Adding heap-page statistics to blink-gc memory dump provider.

Source/platform/heap/Heap.cpp

Index: Source/platform/heap/Heap.cpp
diff --git a/Source/platform/heap/Heap.cpp b/Source/platform/heap/Heap.cpp
index 78e44c0415c2c5b0801cb09b3dfba62428e4b581..ac38009a060ef6080591eed7ecea9daa99ba9aac 100644
--- a/Source/platform/heap/Heap.cpp
+++ b/Source/platform/heap/Heap.cpp
@@ -217,11 +217,12 @@ void BaseHeap::cleanupPages()
 
 void BaseHeap::takeSnapshot(const String& dumpBaseName)
 {
+    WebMemoryAllocatorDump* allocatorDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(dumpBaseName);
     size_t pageCount = 0;
     for (BasePage* page = m_firstUnsweptPage; page; page = page->next()) {
+        page->takeSnapshot(dumpBaseName, pageCount);
         pageCount++;
     }
-    WebMemoryAllocatorDump* allocatorDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(dumpBaseName);
     allocatorDump->AddScalar("blink_page_count", "objects", pageCount);
 }
 
@@ -1346,6 +1347,47 @@ void NormalPage::markOrphaned()
     BasePage::markOrphaned();
 }
 
+void NormalPage::takeSnapshot(const String& dumpBaseName, size_t pageIndex)
+{
+    String pageName = dumpBaseName.isolatedCopy();
+    pageName.append(String::format("/page_%zu", pageIndex));

[Primiano Tucci (use gerrit), 2015/05/28 12:47:00]

maybe this is a bit more clear and efficient if you have
String pageName = String::format("%s/page_%zu", dumpBaseName, pageIndex)

[ssid, 2015/05/28 13:06:10]

With offline discussion, this seems better.

+    WebMemoryAllocatorDump* pageDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(pageName);
+
+    HeapObjectHeader* header = nullptr;
+    size_t objectCount = 0;
+    size_t liveCount = 0;
+    size_t deadCount = 0;
+    size_t freeCount = 0;
+    size_t liveSize = 0;
+    size_t deadSize = 0;
+    size_t freeSize = 0;
+    size_t encodedSize = 0;
+    for (Address addr = payload(); addr < payloadEnd(); addr += header->size()) {
+        header = reinterpret_cast<HeapObjectHeader*>(addr);
+        objectCount++;
+        encodedSize += header->encodedSize();

[Primiano Tucci (use gerrit), 2015/05/28 12:47:00]

as above, let's remove this.

[ssid, 2015/05/28 13:06:10]

Done.

+        if (header->isFree()) {
+            freeCount++;
+            freeSize += header->size();
+        } else if (header->isMarked()) {
+            liveCount++;
+            liveSize += header->size();
+        } else {
+            deadCount++;
+            deadSize += header->size();
+        }
+    }
+
+    pageDump->AddScalar("object_count", "objects", objectCount);
+    pageDump->AddScalar("encoded_size", "bytes", encodedSize);
+    pageDump->AddScalar("live_count", "objects", liveCount);
+    pageDump->AddScalar("dead_count", "objects", deadCount);
+    pageDump->AddScalar("free_count", "objects", freeCount);
+    pageDump->AddScalar("live_size", "bytes", liveSize);
+    pageDump->AddScalar("dead_size", "bytes", deadSize);
+    pageDump->AddScalar("free_size", "bytes", freeSize);
+}
+
 #if ENABLE(GC_PROFILING)
 const GCInfo* NormalPage::findGCInfo(Address address)
 {
@@ -1513,6 +1555,34 @@ void LargeObjectPage::markOrphaned()
     BasePage::markOrphaned();
 }
 
+void LargeObjectPage::takeSnapshot(const String& dumpBaseName, size_t pageIndex)
+{
+    String pageName = dumpBaseName.isolatedCopy();
+    pageName.append(String::format("/page_%zu", pageIndex));

[Primiano Tucci (use gerrit), 2015/05/28 12:47:00]

ditto here

[ssid, 2015/05/28 13:06:10]

ditto.

+    WebMemoryAllocatorDump* pageDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(pageName);
+
+    size_t liveSize = 0;
+    size_t deadSize = 0;
+    size_t liveCount = 0;
+    size_t deadCount = 0;
+    HeapObjectHeader* header = heapObjectHeader();
+    if (header->isMarked()) {
+        liveCount = 1;
+        liveSize += header->size();
+    } else {
+        deadCount = 1;
+        deadSize += header->size();
+    }
+
+    pageDump->AddScalar("object_count", "objects", 1u);
+    pageDump->AddScalar("live_count", "objects", liveCount);
+    pageDump->AddScalar("dead_count", "objects", deadCount);
+    pageDump->AddScalar("live_size", "bytes", liveSize);
+    pageDump->AddScalar("dead_size", "bytes", deadSize);
+    pageDump->AddScalar("free_size", "bytes", 0u);

[Primiano Tucci (use gerrit), 2015/05/28 12:47:00]

Don't dump these if you know that they don't apply for large object pages.
The UI should be smart enough to deal with missing values.

[ssid, 2015/05/28 13:06:09]

Done.

+    pageDump->AddScalar("free_count", "objects", 0u);
+}
+
 #if ENABLE(GC_PROFILING)
 const GCInfo* LargeObjectPage::findGCInfo(Address address)
 {