there is no total and free hugepages.
> 
> I tried the dpdk-testpmd using the DPDK documentation : dpdk-testpmd -l 
> 0-3 -n 4 -- -i --nb-cores=2
> 
> EAL: Detected 48 lcore(s)
> EAL: Detected 2 NUMA nodes
> EAL: Detected static linkage of DPDK
> EAL: Multi-process socket /var/run/dpdk/rte/mp_socket
> EAL: Selected IOVA mode 'PA'
> EAL: 2048 hugepages of size 2097152 reserved, but no mounted hugetlbfs 
> found for that size
> EAL: No free hugepages reported in hugepages-1048576kB
> EAL: No free hugepages reported in hugepages-1048576kB
> EAL: No available hugepages reported in hugepages-1048576kB
> EAL: FATAL: Cannot get hugepage information.
> EAL: Cannot get hugepage information.
> EAL: Error - exiting with code: 1
>    Cause: Cannot init EAL: Permission denied
> 
> 
> So I checked in the /mnt/huge to look if files had been created (ls 
> /mnt/huge/ -la) : Empty folder
> 
> Then I checked if my folder was correctly mounted : mount | grep huge
> pagesize=1GB on /mnt/huge type hugetlbfs 
> (rw,relatime,seclabel,pagesize=1024M)
> 
> Then I tried the helloworld example (make clean && make && 
> ./build/helloworld):
> 
> EAL: Detected 48 lcore(s)
> EAL: Detected 2 NUMA nodes
> EAL: Detected shared linkage of DPDK
> EAL: Multi-process socket /var/run/dpdk/rte/mp_socket
> EAL: Selected IOVA mode 'PA'
> EAL: 2048 hugepages of size 2097152 reserved, but no mounted hugetlbfs 
> found for that size
> EAL: No free 1048576 kB hugepages reported on node 0
> EAL: No free 1048576 kB hugepages reported on node 1
> EAL: No available 1048576 kB hugepages reported
> EAL: FATAL: Cannot get hugepage information.
> EAL: Cannot get hugepage information.
> PANIC in main():
> Cannot init EAL
> 5: [./build/helloworld() [0x40079e]]
> 4: [/lib64/libc.so.6(__libc_start_main+0xf3) [0x7ff43a6f6493]]
> 3: [./build/helloworld() [0x4006e6]]
> 2: [/usr/local/lib64/librte_eal.so.21(__rte_panic+0xba) [0x7ff43aaa4b93]]
> 1: [/usr/local/lib64/librte_eal.so.21(rte_dump_stack+0x1b) [0x7ff43aac79fb]]
> Aborted (core dumped)
> 
> 
> So I guessed the problem came from the : Hugepagesize:    1048576 kB 
> (from cat /proc/meminfo | grep Huge).
> 
> 
> 2 Step adapt documentation
> 
> Then I decided to set the values for 1048576KB:
> 
> bash -c 'echo 4 > 
> /sys/devices/system/node/node0/hugepages/hugepages-1048576kB/nr_hugepages'
> bash -c 'echo 4 > 
> /sys/devices/system/node/node1/hugepages/hugepages-1048576kB/nr_hugepages'
> bash -c 'echo 4 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages'
> 
> 
> So here the result of my meminfo (cat /proc/meminfo | grep Huge) :
> 
> AnonHugePages:     10240 kB
> ShmemHugePages:        0 kB
> FileHugePages:         0 kB
> HugePages_Total:       4
> HugePages_Free:        4
> HugePages_Rsvd:        0
> HugePages_Surp:        0
> Hugepagesize:    1048576 kB
> Hugetlb:         8388608 kB
> 
> So here I have my 4 pages sat.
> 
> Then I retried the previous steps and here what I got :
> 
> dpdk-testpmd -l 0-3 -n 4 -- -i --nb-cores=2
> EAL: Detected 48 lcore(s)
> EAL: Detected 2 NUMA nodes
> EAL: Detected static linkage of DPDK
> EAL: Multi-process socket /var/run/dpdk/rte/mp_socket
> EAL: Selected IOVA mode 'PA'
> EAL: 2048 hugepages of size 2097152 reserved, but no mounted hugetlbfs 
> found for that size
> EAL: Probing VFIO support...
> testpmd: No probed ethernet devices
> Interactive-mode selected
> testpmd: create a new mbuf pool <mb_pool_0>: n=171456, size=2176, socket=0
> testpmd: preferred mempool ops selected: ring_mp_mc
> Done
> testpmd>
> Bye...
> 
> 
> make clean && make && ./build/helloworld
> EAL: Detected 48 lcore(s)
> EAL: Detected 2 NUMA nodes
> EAL: Detected shared linkage of DPDK
> EAL: Multi-process socket /var/run/dpdk/rte/mp_socket
> EAL: Selected IOVA mode 'PA'
> EAL: 2048 hugepages of size 2097152 reserved, but no mounted hugetlbfs 
> found for that size
> TELEMETRY: No legacy callbacks, legacy socket not created
> 
> 
> cat /proc/meminfo | grep Huge
> AnonHugePages:     10240 kB
> ShmemHugePages:        0 kB
> FileHugePages:         0 kB
> HugePages_Total:       4
> HugePages_Free:        3
> HugePages_Rsvd:        0
> HugePages_Surp:        0
> Hugepagesize:    1048576 kB
> Hugetlb:         8388608 kB
> 
> One huge page looks like have been used.
> ls -l /mnt/huge/
> total 1048576
> 1073741824 rtemap_0
> 
> So yes one has been created, but 2048 hugepages of size 2097152 
> reserved, but no mounted hugetlbfs found for that size, happens.
> 
> So to try to understand what happens I reset 
> hugepages-2048kB/nr_hugepages to 0 :
> bash -c 'echo 0 > 
> /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages' && \
> bash -c 'echo 0 > 
> /sys/devices/system/node/node1/hugepages/hugepages-2048kB/nr_hugepages' && \
> bash -c 'echo 0 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages'
> 
> but : dpdk-testpmd -l 0-3 -n 4 -- -i --nb-cores=2EAL: Detected 48 lcore(s)
> EAL: Detected 2 NUMA nodes
> EAL: Detected static linkage of DPDK
> EAL: Multi-process socket /var/run/dpdk/rte/mp_socket
> EAL: Selected IOVA mode 'PA'
> EAL: No available hugepages reported in hugepages-2048kB
> EAL: Probing VFIO support...
> testpmd: No probed ethernet devices
> Interactive-mode selected
> testpmd: create a new mbuf pool <mb_pool_0>: n=171456, size=2176, socket=0
> testpmd: preferred mempool ops selected: ring_mp_mc
> Done
> 
> So here on this part I really don't understand, my /proc/meminfo tells 
> me I need to use the 1048576kB part but dpdk-testpmd the 2048kB.
> 
> Then I searched an alternative to these commands in your documentation 
> and found : dpdk-hugpages.py
> 
> 
> 3 Step alternative
> 
> https://doc.dpdk.org/guides-20.11/tools/hugepages.html
> (There is an error on the documentation : dpdk-hugpages instead of 
> dpdk-hugepages)
> 
> So I reset every files, and removed my mount and my folder.
> 
> umount /mnt/huge
> rm -rf /mnt/huge
> bash -c 'echo 0 > 
> /sys/devices/system/node/node0/hugepages/hugepages-1048576kB/nr_hugepages'
> bash -c 'echo 0 > 
> /sys/devices/system/node/node1/hugepages/hugepages-1048576kB/nr_hugepages'
> bash -c 'echo 0 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages'
> 
> cat /proc/meminfo | grep Huge
> AnonHugePages:     10240 kB
> ShmemHugePages:        0 kB
> FileHugePages:         0 kB
> HugePages_Total:       0
> HugePages_Free:        0
> HugePages_Rsvd:        0
> HugePages_Surp:        0
> Hugepagesize:    1048576 kB
> Hugetlb:               0 kB
> 
> 
> dpdk-hugpages.py -s
> 
> Node Pages Size Total
> 
> Hugepages not mounted
> 
> 
> So here I have an cleaned hugepage environment.
> Then I tried to reallocate hugepages with the python script: 
> dpdk-hugepages.py -p 1G --setup 4G
> 
> dpdk-hugepages.py -s
> Node Pages Size Total
> 0    4     1Gb    4Gb
> 1    4     1Gb    4G
> 
> 
> So I got my 4 pages of 1GB and retried the previous steps :
> 
> cat /proc/meminfo | grep Huge
> AnonHugePages:     10240 kB
> ShmemHugePages:        0 kB
> FileHugePages:         0 kB
> HugePages_Total:       8
> HugePages_Free:        8
> HugePages_Rsvd:        0
> HugePages_Surp:        0
> Hugepagesize:    1048576 kB
> Hugetlb:         8388608 kB
> 
> Here it says I got 8 hugepages of 1GB so I don't understand why, because 
> the python script tells the opposite.
> 
> dpdk-testpmd -l 0-3 -n 4 -- -i --nb-cores=2EAL: Detected 48 lcore(s)
> EAL: Detected 2 NUMA nodes
> EAL: Detected static linkage of DPDK
> EAL: Multi-process socket /var/run/dpdk/rte/mp_socket
> EAL: Selected IOVA mode 'PA'
> EAL: No available hugepages reported in hugepages-2048kB
> EAL: Probing VFIO support...
> testpmd: No probed ethernet devices
> Interactive-mode selected
> testpmd: create a new mbuf pool <mb_pool_0>: n=171456, size=2176, socket=0
> testpmd: preferred mempool ops selected: ring_mp_mc
> Done
> 
> Same for the helloworld.
> 
> Then I cleared my environment:
> 
> dpdk-hugepages.py -u && dpdk-hugepages.py -c && dpdk-hugepages.py -s
> Node Pages Size Total
> 
> Hugepages not mounted
> 
> 
> Then as the error says that there are no available hugepages reported in 
> hugepages-2048kB i tried with Mb :
> dpdk-hugepages.py -p 1024M --setup 4G && dpdk-hugepages.py -s
> Node Pages Size Total
> 0    4     1Gb    4Gb
> 1    4     1Gb    4Gb
> 
> But same error happened.
> 
> 
> 4 Question
> 
> So I don't succeed to resolve this issue of testing the DPDK with 
> helloworld and dpdk-testpmd.
> 
> Have I missed something in the creation of the hugepages ?
> 
> Could you please, provide help ?
> 
> Best,
> 
> 
>