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

Source/platform/heap/Heap.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 199 matching lines @@
     // Add the BaseHeap's pages to the orphanedPagePool.
     for (BasePage* page = m_firstPage; page; page = page->next()) {
         Heap::decreaseAllocatedSpace(page->size());
         Heap::orphanedPagePool()->addOrphanedPage(heapIndex(), page);
     }
     m_firstPage = nullptr;
 }
 
 void BaseHeap::takeSnapshot(const String& dumpBaseName)
 {
+    WebMemoryAllocatorDump* allocatorDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(dumpBaseName);

[haraken, 2015/05/29 02:11:30]

I'm just curious but does the place we create the allocatorDump matter? i.e., is
it important that we create the allocatorDump for the BaseHeap before creating
allocatorDumps for BaseHeapPages?

[Primiano Tucci (use gerrit), 2015/05/29 08:32:50]

Do you mean the order or the call site?
The order in which the dumps are created is irrelevant (in fact, at the end they
end up in a dictionary which will hash them).

The callsite: well, in general we have to make sure that we create all our dumps
before returning the outer onMemoryDump(WebProcessMemoryDump*) call.

Here in BlinkGC we use an extra little trick: we create an extra
WebProcessMemoryDump (see [1]) that is always available and we use as a "buffer"
to create all the allocatorDumps like this one here when traversing the oilpan
GC structs. At the end we simply merge (see [2])
the buffer WPMD into the real one that meminfra expects (the argument of
onMemoryDump).
In this way we can guarantee that even if, for whatever reason, you force a
Heap::collectGarbage(takeSnapshow) outside of onMemoryDump(...), everything
works fine (you will just end up collecting useless WPMD that will be dropped
before the next dump).

[1]
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...

[2]
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...

[ssid, 2015/05/29 10:57:19]

Just had a chat with primiano@. It is not necessary to move this, but looks
cleaner to create the root after children.

     size_t pageCount = 0;
     for (BasePage* page = m_firstUnsweptPage; page; page = page->next()) {
+        page->takeSnapshot(dumpBaseName, pageCount);

[haraken, 2015/05/29 02:11:30]

pageCount => pageIndex

[ssid, 2015/05/29 10:57:19]

Done.

[ssid, 2015/05/29 10:57:19]

Done.

         pageCount++;
     }
-    WebMemoryAllocatorDump* allocatorDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(dumpBaseName);
     allocatorDump->AddScalar("blink_page_count", "objects", pageCount);
 }
 
 #if ENABLE(ASSERT) || ENABLE(GC_PROFILING)
 BasePage* BaseHeap::findPageFromAddress(Address address)
 {
     for (BasePage* page = m_firstPage; page; page = page->next()) {
         if (page->contains(address))
             return page;
     }
@@ skipping 1152 matching lines @@
     // cross thread pointer usage.
 #if defined(ADDRESS_SANITIZER)
     // This needs to zap poisoned memory as well.
     // Force unpoison memory before memset.
     ASAN_UNPOISON_MEMORY_REGION(payload(), payloadSize());
 #endif
     memset(payload(), orphanedZapValue, payloadSize());
     BasePage::markOrphaned();
 }
 
+void NormalPage::takeSnapshot(const String& dumpBaseName, size_t pageIndex)
+{
+    String pageName = dumpBaseName.isolatedCopy();

[haraken, 2015/05/29 02:11:30]

Instead of passing const String& and calling isolatedCopy, I'd prefer just
passing 'String'.

[Primiano Tucci (use gerrit), 2015/05/29 08:32:50]

+1

+    pageName.append(String::format("/page_%zu", pageIndex));
+    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;
+    for (Address addr = payload(); addr < payloadEnd(); addr += header->size()) {

[haraken, 2015/05/29 02:11:30]

addr => headerAddress

[ssid, 2015/05/29 10:57:19]

Done.

+        header = reinterpret_cast<HeapObjectHeader*>(addr);
+        objectCount++;
+        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);

[haraken, 2015/05/29 02:11:30]

Remove objectCount. The freed area is not an object, so it doesn't make sense to
count up the total number of headers and report it.

[ssid, 2015/05/29 10:57:19]

Done, thanks.

+    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)
 {
     if (address < payload())
         return nullptr;
 
     HeapObjectHeader* header = findHeaderFromAddress(address);
     if (!header)
         return nullptr;
 
@@ skipping 156 matching lines @@
 }
 
 void LargeObjectPage::markOrphaned()
 {
     // Zap the payload with a recognizable value to detect any incorrect
     // cross thread pointer usage.
     memset(payload(), orphanedZapValue, payloadSize());
     BasePage::markOrphaned();
 }
 
+void LargeObjectPage::takeSnapshot(const String& dumpBaseName, size_t pageIndex)
+{
+    String pageName = dumpBaseName.isolatedCopy();
+    pageName.append(String::format("/page_%zu", pageIndex));
+    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);

[haraken, 2015/05/29 02:11:30]

Remove this.

[ssid, 2015/05/29 10:57:19]

Done.

+    pageDump->AddScalar("live_count", "objects", liveCount);
+    pageDump->AddScalar("dead_count", "objects", deadCount);
+    pageDump->AddScalar("live_size", "bytes", liveSize);
+    pageDump->AddScalar("dead_size", "bytes", deadSize);
+}
+
 #if ENABLE(GC_PROFILING)
 const GCInfo* LargeObjectPage::findGCInfo(Address address)
 {
     if (!containedInObjectPayload(address))
         return nullptr;
     HeapObjectHeader* header = heapObjectHeader();
     return Heap::gcInfo(header->gcInfoIndex());
 }
 
 void LargeObjectPage::snapshot(TracedValue* json, ThreadState::SnapshotInfo* info)
@@ skipping 723 matching lines @@
 size_t Heap::s_allocatedObjectSize = 0;
 size_t Heap::s_allocatedSpace = 0;
 size_t Heap::s_markedObjectSize = 0;
 // We don't want to use 0 KB for the initial value because it may end up
 // triggering the first GC of some thread too prematurely.
 size_t Heap::s_estimatedLiveObjectSize = 512 * 1024;
 size_t Heap::s_externalObjectSizeAtLastGC = 0;
 double Heap::s_estimatedMarkingTimePerByte = 0.0;
 
 } // namespace blink