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Changeset 277381 in webkit

Timestamp:

May 12, 2021, 11:34:55 AM (5 years ago)

Author:

commit-queue@webkit.org

Message:

Introduced a (rare) deadlock

Reverted changeset:

Location:

trunk/Source/JavaScriptCore

Files:

-              r277370
+              r277381
+-05-12  Commit Queue  <commit-queue@webkit.org>
+        Unreviewed, reverting r277346.
+        https://bugs.webkit.org/show_bug.cgi?id=225705
+        Introduced a (rare) deadlock
+        Reverted changeset:
+        "ConservativeRoots triggers page demand on Speedometer"
+        https://bugs.webkit.org/show_bug.cgi?id=225676
+        https://trac.webkit.org/changeset/277346
 -05-12  Mark Lam  <mark.lam@apple.com>

-              r277346
+              r277381
 ConservativeRoots::ConservativeRoots(Heap& heap)
+    : m_heap(heap)
+    : m_roots(m_inlineRoots)
+    , m_size(0)
+    , m_capacity(inlineCapacity)
+    , m_heap(heap)
+{
+}
 …
 ConservativeRoots::~ConservativeRoots()
+{
+    if (m_roots != m_inlineRoots)
+        OSAllocator::decommitAndRelease(m_roots, m_capacity * sizeof(HeapCell*));
+}
+void ConservativeRoots::grow()
+{
+    size_t newCapacity = m_capacity == inlineCapacity ? nonInlineCapacity : m_capacity * 2;
+    HeapCell** newRoots = static_cast<HeapCell**>(OSAllocator::reserveAndCommit(newCapacity * sizeof(HeapCell*)));
+    memcpy(newRoots, m_roots, m_size * sizeof(HeapCell*));
+    if (m_roots != m_inlineRoots)
+        OSAllocator::decommitAndRelease(m_roots, m_capacity * sizeof(HeapCell*));
+    m_capacity = newCapacity;
+    m_roots = newRoots;
+}
 …
                 markHook.markKnownJSCell(static_cast<JSCell*>(p));
+            m_roots.append(bitwise_cast<HeapCell*>(p));
+            if (m_size == m_capacity)
+                grow();
+            m_roots[m_size++] = bitwise_cast<HeapCell*>(p);
         });
+}

-              r277346
+              r277381
 class ConservativeRoots {
-    static constexpr size_t inlineCapacity = 1024;
 public:
     ConservativeRoots(Heap&);
 …
     void add(void* begin, void* end, JITStubRoutineSet&, CodeBlockSet&);
+    const Vector<HeapCell*, inlineCapacity>& roots() const { return m_roots; };
+    size_t size() const;
+    HeapCell** roots() const;
 private:
+    static constexpr size_t inlineCapacity = 128;
+    static constexpr size_t nonInlineCapacity = 8192 / sizeof(HeapCell*);
     template<typename MarkHook>
     void genericAddPointer(void*, HeapVersion markingVersion, HeapVersion newlyAllocatedVersion, TinyBloomFilter, MarkHook&);
 …
     void genericAddSpan(void*, void* end, MarkHook&);
+    void grow();
+    HeapCell** m_roots;
+    size_t m_size;
+    size_t m_capacity;
     Heap& m_heap;
     Vector<HeapCell*, inlineCapacity> m_roots;
+    HeapCell* m_inlineRoots[inlineCapacity];
 };
+inline size_t ConservativeRoots::size() const
+{
+    return m_size;
+}
+inline HeapCell** ConservativeRoots::roots() const
+{
+    return m_roots;
+}
 } // namespace JSC

-              r277346
+              r277381
 void SlotVisitor::append(const ConservativeRoots& conservativeRoots)
+{
+    for (auto root : conservativeRoots.roots())
+        appendJSCellOrAuxiliary(root);
+    HeapCell** roots = conservativeRoots.roots();
+    size_t size = conservativeRoots.size();
+    for (size_t i = 0; i < size; ++i)
+        appendJSCellOrAuxiliary(roots[i]);
+}

-              r277346
+              r277381
     };
+    for (auto root : conservativeRoots.roots())
+        appendJSCellOrAuxiliary(root);
+    HeapCell** roots = conservativeRoots.roots();
+    size_t size = conservativeRoots.size();
+    for (size_t i = 0; i < size; ++i)
+        appendJSCellOrAuxiliary(roots[i]);
+}

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