RFR (XXS): 8165153: Crash in rebuild_cpu_to_node_map
david.holmes at oracle.com
Wed Sep 7 01:00:57 UTC 2016
The NUMA rebuild_cpu_to_node_map code is intended to map from physical
CPU ID's to nodes on a system. To determine how many CPUs there are it
uses os::active_processor_count(). That is actually incorrect as it
needs to how many CPUs the system has, not how many have been made
available to the JVM. This worked** in the past because the
active_processor_count() returned the number of online CPUs. However,
after the fix for 6515172, it returned the number of available CPUs, as
The fix is to change that code to use processor_count(), which is the
number of configured CPUs on the system.
** The old code would likely also fail if the number of online CPUs
dynamically increased after the JVM was started!
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