Uploaded image for project: 'JDK'
  1. JDK
  2. JDK-6888898

CMS: ReduceInitialCardMarks unsafe in the presence of cms precleaning

    XMLWordPrintable

    Details

    • Type: Bug
    • Status: Resolved
    • Priority: P2
    • Resolution: Fixed
    • Affects Version/s: hs14, hs17
    • Fix Version/s: hs17
    • Component/s: hotspot
    • Labels:
      None
    • Subcomponent:
      gc
    • Introduced In Build:
      b03
    • Introduced In Version:
    • Resolved In Build:
      b04
    • CPU:
      generic, x86
    • OS:
      generic, solaris

      Backports

        Description

        ReduceInitialCardMarks elides card marks for TLAB allocations
        in young gen (fine for CMS), but for the case of slow-path allocation
        makes up by card-marking the allocated object (potentially in the
        old gen) before initialization. This latter is unsafe wrt CMS' precleaning
        which might scan the marked cards before they have been initialized
        by the mutator and thus lose those updates.
        Deleted incorrect comment/update here.

          Attachments

            Issue Links

              Activity

                People

                Assignee:
                ysr Y. Ramakrishna
                Reporter:
                ysr Y. Ramakrishna
                Votes:
                0 Vote for this issue
                Watchers:
                3 Start watching this issue

                  Dates

                  Created:
                  Updated:
                  Resolved:
                  Imported:
                  Indexed: