Roll Skia to 2ced78866fcadd98895777c8dffe92e229775181

skia/ext/SkMemory_new_handler.cpp

Index: skia/ext/SkMemory_new_handler.cpp
diff --git a/skia/ext/SkMemory_new_handler.cpp b/skia/ext/SkMemory_new_handler.cpp
index 7400c71809b2f601a09845dbd2ea01cb8bee55c2..d4080a13447aa983e6a9f66a607a49832b2d29b3 100644
--- a/skia/ext/SkMemory_new_handler.cpp
+++ b/skia/ext/SkMemory_new_handler.cpp
@@ -2,21 +2,18 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include <stdio.h>
 #include <stdlib.h>
-#include <new>
 
 #include "base/process/memory.h"
 
 #include "third_party/skia/include/core/SkTypes.h"
-#include "third_party/skia/include/core/SkThread.h"
 
-// This implementation of sk_malloc_flags() and friends is identical to
-// SkMemory_malloc.cpp, except that it disables the CRT's new_handler during
-// malloc() and calloc() when SK_MALLOC_THROW is not set (because our normal
-// new_handler itself will crash on failure when using tcmalloc).
-
-SK_DECLARE_STATIC_MUTEX(gSkNewHandlerMutex);
+// This implementation of sk_malloc_flags() and friends is similar to
+// SkMemory_malloc.cpp, except it uses base::UncheckedMalloc and friends
+// for non-SK_MALLOC_THROW calls.
+//
+// The name of this file is historic: a previous implementation tried to
+// use std::set_new_handler() for the same effect, but it didn't actually work.
 
 static inline void* throw_on_failure(size_t size, void* p) {
     if (size > 0 && p == NULL) {
@@ -46,21 +43,35 @@ void sk_free(void* p) {
     }
 }
 
+// We get lots of bugs filed on us that amount to overcommiting bitmap memory,
+// then some time later failing to back that VM with physical memory.
+// They're hard to track down, so in Debug mode we touch all memory right up front.
+//
+// For malloc, fill is an arbitrary byte and ideally not 0.  For calloc, it's got to be 0.
+static void* prevent_overcommit(int fill, size_t size, void* p) {
+    // We probably only need to touch one byte per page, but memset makes things easy.
+    SkDEBUGCODE(memset(p, fill, size));
+    return p;
+}
+
 void* sk_malloc_throw(size_t size) {
-    return throw_on_failure(size, malloc(size));
+    return prevent_overcommit(0x42, size, throw_on_failure(size, malloc(size)));
 }
 
 static void* sk_malloc_nothrow(size_t size) {
     // TODO(b.kelemen): we should always use UncheckedMalloc but currently it
     // doesn't work as intended everywhere.
+    void* result;
 #if  defined(OS_IOS)
-    return malloc(size);
+    result = malloc(size);
 #else
-    void* result;
     // It's the responsibility of the caller to check the return value.
     ignore_result(base::UncheckedMalloc(size, &result));
-    return result;
 #endif
+    if (result) {
+        prevent_overcommit(0x47, size, result);
+    }
+    return result;
 }
 
 void* sk_malloc_flags(size_t size, unsigned flags) {
@@ -71,18 +82,21 @@ void* sk_malloc_flags(size_t size, unsigned flags) {
 }
 
 void* sk_calloc_throw(size_t size) {
-    return throw_on_failure(size, calloc(size, 1));
+    return prevent_overcommit(0, size, throw_on_failure(size, calloc(size, 1)));
 }
 
 void* sk_calloc(size_t size) {
     // TODO(b.kelemen): we should always use UncheckedCalloc but currently it
     // doesn't work as intended everywhere.
+    void* result;
 #if  defined(OS_IOS)
-    return calloc(1, size);
+    result = calloc(1, size);
 #else
-    void* result;
     // It's the responsibility of the caller to check the return value.
     ignore_result(base::UncheckedCalloc(size, 1, &result));
-    return result;
 #endif
+    if (result) {
+        prevent_overcommit(0, size, result);
+    }
+    return result;
 }