Add a UseCounter that measures the amount of memory used in PartitionAlloc

Source/wtf/PartitionAlloc.cpp

Index: Source/wtf/PartitionAlloc.cpp
diff --git a/Source/wtf/PartitionAlloc.cpp b/Source/wtf/PartitionAlloc.cpp
index 43fd01be3a08a82bcb8924c492edd71c1eff0245..6f3a19add76976fa988506d86aff3e4488bd7bb7 100644
--- a/Source/wtf/PartitionAlloc.cpp
+++ b/Source/wtf/PartitionAlloc.cpp
@@ -30,6 +30,7 @@
 
 #include "config.h"
 #include "wtf/PartitionAlloc.h"
+#include "wtf/Partitions.h"

[Chris Evans, 2015/04/02 15:53:01]

Hmm -- this introduces a circular dependency. Not a huge deal but I do try to
keep PartitionAlloc as dependency-free as possible.

Would it be possible to have the client register a callback via a new function
in PartitionAlloc.h?

[haraken, 2015/04/02 23:31:31]

Done.

 
 #include <string.h>
 
@@ -356,6 +357,7 @@ static ALWAYS_INLINE void* partitionAllocPartitionPages(PartitionRootBase* root,
         root->nextPartitionPage += totalSize;
         root->totalSizeOfCommittedPages += totalSize;
         ASSERT(root->totalSizeOfCommittedPages <= root->totalSizeOfSuperPages + root->totalSizeOfDirectMappedPages);
+        Partitions::recordMemoryUsageIfNeeded();

[Chris Evans, 2015/04/02 15:53:01]

To reduce minor code duplication, can we pull both the updating of the variable,
the ASSERT, and the firing of the callback into a new function, something like
partitionUpdateMemoryAccounting() ?

[haraken, 2015/04/02 23:31:32]

Done.

         return ret;
     }
 
@@ -370,6 +372,7 @@ static ALWAYS_INLINE void* partitionAllocPartitionPages(PartitionRootBase* root,
     root->totalSizeOfSuperPages += kSuperPageSize;
     root->totalSizeOfCommittedPages += totalSize;
     ASSERT(root->totalSizeOfCommittedPages <= root->totalSizeOfSuperPages + root->totalSizeOfDirectMappedPages);
+    Partitions::recordMemoryUsageIfNeeded();
 
     root->nextSuperPage = superPage + kSuperPageSize;
     char* ret = superPage + kPartitionPageSize;
@@ -615,6 +618,7 @@ static ALWAYS_INLINE void* partitionDirectMap(PartitionRootBase* root, int flags
     root->totalSizeOfCommittedPages += committedPageSize;
     root->totalSizeOfDirectMappedPages += committedPageSize;
     ASSERT(root->totalSizeOfCommittedPages <= root->totalSizeOfSuperPages + root->totalSizeOfDirectMappedPages);
+    Partitions::recordMemoryUsageIfNeeded();

[Chris Evans, 2015/04/02 15:53:01]

For consistency, we should probably call the callback whenever
totalSizeOfCommittedPages is called?

I don't see any calls directly after we've subtracted from the variable, so my
guess is that we've missed a place or two?

[haraken, 2015/04/02 23:31:31]

Done. Actually we don't need to report memory usage when we subtracted from the
variable (since we report the memory usage only when we see a new value high)
though.

 
     // TODO: we may want to let the operating system place these allocations
     // where it pleases. On 32-bit, this might limit address space