From 45fc141d29161e6957e95604a3a79dc6c0f7a830 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Markus=20Gr=C3=B6nlund?= Date: Fri, 6 Mar 2026 10:23:33 +0000 Subject: [PATCH] 8379230: JFR: Do not store leak context edge idx in markWord Reviewed-by: egahlin --- .../jfr/leakprofiler/chains/edgeStore.cpp | 80 +++++++------------ .../jfr/leakprofiler/chains/edgeStore.hpp | 3 +- 2 files changed, 31 insertions(+), 52 deletions(-) diff --git a/src/hotspot/share/jfr/leakprofiler/chains/edgeStore.cpp b/src/hotspot/share/jfr/leakprofiler/chains/edgeStore.cpp index 9aef92c4182..2c341f2385e 100644 --- a/src/hotspot/share/jfr/leakprofiler/chains/edgeStore.cpp +++ b/src/hotspot/share/jfr/leakprofiler/chains/edgeStore.cpp @@ -1,5 +1,5 @@ /* - * Copyright (c) 2014, 2025, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 2014, 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 @@ -26,8 +26,10 @@ #include "jfr/leakprofiler/chains/edgeUtils.hpp" #include "jfr/leakprofiler/sampling/objectSample.hpp" #include "jfr/leakprofiler/utilities/unifiedOopRef.inline.hpp" +#include "jfr/recorder/service/jfrOptionSet.hpp" #include "oops/oop.inline.hpp" #include "runtime/safepoint.hpp" +#include "utilities/resizableHashTable.hpp" StoredEdge::StoredEdge(const Edge* parent, UnifiedOopRef reference) : Edge(parent, reference), _gc_root_id(0), _skip_length(0) {} @@ -216,84 +218,62 @@ bool EdgeStore::put_edges(StoredEdge** previous, const Edge** current, size_t li return nullptr == *current; } -static GrowableArray* _leak_context_edges = nullptr; +typedef ResizeableHashTable SampleToLeakContextEdgeMap; +static SampleToLeakContextEdgeMap* _sample_to_leak_context_edge_map = nullptr; EdgeStore::EdgeStore() : _edges(new EdgeHashTable(this)) {} EdgeStore::~EdgeStore() { assert(_edges != nullptr, "invariant"); delete _edges; - delete _leak_context_edges; - _leak_context_edges = nullptr; + delete _sample_to_leak_context_edge_map; + _sample_to_leak_context_edge_map = nullptr; } -static int leak_context_edge_idx(const ObjectSample* sample) { +static const StoredEdge* leak_context_edge(const ObjectSample* sample) { assert(sample != nullptr, "invariant"); - return static_cast(sample->object()->mark().value()) >> markWord::lock_bits; + assert(_sample_to_leak_context_edge_map != nullptr, "invariant"); + const StoredEdge** edge = _sample_to_leak_context_edge_map->get(p2u(sample->object())); + return edge != nullptr ? *edge : nullptr; } bool EdgeStore::has_leak_context(const ObjectSample* sample) const { - const int idx = leak_context_edge_idx(sample); - if (idx == 0) { - return false; - } - assert(idx > 0, "invariant"); - assert(_leak_context_edges != nullptr, "invariant"); - assert(idx < _leak_context_edges->length(), "invariant"); - assert(_leak_context_edges->at(idx) != nullptr, "invariant"); - return true; + return _sample_to_leak_context_edge_map != nullptr && leak_context_edge(sample) != nullptr; } const StoredEdge* EdgeStore::get(const ObjectSample* sample) const { assert(sample != nullptr, "invariant"); - if (_leak_context_edges != nullptr) { + if (_sample_to_leak_context_edge_map != nullptr) { assert(SafepointSynchronize::is_at_safepoint(), "invariant"); - const int idx = leak_context_edge_idx(sample); - if (idx > 0) { - assert(idx < _leak_context_edges->length(), "invariant"); - const StoredEdge* const edge =_leak_context_edges->at(idx); - assert(edge != nullptr, "invariant"); + const StoredEdge* const edge = leak_context_edge(sample); + if (edge != nullptr) { return edge; } } return get(UnifiedOopRef::encode_in_native(sample->object_addr())); } -#ifdef ASSERT -// max_idx to ensure idx fit in lower 32-bits of markword together with lock bits. -static constexpr const int max_idx = right_n_bits(32 - markWord::lock_bits); +static constexpr const unsigned max_map_size = max_jint >> 1; -static void store_idx_precondition(oop sample_object, int idx) { - assert(sample_object != nullptr, "invariant"); - assert(sample_object->mark().is_marked(), "invariant"); - assert(idx > 0, "invariant"); - assert(idx <= max_idx, "invariant"); -} -#endif - -static void store_idx_in_markword(oop sample_object, int idx) { - DEBUG_ONLY(store_idx_precondition(sample_object, idx);) - const markWord idx_mark_word(sample_object->mark().value() | idx << markWord::lock_bits); - sample_object->set_mark(idx_mark_word); - assert(sample_object->mark().is_marked(), "must still be marked"); -} - -static const int initial_size = 64; - -static int save(const StoredEdge* edge) { - assert(edge != nullptr, "invariant"); - if (_leak_context_edges == nullptr) { - _leak_context_edges = new (mtTracing) GrowableArray(initial_size, mtTracing); - _leak_context_edges->append(nullptr); // next idx now at 1, for disambiguation in markword. +static inline unsigned map_size() { + assert(JfrOptionSet::old_object_queue_size() > 0, "invariant"); + unsigned size = JfrOptionSet::old_object_queue_size(); + size = round_up_power_of_2(size); + if (size < 1024) { + return 1024; } - return _leak_context_edges->append(edge); + size <<= 1; + return size >= max_map_size ? max_map_size : size; } -// We associate the leak context edge with the leak candidate object by saving the -// edge in an array and storing the array idx (shifted) into the markword of the candidate object. static void associate_with_candidate(const StoredEdge* leak_context_edge) { assert(leak_context_edge != nullptr, "invariant"); - store_idx_in_markword(leak_context_edge->pointee(), save(leak_context_edge)); + if (_sample_to_leak_context_edge_map == nullptr) { + const unsigned size = map_size(); + _sample_to_leak_context_edge_map = new (mtTracing) SampleToLeakContextEdgeMap(size, size); + } + assert(_sample_to_leak_context_edge_map != nullptr, "invariant"); + _sample_to_leak_context_edge_map->put(p2u(leak_context_edge->pointee()), leak_context_edge); } StoredEdge* EdgeStore::associate_leak_context_with_candidate(const Edge* edge) { diff --git a/src/hotspot/share/jfr/leakprofiler/chains/edgeStore.hpp b/src/hotspot/share/jfr/leakprofiler/chains/edgeStore.hpp index e920fd64ea9..460314854b7 100644 --- a/src/hotspot/share/jfr/leakprofiler/chains/edgeStore.hpp +++ b/src/hotspot/share/jfr/leakprofiler/chains/edgeStore.hpp @@ -1,5 +1,5 @@ /* - * Copyright (c) 2014, 2021, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 2014, 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 @@ -39,7 +39,6 @@ class StoredEdge : public Edge { size_t _skip_length; public: - StoredEdge(); StoredEdge(const Edge* parent, UnifiedOopRef reference); StoredEdge(const Edge& edge); StoredEdge(const StoredEdge& edge);