PartitionAlloc: fixes and improvements to large-chunk size tracking.

Source/wtf/PartitionAllocTest.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 633 matching lines @@
     // We only run the check when asserts are disabled because when they are
     // enabled, the allocated area is overwritten with an "uninitialized"
     // byte pattern.
     EXPECT_EQ(0, *(reinterpret_cast<char*>(newPtr) + (size - 1)));
 #endif
     partitionFreeGeneric(genericAllocator.root(), newPtr);
     partitionFreeGeneric(genericAllocator.root(), ptr3);
     partitionFreeGeneric(genericAllocator.root(), ptr4);
 
     // Can we allocate a massive (512MB) size?
-    ptr = partitionAllocGeneric(genericAllocator.root(), 512 * 1024 * 1024);
+    // Allocate 512MB, but +1, to test for cookie writing alignment issues.
+    ptr = partitionAllocGeneric(genericAllocator.root(), 512 * 1024 * 1024 + 1);
     partitionFreeGeneric(genericAllocator.root(), ptr);
 
     // Check a more reasonable, but still direct mapped, size.
     // Chop a system page and a byte off to test for rounding errors.
     size = 20 * 1024 * 1024;
     size -= kSystemPageSize;
     size -= 1;
     ptr = partitionAllocGeneric(genericAllocator.root(), size);
     char* charPtr = reinterpret_cast<char*>(ptr);
     *(charPtr + (size - 1)) = 'A';
@@ skipping 807 matching lines @@
         // Whilst we're here, allocate again and free with different ordering
         // to give a workout to our linked list code.
         ptr = partitionAllocGeneric(genericAllocator.root(), sizeSmaller);
         ptr2 = partitionAllocGeneric(genericAllocator.root(), sizeBigger);
         partitionFreeGeneric(genericAllocator.root(), ptr);
         partitionFreeGeneric(genericAllocator.root(), ptr2);
     }
 
     // This test checks large-but-not-quite-direct allocations.
     {
-        void* ptr = partitionAllocGeneric(genericAllocator.root(), 65537);
+        void* ptr = partitionAllocGeneric(genericAllocator.root(), 65536 + 1);
 
         {
             MockPartitionStatsDumper mockStatsDumperGeneric;
             partitionDumpStatsGeneric(genericAllocator.root(), "mock_generic_allocator", &mockStatsDumperGeneric);
             EXPECT_TRUE(mockStatsDumperGeneric.IsMemoryAllocationRecorded());
 
             size_t slotSize = 65536 + (65536 / kGenericNumBucketsPerOrder);
             const PartitionBucketMemoryStats* stats = mockStatsDumperGeneric.GetBucketStats(slotSize);
             EXPECT_TRUE(stats);
             EXPECT_TRUE(stats->isValid);
             EXPECT_FALSE(stats->isDirectMap);
             EXPECT_EQ(slotSize, stats->bucketSlotSize);
             EXPECT_EQ(65536 + kSystemPageSize, stats->activeBytes);
             EXPECT_EQ(slotSize, stats->residentBytes);
             EXPECT_EQ(0u, stats->decommittableBytes);
             EXPECT_EQ(1u, stats->numFullPages);
             EXPECT_EQ(0u, stats->numActivePages);
             EXPECT_EQ(0u, stats->numEmptyPages);
             EXPECT_EQ(0u, stats->numDecommittedPages);
         }
 
         partitionFreeGeneric(genericAllocator.root(), ptr);
+
+        void* ptr2 = partitionAllocGeneric(genericAllocator.root(), 65536 + kSystemPageSize + 1);
+        EXPECT_EQ(ptr, ptr2);
+
+        {
+            MockPartitionStatsDumper mockStatsDumperGeneric;
+            partitionDumpStatsGeneric(genericAllocator.root(), "mock_generic_allocator", &mockStatsDumperGeneric);
+            EXPECT_TRUE(mockStatsDumperGeneric.IsMemoryAllocationRecorded());
+
+            size_t slotSize = 65536 + (65536 / kGenericNumBucketsPerOrder);
+            const PartitionBucketMemoryStats* stats = mockStatsDumperGeneric.GetBucketStats(slotSize);
+            EXPECT_TRUE(stats);
+            EXPECT_TRUE(stats->isValid);
+            EXPECT_FALSE(stats->isDirectMap);
+            EXPECT_EQ(slotSize, stats->bucketSlotSize);
+            EXPECT_EQ(slotSize, stats->activeBytes);
+            EXPECT_EQ(slotSize, stats->residentBytes);
+            EXPECT_EQ(0u, stats->decommittableBytes);
+            EXPECT_EQ(1u, stats->numFullPages);
+            EXPECT_EQ(0u, stats->numActivePages);
+            EXPECT_EQ(0u, stats->numEmptyPages);
+            EXPECT_EQ(0u, stats->numDecommittedPages);
+        }
+
+        partitionFreeGeneric(genericAllocator.root(), ptr2);
     }
 
     TestShutdown();
 }
 
 // Tests the API to purge freeable memory.
 TEST(PartitionAllocTest, Purge)
 {
     TestSetup();
 
@@ skipping 49 matching lines @@
     EXPECT_EQ(32u, countLeadingZerosSizet(0u));
     EXPECT_EQ(31u, countLeadingZerosSizet(1u));
     EXPECT_EQ(1u, countLeadingZerosSizet(1u << 30));
     EXPECT_EQ(0u, countLeadingZerosSizet(1u << 31));
 #endif
 }
 
 } // namespace WTF
 
 #endif // !defined(MEMORY_TOOL_REPLACES_ALLOCATOR)