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  1. JDK
  2. JDK-8077276

allocating heap with UseLargePages and HugeTLBFS may trash existing memory mappings (linux)

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    • Bug
    • Resolution: Fixed
    • P4
    • 9
    • 9
    • hotspot
    • None
    • gc
    • b66
    • linux

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      Description

        Code review showed that on Linux, if heap is allocated via reserve_memory_special_huge_tlbfs_mixed(), mmap(addr, MAP_FIXED) gets called to establish heap memory which will trash existing mappings which happen to be located in that area.

        I could also reproduce this experimentally.

        The error is that reserve_memory_special_huge_tlbfs_mixed() calls os::reserve_memory() with a requested_addr != null to establish an initial memory mapping where none existed before.

        It might be smart to get rid of the requested_addr parameter to os::reserve_memory altogether, see http://comments.gmane.org/gmane.comp.java.openjdk.hotspot.devel/18049. I don't think there is a way this parameter can be used correctly in this API.

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                stuefe Thomas Stuefe
                stuefe Thomas Stuefe
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                  Created:
                  Updated:
                  Resolved: