PartitionAlloc: Count direct mapped pages as committed

Source/wtf/PartitionAlloc.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 311 matching lines @@
     root->totalSizeOfCommittedPages += len;
 }
 
 static ALWAYS_INLINE void* partitionAllocPartitionPages(PartitionRootBase* root, int flags, uint16_t numPartitionPages)
 {
     ASSERT(!(reinterpret_cast<uintptr_t>(root->nextPartitionPage) % kPartitionPageSize));
     ASSERT(!(reinterpret_cast<uintptr_t>(root->nextPartitionPageEnd) % kPartitionPageSize));
     RELEASE_ASSERT(numPartitionPages <= kNumPartitionPagesPerSuperPage);
     size_t totalSize = kPartitionPageSize * numPartitionPages;
     root->totalSizeOfCommittedPages += totalSize;
+    if (root->totalSizeOfCommittedPages > kMaxPartitionSize)
+        partitionFull();
     size_t numPartitionPagesLeft = (root->nextPartitionPageEnd - root->nextPartitionPage) >> kPartitionPageShift;
     if (LIKELY(numPartitionPagesLeft >= numPartitionPages)) {
         // In this case, we can still hand out pages from the current super page
         // allocation.
         char* ret = root->nextPartitionPage;
         root->nextPartitionPage += totalSize;
         return ret;
     }
 
     // Need a new super page.
     root->totalSizeOfSuperPages += kSuperPageSize;
-    if (root->totalSizeOfSuperPages > kMaxPartitionSize)
-        partitionFull();
     char* requestedAddress = root->nextSuperPage;
     char* superPage = reinterpret_cast<char*>(allocPages(requestedAddress, kSuperPageSize, kSuperPageSize));
     if (UNLIKELY(!superPage)) {
         if (flags & PartitionAllocReturnNull)
             return 0;
         partitionOutOfMemory();
     }
     root->nextSuperPage = superPage + kSuperPageSize;
     char* ret = superPage + kPartitionPageSize;
     root->nextPartitionPage = ret + totalSize;
@@ skipping 216 matching lines @@
     // a bunch of system pages more than "size":
     // - The first few system pages are the partition page in which the super
     // page metadata is stored. We fault just one system page out of a partition
     // page sized clump.
     // - We add a trailing guard page.
     size_t mapSize = size + kPartitionPageSize + kSystemPageSize;
     // Round up to the allocation granularity.
     mapSize += kPageAllocationGranularityOffsetMask;
     mapSize &= kPageAllocationGranularityBaseMask;
 
+    root->totalSizeOfCommittedPages += size;

[Chris Evans, 2014/10/15 22:06:16]

I think we might as well try and be fully accurate: the metadata page will also
be committed so hows about "size + kSystemPageSize" ?

[Jens Widell, 2014/10/16 11:09:53]

Done.

+    if (root->totalSizeOfCommittedPages > kMaxPartitionSize)
+        partitionFull();
+
     // TODO: we may want to let the operating system place these allocations
     // where it pleases. On 32-bit, this might limit address space
     // fragmentation and on 64-bit, this might have useful savings for TLB
     // and page table overhead.
     // TODO: if upsizing realloc()s are common on large sizes, we could
     // consider over-allocating address space on 64-bit, "just in case".
     // TODO: consider pre-populating page tables (e.g. MAP_POPULATE on Linux,
     // MADV_WILLNEED on POSIX).
     // TODO: these pages will be zero-filled. Consider internalizing an
     // allocZeroed() API so we can avoid a memset() entirely in this case.
@@ skipping 36 matching lines @@
 }
 
 static ALWAYS_INLINE void partitionDirectUnmap(PartitionPage* page)
 {
     size_t unmapSize = partitionPageToDirectMapExtent(page)->mapSize;
 
     // Add on the size of the trailing guard page and preceeding partition
     // page.
     unmapSize += kPartitionPageSize + kSystemPageSize;
 
+    PartitionRootBase* root = partitionPageToRoot(page);
+    root->totalSizeOfCommittedPages -= page->bucket->slotSize;

[Chris Evans, 2014/10/15 22:06:16]

+ kSystemPageSize as per above?

[Jens Widell, 2014/10/16 11:09:53]

Done.

+
     ASSERT(!(unmapSize & kPageAllocationGranularityOffsetMask));
 
     char* ptr = reinterpret_cast<char*>(partitionPageToPointer(page));
     // Account for the mapping starting a partition page before the actual
     // allocation address.
     ptr -= kPartitionPageSize;
 
     freePages(ptr, unmapSize);
 }
 
@@ skipping 328 matching lines @@
     printf("total live: %zu bytes\n", totalLive);
     printf("total resident: %zu bytes\n", totalResident);
     printf("total freeable: %zu bytes\n", totalFreeable);
     fflush(stdout);
 }
 
 #endif // !NDEBUG
 
 } // namespace WTF