RFR: 8170888: [linux] Experimental support for cgroup memory limits in container (ie Docker) environments

[Kim Barrett]

> On Dec 8, 2016, at 9:59 PM, David Holmes <david.holmes at oracle.com> wrote:
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8170888
> 
> webrev: http://cr.openjdk.java.net/~dholmes/8170888/webrev/

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src/share/vm/runtime/arguments.cpp 
2050       fscanf(fp, JULONG_FORMAT, &cgroup_max);
2051       if (cgroup_max > 0) {

Missing check of fscanf result.  I don't see anything in the doc for
fscanf that promises an argument won't be clobbered if there are match
failures, errors, or fewer inputs than specified in the format string.
Even if that no such clobbering happens, as written we have a really
rare failure mode -- in cgroup context, but inopportune EINTR -- that
gets reported as a parse failure warning and ignoring the cgroup limit.

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src/share/vm/runtime/arguments.cpp 
2054         log_info(gc, heap)("Setting phys_mem to the min of cgroup limit ("

log_info seems a little noisy, especially considering that we
ultimately announce the final ergonomic (Min|Max)HeapSize with
log_trace.

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src/share/vm/runtime/arguments.cpp 

Trivial style nit:

2058       }
2059       else {

2063     }
2064     else {

should be "  } else {"

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