RFR: 8295402: G1: Tighten assertion in G1ScanHRForRegionClosure::scan_heap_roots

[Thomas Schatzl]

On Mon, 17 Oct 2022 10:10:33 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> Simple change of asserting the to-be-scanned card is strictly dirty.
> 
> Test: tier1-6

Lgtm.

src/hotspot/share/gc/g1/g1RemSet.cpp line 840:

> 838:           assert(value == CardTable::dirty_card_val(), "is %d at region %u idx " SIZE_FORMAT, value, region_idx, first_scan_idx);
> 839:         }
> 840: #endif

Suggestion:

          DEBUG_ONLY(CardTable::CardValue value = *_ct->byte_for_index(region_card_base_idx + first_scan_idx);)
          assert(value == CardTable::dirty_card_val(), "is %d at region %u idx " SIZE_FORMAT, value, region_idx, first_scan_idx);

Just fyi, an alternative that does not create that many lines with almost no content.

-------------

Marked as reviewed by tschatzl (Reviewer).

PR: https://git.openjdk.org/jdk/pull/10725