Index: third_party/tcmalloc/chromium/src/central_freelist.h |
diff --git a/third_party/tcmalloc/chromium/src/central_freelist.h b/third_party/tcmalloc/chromium/src/central_freelist.h |
index e09210ad73ee96830a8ad665f9c67080a616e4bb..4fd5799de9ab53a6458942edaa056b7b56e174b5 100644 |
--- a/third_party/tcmalloc/chromium/src/central_freelist.h |
+++ b/third_party/tcmalloc/chromium/src/central_freelist.h |
@@ -48,6 +48,11 @@ namespace tcmalloc { |
// Data kept per size-class in central cache. |
class CentralFreeList { |
public: |
+ // A CentralFreeList may be used before its constructor runs. |
+ // So we prevent lock_'s constructor from doing anything to the |
+ // lock_ state. |
+ CentralFreeList() : lock_(base::LINKER_INITIALIZED) { } |
+ |
void Init(size_t cl); |
// These methods all do internal locking. |
@@ -68,6 +73,12 @@ class CentralFreeList { |
// Returns the number of free objects in the transfer cache. |
int tc_length(); |
+ // Returns the memory overhead (internal fragmentation) attributable |
+ // to the freelist. This is memory lost when the size of elements |
+ // in a freelist doesn't exactly divide the page-size (an 8192-byte |
+ // page full of 5-byte objects would have 2 bytes memory overhead). |
+ size_t OverheadBytes(); |
+ |
private: |
// TransferCache is used to cache transfers of |
// sizemap.num_objects_to_move(size_class) back and forth between |
@@ -77,16 +88,16 @@ class CentralFreeList { |
void *tail; // Tail of chain of objects. |
}; |
- // A central cache freelist can have anywhere from 0 to kNumTransferEntries |
- // slots to put link list chains into. To keep memory usage bounded the total |
- // number of TCEntries across size classes is fixed. Currently each size |
- // class is initially given one TCEntry which also means that the maximum any |
- // one class can have is kNumClasses. |
+ // A central cache freelist can have anywhere from 0 to kMaxNumTransferEntries |
+ // slots to put link list chains into. |
#ifdef TCMALLOC_SMALL_BUT_SLOW |
// For the small memory model, the transfer cache is not used. |
- static const int kNumTransferEntries = 0; |
+ static const int kMaxNumTransferEntries = 0; |
#else |
- static const int kNumTransferEntries = kNumClasses; |
+ // Starting point for the the maximum number of entries in the transfer cache. |
+ // This actual maximum for a given size class may be lower than this |
+ // maximum value. |
+ static const int kMaxNumTransferEntries = 64; |
#endif |
// REQUIRES: lock_ is held |
@@ -145,12 +156,15 @@ class CentralFreeList { |
size_t size_class_; // My size class |
Span empty_; // Dummy header for list of empty spans |
Span nonempty_; // Dummy header for list of non-empty spans |
+ size_t num_spans_; // Number of spans in empty_ plus nonempty_ |
size_t counter_; // Number of free objects in cache entry |
- // Here we reserve space for TCEntry cache slots. Since one size class can |
- // end up getting all the TCEntries quota in the system we just preallocate |
- // sufficient number of entries here. |
- TCEntry tc_slots_[kNumTransferEntries]; |
+ // Here we reserve space for TCEntry cache slots. Space is preallocated |
+ // for the largest possible number of entries than any one size class may |
+ // accumulate. Not all size classes are allowed to accumulate |
+ // kMaxNumTransferEntries, so there is some wasted space for those size |
+ // classes. |
+ TCEntry tc_slots_[kMaxNumTransferEntries]; |
// Number of currently used cached entries in tc_slots_. This variable is |
// updated under a lock but can be read without one. |
@@ -159,6 +173,8 @@ class CentralFreeList { |
// adaptive value that is increased if there is lots of traffic |
// on a given size class. |
int32_t cache_size_; |
+ // Maximum size of the cache for a given size class. |
+ int32_t max_cache_size_; |
}; |
// Pads each CentralCache object to multiple of 64 bytes. Since some |