Bug 605362, part 3: Add MemoryReporters for shmem. r=vlad

ipc/glue/SharedMemory.cpp

@@ -40,11 +40,40 @@
 
 #include <math.h>
 
+#include "nsIMemoryReporter.h"
 #include "mozilla/ipc/SharedMemory.h"
 
 namespace mozilla {
 namespace ipc {
 
+static PRInt64 gShmemAllocated;
+static PRInt64 gShmemMapped;
+static PRInt64 GetShmemAllocated(void*) { return gShmemAllocated; }
+static PRInt64 GetShmemMapped(void*) { return gShmemMapped; }
+
+NS_MEMORY_REPORTER_IMPLEMENT(ShmemAllocated,
+                             "shmem/allocated",
+                             "Shmem bytes accessible (not necessarily mapped)",
+                             GetShmemAllocated,
+                             nsnull)
+NS_MEMORY_REPORTER_IMPLEMENT(ShmemMapped,
+                             "shmem/mapped",
+                             "Shmem bytes mapped into address space",
+                             GetShmemMapped,
+                             nsnull)
+
+SharedMemory::SharedMemory()
+{
+  // NB: SharedMemory is main-thread-only at the moment, but that may
+  // change soon
+  static bool registered;
+  if (!registered) {
+    NS_RegisterMemoryReporter(new NS_MEMORY_REPORTER_NAME(ShmemAllocated));
+    NS_RegisterMemoryReporter(new NS_MEMORY_REPORTER_NAME(ShmemMapped));
+    registered = true;
+  }
+}
+
 /*static*/ size_t
 SharedMemory::PageAlignedSize(size_t aSize)
 {
@@ -53,5 +82,33 @@ SharedMemory::PageAlignedSize(size_t aSize)
   return pageSize * nPagesNeeded;
 }
 
+/*static*/ void
+SharedMemory::Created(size_t aNBytes)
+{
+  gShmemAllocated += aNBytes;
+}
+
+/*static*/ void
+SharedMemory::Mapped(size_t aNBytes)
+{
+  gShmemMapped += aNBytes;
+}
+
+/*static*/ void
+SharedMemory::Unmapped(size_t aNBytes)
+{
+  NS_ABORT_IF_FALSE(gShmemMapped >= PRInt64(aNBytes),
+                    "Can't unmap more than mapped");
+  gShmemMapped -= aNBytes;
+}
+
+/*static*/ void
+SharedMemory::Destroyed(size_t aNBytes)
+{
+  NS_ABORT_IF_FALSE(gShmemAllocated >= PRInt64(aNBytes),
+                    "Can't destroy more than allocated");
+  gShmemAllocated -= aNBytes;
+}
+
 } // namespace ipc
 } // namespace mozilla

ipc/glue/SharedMemory.h

@@ -104,6 +104,21 @@ public:
   static void SystemProtect(char* aAddr, size_t aSize, int aRights);
   static size_t SystemPageSize();
   static size_t PageAlignedSize(size_t aSize);
+
+protected:
+  SharedMemory();
+
+  // Implementations should call these methods on shmem usage changes,
+  // but *only if* the OS-specific calls are known to have succeeded.
+  // The methods are expected to be called in the pattern
+  //
+  //   Created (Mapped Unmapped)* Destroy
+  //
+  // but this isn't checked.
+  static void Created(size_t aNBytes);
+  static void Mapped(size_t aNBytes);
+  static void Unmapped(size_t aNBytes);
+  static void Destroyed(size_t aNBytes);
 };
 
 } // namespace ipc