TCMalloc: restrict maximum size of memory ranges

third_party/tcmalloc/chromium/src/page_heap.cc

Index: third_party/tcmalloc/chromium/src/page_heap.cc
diff --git a/third_party/tcmalloc/chromium/src/page_heap.cc b/third_party/tcmalloc/chromium/src/page_heap.cc
index 402dc1f9e8a9a9421beb91cfbdcc28119a37f9b1..910cfd131a9f24b31f80a2a3e350ffa851b08c82 100644
--- a/third_party/tcmalloc/chromium/src/page_heap.cc
+++ b/third_party/tcmalloc/chromium/src/page_heap.cc
@@ -467,6 +467,11 @@ bool PageHeap::GrowHeap(Length n) {
   ASSERT(kMaxPages >= kMinSystemAlloc);
   if (n > kMaxValidPages) return false;
   Length ask = (n>kMinSystemAlloc) ? n : static_cast<Length>(kMinSystemAlloc);
+  // For most allocators it's ok to check for size here as they won't generally
+  // grow existing mappings. Some implementations, such as the Linux brk heap
+  // implementation will however require additional checks.
+  if (!IsContiguousAllocSizePermitted(n << kPageShift))

[jln (very slow on Chromium), 2013/01/11 06:02:29]

It's a bit ugly to have the check here *and* in the Linux Brk allocator.

An alternative would be to either patch every allocator implementation
individually.

+    return false;
   size_t actual_size;
   void* ptr = TCMalloc_SystemAlloc(ask << kPageShift, &actual_size, kPageSize);
   if (ptr == NULL) {