Add a UseCounter that measures the amount of memory used in PartitionAlloc

Source/wtf/PartitionAlloc.h

Index: Source/wtf/PartitionAlloc.h
diff --git a/Source/wtf/PartitionAlloc.h b/Source/wtf/PartitionAlloc.h
index 0153c6c9202b312cf16df8c1aa966b9d88bbaafd..52376a575ee3f828c2390f503a1aea1e471b78ae 100644
--- a/Source/wtf/PartitionAlloc.h
+++ b/Source/wtf/PartitionAlloc.h
@@ -276,6 +276,8 @@ struct PartitionSuperPageExtentEntry {
     PartitionSuperPageExtentEntry* next;
 };
 

[Chris Evans, 2015/04/03 22:14:21]

Nit: add comment here: "This callback can be called on any thread."

+typedef void (*ReportMemoryUsageFunction)();

[Chris Evans, 2015/04/03 22:14:21]

Nit: I'm not sure about the name of this callback function. It doesn't take any
parameters, so we're not really "report"ing anything.
Maybe "NotifyCommittedMemoryChangedFunction" or something like that?

+
 struct WTF_EXPORT PartitionRootBase {
     size_t totalSizeOfCommittedPages;
     size_t totalSizeOfSuperPages;
@@ -292,6 +294,7 @@ struct WTF_EXPORT PartitionRootBase {
     PartitionPage* globalEmptyPageRing[kMaxFreeableSpans];
     int16_t globalEmptyPageRingIndex;
     uintptr_t invertedSelf;
+    ReportMemoryUsageFunction reportMemoryUsageFunction;
 
     static int gInitializedLock;
     static bool gInitialized;
@@ -329,9 +332,9 @@ enum PartitionAllocFlags {
     PartitionAllocReturnNull = 1 << 0,
 };
 
-WTF_EXPORT void partitionAllocInit(PartitionRoot*, size_t numBuckets, size_t maxAllocation);
+WTF_EXPORT void partitionAllocInit(PartitionRoot*, size_t numBuckets, size_t maxAllocation, ReportMemoryUsageFunction);
 WTF_EXPORT bool partitionAllocShutdown(PartitionRoot*);
-WTF_EXPORT void partitionAllocGenericInit(PartitionRootGeneric*);
+WTF_EXPORT void partitionAllocGenericInit(PartitionRootGeneric*, ReportMemoryUsageFunction);
 WTF_EXPORT bool partitionAllocGenericShutdown(PartitionRootGeneric*);
 
 WTF_EXPORT NEVER_INLINE void* partitionAllocSlowPath(PartitionRootBase*, int, size_t, PartitionBucket*);
@@ -667,7 +670,10 @@ class SizeSpecificPartitionAllocator {
 public:
     static const size_t kMaxAllocation = N - kAllocationGranularity;
     static const size_t kNumBuckets = N / kAllocationGranularity;
-    void init() { partitionAllocInit(&m_partitionRoot, kNumBuckets, kMaxAllocation); }
+    void init(ReportMemoryUsageFunction reportMemoryUsageFunction = nullptr)
+    {
+        partitionAllocInit(&m_partitionRoot, kNumBuckets, kMaxAllocation, reportMemoryUsageFunction);
+    }
     bool shutdown() { return partitionAllocShutdown(&m_partitionRoot); }
     ALWAYS_INLINE PartitionRoot* root() { return &m_partitionRoot; }
 private:
@@ -677,7 +683,10 @@ private:
 
 class PartitionAllocatorGeneric {
 public:
-    void init() { partitionAllocGenericInit(&m_partitionRoot); }
+    void init(ReportMemoryUsageFunction reportMemoryUsageFunction = nullptr)
+    {
+        partitionAllocGenericInit(&m_partitionRoot, reportMemoryUsageFunction);
+    }
     bool shutdown() { return partitionAllocGenericShutdown(&m_partitionRoot); }
     ALWAYS_INLINE PartitionRootGeneric* root() { return &m_partitionRoot; }
 private: