FRF: 8216975 Using ForceNUMA does not disable adaptive sizing with parallel gc

Kim Barrett kim.barrett at
Wed Feb 19 15:23:09 UTC 2020

> On Feb 19, 2020, at 3:35 AM, Ivan Walulya <ivan.walulya at> wrote:
> Hi all,
> Please review a minor modification to disable adaptive sizing when ForceNuma is used with ParallelGC and UseLargePages on Linux OS.
> Bug:
> <>Webrev: <>
> Testing: Tier 1 - 3
> //Ivan

Setting UseNUMA true when Linux::libnuma_init returns false seems
unlikely to work.  The description of ForceNUMA is

    Force NUMA optimizations on single-node/UMA systems

which suggests how it's presently being used in numa_init is wrong.  I
think the current use should be removed and this conditional clause

5129       // If there's only one node (they start from 0) or if the process
5130       // is bound explicitly to a single node using membind, disable NUMA.
5131       UseNUMA = false;

should instead use

  UseNUMA = ForceNUMA

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