RFR: 8220658: Improve the readability of container information in the error log

[David Holmes]

Hi Jie,

On 14/03/2019 8:00 pm, Jie Fu wrote:
> Hi all,
> 
> Bug:    https://bugs.openjdk.java.net/browse/JDK-8220658
> Webrev: http://cr.openjdk.java.net/~jiefu/8220658/webrev.00/

This seems a reasonable improvement, but I have a couple of suggestions. 
To avoid so much duplication you can change this structure:

    if (i > 0) {
      st->print("cpu_quota: %d\n", i);
    } else {
      st->print("cpu_quota: %s\n", i == OSCONTAINER_ERROR ? "failed" : 
"no quota");
    }

to this:

    st->print("cpu_quota: ");
    if (i > 0) {
       st->print("%d\n", i);
    } else {
      st->print("%s\n", i == OSCONTAINER_ERROR ? "failed" : "no quota");
    }

Also I suggest replacing "failed" with "not supported".

Finally one minor typo: s/"no share"/"no shares"/

Thanks,
David
-----

> In the VM's error log, the container information was dumpped as:
> ---------------------------------
> container (cgroup) information:
> container_type: cgroupv1
> cpu_cpuset_cpus: 0-11
> cpu_memory_nodes: 0
> active_processor_count: 12
> cpu_quota: -1
> cpu_period: 100000
> cpu_shares: -1
> memory_limit_in_bytes: -1
> memory_and_swap_limit_in_bytes: -2
> memory_soft_limit_in_bytes: -1
> memory_usage_in_bytes: 11690164224
> memory_max_usage_in_bytes: 1806413824
> ---------------------------------
> 
> Items such as "memory_limit_in_bytes" and 
> "memory_and_swap_limit_in_bytes" are difficult to understand.
> 
> It might be more human-readable if we could dump it like this:
> ---------------------------------
> container (cgroup) information:
> container_type: cgroupv1
> cpu_cpuset_cpus: 0-11
> cpu_memory_nodes: 0
> active_processor_count: 12
> cpu_quota: no quota
> cpu_period: 100000
> cpu_shares: no share
> memory_limit_in_bytes: unlimited
> memory_and_swap_limit_in_bytes: failed
> memory_soft_limit_in_bytes: unlimited
> memory_usage_in_bytes: 11690164224
> memory_max_usage_in_bytes: 1806413824
> ---------------------------------
> 
> I made this patch to improve the readability of container information in 
> the error log.
> The change has been tested with hotspot:tier1 on Linux/x86-64.
> 
> Could you please review it?
> Thanks a lot.
> 
> Best regards,
> Jie
> 
>