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  1. JDK
  2. JDK-8256155

Allow multiple large page sizes to be used on Linux

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Details

    • Enhancement
    • Resolution: Fixed
    • P4
    • 17
    • None
    • hotspot
    • None
    • gc
    • b24
    • linux

    Description

      When using LargePageSizeInBytes=1G, os::Linux::reserve_memory_special_huge_tlbfs* cannot select large pages smaller than 1G. Code heap usually uses less than 1G, so currently the code precludes code heap from using
      Large pages in this circumstance and when os::Linux::reserve_memory_special_huge_tlbfs* is called page sizes fall back to Linux::page_size() (usually 4k).

      This change allows the above use case by populating all large_page_sizes present in /sys/kernel/mm/hugepages in _page_sizes upon calling os::Linux::setup_large_page_size().

      In os::Linux::reserve_memory_special_huge_tlbfs* we then select the largest large page size available in _page_sizes that is smaller than bytes being reserved.

      Attachments

        Issue Links

          csr for

          CSR - null JDK-8265517 Change definition of LargePageSizeInBytes

          • P4 - Minor loss of function, or other problem where easy workaround is present.
          • Closed
          relates to

          Enhancement - null JDK-8266349 Pass down requested page size to reserve_memory_special

          • P3 - Major loss of function.
          • Resolved

          Enhancement - null JDK-8257588 Make os::_page_sizes a bitmask

          • P4 - Minor loss of function, or other problem where easy workaround is present.
          • Resolved

          Enhancement - null JDK-8271195 Use largest available large page size smaller than LargePageSizeInBytes when available

          • P4 - Minor loss of function, or other problem where easy workaround is present.
          • Resolved
          links to

          Commit Commit openjdk/jdk/94cfeb9c

          Review Review openjdk/jdk/1153

          Review Review openjdk/jdk/1153

          Activity

            People

              mgkwill Marcus Williams
              sviswanathan Sandhya Viswanathan
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              Dates

                Created:
                Updated:
                Resolved: