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8380390: Shenandoah: Missing store barrier when resetting bitmaps #31518

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8380390: Shenandoah: Missing store barrier when resetting bitmaps #31518

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1 change: 1 addition & 0 deletions src/hotspot/share/gc/shenandoah/shenandoahHeapRegion.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -280,6 +280,7 @@ class ShenandoahHeapRegion {
// clears the self_fwd bits. Safety-net reset on region recycle.
ShenandoahSharedFlag _has_self_forwards;

// This is only read/written by a gc worker to avoid unnecessary bitmap resets
bool _needs_bitmap_reset;

public:
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6 changes: 4 additions & 2 deletions src/hotspot/share/gc/shenandoah/shenandoahMarkingContext.cpp
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@@ -1,7 +1,7 @@
/*
* Copyright (c) 2018, 2021, Red Hat, Inc. All rights reserved.
* Copyright (c) 2018, 2026, Red Hat, Inc. All rights reserved.
* Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
* Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2026, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
Expand All @@ -27,6 +27,7 @@
#include "gc/shared/markBitMap.inline.hpp"
#include "gc/shenandoah/shenandoahHeap.inline.hpp"
#include "gc/shenandoah/shenandoahMarkingContext.hpp"
#include "runtime/orderAccess.hpp"

ShenandoahMarkingContext::ShenandoahMarkingContext(MemRegion heap_region, MemRegion bitmap_region, size_t num_regions) :
_mark_bit_map(heap_region, bitmap_region),
Expand Down Expand Up @@ -90,6 +91,7 @@ void ShenandoahMarkingContext::clear_bitmap(ShenandoahHeapRegion* r) {

if (top_bitmap > bottom) {
_mark_bit_map.clear_range_large(MemRegion(bottom, top_bitmap));
OrderAccess::storestore();
_top_bitmaps[r->index()] = bottom;
}

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