JDK-6677036 : investigate mapping the code cache with large pages on linux
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: runtime
  • Affected Version: hs11
  • Priority: P5
  • Status: Closed
  • Resolution: Not an Issue
  • OS: generic
  • CPU: generic
  • Submitted: 2008-03-18
  • Updated: 2017-01-25
  • Resolved: 2014-03-12
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Description
On linux the code cache cannot be mapped using large pages because linux shared memory does not allow executable permissions to be set.  From the shmget man page:

       ...
       mode_flags (lowest 9 bits)
                   specifying  the  permissions  granted to the owner, group,
                   and world.  Presently, the  execute  permissions  are  not
                   used by the system.

If/when linux shared mem supports execute permission, or if/when linux gets another method of obtaining large page memory, the JVM should map the code cache with large pages.

Comments
This is already true in JDK9, closing as not an issue.
12-03-2014