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authorrobot-piglet <robot-piglet@yandex-team.com>2023-12-02 01:45:21 +0300
committerrobot-piglet <robot-piglet@yandex-team.com>2023-12-02 02:42:50 +0300
commit9c43d58f75cf086b744cf4fe2ae180e8f37e4a0c (patch)
tree9f88a486917d371d099cd712efd91b4c122d209d /contrib/deprecated/galloc/tcmalloc.cc
parent32fb6dda1feb24f9ab69ece5df0cb9ec238ca5e6 (diff)
downloadydb-9c43d58f75cf086b744cf4fe2ae180e8f37e4a0c.tar.gz
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diff --git a/contrib/deprecated/galloc/tcmalloc.cc b/contrib/deprecated/galloc/tcmalloc.cc
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+// Copyright (c) 2005, 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
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// ---
+// Author: Sanjay Ghemawat <opensource@google.com>
+//
+// A malloc that uses a per-thread cache to satisfy small malloc requests.
+// (The time for malloc/free of a small object drops from 300 ns to 50 ns.)
+//
+// See doc/tcmalloc.html for a high-level
+// description of how this malloc works.
+//
+// SYNCHRONIZATION
+// 1. The thread-specific lists are accessed without acquiring any locks.
+// This is safe because each such list is only accessed by one thread.
+// 2. We have a lock per central free-list, and hold it while manipulating
+// the central free list for a particular size.
+// 3. The central page allocator is protected by "pageheap_lock".
+// 4. The pagemap (which maps from page-number to descriptor),
+// can be read without holding any locks, and written while holding
+// the "pageheap_lock".
+//
+// This multi-threaded access to the pagemap is safe for fairly
+// subtle reasons. We basically assume that when an object X is
+// allocated by thread A and deallocated by thread B, there must
+// have been appropriate synchronization in the handoff of object
+// X from thread A to thread B.
+//
+// TODO: Bias reclamation to larger addresses
+// TODO: implement mallinfo/mallopt
+// TODO: Better testing
+// TODO: Return memory to system
+//
+// 9/28/2003 (new page-level allocator replaces ptmalloc2):
+// * malloc/free of small objects goes from ~300 ns to ~50 ns.
+// * allocation of a reasonably complicated struct
+// goes from about 1100 ns to about 300 ns.
+
+#include <new>
+
+#include <stdio.h>
+#include <stddef.h>
+
+#if defined(_linux_)
+ #include <malloc.h>
+#endif
+
+#if defined(_darwin_)
+ #include <malloc/malloc.h>
+#endif
+
+#include <string.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdarg.h>
+
+#include "commandlineflags.h"
+#include "malloc_hook.h"
+#include "malloc_extension.h"
+#include "stacktrace.h"
+#include "internal_logging.h"
+#include "internal_spinlock.h"
+#include "pagemap.h"
+#include "system-alloc.h"
+
+#include <util/system/tls.h>
+
+#if defined(Y_HAVE_FAST_POD_TLS)
+Y_POD_STATIC_THREAD(void*) my_heap((void*)0);
+#endif
+
+static inline void SetHeap(pthread_key_t key, const void* pointer) {
+ pthread_setspecific(key, pointer);
+
+#if defined(Y_HAVE_FAST_POD_TLS)
+ my_heap = (void*)pointer;
+#endif
+}
+
+static inline void* GetHeap(pthread_key_t key) {
+#if defined(Y_HAVE_FAST_POD_TLS)
+ return my_heap;
+#else
+ return pthread_getspecific(key);
+#endif
+}
+
+//-------------------------------------------------------------------
+// Configuration
+//-------------------------------------------------------------------
+
+// Not all possible combinations of the following parameters make
+// sense. In particular, if kMaxSize increases, you may have to
+// increase kNumClasses as well.
+static const size_t kPageShift = 12;
+static const size_t kPageSize = 1 << kPageShift;
+static const size_t kMaxSize = 8u * kPageSize;
+static const size_t kAlignShift = 4;
+static const size_t kAlignment = 1 << kAlignShift;
+static const size_t kNumClasses = 170;
+
+// Allocates a big block of memory for the pagemap once we reach more than
+// 128MB
+static const size_t kPageMapBigAllocationThreshold = 128 << 20;
+
+// Minimum number of pages to fetch from system at a time. Must be
+// significantly bigger than kBlockSize to amortize system-call
+// overhead, and also to reduce external fragementation. Also, we
+// should keep this value big because various incarnations of Linux
+// have small limits on the number of mmap() regions per
+// address-space.
+static const size_t kMinSystemAlloc = 1 << (20 - kPageShift);
+
+// Number of objects to move between a per-thread list and a central
+// list in one shot. We want this to be not too small so we can
+// amortize the lock overhead for accessing the central list. Making
+// it too big may temporarily cause unnecessary memory wastage in the
+// per-thread free list until the scavenger cleans up the list.
+static int num_objects_to_move[kNumClasses];
+
+// Maximum length we allow a per-thread free-list to have before we
+// move objects from it into the corresponding central free-list. We
+// want this big to avoid locking the central free-list too often. It
+// should not hurt to make this list somewhat big because the
+// scavenging code will shrink it down when its contents are not in use.
+static const int kMaxFreeListLength = 256;
+
+// Lower and upper bounds on the per-thread cache sizes
+static const size_t kMinThreadCacheSize = kMaxSize * 2;
+static const size_t kMaxThreadCacheSize = 2 << 20;
+
+// Default bound on the total amount of thread caches
+static const size_t kDefaultOverallThreadCacheSize = 16 << 20;
+
+// For all span-lengths < kMaxPages we keep an exact-size list.
+// REQUIRED: kMaxPages >= kMinSystemAlloc;
+static const size_t kMaxPages = kMinSystemAlloc;
+
+/* The smallest prime > 2^n */
+static int primes_list[] = {
+ // Small values might cause high rates of sampling
+ // and hence commented out.
+ // 2, 5, 11, 17, 37, 67, 131, 257,
+ // 521, 1031, 2053, 4099, 8209, 16411,
+ 32771, 65537, 131101, 262147, 524309, 1048583,
+ 2097169, 4194319, 8388617, 16777259, 33554467 };
+
+// Twice the approximate gap between sampling actions.
+// I.e., we take one sample approximately once every
+// tcmalloc_sample_parameter/2
+// bytes of allocation, i.e., ~ once every 128KB.
+// Must be a prime number.
+DEFINE_int64(tcmalloc_sample_parameter, 262147,
+ "Twice the approximate gap between sampling actions."
+ " Must be a prime number. Otherwise will be rounded up to a "
+ " larger prime number");
+static size_t sample_period = 262147;
+// Protects sample_period above
+static SpinLock sample_period_lock = SPINLOCK_INITIALIZER;
+
+//-------------------------------------------------------------------
+// Mapping from size to size_class and vice versa
+//-------------------------------------------------------------------
+
+// A pair of arrays we use for implementing the mapping from a size to
+// its size class. Indexed by "floor(lg(size))".
+static const int kSizeBits = 8 * sizeof(size_t);
+static unsigned char size_base[kSizeBits];
+static unsigned char size_shift[kSizeBits];
+
+// Mapping from size class to size
+static size_t class_to_size[kNumClasses];
+
+// Mapping from size class to number of pages to allocate at a time
+static size_t class_to_pages[kNumClasses];
+
+
+
+// TransferCache is used to cache transfers of num_objects_to_move[size_class]
+// back and forth between thread caches and the central cache for a given size
+// class.
+struct TCEntry {
+ void *head; // Head of chain of objects.
+ 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.
+static const int kNumTransferEntries = kNumClasses;
+
+// Return floor(log2(n)) for n > 0.
+#if (defined __i386__ || defined __x86_64__) && defined __GNUC__
+static inline int LgFloor(size_t n) {
+ // "ro" for the input spec means the input can come from either a
+ // register ("r") or offsetable memory ("o").
+ size_t result;
+ __asm__("bsr %1, %0"
+ : "=r" (result) // Output spec
+ : "ro" (n) // Input spec
+ : "cc" // Clobbers condition-codes
+ );
+ return result;
+}
+#else
+// Note: the following only works for "n"s that fit in 32-bits, but
+// that is fine since we only use it for small sizes.
+static inline int LgFloor(size_t n) {
+ int log = 0;
+ for (int i = 4; i >= 0; --i) {
+ int shift = (1 << i);
+ size_t x = n >> shift;
+ if (x != 0) {
+ n = x;
+ log += shift;
+ }
+ }
+ ASSERT(n == 1);
+ return log;
+}
+#endif
+
+
+// Some very basic linked list functions for dealing with using void * as
+// storage.
+
+static inline void *SLL_Next(void *t) {
+ return *(reinterpret_cast<void**>(t));
+}
+
+static inline void SLL_SetNext(void *t, void *n) {
+ *(reinterpret_cast<void**>(t)) = n;
+}
+
+static inline void SLL_Push(void **list, void *element) {
+ SLL_SetNext(element, *list);
+ *list = element;
+}
+
+static inline void *SLL_Pop(void **list) {
+ void *result = *list;
+ *list = SLL_Next(*list);
+ return result;
+}
+
+
+// Remove N elements from a linked list to which head points. head will be
+// modified to point to the new head. start and end will point to the first
+// and last nodes of the range. Note that end will point to NULL after this
+// function is called.
+static inline void SLL_PopRange(void **head, int N, void **start, void **end) {
+ if (N == 0) {
+ *start = NULL;
+ *end = NULL;
+ return;
+ }
+
+ void *tmp = *head;
+ for (int i = 1; i < N; ++i) {
+ tmp = SLL_Next(tmp);
+ }
+
+ *start = *head;
+ *end = tmp;
+ *head = SLL_Next(tmp);
+ // Unlink range from list.
+ SLL_SetNext(tmp, NULL);
+}
+
+static inline void SLL_PushRange(void **head, void *start, void *end) {
+ if (!start) return;
+ SLL_SetNext(end, *head);
+ *head = start;
+}
+
+static inline size_t SLL_Size(void *head) {
+ int count = 0;
+ while (head) {
+ count++;
+ head = SLL_Next(head);
+ }
+ return count;
+}
+
+// Setup helper functions.
+
+static inline size_t SizeClass(size_t size) {
+ if (size == 0) size = 1;
+ const size_t lg = LgFloor(size);
+ const size_t align = size_shift[lg];
+ return static_cast<size_t>(size_base[lg]) + ((size-1) >> align);
+}
+
+// Get the byte-size for a specified class
+static inline size_t ByteSizeForClass(size_t cl) {
+ return class_to_size[cl];
+}
+
+
+static int NumMoveSize(size_t size) {
+ if (size == 0) return 0;
+ // Use approx 64k transfers between thread and central caches.
+ int num = static_cast<int>(64.0 * 1024.0 / size);
+ if (num < 2) num = 2;
+ // Clamp well below kMaxFreeListLength to avoid ping pong between central
+ // and thread caches.
+ if (num > static_cast<int>(0.8 * kMaxFreeListLength))
+ num = static_cast<int>(0.8 * kMaxFreeListLength);
+
+ // Also, avoid bringing in too many objects into small object free
+ // lists. There are lots of such lists, and if we allow each one to
+ // fetch too many at a time, we end up having to scavenge too often
+ // (especially when there are lots of threads and each thread gets a
+ // small allowance for its thread cache).
+ //
+ // TODO: Make thread cache free list sizes dynamic so that we do not
+ // have to equally divide a fixed resource amongst lots of threads.
+ if (num > 32) num = 32;
+
+ return num;
+}
+
+// Initialize the mapping arrays
+static void InitSizeClasses() {
+ // Special initialization for small sizes
+ for (unsigned int lg = 0; lg < kAlignShift; lg++) {
+ size_base[lg] = 1;
+ size_shift[lg] = kAlignShift;
+ }
+
+ int next_class = 1;
+ int alignshift = kAlignShift;
+ int last_lg = -1;
+ for (size_t size = kAlignment; size <= kMaxSize; size += (1 << alignshift)) {
+ int lg = LgFloor(size);
+ if (lg > last_lg) {
+ // Increase alignment every so often.
+ //
+ // Since we double the alignment every time size doubles and
+ // size >= 128, this means that space wasted due to alignment is
+ // at most 16/128 i.e., 12.5%. Plus we cap the alignment at 256
+ // bytes, so the space wasted as a percentage starts falling for
+ // sizes > 2K.
+ if ((lg >= 7) && (alignshift < 8)) {
+ alignshift++;
+ }
+ size_base[lg] = next_class - ((size-1) >> alignshift);
+ size_shift[lg] = alignshift;
+ }
+
+ class_to_size[next_class] = size;
+ last_lg = lg;
+
+ next_class++;
+ }
+ if ((size_t)next_class >= kNumClasses) {
+ MESSAGE("used up too many size classes: %d\n", next_class);
+ abort();
+ }
+
+ // Initialize the number of pages we should allocate to split into
+ // small objects for a given class.
+ for (size_t cl = 1; cl < (size_t)next_class; cl++) {
+ // Allocate enough pages so leftover is less than 1/8 of total.
+ // This bounds wasted space to at most 12.5%.
+ size_t psize = kPageSize;
+ const size_t s = class_to_size[cl];
+ while ((psize % s) > (psize >> 3)) {
+ psize += kPageSize;
+ }
+ class_to_pages[cl] = psize >> kPageShift;
+ }
+
+ // Double-check sizes just to be safe
+ for (size_t size = 0; size <= kMaxSize; size++) {
+ const unsigned int sc = SizeClass(size);
+ if (sc == 0) {
+ MESSAGE("Bad size class %u for %" PRIuS "\n", sc, size);
+ abort();
+ }
+ if (sc > 1 && size <= class_to_size[sc-1]) {
+ MESSAGE("Allocating unnecessarily large class %u for %" PRIuS
+ "\n", sc, size);
+ abort();
+ }
+ if (sc >= kNumClasses) {
+ MESSAGE("Bad size class %u for %" PRIuS "\n", sc, size);
+ abort();
+ }
+ const size_t s = class_to_size[sc];
+ if (size > s) {
+ MESSAGE("Bad size %" PRIuS " for %" PRIuS " (sc = %u)\n", s, size, sc);
+ abort();
+ }
+ if (s == 0) {
+ MESSAGE("Bad size %" PRIuS " for %" PRIuS " (sc = %u)\n", s, size, sc);
+ abort();
+ }
+ }
+
+ // Initialize the num_objects_to_move array.
+ for (size_t cl = 1; cl < kNumClasses; ++cl) {
+ num_objects_to_move[cl] = NumMoveSize(ByteSizeForClass(cl));
+ }
+}
+
+// -------------------------------------------------------------------------
+// Simple allocator for objects of a specified type. External locking
+// is required before accessing one of these objects.
+// -------------------------------------------------------------------------
+
+// Metadata allocator -- keeps stats about how many bytes allocated
+static uint64_t metadata_system_bytes = 0;
+static void* MetaDataAlloc(size_t bytes) {
+ void* result = TCMalloc_SystemAlloc(bytes);
+ if (result != NULL) {
+ metadata_system_bytes += bytes;
+ }
+ return result;
+}
+
+template <class T>
+class PageHeapAllocator {
+ private:
+ // How much to allocate from system at a time
+ static const int kAllocIncrement = 128 << 10;
+
+ // Aligned size of T
+ static const size_t kAlignedSize
+ = (((sizeof(T) + kAlignment - 1) / kAlignment) * kAlignment);
+
+ // Free area from which to carve new objects
+ char* free_area_;
+ size_t free_avail_;
+
+ // Free list of already carved objects
+ void* free_list_;
+
+ // Number of allocated but unfreed objects
+ int inuse_;
+
+ public:
+ void Init() {
+ ASSERT(kAlignedSize <= kAllocIncrement);
+ inuse_ = 0;
+ free_area_ = NULL;
+ free_avail_ = 0;
+ free_list_ = NULL;
+ // Reserve some space at the beginning to avoid fragmentation.
+ Delete(New());
+ }
+
+ T* New() {
+ // Consult free list
+ void* result;
+ if (free_list_ != NULL) {
+ result = free_list_;
+ free_list_ = *(reinterpret_cast<void**>(result));
+ } else {
+ if (free_avail_ < kAlignedSize) {
+ // Need more room
+ free_area_ = reinterpret_cast<char*>(MetaDataAlloc(kAllocIncrement));
+ if (free_area_ == NULL) abort();
+ free_avail_ = kAllocIncrement;
+ }
+ result = free_area_;
+ free_area_ += kAlignedSize;
+ free_avail_ -= kAlignedSize;
+ }
+ inuse_++;
+ return reinterpret_cast<T*>(result);
+ }
+
+ void Delete(T* p) {
+ *(reinterpret_cast<void**>(p)) = free_list_;
+ free_list_ = p;
+ inuse_--;
+ }
+
+ int inuse() const { return inuse_; }
+};
+
+// -------------------------------------------------------------------------
+// Span - a contiguous run of pages
+// -------------------------------------------------------------------------
+
+// Type that can hold a page number
+typedef uintptr_t PageID;
+
+// Type that can hold the length of a run of pages
+typedef uintptr_t Length;
+
+// Convert byte size into pages
+static inline Length pages(size_t bytes) {
+ return ((bytes + kPageSize - 1) >> kPageShift);
+}
+
+// Convert a user size into the number of bytes that will actually be
+// allocated
+static size_t AllocationSize(size_t bytes) {
+ if (bytes > kMaxSize) {
+ // Large object: we allocate an integral number of pages
+ return pages(bytes) << kPageShift;
+ } else {
+ // Small object: find the size class to which it belongs
+ return ByteSizeForClass(SizeClass(bytes));
+ }
+}
+
+// Information kept for a span (a contiguous run of pages).
+struct Span {
+ PageID start; // Starting page number
+ Length length; // Number of pages in span
+ Span* next; // Used when in link list
+ Span* prev; // Used when in link list
+ void* objects; // Linked list of free objects
+ unsigned int free : 1; // Is the span free
+ unsigned int sample : 1; // Sampled object?
+ unsigned int sizeclass : 8; // Size-class for small objects (or 0)
+ unsigned int refcount : 11; // Number of non-free objects
+
+#undef SPAN_HISTORY
+#ifdef SPAN_HISTORY
+ // For debugging, we can keep a log events per span
+ int nexthistory;
+ char history[64];
+ int value[64];
+#endif
+};
+
+#ifdef SPAN_HISTORY
+void Event(Span* span, char op, int v = 0) {
+ span->history[span->nexthistory] = op;
+ span->value[span->nexthistory] = v;
+ span->nexthistory++;
+ if (span->nexthistory == sizeof(span->history)) span->nexthistory = 0;
+}
+#else
+#define Event(s,o,v) ((void) 0)
+#endif
+
+// Allocator/deallocator for spans
+static PageHeapAllocator<Span> span_allocator;
+static Span* NewSpan(PageID p, Length len) {
+ Span* result = span_allocator.New();
+ memset(result, 0, sizeof(*result));
+ result->start = p;
+ result->length = len;
+#ifdef SPAN_HISTORY
+ result->nexthistory = 0;
+#endif
+ return result;
+}
+
+static void DeleteSpan(Span* span) {
+#ifndef NDEBUG
+ // In debug mode, trash the contents of deleted Spans
+ memset(span, 0x3f, sizeof(*span));
+#endif
+ span_allocator.Delete(span);
+}
+
+// -------------------------------------------------------------------------
+// Doubly linked list of spans.
+// -------------------------------------------------------------------------
+
+static void DLL_Init(Span* list) {
+ list->next = list;
+ list->prev = list;
+}
+
+static void DLL_Remove(Span* span) {
+ span->prev->next = span->next;
+ span->next->prev = span->prev;
+ span->prev = NULL;
+ span->next = NULL;
+}
+
+static inline bool DLL_IsEmpty(const Span* list) {
+ return list->next == list;
+}
+
+static unsigned int DLL_Length(const Span* list) {
+ unsigned int result = 0;
+ for (Span* s = list->next; s != list; s = s->next) {
+ result++;
+ }
+ return result;
+}
+
+#if 0 /* Not needed at the moment -- causes compiler warnings if not used */
+static void DLL_Print(const char* label, const Span* list) {
+ MESSAGE("%-10s %p:", label, list);
+ for (const Span* s = list->next; s != list; s = s->next) {
+ MESSAGE(" <%p,%u,%u>", s, s->start, s->length);
+ }
+ MESSAGE("\n");
+}
+#endif
+
+static void DLL_Prepend(Span* list, Span* span) {
+ ASSERT(span->next == NULL);
+ ASSERT(span->prev == NULL);
+ span->next = list->next;
+ span->prev = list;
+ list->next->prev = span;
+ list->next = span;
+}
+
+static void DLL_InsertOrdered(Span* list, Span* span) {
+ ASSERT(span->next == NULL);
+ ASSERT(span->prev == NULL);
+ // Look for appropriate place to insert
+ Span* x = list;
+ while ((x->next != list) && (x->next->start < span->start)) {
+ x = x->next;
+ }
+ span->next = x->next;
+ span->prev = x;
+ x->next->prev = span;
+ x->next = span;
+}
+
+// -------------------------------------------------------------------------
+// Stack traces kept for sampled allocations
+// The following state is protected by pageheap_lock_.
+// -------------------------------------------------------------------------
+
+static const int kMaxStackDepth = 31;
+struct StackTrace {
+ uintptr_t size; // Size of object
+ int depth; // Number of PC values stored in array below
+ void* stack[kMaxStackDepth];
+};
+static PageHeapAllocator<StackTrace> stacktrace_allocator;
+static Span sampled_objects;
+
+// Linked list of stack traces recorded every time we allocated memory
+// from the system. Useful for finding allocation sites that cause
+// increase in the footprint of the system. The linked list pointer
+// is stored in trace->stack[kMaxStackDepth-1].
+static StackTrace* growth_stacks = NULL;
+
+// -------------------------------------------------------------------------
+// Map from page-id to per-page data
+// -------------------------------------------------------------------------
+
+// We use PageMap2<> for 32-bit and PageMap3<> for 64-bit machines.
+
+// Selector class -- general selector uses 3-level map
+template <int BITS> class MapSelector {
+ public:
+ typedef TCMalloc_PageMap3<BITS-kPageShift> Type;
+};
+
+// A two-level map for 32-bit machines
+template <> class MapSelector<32> {
+ public:
+ typedef TCMalloc_PageMap2<32-kPageShift> Type;
+};
+
+// -------------------------------------------------------------------------
+// Page-level allocator
+// * Eager coalescing
+//
+// Heap for page-level allocation. We allow allocating and freeing a
+// contiguous runs of pages (called a "span").
+// -------------------------------------------------------------------------
+
+class TCMalloc_PageHeap {
+ public:
+ TCMalloc_PageHeap();
+
+ // Allocate a run of "n" pages. Returns zero if out of memory.
+ // Caller should not pass "n == 0" -- instead, n should have
+ // been rounded up already.
+ Span* New(Length n);
+
+ // Delete the span "[p, p+n-1]".
+ // REQUIRES: span was returned by earlier call to New() and
+ // has not yet been deleted.
+ void Delete(Span* span);
+
+ // Mark an allocated span as being used for small objects of the
+ // specified size-class.
+ // REQUIRES: span was returned by an earlier call to New()
+ // and has not yet been deleted.
+ void RegisterSizeClass(Span* span, size_t sc);
+
+ // Split an allocated span into two spans: one of length "n" pages
+ // followed by another span of length "span->length - n" pages.
+ // Modifies "*span" to point to the first span of length "n" pages.
+ // Returns a pointer to the second span.
+ //
+ // REQUIRES: "0 < n < span->length"
+ // REQUIRES: !span->free
+ // REQUIRES: span->sizeclass == 0
+ Span* Split(Span* span, Length n);
+
+ // Return the descriptor for the specified page.
+ inline Span* GetDescriptor(PageID p) const {
+ return reinterpret_cast<Span*>(pagemap_.get(p));
+ }
+
+ // Dump state to stderr
+ void Dump(TCMalloc_Printer* out);
+
+ // Return number of bytes allocated from system
+ inline uint64_t SystemBytes() const { return system_bytes_; }
+
+ // Return number of free bytes in heap
+ uint64_t FreeBytes() const {
+ return (static_cast<uint64_t>(free_pages_) << kPageShift);
+ }
+
+ bool Check();
+ bool CheckList(Span* list, Length min_pages, Length max_pages);
+
+ private:
+ // Pick the appropriate map type based on pointer size
+ typedef MapSelector<8*sizeof(uintptr_t)>::Type PageMap;
+ PageMap pagemap_;
+
+ // List of free spans of length >= kMaxPages
+ Span large_;
+
+ // Array mapping from span length to a doubly linked list of free spans
+ Span free_[kMaxPages];
+
+ // Number of pages kept in free lists
+ uintptr_t free_pages_;
+
+ // Bytes allocated from system
+ uint64_t system_bytes_;
+
+ bool GrowHeap(Length n);
+
+ // REQUIRES span->length >= n
+ // Remove span from its free list, and move any leftover part of
+ // span into appropriate free lists. Also update "span" to have
+ // length exactly "n" and mark it as non-free so it can be returned
+ // to the client.
+ void Carve(Span* span, Length n);
+
+ void RecordSpan(Span* span) {
+ pagemap_.set(span->start, span);
+ if (span->length > 1) {
+ pagemap_.set(span->start + span->length - 1, span);
+ }
+ }
+};
+
+TCMalloc_PageHeap::TCMalloc_PageHeap() : pagemap_(MetaDataAlloc),
+ free_pages_(0),
+ system_bytes_(0) {
+ DLL_Init(&large_);
+ for (unsigned int i = 0; i < kMaxPages; i++) {
+ DLL_Init(&free_[i]);
+ }
+}
+
+Span* TCMalloc_PageHeap::New(Length n) {
+ ASSERT(Check());
+
+ // n==0 occurs iff pages() overflowed when we added kPageSize-1 to n
+ if (n == 0) return NULL;
+
+ // Find first size >= n that has a non-empty list
+ for (Length s = n; s < kMaxPages; s++) {
+ if (!DLL_IsEmpty(&free_[s])) {
+ Span* result = free_[s].next;
+ Carve(result, n);
+ ASSERT(Check());
+ free_pages_ -= n;
+ return result;
+ }
+ }
+
+ // Look in large list. If we first do not find something, we try to
+ // grow the heap and try again.
+ for (int i = 0; i < 2; i++) {
+ // find the best span (closest to n in size)
+ Span *best = NULL;
+ for (Span* span = large_.next; span != &large_; span = span->next) {
+ if (span->length >= n &&
+ (best == NULL || span->length < best->length)) {
+ best = span;
+ }
+ }
+ if (best != NULL) {
+ Carve(best, n);
+ ASSERT(Check());
+ free_pages_ -= n;
+ return best;
+ }
+ if (i == 0) {
+ // Nothing suitable in large list. Grow the heap and look again.
+ if (!GrowHeap(n)) {
+ ASSERT(Check());
+ return NULL;
+ }
+ }
+ }
+ return NULL;
+}
+
+Span* TCMalloc_PageHeap::Split(Span* span, Length n) {
+ ASSERT(0 < n);
+ ASSERT(n < span->length);
+ ASSERT(!span->free);
+ ASSERT(span->sizeclass == 0);
+ Event(span, 'T', n);
+
+ const int extra = span->length - n;
+ Span* leftover = NewSpan(span->start + n, extra);
+ Event(leftover, 'U', extra);
+ RecordSpan(leftover);
+ pagemap_.set(span->start + n - 1, span); // Update map from pageid to span
+ span->length = n;
+
+ return leftover;
+}
+
+void TCMalloc_PageHeap::Carve(Span* span, Length n) {
+ ASSERT(n > 0);
+ DLL_Remove(span);
+ span->free = 0;
+ Event(span, 'A', n);
+
+ const int extra = span->length - n;
+ ASSERT(extra >= 0);
+ if (extra > 0) {
+ Span* leftover = NewSpan(span->start + n, extra);
+ leftover->free = 1;
+ Event(leftover, 'S', extra);
+ RecordSpan(leftover);
+ if ((unsigned int)extra < kMaxPages) {
+ DLL_Prepend(&free_[extra], leftover);
+ } else {
+ DLL_InsertOrdered(&large_, leftover);
+ }
+ span->length = n;
+ pagemap_.set(span->start + n - 1, span);
+ }
+}
+
+void TCMalloc_PageHeap::Delete(Span* span) {
+ ASSERT(Check());
+ ASSERT(!span->free);
+ ASSERT(span->length > 0);
+ ASSERT(GetDescriptor(span->start) == span);
+ ASSERT(GetDescriptor(span->start + span->length - 1) == span);
+ span->sizeclass = 0;
+ span->sample = 0;
+
+ // Coalesce -- we guarantee that "p" != 0, so no bounds checking
+ // necessary. We do not bother resetting the stale pagemap
+ // entries for the pieces we are merging together because we only
+ // care about the pagemap entries for the boundaries.
+ const PageID p = span->start;
+ const Length n = span->length;
+ Span* prev = GetDescriptor(p-1);
+ if (prev != NULL && prev->free) {
+ // Merge preceding span into this span
+ ASSERT(prev->start + prev->length == p);
+ const Length len = prev->length;
+ DLL_Remove(prev);
+ DeleteSpan(prev);
+ span->start -= len;
+ span->length += len;
+ pagemap_.set(span->start, span);
+ Event(span, 'L', len);
+ }
+ Span* next = GetDescriptor(p+n);
+ if (next != NULL && next->free) {
+ // Merge next span into this span
+ ASSERT(next->start == p+n);
+ const Length len = next->length;
+ DLL_Remove(next);
+ DeleteSpan(next);
+ span->length += len;
+ pagemap_.set(span->start + span->length - 1, span);
+ Event(span, 'R', len);
+ }
+
+ Event(span, 'D', span->length);
+ span->free = 1;
+ if (span->length < kMaxPages) {
+ DLL_Prepend(&free_[span->length], span);
+ } else {
+ DLL_InsertOrdered(&large_, span);
+ }
+ free_pages_ += n;
+
+ ASSERT(Check());
+}
+
+void TCMalloc_PageHeap::RegisterSizeClass(Span* span, size_t sc) {
+ // Associate span object with all interior pages as well
+ ASSERT(!span->free);
+ ASSERT(GetDescriptor(span->start) == span);
+ ASSERT(GetDescriptor(span->start+span->length-1) == span);
+ Event(span, 'C', sc);
+ span->sizeclass = sc;
+ for (Length i = 1; i < span->length-1; i++) {
+ pagemap_.set(span->start+i, span);
+ }
+}
+
+void TCMalloc_PageHeap::Dump(TCMalloc_Printer* out) {
+ int nonempty_sizes = 0;
+ for (unsigned int s = 0; s < kMaxPages; s++) {
+ if (!DLL_IsEmpty(&free_[s])) nonempty_sizes++;
+ }
+ out->printf("------------------------------------------------\n");
+ out->printf("PageHeap: %d sizes; %6.1f MB free\n", nonempty_sizes,
+ (static_cast<double>(free_pages_) * kPageSize) / 1048576.0);
+ out->printf("------------------------------------------------\n");
+ uint64_t cumulative = 0;
+ for (unsigned int s = 0; s < kMaxPages; s++) {
+ if (!DLL_IsEmpty(&free_[s])) {
+ const unsigned int list_length = DLL_Length(&free_[s]);
+ uint64_t s_pages = s * list_length;
+ cumulative += s_pages;
+ out->printf("%6u pages * %6u spans ~ %6.1f MB; %6.1f MB cum\n",
+ s, list_length,
+ (s_pages << kPageShift) / 1048576.0,
+ (cumulative << kPageShift) / 1048576.0);
+ }
+ }
+
+ uint64_t large_pages = 0;
+ unsigned int large_spans = 0;
+ for (Span* s = large_.next; s != &large_; s = s->next) {
+ out->printf(" [ %6" PRIuS " pages ]\n", s->length);
+ large_pages += s->length;
+ large_spans++;
+ }
+ cumulative += large_pages;
+ out->printf(">255 large * %6u spans ~ %6.1f MB; %6.1f MB cum\n",
+ large_spans,
+ (large_pages << kPageShift) / 1048576.0,
+ (cumulative << kPageShift) / 1048576.0);
+}
+
+static void RecordGrowth(size_t growth) {
+ StackTrace* t = stacktrace_allocator.New();
+ t->depth = GetStackTrace(t->stack, kMaxStackDepth-1, 3);
+ t->size = growth;
+ t->stack[kMaxStackDepth-1] = reinterpret_cast<void*>(growth_stacks);
+ growth_stacks = t;
+}
+
+bool TCMalloc_PageHeap::GrowHeap(Length n) {
+ ASSERT(kMaxPages >= kMinSystemAlloc);
+ Length ask = (n>kMinSystemAlloc) ? n : static_cast<Length>(kMinSystemAlloc);
+ void* ptr = TCMalloc_SystemAlloc(ask << kPageShift, kPageSize);
+ if (ptr == NULL) {
+ if (n < ask) {
+ // Try growing just "n" pages
+ ask = n;
+ ptr = TCMalloc_SystemAlloc(ask << kPageShift, kPageSize);
+ }
+ if (ptr == NULL) return false;
+ }
+ RecordGrowth(ask << kPageShift);
+
+ uint64_t old_system_bytes = system_bytes_;
+ system_bytes_ += (ask << kPageShift);
+ const PageID p = reinterpret_cast<uintptr_t>(ptr) >> kPageShift;
+ ASSERT(p > 0);
+
+ // If we have already a lot of pages allocated, just pre allocate a bunch of
+ // memory for the page map. This prevents fragmentation by pagemap metadata
+ // when a program keeps allocating and freeing large blocks.
+
+ if (old_system_bytes < kPageMapBigAllocationThreshold
+ && system_bytes_ >= kPageMapBigAllocationThreshold) {
+ pagemap_.PreallocateMoreMemory();
+ }
+
+ // Make sure pagemap_ has entries for all of the new pages.
+ // Plus ensure one before and one after so coalescing code
+ // does not need bounds-checking.
+ if (pagemap_.Ensure(p-1, ask+2)) {
+ // Pretend the new area is allocated and then Delete() it to
+ // cause any necessary coalescing to occur.
+ //
+ // We do not adjust free_pages_ here since Delete() will do it for us.
+ Span* span = NewSpan(p, ask);
+ RecordSpan(span);
+ Delete(span);
+ ASSERT(Check());
+ return true;
+ } else {
+ // We could not allocate memory within "pagemap_"
+ // TODO: Once we can return memory to the system, return the new span
+ return false;
+ }
+}
+
+bool TCMalloc_PageHeap::Check() {
+ ASSERT(free_[0].next == &free_[0]);
+ CheckList(&large_, kMaxPages, 1000000000);
+ for (Length s = 1; s < kMaxPages; s++) {
+ CheckList(&free_[s], s, s);
+ }
+ return true;
+}
+
+bool TCMalloc_PageHeap::CheckList(Span* list, Length min_pages, Length max_pages) {
+ for (Span* s = list->next; s != list; s = s->next) {
+ CHECK_CONDITION(s->free);
+ CHECK_CONDITION(s->length >= min_pages);
+ CHECK_CONDITION(s->length <= max_pages);
+ CHECK_CONDITION(GetDescriptor(s->start) == s);
+ CHECK_CONDITION(GetDescriptor(s->start+s->length-1) == s);
+ }
+ return true;
+}
+
+//-------------------------------------------------------------------
+// Free list
+//-------------------------------------------------------------------
+
+class TCMalloc_ThreadCache_FreeList {
+ private:
+ void* list_; // Linked list of nodes
+ uint16_t length_; // Current length
+ uint16_t lowater_; // Low water mark for list length
+
+ public:
+ void Init() {
+ list_ = NULL;
+ length_ = 0;
+ lowater_ = 0;
+ }
+
+ // Return current length of list
+ int length() const {
+ return length_;
+ }
+
+ // Is list empty?
+ bool empty() const {
+ return list_ == NULL;
+ }
+
+ // Low-water mark management
+ int lowwatermark() const { return lowater_; }
+ void clear_lowwatermark() { lowater_ = length_; }
+
+ void Push(void* ptr) {
+ SLL_Push(&list_, ptr);
+ length_++;
+ }
+
+ void* Pop() {
+ ASSERT(list_ != NULL);
+ length_--;
+ if (length_ < lowater_) lowater_ = length_;
+ return SLL_Pop(&list_);
+ }
+
+ void PushRange(int N, void *start, void *end) {
+ SLL_PushRange(&list_, start, end);
+ length_ += N;
+ }
+
+ void PopRange(int N, void **start, void **end) {
+ SLL_PopRange(&list_, N, start, end);
+ ASSERT(length_ >= N);
+ length_ -= N;
+ if (length_ < lowater_) lowater_ = length_;
+ }
+};
+
+//-------------------------------------------------------------------
+// Data kept per thread
+//-------------------------------------------------------------------
+
+class TCMalloc_ThreadCache {
+ private:
+ typedef TCMalloc_ThreadCache_FreeList FreeList;
+
+ size_t size_; // Combined size of data
+ pthread_t tid_; // Which thread owns it
+ bool in_setspecific_; // In call to pthread_setspecific?
+ FreeList list_[kNumClasses]; // Array indexed by size-class
+
+ // We sample allocations, biased by the size of the allocation
+ uint32_t rnd_; // Cheap random number generator
+ size_t bytes_until_sample_; // Bytes until we sample next
+
+ public:
+ // All ThreadCache objects are kept in a linked list (for stats collection)
+ TCMalloc_ThreadCache* next_;
+ TCMalloc_ThreadCache* prev_;
+
+ void Init(pthread_t tid);
+ void Cleanup();
+
+ // Accessors (mostly just for printing stats)
+ int freelist_length(size_t cl) const { return list_[cl].length(); }
+
+ // Total byte size in cache
+ size_t Size() const { return size_; }
+
+ void* Allocate(size_t size);
+ void Deallocate(void* ptr, size_t size_class);
+
+ void FetchFromCentralCache(size_t cl);
+ void ReleaseToCentralCache(size_t cl, int N);
+ void Scavenge();
+ void Print() const;
+
+ // Record allocation of "k" bytes. Return true iff allocation
+ // should be sampled
+ bool SampleAllocation(size_t k);
+
+ // Pick next sampling point
+ void PickNextSample();
+
+ static void InitModule();
+ static void InitTSD();
+ static TCMalloc_ThreadCache* GetCache();
+ static TCMalloc_ThreadCache* GetCacheIfPresent();
+ static void* CreateCacheIfNecessary();
+ static void DeleteCache(void* ptr);
+ static void RecomputeThreadCacheSize();
+};
+
+//-------------------------------------------------------------------
+// Data kept per size-class in central cache
+//-------------------------------------------------------------------
+
+class TCMalloc_Central_FreeList {
+ public:
+ void Init(size_t cl);
+
+ // These methods all do internal locking.
+
+ // Insert the specified range into the central freelist. N is the number of
+ // elements in the range.
+ void InsertRange(void *start, void *end, int N);
+
+ // Returns the actual number of fetched elements into N.
+ void RemoveRange(void **start, void **end, int *N);
+
+ // Returns the number of free objects in cache.
+ int length() {
+ SpinLockHolder h(&lock_);
+ return counter_;
+ }
+
+ // Returns the number of free objects in the transfer cache.
+ int tc_length() {
+ SpinLockHolder h(&lock_);
+ return used_slots_ * num_objects_to_move[size_class_];
+ }
+
+ private:
+ // REQUIRES: lock_ is held
+ // Remove object from cache and return.
+ // Return NULL if no free entries in cache.
+ void* FetchFromSpans();
+
+ // REQUIRES: lock_ is held
+ // Remove object from cache and return. Fetches
+ // from pageheap if cache is empty. Only returns
+ // NULL on allocation failure.
+ void* FetchFromSpansSafe();
+
+ // REQUIRES: lock_ is held
+ // Release a linked list of objects to spans.
+ // May temporarily release lock_.
+ void ReleaseListToSpans(void *start);
+
+ // REQUIRES: lock_ is held
+ // Release an object to spans.
+ // May temporarily release lock_.
+ void ReleaseToSpans(void* object);
+
+ // REQUIRES: lock_ is held
+ // Populate cache by fetching from the page heap.
+ // May temporarily release lock_.
+ void Populate();
+
+ // REQUIRES: lock is held.
+ // Tries to make room for a TCEntry. If the cache is full it will try to
+ // expand it at the cost of some other cache size. Return false if there is
+ // no space.
+ bool MakeCacheSpace();
+
+ // REQUIRES: lock_ for locked_size_class is held.
+ // Picks a "random" size class to steal TCEntry slot from. In reality it
+ // just iterates over the sizeclasses but does so without taking a lock.
+ // Returns true on success.
+ // May temporarily lock a "random" size class.
+ static bool EvictRandomSizeClass(size_t locked_size_class, bool force);
+
+ // REQUIRES: lock_ is *not* held.
+ // Tries to shrink the Cache. If force is true it will relase objects to
+ // spans if it allows it to shrink the cache. Return false if it failed to
+ // shrink the cache. Decrements cache_size_ on succeess.
+ // May temporarily take lock_. If it takes lock_, the locked_size_class
+ // lock is released to the thread from holding two size class locks
+ // concurrently which could lead to a deadlock.
+ bool ShrinkCache(int locked_size_class, bool force);
+
+ // This lock protects all the data members. cached_entries and cache_size_
+ // may be looked at without holding the lock.
+ SpinLock lock_;
+
+ // We keep linked lists of empty and non-empty spans.
+ 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 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];
+
+ // Number of currently used cached entries in tc_slots_. This variable is
+ // updated under a lock but can be read without one.
+ int32_t used_slots_;
+ // The current number of slots for this size class. This is an
+ // adaptive value that is increased if there is lots of traffic
+ // on a given size class.
+ int32_t cache_size_;
+};
+
+// Pad each CentralCache object to multiple of 64 bytes
+class TCMalloc_Central_FreeListPadded : public TCMalloc_Central_FreeList {
+ private:
+ char pad_[(64 - (sizeof(TCMalloc_Central_FreeList) % 64)) % 64];
+};
+
+//-------------------------------------------------------------------
+// Global variables
+//-------------------------------------------------------------------
+
+// Central cache -- a collection of free-lists, one per size-class.
+// We have a separate lock per free-list to reduce contention.
+static TCMalloc_Central_FreeListPadded central_cache[kNumClasses];
+
+// Page-level allocator
+static SpinLock pageheap_lock = SPINLOCK_INITIALIZER;
+static char pageheap_memory[sizeof(TCMalloc_PageHeap)];
+static bool phinited = false;
+
+// Avoid extra level of indirection by making "pageheap" be just an alias
+// of pageheap_memory.
+#define pageheap ((TCMalloc_PageHeap*) pageheap_memory)
+
+// Thread-specific key. Initialization here is somewhat tricky
+// because some Linux startup code invokes malloc() before it
+// is in a good enough state to handle pthread_keycreate().
+// Therefore, we use TSD keys only after tsd_inited is set to true.
+// Until then, we use a slow path to get the heap object.
+static bool tsd_inited = false;
+static pthread_key_t heap_key;
+
+// Allocator for thread heaps
+static PageHeapAllocator<TCMalloc_ThreadCache> threadheap_allocator;
+
+// Linked list of heap objects. Protected by pageheap_lock.
+static TCMalloc_ThreadCache* thread_heaps = NULL;
+static int thread_heap_count = 0;
+
+// Overall thread cache size. Protected by pageheap_lock.
+static size_t overall_thread_cache_size = kDefaultOverallThreadCacheSize;
+
+// Global per-thread cache size. Writes are protected by
+// pageheap_lock. Reads are done without any locking, which should be
+// fine as long as size_t can be written atomically and we don't place
+// invariants between this variable and other pieces of state.
+static volatile size_t per_thread_cache_size = kMaxThreadCacheSize;
+
+//-------------------------------------------------------------------
+// Central cache implementation
+//-------------------------------------------------------------------
+
+void TCMalloc_Central_FreeList::Init(size_t cl) {
+ lock_.Init();
+ size_class_ = cl;
+ DLL_Init(&empty_);
+ DLL_Init(&nonempty_);
+ counter_ = 0;
+
+ cache_size_ = 1;
+ used_slots_ = 0;
+ ASSERT(cache_size_ <= kNumTransferEntries);
+}
+
+void TCMalloc_Central_FreeList::ReleaseListToSpans(void* start) {
+ while (start) {
+ void *next = SLL_Next(start);
+ ReleaseToSpans(start);
+ start = next;
+ }
+}
+
+void TCMalloc_Central_FreeList::ReleaseToSpans(void* object) {
+ const PageID p = reinterpret_cast<uintptr_t>(object) >> kPageShift;
+ Span* span = pageheap->GetDescriptor(p);
+ ASSERT(span != NULL);
+ ASSERT(span->refcount > 0);
+
+ // If span is empty, move it to non-empty list
+ if (span->objects == NULL) {
+ DLL_Remove(span);
+ DLL_Prepend(&nonempty_, span);
+ Event(span, 'N', 0);
+ }
+
+ // The following check is expensive, so it is disabled by default
+ if (false) {
+ // Check that object does not occur in list
+ int got = 0;
+ for (void* p = span->objects; p != NULL; p = *((void**) p)) {
+ ASSERT(p != object);
+ got++;
+ }
+ ASSERT(got + span->refcount ==
+ (span->length<<kPageShift)/ByteSizeForClass(span->sizeclass));
+ }
+
+ counter_++;
+ span->refcount--;
+ if (span->refcount == 0) {
+ Event(span, '#', 0);
+ counter_ -= (span->length<<kPageShift) / ByteSizeForClass(span->sizeclass);
+ DLL_Remove(span);
+
+ // Release central list lock while operating on pageheap
+ lock_.Unlock();
+ {
+ SpinLockHolder h(&pageheap_lock);
+ pageheap->Delete(span);
+ }
+ lock_.Lock();
+ } else {
+ *(reinterpret_cast<void**>(object)) = span->objects;
+ span->objects = object;
+ }
+}
+
+bool TCMalloc_Central_FreeList::EvictRandomSizeClass(
+ size_t locked_size_class, bool force) {
+ static unsigned int race_counter = 0;
+ unsigned int t = race_counter++; // Updated without a lock, but who cares.
+ if (t >= kNumClasses) {
+ while (t >= kNumClasses) {
+ t -= kNumClasses;
+ }
+ race_counter = t;
+ }
+ ASSERT(t >= 0);
+ ASSERT(t < kNumClasses);
+ if (t == locked_size_class) return false;
+ return central_cache[t].ShrinkCache(locked_size_class, force);
+}
+
+bool TCMalloc_Central_FreeList::MakeCacheSpace() {
+ // Is there room in the cache?
+ if (used_slots_ < cache_size_) return true;
+ // Check if we can expand this cache?
+ if (cache_size_ == kNumTransferEntries) return false;
+ // Ok, we'll try to grab an entry from some other size class.
+ if (EvictRandomSizeClass(size_class_, false) ||
+ EvictRandomSizeClass(size_class_, true)) {
+ // Succeeded in evicting, we're going to make our cache larger.
+ cache_size_++;
+ return true;
+ }
+ return false;
+}
+
+
+namespace {
+class LockInverter {
+ private:
+ TCMalloc_SpinLock *held_, *temp_;
+ public:
+ inline explicit LockInverter(TCMalloc_SpinLock* held, TCMalloc_SpinLock *temp)
+ : held_(held), temp_(temp) { held_->Unlock(); temp_->Lock(); }
+ inline ~LockInverter() { temp_->Unlock(); held_->Lock(); }
+};
+}
+
+bool TCMalloc_Central_FreeList::ShrinkCache(int locked_size_class, bool force) {
+ // Start with a quick check without taking a lock.
+ if (cache_size_ == 0) return false;
+ // We don't evict from a full cache unless we are 'forcing'.
+ if (force == false && used_slots_ == cache_size_) return false;
+
+ // Grab lock, but first release the other lock held by this thread. We use
+ // the lock inverter to ensure that we never hold two size class locks
+ // concurrently. That can create a deadlock because there is no well
+ // defined nesting order.
+ LockInverter li(&central_cache[locked_size_class].lock_, &lock_);
+ ASSERT(used_slots_ <= cache_size_);
+ ASSERT(0 <= cache_size_);
+ if (cache_size_ == 0) return false;
+ if (used_slots_ == cache_size_) {
+ if (force == false) return false;
+ // ReleaseListToSpans releases the lock, so we have to make all the
+ // updates to the central list before calling it.
+ cache_size_--;
+ used_slots_--;
+ ReleaseListToSpans(tc_slots_[used_slots_].head);
+ return true;
+ }
+ cache_size_--;
+ return true;
+}
+
+void TCMalloc_Central_FreeList::InsertRange(void *start, void *end, int N) {
+ SpinLockHolder h(&lock_);
+ if (N == num_objects_to_move[size_class_] &&
+ MakeCacheSpace()) {
+ int slot = used_slots_++;
+ ASSERT(slot >=0);
+ ASSERT(slot < kNumTransferEntries);
+ TCEntry *entry = &tc_slots_[slot];
+ entry->head = start;
+ entry->tail = end;
+ return;
+ }
+ ReleaseListToSpans(start);
+}
+
+void TCMalloc_Central_FreeList::RemoveRange(void **start, void **end, int *N) {
+ int num = *N;
+ ASSERT(num > 0);
+
+ SpinLockHolder h(&lock_);
+ if (num == num_objects_to_move[size_class_] && used_slots_ > 0) {
+ int slot = --used_slots_;
+ ASSERT(slot >= 0);
+ TCEntry *entry = &tc_slots_[slot];
+ *start = entry->head;
+ *end = entry->tail;
+ return;
+ }
+
+ // TODO: Prefetch multiple TCEntries?
+ void *tail = FetchFromSpansSafe();
+ if (!tail) {
+ // We are completely out of memory.
+ *start = *end = NULL;
+ *N = 0;
+ return;
+ }
+
+ SLL_SetNext(tail, NULL);
+ void *head = tail;
+ int count = 1;
+ while (count < num) {
+ void *t = FetchFromSpans();
+ if (!t) break;
+ SLL_Push(&head, t);
+ count++;
+ }
+ *start = head;
+ *end = tail;
+ *N = count;
+}
+
+
+void* TCMalloc_Central_FreeList::FetchFromSpansSafe() {
+ void *t = FetchFromSpans();
+ if (!t) {
+ Populate();
+ t = FetchFromSpans();
+ }
+ return t;
+}
+
+void* TCMalloc_Central_FreeList::FetchFromSpans() {
+ if (DLL_IsEmpty(&nonempty_)) return NULL;
+ Span* span = nonempty_.next;
+
+ ASSERT(span->objects != NULL);
+ span->refcount++;
+ void* result = span->objects;
+ span->objects = *(reinterpret_cast<void**>(result));
+ if (span->objects == NULL) {
+ // Move to empty list
+ DLL_Remove(span);
+ DLL_Prepend(&empty_, span);
+ Event(span, 'E', 0);
+ }
+ counter_--;
+ return result;
+}
+
+// Fetch memory from the system and add to the central cache freelist.
+void TCMalloc_Central_FreeList::Populate() {
+ // Release central list lock while operating on pageheap
+ lock_.Unlock();
+ const size_t npages = class_to_pages[size_class_];
+
+ Span* span;
+ {
+ SpinLockHolder h(&pageheap_lock);
+ span = pageheap->New(npages);
+ if (span) pageheap->RegisterSizeClass(span, size_class_);
+ }
+ if (span == NULL) {
+ MESSAGE("allocation failed: %d\n", errno);
+ lock_.Lock();
+ return;
+ }
+
+ // Split the block into pieces and add to the free-list
+ // TODO: coloring of objects to avoid cache conflicts?
+ void** tail = &span->objects;
+ char* ptr = reinterpret_cast<char*>(span->start << kPageShift);
+ char* limit = ptr + (npages << kPageShift);
+ const size_t size = ByteSizeForClass(size_class_);
+ int num = 0;
+ while (ptr + size <= limit) {
+ *tail = ptr;
+ tail = reinterpret_cast<void**>(ptr);
+ ptr += size;
+ num++;
+ }
+ ASSERT(ptr <= limit);
+ *tail = NULL;
+ span->refcount = 0; // No sub-object in use yet
+
+ // Add span to list of non-empty spans
+ lock_.Lock();
+ DLL_Prepend(&nonempty_, span);
+ counter_ += num;
+}
+
+//-------------------------------------------------------------------
+// TCMalloc_ThreadCache implementation
+//-------------------------------------------------------------------
+
+inline bool TCMalloc_ThreadCache::SampleAllocation(size_t k) {
+ if (bytes_until_sample_ < k) {
+ PickNextSample();
+ return true;
+ } else {
+ bytes_until_sample_ -= k;
+ return false;
+ }
+}
+
+void TCMalloc_ThreadCache::Init(pthread_t tid) {
+ size_ = 0;
+ next_ = NULL;
+ prev_ = NULL;
+ tid_ = tid;
+ in_setspecific_ = false;
+ for (size_t cl = 0; cl < kNumClasses; ++cl) {
+ list_[cl].Init();
+ }
+
+ // Initialize RNG -- run it for a bit to get to good values
+ rnd_ = static_cast<uint32_t>(reinterpret_cast<uintptr_t>(this));
+ for (int i = 0; i < 100; i++) {
+ PickNextSample();
+ }
+}
+
+void TCMalloc_ThreadCache::Cleanup() {
+ // Put unused memory back into central cache
+ for (unsigned int cl = 0; cl < kNumClasses; ++cl) {
+ if (list_[cl].length() > 0) {
+ ReleaseToCentralCache(cl, list_[cl].length());
+ }
+ }
+}
+
+inline void* TCMalloc_ThreadCache::Allocate(size_t size) {
+ ASSERT(size <= kMaxSize);
+ const size_t cl = SizeClass(size);
+ FreeList* list = &list_[cl];
+ if (list->empty()) {
+ FetchFromCentralCache(cl);
+ if (list->empty()) return NULL;
+ }
+ size_ -= ByteSizeForClass(cl);
+ return list->Pop();
+}
+
+inline void TCMalloc_ThreadCache::Deallocate(void* ptr, size_t cl) {
+ size_ += ByteSizeForClass(cl);
+ FreeList* list = &list_[cl];
+ list->Push(ptr);
+ // If enough data is free, put back into central cache
+ if (list->length() > kMaxFreeListLength) {
+ ReleaseToCentralCache(cl, num_objects_to_move[cl]);
+ }
+ if (size_ >= per_thread_cache_size) Scavenge();
+}
+
+// Remove some objects of class "cl" from central cache and add to thread heap
+void TCMalloc_ThreadCache::FetchFromCentralCache(size_t cl) {
+ int fetch_count = num_objects_to_move[cl];
+ void *start, *end;
+ central_cache[cl].RemoveRange(&start, &end, &fetch_count);
+ list_[cl].PushRange(fetch_count, start, end);
+ size_ += ByteSizeForClass(cl) * fetch_count;
+}
+
+// Remove some objects of class "cl" from thread heap and add to central cache
+void TCMalloc_ThreadCache::ReleaseToCentralCache(size_t cl, int N) {
+ ASSERT(N > 0);
+ FreeList* src = &list_[cl];
+ if (N > src->length()) N = src->length();
+ size_ -= N*ByteSizeForClass(cl);
+
+ // We return prepackaged chains of the correct size to the central cache.
+ // TODO: Use the same format internally in the thread caches?
+ int batch_size = num_objects_to_move[cl];
+ while (N > batch_size) {
+ void *tail, *head;
+ src->PopRange(batch_size, &head, &tail);
+ central_cache[cl].InsertRange(head, tail, batch_size);
+ N -= batch_size;
+ }
+ void *tail, *head;
+ src->PopRange(N, &head, &tail);
+ central_cache[cl].InsertRange(head, tail, N);
+}
+
+// Release idle memory to the central cache
+void TCMalloc_ThreadCache::Scavenge() {
+ // If the low-water mark for the free list is L, it means we would
+ // not have had to allocate anything from the central cache even if
+ // we had reduced the free list size by L. We aim to get closer to
+ // that situation by dropping L/2 nodes from the free list. This
+ // may not release much memory, but if so we will call scavenge again
+ // pretty soon and the low-water marks will be high on that call.
+ //int64 start = CycleClock::Now();
+
+ for (unsigned int cl = 0; cl < kNumClasses; cl++) {
+ FreeList* list = &list_[cl];
+ const int lowmark = list->lowwatermark();
+ if (lowmark > 0) {
+ const int drop = (lowmark > 1) ? lowmark/2 : 1;
+ ReleaseToCentralCache(cl, drop);
+ }
+ list->clear_lowwatermark();
+ }
+
+ //int64 finish = CycleClock::Now();
+ //CycleTimer ct;
+ //MESSAGE("GC: %.0f ns\n", ct.CyclesToUsec(finish-start)*1000.0);
+}
+
+inline TCMalloc_ThreadCache* TCMalloc_ThreadCache::GetCache() {
+ void* ptr = NULL;
+ if (!tsd_inited) {
+ InitModule();
+ } else {
+ ptr = GetHeap(heap_key);
+ }
+ if (ptr == NULL) ptr = CreateCacheIfNecessary();
+ return reinterpret_cast<TCMalloc_ThreadCache*>(ptr);
+}
+
+// In deletion paths, we do not try to create a thread-cache. This is
+// because we may be in the thread destruction code and may have
+// already cleaned up the cache for this thread.
+inline TCMalloc_ThreadCache* TCMalloc_ThreadCache::GetCacheIfPresent() {
+ if (!tsd_inited) return NULL;
+ return reinterpret_cast<TCMalloc_ThreadCache*>
+ (GetHeap(heap_key));
+}
+
+void TCMalloc_ThreadCache::PickNextSample() {
+ // Make next "random" number
+ // x^32+x^22+x^2+x^1+1 is a primitive polynomial for random numbers
+ static const uint32_t kPoly = (1 << 22) | (1 << 2) | (1 << 1) | (1 << 0);
+ uint32_t r = rnd_;
+ rnd_ = (r << 1) ^ ((static_cast<int32_t>(r) >> 31) & kPoly);
+
+ // Next point is "rnd_ % (sample_period)". I.e., average
+ // increment is "sample_period/2".
+ const int flag_value = FLAGS_tcmalloc_sample_parameter;
+ static int last_flag_value = -1;
+
+ if (flag_value != last_flag_value) {
+ SpinLockHolder h(&sample_period_lock);
+ unsigned int i;
+ for (i = 0; i < (sizeof(primes_list)/sizeof(primes_list[0]) - 1); i++) {
+ if (primes_list[i] >= flag_value) {
+ break;
+ }
+ }
+ sample_period = primes_list[i];
+ last_flag_value = flag_value;
+ }
+ bytes_until_sample_ = rnd_ % sample_period;
+}
+
+void TCMalloc_ThreadCache::InitModule() {
+ // There is a slight potential race here because of double-checked
+ // locking idiom. However, as long as the program does a small
+ // allocation before switching to multi-threaded mode, we will be
+ // fine. We increase the chances of doing such a small allocation
+ // by doing one in the constructor of the module_enter_exit_hook
+ // object declared below.
+ SpinLockHolder h(&pageheap_lock);
+ if (!phinited) {
+ InitSizeClasses();
+ threadheap_allocator.Init();
+ span_allocator.Init();
+ span_allocator.New(); // Reduce cache conflicts
+ span_allocator.New(); // Reduce cache conflicts
+ stacktrace_allocator.Init();
+ DLL_Init(&sampled_objects);
+ for (unsigned int i = 0; i < kNumClasses; ++i) {
+ central_cache[i].Init(i);
+ }
+ new ((void*)pageheap_memory) TCMalloc_PageHeap;
+ phinited = 1;
+ }
+}
+
+void TCMalloc_ThreadCache::InitTSD() {
+ ASSERT(!tsd_inited);
+ pthread_key_create(&heap_key, DeleteCache);
+ tsd_inited = true;
+
+ // We may have used a fake pthread_t for the main thread. Fix it.
+ pthread_t zero;
+ memset(&zero, 0, sizeof(zero));
+ SpinLockHolder h(&pageheap_lock);
+ for (TCMalloc_ThreadCache* h = thread_heaps; h != NULL; h = h->next_) {
+ if (h->tid_ == zero) {
+ h->tid_ = pthread_self();
+ }
+ }
+}
+
+void* TCMalloc_ThreadCache::CreateCacheIfNecessary() {
+ // Initialize per-thread data if necessary
+ TCMalloc_ThreadCache* heap = NULL;
+ {
+ SpinLockHolder h(&pageheap_lock);
+
+ // Early on in glibc's life, we cannot even call pthread_self()
+ pthread_t me;
+ if (!tsd_inited) {
+ memset(&me, 0, sizeof(me));
+ } else {
+ me = pthread_self();
+ }
+
+ // This may be a recursive malloc call from pthread_setspecific()
+ // In that case, the heap for this thread has already been created
+ // and added to the linked list. So we search for that first.
+ for (TCMalloc_ThreadCache* h = thread_heaps; h != NULL; h = h->next_) {
+ if (h->tid_ == me) {
+ heap = h;
+ break;
+ }
+ }
+
+ if (heap == NULL) {
+ // Create the heap and add it to the linked list
+ heap = threadheap_allocator.New();
+ heap->Init(me);
+ heap->next_ = thread_heaps;
+ heap->prev_ = NULL;
+ if (thread_heaps != NULL) thread_heaps->prev_ = heap;
+ thread_heaps = heap;
+ thread_heap_count++;
+ RecomputeThreadCacheSize();
+ }
+ }
+
+ // We call pthread_setspecific() outside the lock because it may
+ // call malloc() recursively. We check for the recursive call using
+ // the "in_setspecific_" flag so that we can avoid calling
+ // pthread_setspecific() if we are already inside pthread_setspecific().
+ if (!heap->in_setspecific_ && tsd_inited) {
+ heap->in_setspecific_ = true;
+ SetHeap(heap_key, heap);
+ heap->in_setspecific_ = false;
+ }
+ return heap;
+}
+
+void TCMalloc_ThreadCache::DeleteCache(void* ptr) {
+#if defined(Y_HAVE_FAST_POD_TLS)
+ my_heap = 0;
+#endif
+
+ // Remove all memory from heap
+ TCMalloc_ThreadCache* heap;
+ heap = reinterpret_cast<TCMalloc_ThreadCache*>(ptr);
+ heap->Cleanup();
+
+ // Remove from linked list
+ SpinLockHolder h(&pageheap_lock);
+ if (heap->next_ != NULL) heap->next_->prev_ = heap->prev_;
+ if (heap->prev_ != NULL) heap->prev_->next_ = heap->next_;
+ if (thread_heaps == heap) thread_heaps = heap->next_;
+ thread_heap_count--;
+ RecomputeThreadCacheSize();
+
+ threadheap_allocator.Delete(heap);
+}
+
+void TCMalloc_ThreadCache::RecomputeThreadCacheSize() {
+ // Divide available space across threads
+ int n = thread_heap_count > 0 ? thread_heap_count : 1;
+ size_t space = overall_thread_cache_size / n;
+
+ // Limit to allowed range
+ if (space < kMinThreadCacheSize) space = kMinThreadCacheSize;
+ if (space > kMaxThreadCacheSize) space = kMaxThreadCacheSize;
+
+ per_thread_cache_size = space;
+}
+
+void TCMalloc_ThreadCache::Print() const {
+ for (unsigned int cl = 0; cl < kNumClasses; ++cl) {
+ MESSAGE(" %5" PRIuS " : %4d len; %4d lo\n",
+ ByteSizeForClass(cl),
+ list_[cl].length(),
+ list_[cl].lowwatermark());
+ }
+}
+
+// Extract interesting stats
+struct TCMallocStats {
+ uint64_t system_bytes; // Bytes alloced from system
+ uint64_t thread_bytes; // Bytes in thread caches
+ uint64_t central_bytes; // Bytes in central cache
+ uint64_t transfer_bytes; // Bytes in central transfer cache
+ uint64_t pageheap_bytes; // Bytes in page heap
+ uint64_t metadata_bytes; // Bytes alloced for metadata
+};
+
+// Get stats into "r". Also get per-size-class counts if class_count != NULL
+static void ExtractStats(TCMallocStats* r, uint64_t* class_count) {
+ r->central_bytes = 0;
+ r->transfer_bytes = 0;
+ for (unsigned int cl = 0; cl < kNumClasses; ++cl) {
+ const int length = central_cache[cl].length();
+ const int tc_length = central_cache[cl].tc_length();
+ r->central_bytes += static_cast<uint64_t>(ByteSizeForClass(cl)) * length;
+ r->transfer_bytes +=
+ static_cast<uint64_t>(ByteSizeForClass(cl)) * tc_length;
+ if (class_count) class_count[cl] = length + tc_length;
+ }
+
+ // Add stats from per-thread heaps
+ r->thread_bytes = 0;
+ { // scope
+ SpinLockHolder h(&pageheap_lock);
+ for (TCMalloc_ThreadCache* h = thread_heaps; h != NULL; h = h->next_) {
+ r->thread_bytes += h->Size();
+ if (class_count) {
+ for (unsigned int cl = 0; cl < kNumClasses; ++cl) {
+ class_count[cl] += h->freelist_length(cl);
+ }
+ }
+ }
+ }
+
+ { //scope
+ SpinLockHolder h(&pageheap_lock);
+ r->system_bytes = pageheap->SystemBytes();
+ r->metadata_bytes = metadata_system_bytes;
+ r->pageheap_bytes = pageheap->FreeBytes();
+ }
+}
+
+// WRITE stats to "out"
+static void DumpStats(TCMalloc_Printer* out, int level) {
+ TCMallocStats stats;
+ uint64_t class_count[kNumClasses];
+ ExtractStats(&stats, (level >= 2 ? class_count : NULL));
+
+ if (level >= 2) {
+ out->printf("------------------------------------------------\n");
+ uint64_t cumulative = 0;
+ for (unsigned int cl = 0; cl < kNumClasses; ++cl) {
+ if (class_count[cl] > 0) {
+ uint64_t class_bytes = class_count[cl] * ByteSizeForClass(cl);
+ cumulative += class_bytes;
+ out->printf("class %3u [ %8" PRIuS " bytes ] : "
+ "%8" LLU " objs; %5.1f MB; %5.1f cum MB\n",
+ cl, ByteSizeForClass(cl),
+ class_count[cl],
+ class_bytes / 1048576.0,
+ cumulative / 1048576.0);
+ }
+ }
+
+ SpinLockHolder h(&pageheap_lock);
+ pageheap->Dump(out);
+ }
+
+ const uint64_t bytes_in_use = stats.system_bytes
+ - stats.pageheap_bytes
+ - stats.central_bytes
+ - stats.transfer_bytes
+ - stats.thread_bytes;
+
+ out->printf("------------------------------------------------\n"
+ "MALLOC: %12" LLU " Heap size\n"
+ "MALLOC: %12" LLU " Bytes in use by application\n"
+ "MALLOC: %12" LLU " Bytes free in page heap\n"
+ "MALLOC: %12" LLU " Bytes free in central cache\n"
+ "MALLOC: %12" LLU " Bytes free in transfer cache\n"
+ "MALLOC: %12" LLU " Bytes free in thread caches\n"
+ "MALLOC: %12" LLU " Spans in use\n"
+ "MALLOC: %12" LLU " Thread heaps in use\n"
+ "MALLOC: %12" LLU " Metadata allocated\n"
+ "------------------------------------------------\n",
+ stats.system_bytes,
+ bytes_in_use,
+ stats.pageheap_bytes,
+ stats.central_bytes,
+ stats.transfer_bytes,
+ stats.thread_bytes,
+ uint64_t(span_allocator.inuse()),
+ uint64_t(threadheap_allocator.inuse()),
+ stats.metadata_bytes);
+}
+
+static void PrintStats(int level) {
+ const int kBufferSize = 16 << 10;
+ char* buffer = new char[kBufferSize];
+ TCMalloc_Printer printer(buffer, kBufferSize);
+ DumpStats(&printer, level);
+ write(STDERR_FILENO, buffer, strlen(buffer));
+ delete[] buffer;
+}
+
+static void** DumpStackTraces() {
+ // Count how much space we need
+ int needed_slots = 0;
+ {
+ SpinLockHolder h(&pageheap_lock);
+ for (Span* s = sampled_objects.next; s != &sampled_objects; s = s->next) {
+ StackTrace* stack = reinterpret_cast<StackTrace*>(s->objects);
+ needed_slots += 3 + stack->depth;
+ }
+ needed_slots += 100; // Slop in case sample grows
+ needed_slots += needed_slots/8; // An extra 12.5% slop
+ }
+
+ void** result = new void*[needed_slots];
+ if (result == NULL) {
+ MESSAGE("tcmalloc: could not allocate %d slots for stack traces\n",
+ needed_slots);
+ return NULL;
+ }
+
+ SpinLockHolder h(&pageheap_lock);
+ int used_slots = 0;
+ for (Span* s = sampled_objects.next; s != &sampled_objects; s = s->next) {
+ ASSERT(used_slots < needed_slots); // Need to leave room for terminator
+ StackTrace* stack = reinterpret_cast<StackTrace*>(s->objects);
+ if (used_slots + 3 + stack->depth >= needed_slots) {
+ // No more room
+ break;
+ }
+
+ result[used_slots+0] = reinterpret_cast<void*>(1);
+ result[used_slots+1] = reinterpret_cast<void*>(stack->size);
+ result[used_slots+2] = reinterpret_cast<void*>(stack->depth);
+ for (int d = 0; d < stack->depth; d++) {
+ result[used_slots+3+d] = stack->stack[d];
+ }
+ used_slots += 3 + stack->depth;
+ }
+ result[used_slots] = reinterpret_cast<void*>(0);
+ return result;
+}
+
+static void** DumpHeapGrowthStackTraces() {
+ // Count how much space we need
+ int needed_slots = 0;
+ {
+ SpinLockHolder h(&pageheap_lock);
+ for (StackTrace* t = growth_stacks;
+ t != NULL;
+ t = reinterpret_cast<StackTrace*>(t->stack[kMaxStackDepth-1])) {
+ needed_slots += 3 + t->depth;
+ }
+ needed_slots += 100; // Slop in case list grows
+ needed_slots += needed_slots/8; // An extra 12.5% slop
+ }
+
+ void** result = new void*[needed_slots];
+ if (result == NULL) {
+ MESSAGE("tcmalloc: could not allocate %d slots for stack traces\n",
+ needed_slots);
+ return NULL;
+ }
+
+ SpinLockHolder h(&pageheap_lock);
+ int used_slots = 0;
+ for (StackTrace* t = growth_stacks;
+ t != NULL;
+ t = reinterpret_cast<StackTrace*>(t->stack[kMaxStackDepth-1])) {
+ ASSERT(used_slots < needed_slots); // Need to leave room for terminator
+ if (used_slots + 3 + t->depth >= needed_slots) {
+ // No more room
+ break;
+ }
+
+ result[used_slots+0] = reinterpret_cast<void*>(1);
+ result[used_slots+1] = reinterpret_cast<void*>(t->size);
+ result[used_slots+2] = reinterpret_cast<void*>(t->depth);
+ for (int d = 0; d < t->depth; d++) {
+ result[used_slots+3+d] = t->stack[d];
+ }
+ used_slots += 3 + t->depth;
+ }
+ result[used_slots] = reinterpret_cast<void*>(0);
+ return result;
+}
+
+// TCMalloc's support for extra malloc interfaces
+class TCMallocImplementation : public MallocExtension {
+ public:
+ virtual void GetStats(char* buffer, int buffer_length) {
+ ASSERT(buffer_length > 0);
+ TCMalloc_Printer printer(buffer, buffer_length);
+
+ // Print level one stats unless lots of space is available
+ if (buffer_length < 10000) {
+ DumpStats(&printer, 1);
+ } else {
+ DumpStats(&printer, 2);
+ }
+ }
+
+ virtual void** ReadStackTraces() {
+ return DumpStackTraces();
+ }
+
+ virtual void** ReadHeapGrowthStackTraces() {
+ return DumpHeapGrowthStackTraces();
+ }
+
+ virtual bool GetNumericProperty(const char* name, size_t* value) {
+ ASSERT(name != NULL);
+
+ if (strcmp(name, "generic.current_allocated_bytes") == 0) {
+ TCMallocStats stats;
+ ExtractStats(&stats, NULL);
+ *value = stats.system_bytes
+ - stats.thread_bytes
+ - stats.central_bytes
+ - stats.pageheap_bytes;
+ return true;
+ }
+
+ if (strcmp(name, "generic.heap_size") == 0) {
+ TCMallocStats stats;
+ ExtractStats(&stats, NULL);
+ *value = stats.system_bytes;
+ return true;
+ }
+
+ if (strcmp(name, "tcmalloc.slack_bytes") == 0) {
+ // We assume that bytes in the page heap are not fragmented too
+ // badly, and are therefore available for allocation.
+ SpinLockHolder l(&pageheap_lock);
+ *value = pageheap->FreeBytes();
+ return true;
+ }
+
+ if (strcmp(name, "tcmalloc.max_total_thread_cache_bytes") == 0) {
+ SpinLockHolder l(&pageheap_lock);
+ *value = overall_thread_cache_size;
+ return true;
+ }
+
+ if (strcmp(name, "tcmalloc.current_total_thread_cache_bytes") == 0) {
+ TCMallocStats stats;
+ ExtractStats(&stats, NULL);
+ *value = stats.thread_bytes;
+ return true;
+ }
+
+ return false;
+ }
+
+ virtual bool SetNumericProperty(const char* name, size_t value) {
+ ASSERT(name != NULL);
+
+ if (strcmp(name, "tcmalloc.max_total_thread_cache_bytes") == 0) {
+ // Clip the value to a reasonable range
+ if (value < kMinThreadCacheSize) value = kMinThreadCacheSize;
+ if (value > (1<<30)) value = (1<<30); // Limit to 1GB
+
+ SpinLockHolder l(&pageheap_lock);
+ overall_thread_cache_size = static_cast<size_t>(value);
+ TCMalloc_ThreadCache::RecomputeThreadCacheSize();
+ return true;
+ }
+
+ return false;
+ }
+};
+
+//-------------------------------------------------------------------
+// Helpers for the exported routines below
+//-------------------------------------------------------------------
+
+static Span* DoSampledAllocation(size_t size) {
+ SpinLockHolder h(&pageheap_lock);
+
+ // Allocate span
+ Span* span = pageheap->New(pages(size == 0 ? 1 : size));
+ if (span == NULL) {
+ return NULL;
+ }
+
+ // Allocate stack trace
+ StackTrace* stack = stacktrace_allocator.New();
+ if (stack == NULL) {
+ // Sampling failed because of lack of memory
+ return span;
+ }
+
+ // Fill stack trace and record properly
+ stack->depth = GetStackTrace(stack->stack, kMaxStackDepth, 1);
+ stack->size = size;
+ span->sample = 1;
+ span->objects = stack;
+ DLL_Prepend(&sampled_objects, span);
+
+ return span;
+}
+
+static inline void* do_malloc(size_t size) {
+ void* ret = NULL;
+
+ if (TCMallocDebug::level >= TCMallocDebug::kVerbose) {
+ MESSAGE("In tcmalloc do_malloc(%" PRIuS")\n", size);
+ }
+ // The following call forces module initialization
+ TCMalloc_ThreadCache* heap = TCMalloc_ThreadCache::GetCache();
+ if ((FLAGS_tcmalloc_sample_parameter > 0) && heap->SampleAllocation(size)) {
+ Span* span = DoSampledAllocation(size);
+ if (span != NULL) {
+ ret = reinterpret_cast<void*>(span->start << kPageShift);
+ }
+ } else if (size > kMaxSize) {
+ // Use page-level allocator
+ SpinLockHolder h(&pageheap_lock);
+ Span* span = pageheap->New(pages(size));
+ if (span != NULL) {
+ ret = reinterpret_cast<void*>(span->start << kPageShift);
+ }
+ } else {
+ ret = heap->Allocate(size);
+ }
+ if (ret == NULL) errno = ENOMEM;
+ return ret;
+}
+
+static inline void do_free(void* ptr) {
+ if (TCMallocDebug::level >= TCMallocDebug::kVerbose)
+ MESSAGE("In tcmalloc do_free(%p)\n", ptr);
+ if (ptr == NULL) return;
+ ASSERT(pageheap != NULL); // Should not call free() before malloc()
+ const PageID p = reinterpret_cast<uintptr_t>(ptr) >> kPageShift;
+ Span* span = pageheap->GetDescriptor(p);
+
+ ASSERT(span != NULL);
+ ASSERT(!span->free);
+ const size_t cl = span->sizeclass;
+ if (cl != 0) {
+ ASSERT(!span->sample);
+ TCMalloc_ThreadCache* heap = TCMalloc_ThreadCache::GetCacheIfPresent();
+ if (heap != NULL) {
+ heap->Deallocate(ptr, cl);
+ } else {
+ // Delete directly into central cache
+ SLL_SetNext(ptr, NULL);
+ central_cache[cl].InsertRange(ptr, ptr, 1);
+ }
+ } else {
+ SpinLockHolder h(&pageheap_lock);
+ ASSERT(reinterpret_cast<uintptr_t>(ptr) % kPageSize == 0);
+ ASSERT(span->start == p);
+ if (span->sample) {
+ DLL_Remove(span);
+ stacktrace_allocator.Delete(reinterpret_cast<StackTrace*>(span->objects));
+ span->objects = NULL;
+ }
+ pageheap->Delete(span);
+ }
+}
+
+// For use by exported routines below that want specific alignments
+//
+// Note: this code can be slow, and can significantly fragment memory.
+// The expectation is that memalign/posix_memalign/valloc/pvalloc will
+// not be invoked very often. This requirement simplifies our
+// implementation and allows us to tune for expected allocation
+// patterns.
+static void* do_memalign(size_t align, size_t size) {
+ ASSERT((align & (align - 1)) == 0);
+ ASSERT(align > 0);
+ if (size + align < size) return NULL; // Overflow
+
+ if (pageheap == NULL) TCMalloc_ThreadCache::InitModule();
+
+ // Allocate at least one byte to avoid boundary conditions below
+ if (size == 0) size = 1;
+
+ if (size <= kMaxSize && align < kPageSize) {
+ // Search through acceptable size classes looking for one with
+ // enough alignment. This depends on the fact that
+ // InitSizeClasses() currently produces several size classes that
+ // are aligned at powers of two. We will waste time and space if
+ // we miss in the size class array, but that is deemed acceptable
+ // since memalign() should be used rarely.
+ unsigned int cl = SizeClass(size);
+ while (cl < kNumClasses && ((class_to_size[cl] & (align - 1)) != 0)) {
+ cl++;
+ }
+ if (cl < kNumClasses) {
+ TCMalloc_ThreadCache* heap = TCMalloc_ThreadCache::GetCache();
+ return heap->Allocate(class_to_size[cl]);
+ }
+ }
+
+ // We will allocate directly from the page heap
+ SpinLockHolder h(&pageheap_lock);
+
+ if (align <= kPageSize) {
+ // Any page-level allocation will be fine
+ // TODO: We could put the rest of this page in the appropriate
+ // TODO: cache but it does not seem worth it.
+ Span* span = pageheap->New(pages(size));
+ if (span == NULL) return NULL;
+ return reinterpret_cast<void*>(span->start << kPageShift);
+ }
+
+ // Allocate extra pages and carve off an aligned portion
+ const int alloc = pages(size + align);
+ Span* span = pageheap->New(alloc);
+ if (span == NULL) return NULL;
+
+ // Skip starting portion so that we end up aligned
+ int skip = 0;
+ while ((((span->start+skip) << kPageShift) & (align - 1)) != 0) {
+ skip++;
+ }
+ ASSERT(skip < alloc);
+ if (skip > 0) {
+ Span* rest = pageheap->Split(span, skip);
+ pageheap->Delete(span);
+ span = rest;
+ }
+
+ // Skip trailing portion that we do not need to return
+ const unsigned int needed = pages(size);
+ ASSERT(span->length >= needed);
+ if (span->length > needed) {
+ Span* trailer = pageheap->Split(span, needed);
+ pageheap->Delete(trailer);
+ }
+ return reinterpret_cast<void*>(span->start << kPageShift);
+}
+
+
+
+// The constructor allocates an object to ensure that initialization
+// runs before main(), and therefore we do not have a chance to become
+// multi-threaded before initialization. We also create the TSD key
+// here. Presumably by the time this constructor runs, glibc is in
+// good enough shape to handle pthread_key_create().
+//
+// The constructor also takes the opportunity to tell STL to use
+// tcmalloc. We want to do this early, before construct time, so
+// all user STL allocations go through tcmalloc (which works really
+// well for STL).
+//
+// The destructor prints stats when the program exits.
+
+class TCMallocGuard {
+ public:
+ TCMallocGuard() {
+ char *envval;
+ if ((envval = getenv("TCMALLOC_DEBUG"))) {
+ TCMallocDebug::level = atoi(envval);
+ MESSAGE("Set tcmalloc debugging level to %d\n", TCMallocDebug::level);
+ }
+ do_free(do_malloc(1));
+ TCMalloc_ThreadCache::InitTSD();
+ do_free(do_malloc(1));
+ MallocExtension::Register(new TCMallocImplementation);
+ }
+
+ ~TCMallocGuard() {
+ const char* env = getenv("MALLOCSTATS");
+ if (env != NULL) {
+ int level = atoi(env);
+ if (level < 1) level = 1;
+ PrintStats(level);
+ }
+ }
+};
+
+static TCMallocGuard module_enter_exit_hook;
+
+
+//-------------------------------------------------------------------
+// Exported routines
+//-------------------------------------------------------------------
+
+// CAVEAT: The code structure below ensures that MallocHook methods are always
+// called from the stack frame of the invoked allocation function.
+// heap-checker.cc depends on this to start a stack trace from
+// the call to the (de)allocation function.
+
+extern "C" void* malloc(size_t size) {
+ void* result = do_malloc(size);
+ MallocHook::InvokeNewHook(result, size);
+ return result;
+}
+
+extern "C" void free(void* ptr) {
+ MallocHook::InvokeDeleteHook(ptr);
+ do_free(ptr);
+}
+
+extern "C" void* calloc(size_t n, size_t elem_size) {
+ // Overflow check
+ const size_t size = n * elem_size;
+ if (elem_size != 0 && size / elem_size != n) return NULL;
+
+ void* result = do_malloc(size);
+ if (result != NULL) {
+ memset(result, 0, size);
+ }
+ MallocHook::InvokeNewHook(result, size);
+ return result;
+}
+
+extern "C" void cfree(void* ptr) {
+ MallocHook::InvokeDeleteHook(ptr);
+ do_free(ptr);
+}
+
+extern "C" void* realloc(void* old_ptr, size_t new_size) {
+ if (old_ptr == NULL) {
+ void* result = do_malloc(new_size);
+ MallocHook::InvokeNewHook(result, new_size);
+ return result;
+ }
+ if (new_size == 0) {
+ MallocHook::InvokeDeleteHook(old_ptr);
+ do_free(old_ptr);
+ return NULL;
+ }
+
+ // Get the size of the old entry
+ const PageID p = reinterpret_cast<uintptr_t>(old_ptr) >> kPageShift;
+ Span* span = pageheap->GetDescriptor(p);
+ size_t old_size;
+ if (span->sizeclass != 0) {
+ old_size = ByteSizeForClass(span->sizeclass);
+ } else {
+ old_size = span->length << kPageShift;
+ }
+
+ // Reallocate if the new size is larger than the old size,
+ // or if the new size is significantly smaller than the old size.
+ if ((new_size > old_size) || (AllocationSize(new_size) < old_size)) {
+ // Need to reallocate
+ void* new_ptr = do_malloc(new_size);
+ if (new_ptr == NULL) {
+ return NULL;
+ }
+ MallocHook::InvokeNewHook(new_ptr, new_size);
+ memcpy(new_ptr, old_ptr, ((old_size < new_size) ? old_size : new_size));
+ MallocHook::InvokeDeleteHook(old_ptr);
+ do_free(old_ptr);
+ return new_ptr;
+ } else {
+ return old_ptr;
+ }
+}
+
+/*
+ * TODO
+ */
+#if defined(USE_INTELCC) || defined(_darwin_) || defined(_freebsd_) || defined(_STLPORT_VERSION)
+ #define OP_THROWNOTHING noexcept
+ #define OP_THROWBADALLOC
+#else
+ #define OP_THROWNOTHING
+ #define OP_THROWBADALLOC
+#endif
+
+static SpinLock set_new_handler_lock = SPINLOCK_INITIALIZER;
+
+static inline void* cpp_alloc(size_t size, bool nothrow) {
+ for (;;) {
+ void* p = do_malloc(size);
+#ifdef PREANSINEW
+ MallocHook::InvokeNewHook(p, size);
+ return p;
+#else
+ if (p == NULL) { // allocation failed
+ // Get the current new handler. NB: this function is not
+ // thread-safe. We make a feeble stab at making it so here, but
+ // this lock only protects against tcmalloc interfering with
+ // itself, not with other libraries calling set_new_handler.
+ std::new_handler nh;
+ {
+ SpinLockHolder h(&set_new_handler_lock);
+ nh = std::set_new_handler(0);
+ (void) std::set_new_handler(nh);
+ }
+ // If no new_handler is established, the allocation failed.
+ if (!nh) {
+ if (nothrow) return 0;
+ throw std::bad_alloc();
+ }
+ // Otherwise, try the new_handler. If it returns, retry the
+ // allocation. If it throws std::bad_alloc, fail the allocation.
+ // if it throws something else, don't interfere.
+ try {
+ (*nh)();
+ } catch (const std::bad_alloc&) {
+ if (!nothrow) throw;
+ MallocHook::InvokeNewHook(p, size);
+ return p;
+ }
+ } else { // allocation success
+ MallocHook::InvokeNewHook(p, size);
+ return p;
+ }
+#endif
+ }
+}
+
+#if !defined(YMAKE)
+void* operator new(size_t size) OP_THROWBADALLOC {
+ return cpp_alloc(size, false);
+}
+
+void* operator new(size_t size, const std::nothrow_t&) OP_THROWNOTHING {
+ return cpp_alloc(size, true);
+}
+
+void operator delete(void* p) OP_THROWNOTHING {
+ MallocHook::InvokeDeleteHook(p);
+ do_free(p);
+}
+
+void operator delete(void* p, const std::nothrow_t&) OP_THROWNOTHING {
+ MallocHook::InvokeDeleteHook(p);
+ do_free(p);
+}
+
+void* operator new[](size_t size) OP_THROWBADALLOC {
+ return cpp_alloc(size, false);
+}
+
+void* operator new[](size_t size, const std::nothrow_t&) OP_THROWNOTHING {
+ return cpp_alloc(size, true);
+}
+
+void operator delete[](void* p) OP_THROWNOTHING {
+ MallocHook::InvokeDeleteHook(p);
+ do_free(p);
+}
+
+void operator delete[](void* p, const std::nothrow_t&) OP_THROWNOTHING {
+ MallocHook::InvokeDeleteHook(p);
+ do_free(p);
+}
+#endif
+
+extern "C" void* memalign(size_t align, size_t size) {
+ void* result = do_memalign(align, size);
+ MallocHook::InvokeNewHook(result, size);
+ return result;
+}
+
+extern "C" int posix_memalign(void** result_ptr, size_t align, size_t size) {
+ if (((align % sizeof(void*)) != 0) ||
+ ((align & (align - 1)) != 0) ||
+ (align == 0)) {
+ return EINVAL;
+ }
+
+ void* result = do_memalign(align, size);
+ MallocHook::InvokeNewHook(result, size);
+ if (result == NULL) {
+ return ENOMEM;
+ } else {
+ *result_ptr = result;
+ return 0;
+ }
+}
+
+extern "C" void* valloc(size_t size) {
+ // Allocate page-aligned object of length >= size bytes
+ if (pagesize == 0) pagesize = getpagesize();
+ void* result = do_memalign(pagesize, size);
+ MallocHook::InvokeNewHook(result, size);
+ return result;
+}
+
+extern "C" void* pvalloc(size_t size) {
+ // Round up size to a multiple of pagesize
+ if (pagesize == 0) pagesize = getpagesize();
+ size = (size + pagesize - 1) & ~(pagesize - 1);
+ void* result = do_memalign(pagesize, size);
+ MallocHook::InvokeNewHook(result, size);
+ return result;
+}
+
+extern "C" void malloc_stats(void) {
+ PrintStats(1);
+}
+
+extern "C" int mallopt(int /*cmd*/, int /*value*/) {
+ return 1; // Indicates error
+}
+
+#if defined(__GLIBC__)
+extern "C" struct mallinfo mallinfo(void) {
+ TCMallocStats stats;
+ ExtractStats(&stats, NULL);
+
+ // Just some of the fields are filled in.
+ struct mallinfo info;
+ memset(&info, 0, sizeof(info));
+
+ // Unfortunately, the struct contains "int" field, so some of the
+ // size values will be truncated.
+ info.arena = static_cast<int>(stats.system_bytes);
+ info.fsmblks = static_cast<int>(stats.thread_bytes
+ + stats.central_bytes
+ + stats.transfer_bytes);
+ info.fordblks = static_cast<int>(stats.pageheap_bytes);
+ info.uordblks = static_cast<int>(stats.system_bytes
+ - stats.thread_bytes
+ - stats.central_bytes
+ - stats.transfer_bytes
+ - stats.pageheap_bytes);
+
+ return info;
+}
+#endif
+
+#if defined(_darwin_)
+extern "C" struct mstats mstats()
+{
+ TCMallocStats stats;
+ ExtractStats( &stats, NULL );
+
+ struct mstats info;
+ memset( &info, 0, sizeof( info ) );
+
+ return info;
+}
+#endif
+
+//-------------------------------------------------------------------
+// Some library routines on RedHat 9 allocate memory using malloc()
+// and free it using __libc_free() (or vice-versa). Since we provide
+// our own implementations of malloc/free, we need to make sure that
+// the __libc_XXX variants also point to the same implementations.
+//-------------------------------------------------------------------
+
+extern "C" {
+#if (defined(HAVE___ATTRIBUTE__) && !defined(_darwin_)) && 0
+ // Potentially faster variants that use the gcc alias extension
+#define ALIAS(x) __attribute__ ((weak, alias (x)))
+ void* __libc_malloc(size_t size) ALIAS("malloc");
+ void __libc_free(void* ptr) ALIAS("free");
+ void* __libc_realloc(void* ptr, size_t size) ALIAS("realloc");
+ void* __libc_calloc(size_t n, size_t size) ALIAS("calloc");
+ void __libc_cfree(void* ptr) ALIAS("cfree");
+ void* __libc_memalign(size_t align, size_t s) ALIAS("memalign");
+ void* __libc_valloc(size_t size) ALIAS("valloc");
+ void* __libc_pvalloc(size_t size) ALIAS("pvalloc");
+ int __posix_memalign(void** r, size_t a, size_t s) ALIAS("posix_memalign");
+#undef ALIAS
+#else
+ // Portable wrappers
+ void* __libc_malloc(size_t size) { return malloc(size); }
+ void __libc_free(void* ptr) { free(ptr); }
+ void* __libc_realloc(void* ptr, size_t size) { return realloc(ptr, size); }
+ void* __libc_calloc(size_t n, size_t size) { return calloc(n, size); }
+ void __libc_cfree(void* ptr) { cfree(ptr); }
+ void* __libc_memalign(size_t align, size_t s) { return memalign(align, s); }
+ void* __libc_valloc(size_t size) { return valloc(size); }
+ void* __libc_pvalloc(size_t size) { return pvalloc(size); }
+ int __posix_memalign(void** r, size_t a, size_t s) {
+ return posix_memalign(r, a, s);
+ }
+#endif
+}
+
+// Override __libc_memalign in libc on linux boxes specially.
+// They have a bug in libc that causes them to (very rarely) allocate
+// with __libc_memalign() yet deallocate with free() and the
+// definitions above don't catch it.
+// This function is an exception to the rule of calling MallocHook method
+// from the stack frame of the allocation function;
+// heap-checker handles this special case explicitly.
+static void *MemalignOverride(size_t align, size_t size, const void* /*caller*/) {
+ void* result = do_memalign(align, size);
+ MallocHook::InvokeNewHook(result, size);
+ return result;
+}
+
+#if !defined(__MALLOC_HOOK_VOLATILE)
+ #define __MALLOC_HOOK_VOLATILE
+#endif
+
+void *(* __MALLOC_HOOK_VOLATILE __memalign_hook)(size_t, size_t, const void *) = MemalignOverride;