[dpdk-users] Current CONFIG_RTE_MAX_MEMSEG=256 is not enough

[dpdk-users] Current CONFIG_RTE_MAX_MEMSEG=256 is not enough

[Cliff Burdick]

Hi, I have a DPDK application that I allocate 2048 2MB hugepages on
startup, and everything works for a while. However, if I clean my code and
run the application again, on occasion, I get the following error:

Current CONFIG_RTE_MAX_MEMSEG=256 is not enough

Please either increase it or request less amount of memory.

PANIC in rte_eal_init():

Cannot init memory

8: [app() [0x412f4b]]

7: [/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf5)
[0x7fa65918df45]]

6: [app() [0x4122b9]]

5: [app() [0x57494e]]

4: [app() [0x565c3f]]

3: [app() [0x457163]]

2: [app() [0x40af2f]]

1: [app() [0x4512ba]]


I know I can increase this parameter in the DPDK config, but I'm not sure
why that's the solution and that it runs fine for so long until hitting
this. Should I just increase that, or is there another issue at play?

Re: [dpdk-users] Current CONFIG_RTE_MAX_MEMSEG=256 is not enough

[Paul Emmerich]

Cliff Burdick:
> I know I can increase this parameter in the DPDK config, but I'm not sure
> why that's the solution and that it runs fine for so long until hitting
> this. Should I just increase that, or is there another issue at play?

The problem is memory fragmentation, a reboot might solve this.
I've also got a server that gets this message from time to time and 
encountered no ill effects from simply increasing the config setting.

  Paul

Re: [dpdk-users] Current CONFIG_RTE_MAX_MEMSEG=256 is not enough

[Muhammad Zain-ul-Abideen]

It might be a memory leakage, or unhandeled exception, because what i
understood is that at start up it works fine but later on 2nd or 3rd
attempt huge pages are not free, kindly see is any thread from the process
is active, may be a zombie apocalypse.

Re: [dpdk-users] Current CONFIG_RTE_MAX_MEMSEG=256 is not enough

[De Lara Guarch, Pablo]

Hi,

> -----Original Message-----
> From: users [mailto:users-bounces@dpdk.org] On Behalf Of Muhammad Zain-
> ul-Abideen
> Sent: Thursday, October 13, 2016 10:01 AM
> To: Paul Emmerich
> Cc: users
> Subject: Re: [dpdk-users] Current CONFIG_RTE_MAX_MEMSEG=256 is not
> enough
> 
> It might be a memory leakage, or unhandeled exception, because what i
> understood is that at start up it works fine but later on 2nd or 3rd
> attempt huge pages are not free, kindly see is any thread from the process
> is active, may be a zombie apocalypse.

As Paul said, it looks like memory fragmentation.
To guarantee that you won't encounter this problem again, you can reserve
the hugepages at boot time, using the kernel parameter nr_hugepages.

Pablo