RFR: 8296414: [BACKOUT] JDK-8295319: pending_cards_at_gc_start doesn't include cards in thread buffers

[Thomas Schatzl]

Hi all,

  can I have reviews for this clean backout of JDK-8295319: pending_cards_at_gc_start doesn't include cards in thread buffers because it causes quite a few crashes.

Clean revert.

Thanks,
  Thomas

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Commit messages:
 - Revert "8295319: pending_cards_at_gc_start doesn't include cards in thread buffers"

Changes: https://git.openjdk.org/jdk/pull/10993/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10993&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8296414
  Stats: 107 lines in 7 files changed: 41 ins; 39 del; 27 mod
  Patch: https://git.openjdk.org/jdk/pull/10993.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10993/head:pull/10993

PR: https://git.openjdk.org/jdk/pull/10993