+++ /dev/null
-// Copyright (c) 2005, 2007, Google Inc.
-// All rights reserved.
-// Copyright (C) 2005, 2006, 2007, 2008, 2009, 2011 Apple 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".
-// 5. To improve performance, a subset of the information one can get
-// from the pagemap is cached in a data structure, pagemap_cache_,
-// that atomically reads and writes its entries. This cache can be
-// read and written without locking.
-//
-// 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. The same logic applies to pagemap_cache_.
-//
-// THE PAGEID-TO-SIZECLASS CACHE
-// Hot PageID-to-sizeclass mappings are held by pagemap_cache_. If this cache
-// returns 0 for a particular PageID then that means "no information," not that
-// the sizeclass is 0. The cache may have stale information for pages that do
-// not hold the beginning of any free()'able object. Staleness is eliminated
-// in Populate() for pages with sizeclass > 0 objects, and in do_malloc() and
-// do_memalign() for all other relevant pages.
-//
-// TODO: Bias reclamation to larger addresses
-// TODO: implement mallinfo/mallopt
-// TODO: Better testing
-//
-// 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 "config.h"
-#include "FastMalloc.h"
-
-#include "Assertions.h"
-#include <limits>
-#if ENABLE(WTF_MULTIPLE_THREADS)
-#include <pthread.h>
-#endif
-#include <wtf/StdLibExtras.h>
-
-#ifndef NO_TCMALLOC_SAMPLES
-#ifdef WTF_CHANGES
-#define NO_TCMALLOC_SAMPLES
-#endif
-#endif
-
-#if !(defined(USE_SYSTEM_MALLOC) && USE_SYSTEM_MALLOC) && defined(NDEBUG)
-#define FORCE_SYSTEM_MALLOC 0
-#else
-#define FORCE_SYSTEM_MALLOC 1
-#endif
-
-// Use a background thread to periodically scavenge memory to release back to the system
-#define USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY 0
-
-#ifndef NDEBUG
-namespace WTF {
-
-#if ENABLE(WTF_MULTIPLE_THREADS)
-static pthread_key_t isForbiddenKey;
-static pthread_once_t isForbiddenKeyOnce = PTHREAD_ONCE_INIT;
-static void initializeIsForbiddenKey()
-{
- pthread_key_create(&isForbiddenKey, 0);
-}
-
-#if !ASSERT_DISABLED
-static bool isForbidden()
-{
- pthread_once(&isForbiddenKeyOnce, initializeIsForbiddenKey);
- return !!pthread_getspecific(isForbiddenKey);
-}
-#endif
-
-void fastMallocForbid()
-{
- pthread_once(&isForbiddenKeyOnce, initializeIsForbiddenKey);
- pthread_setspecific(isForbiddenKey, &isForbiddenKey);
-}
-
-void fastMallocAllow()
-{
- pthread_once(&isForbiddenKeyOnce, initializeIsForbiddenKey);
- pthread_setspecific(isForbiddenKey, 0);
-}
-
-#else
-
-static bool staticIsForbidden;
-static bool isForbidden()
-{
- return staticIsForbidden;
-}
-
-void fastMallocForbid()
-{
- staticIsForbidden = true;
-}
-
-void fastMallocAllow()
-{
- staticIsForbidden = false;
-}
-#endif // ENABLE(WTF_MULTIPLE_THREADS)
-
-} // namespace WTF
-#endif // NDEBUG
-
-#include <string.h>
-
-namespace WTF {
-
-
-namespace Internal {
-#if !ENABLE(WTF_MALLOC_VALIDATION)
-void fastMallocMatchFailed(void*);
-#else
-COMPILE_ASSERT(((sizeof(ValidationHeader) % sizeof(AllocAlignmentInteger)) == 0), ValidationHeader_must_produce_correct_alignment);
-#endif
-void fastMallocMatchFailed(void*)
-{
- CRASH();
-}
-
-} // namespace Internal
-
-
-void* fastZeroedMalloc(size_t n)
-{
- void* result = fastMalloc(n);
- memset(result, 0, n);
- return result;
-}
-
-char* fastStrDup(const char* src)
-{
- size_t len = strlen(src) + 1;
- char* dup = static_cast<char*>(fastMalloc(len));
- memcpy(dup, src, len);
- return dup;
-}
-
-TryMallocReturnValue tryFastZeroedMalloc(size_t n)
-{
- void* result;
- if (!tryFastMalloc(n).getValue(result))
- return 0;
- memset(result, 0, n);
- return result;
-}
-
-} // namespace WTF
-
-#if FORCE_SYSTEM_MALLOC
-
-#if PLATFORM(BREWMP)
-#include "brew/SystemMallocBrew.h"
-#endif
-
-#if OS(DARWIN)
-#include <malloc/malloc.h>
-#elif OS(WINDOWS)
-#include <malloc.h>
-#endif
-
-namespace WTF {
-
-TryMallocReturnValue tryFastMalloc(size_t n)
-{
- ASSERT(!isForbidden());
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
- if (std::numeric_limits<size_t>::max() - Internal::ValidationBufferSize <= n) // If overflow would occur...
- return 0;
-
- void* result = malloc(n + Internal::ValidationBufferSize);
- if (!result)
- return 0;
- Internal::ValidationHeader* header = static_cast<Internal::ValidationHeader*>(result);
- header->m_size = n;
- header->m_type = Internal::AllocTypeMalloc;
- header->m_prefix = static_cast<unsigned>(Internal::ValidationPrefix);
- result = header + 1;
- *Internal::fastMallocValidationSuffix(result) = Internal::ValidationSuffix;
- fastMallocValidate(result);
- return result;
-#else
- return malloc(n);
-#endif
-}
-
-void* fastMalloc(size_t n)
-{
- ASSERT(!isForbidden());
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
- TryMallocReturnValue returnValue = tryFastMalloc(n);
- void* result;
- if (!returnValue.getValue(result))
- CRASH();
-#else
- void* result = malloc(n);
-#endif
-
- if (!result) {
-#if PLATFORM(BREWMP)
- // The behavior of malloc(0) is implementation defined.
- // To make sure that fastMalloc never returns 0, retry with fastMalloc(1).
- if (!n)
- return fastMalloc(1);
-#endif
- CRASH();
- }
-
- return result;
-}
-
-TryMallocReturnValue tryFastCalloc(size_t n_elements, size_t element_size)
-{
- ASSERT(!isForbidden());
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
- size_t totalBytes = n_elements * element_size;
- if (n_elements > 1 && element_size && (totalBytes / element_size) != n_elements)
- return 0;
-
- TryMallocReturnValue returnValue = tryFastMalloc(totalBytes);
- void* result;
- if (!returnValue.getValue(result))
- return 0;
- memset(result, 0, totalBytes);
- fastMallocValidate(result);
- return result;
-#else
- return calloc(n_elements, element_size);
-#endif
-}
-
-void* fastCalloc(size_t n_elements, size_t element_size)
-{
- ASSERT(!isForbidden());
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
- TryMallocReturnValue returnValue = tryFastCalloc(n_elements, element_size);
- void* result;
- if (!returnValue.getValue(result))
- CRASH();
-#else
- void* result = calloc(n_elements, element_size);
-#endif
-
- if (!result) {
-#if PLATFORM(BREWMP)
- // If either n_elements or element_size is 0, the behavior of calloc is implementation defined.
- // To make sure that fastCalloc never returns 0, retry with fastCalloc(1, 1).
- if (!n_elements || !element_size)
- return fastCalloc(1, 1);
-#endif
- CRASH();
- }
-
- return result;
-}
-
-void fastFree(void* p)
-{
- ASSERT(!isForbidden());
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
- if (!p)
- return;
-
- fastMallocMatchValidateFree(p, Internal::AllocTypeMalloc);
- Internal::ValidationHeader* header = Internal::fastMallocValidationHeader(p);
- memset(p, 0xCC, header->m_size);
- free(header);
-#else
- free(p);
-#endif
-}
-
-TryMallocReturnValue tryFastRealloc(void* p, size_t n)
-{
- ASSERT(!isForbidden());
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
- if (p) {
- if (std::numeric_limits<size_t>::max() - Internal::ValidationBufferSize <= n) // If overflow would occur...
- return 0;
- fastMallocValidate(p);
- Internal::ValidationHeader* result = static_cast<Internal::ValidationHeader*>(realloc(Internal::fastMallocValidationHeader(p), n + Internal::ValidationBufferSize));
- if (!result)
- return 0;
- result->m_size = n;
- result = result + 1;
- *fastMallocValidationSuffix(result) = Internal::ValidationSuffix;
- fastMallocValidate(result);
- return result;
- } else {
- return fastMalloc(n);
- }
-#else
- return realloc(p, n);
-#endif
-}
-
-void* fastRealloc(void* p, size_t n)
-{
- ASSERT(!isForbidden());
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
- TryMallocReturnValue returnValue = tryFastRealloc(p, n);
- void* result;
- if (!returnValue.getValue(result))
- CRASH();
-#else
- void* result = realloc(p, n);
-#endif
-
- if (!result)
- CRASH();
- return result;
-}
-
-void releaseFastMallocFreeMemory() { }
-
-FastMallocStatistics fastMallocStatistics()
-{
- FastMallocStatistics statistics = { 0, 0, 0 };
- return statistics;
-}
-
-size_t fastMallocSize(const void* p)
-{
-#if ENABLE(WTF_MALLOC_VALIDATION)
- return Internal::fastMallocValidationHeader(const_cast<void*>(p))->m_size;
-#elif OS(DARWIN)
- return malloc_size(p);
-#elif OS(WINDOWS) && !PLATFORM(BREWMP)
- // Brew MP uses its own memory allocator, so _msize does not work on the Brew MP simulator.
- return _msize(const_cast<void*>(p));
-#else
- return 1;
-#endif
-}
-
-} // namespace WTF
-
-#if OS(DARWIN)
-// This symbol is present in the JavaScriptCore exports file even when FastMalloc is disabled.
-// It will never be used in this case, so it's type and value are less interesting than its presence.
-extern "C" const int jscore_fastmalloc_introspection = 0;
-#endif
-
-#else // FORCE_SYSTEM_MALLOC
-
-#if HAVE(STDINT_H)
-#include <stdint.h>
-#elif HAVE(INTTYPES_H)
-#include <inttypes.h>
-#else
-#include <sys/types.h>
-#endif
-
-#include "AlwaysInline.h"
-#include "Assertions.h"
-#include "TCPackedCache.h"
-#include "TCPageMap.h"
-#include "TCSpinLock.h"
-#include "TCSystemAlloc.h"
-#include <algorithm>
-#include <limits>
-#include <pthread.h>
-#include <stdarg.h>
-#include <stddef.h>
-#include <stdio.h>
-#if HAVE(ERRNO_H)
-#include <errno.h>
-#endif
-#if OS(UNIX)
-#include <unistd.h>
-#endif
-#if OS(WINDOWS)
-#ifndef WIN32_LEAN_AND_MEAN
-#define WIN32_LEAN_AND_MEAN
-#endif
-#include <windows.h>
-#endif
-
-#ifdef WTF_CHANGES
-
-#if OS(DARWIN)
-#include "MallocZoneSupport.h"
-#include <wtf/HashSet.h>
-#include <wtf/Vector.h>
-#endif
-
-#if HAVE(HEADER_DETECTION_H)
-#include "HeaderDetection.h"
-#endif
-
-#if HAVE(DISPATCH_H)
-#include <dispatch/dispatch.h>
-#endif
-
-#if HAVE(PTHREAD_MACHDEP_H)
-#include <System/pthread_machdep.h>
-
-#if defined(__PTK_FRAMEWORK_JAVASCRIPTCORE_KEY0)
-#define WTF_USE_PTHREAD_GETSPECIFIC_DIRECT 1
-#endif
-#endif
-
-#ifndef PRIuS
-#define PRIuS "zu"
-#endif
-
-// Calling pthread_getspecific through a global function pointer is faster than a normal
-// call to the function on Mac OS X, and it's used in performance-critical code. So we
-// use a function pointer. But that's not necessarily faster on other platforms, and we had
-// problems with this technique on Windows, so we'll do this only on Mac OS X.
-#if OS(DARWIN)
-#if !USE(PTHREAD_GETSPECIFIC_DIRECT)
-static void* (*pthread_getspecific_function_pointer)(pthread_key_t) = pthread_getspecific;
-#define pthread_getspecific(key) pthread_getspecific_function_pointer(key)
-#else
-#define pthread_getspecific(key) _pthread_getspecific_direct(key)
-#define pthread_setspecific(key, val) _pthread_setspecific_direct(key, (val))
-#endif
-#endif
-
-#define DEFINE_VARIABLE(type, name, value, meaning) \
- namespace FLAG__namespace_do_not_use_directly_use_DECLARE_##type##_instead { \
- type FLAGS_##name(value); \
- char FLAGS_no##name; \
- } \
- using FLAG__namespace_do_not_use_directly_use_DECLARE_##type##_instead::FLAGS_##name
-
-#define DEFINE_int64(name, value, meaning) \
- DEFINE_VARIABLE(int64_t, name, value, meaning)
-
-#define DEFINE_double(name, value, meaning) \
- DEFINE_VARIABLE(double, name, value, meaning)
-
-namespace WTF {
-
-#define malloc fastMalloc
-#define calloc fastCalloc
-#define free fastFree
-#define realloc fastRealloc
-
-#define MESSAGE LOG_ERROR
-#define CHECK_CONDITION ASSERT
-
-#if OS(DARWIN)
-struct Span;
-class TCMalloc_Central_FreeListPadded;
-class TCMalloc_PageHeap;
-class TCMalloc_ThreadCache;
-template <typename T> class PageHeapAllocator;
-
-class FastMallocZone {
-public:
- static void init();
-
- static kern_return_t enumerate(task_t, void*, unsigned typeMmask, vm_address_t zoneAddress, memory_reader_t, vm_range_recorder_t);
- static size_t goodSize(malloc_zone_t*, size_t size) { return size; }
- static boolean_t check(malloc_zone_t*) { return true; }
- static void print(malloc_zone_t*, boolean_t) { }
- static void log(malloc_zone_t*, void*) { }
- static void forceLock(malloc_zone_t*) { }
- static void forceUnlock(malloc_zone_t*) { }
- static void statistics(malloc_zone_t*, malloc_statistics_t* stats) { memset(stats, 0, sizeof(malloc_statistics_t)); }
-
-private:
- FastMallocZone(TCMalloc_PageHeap*, TCMalloc_ThreadCache**, TCMalloc_Central_FreeListPadded*, PageHeapAllocator<Span>*, PageHeapAllocator<TCMalloc_ThreadCache>*);
- static size_t size(malloc_zone_t*, const void*);
- static void* zoneMalloc(malloc_zone_t*, size_t);
- static void* zoneCalloc(malloc_zone_t*, size_t numItems, size_t size);
- static void zoneFree(malloc_zone_t*, void*);
- static void* zoneRealloc(malloc_zone_t*, void*, size_t);
- static void* zoneValloc(malloc_zone_t*, size_t) { LOG_ERROR("valloc is not supported"); return 0; }
- static void zoneDestroy(malloc_zone_t*) { }
-
- malloc_zone_t m_zone;
- TCMalloc_PageHeap* m_pageHeap;
- TCMalloc_ThreadCache** m_threadHeaps;
- TCMalloc_Central_FreeListPadded* m_centralCaches;
- PageHeapAllocator<Span>* m_spanAllocator;
- PageHeapAllocator<TCMalloc_ThreadCache>* m_pageHeapAllocator;
-};
-
-#endif
-
-#endif
-
-#ifndef WTF_CHANGES
-// This #ifdef should almost never be set. Set NO_TCMALLOC_SAMPLES if
-// you're porting to a system where you really can't get a stacktrace.
-#ifdef NO_TCMALLOC_SAMPLES
-// We use #define so code compiles even if you #include stacktrace.h somehow.
-# define GetStackTrace(stack, depth, skip) (0)
-#else
-# include <google/stacktrace.h>
-#endif
-#endif
-
-// Even if we have support for thread-local storage in the compiler
-// and linker, the OS may not support it. We need to check that at
-// runtime. Right now, we have to keep a manual set of "bad" OSes.
-#if defined(HAVE_TLS)
- static bool kernel_supports_tls = false; // be conservative
- static inline bool KernelSupportsTLS() {
- return kernel_supports_tls;
- }
-# if !HAVE_DECL_UNAME // if too old for uname, probably too old for TLS
- static void CheckIfKernelSupportsTLS() {
- kernel_supports_tls = false;
- }
-# else
-# include <sys/utsname.h> // DECL_UNAME checked for <sys/utsname.h> too
- static void CheckIfKernelSupportsTLS() {
- struct utsname buf;
- if (uname(&buf) != 0) { // should be impossible
- MESSAGE("uname failed assuming no TLS support (errno=%d)\n", errno);
- kernel_supports_tls = false;
- } else if (strcasecmp(buf.sysname, "linux") == 0) {
- // The linux case: the first kernel to support TLS was 2.6.0
- if (buf.release[0] < '2' && buf.release[1] == '.') // 0.x or 1.x
- kernel_supports_tls = false;
- else if (buf.release[0] == '2' && buf.release[1] == '.' &&
- buf.release[2] >= '0' && buf.release[2] < '6' &&
- buf.release[3] == '.') // 2.0 - 2.5
- kernel_supports_tls = false;
- else
- kernel_supports_tls = true;
- } else { // some other kernel, we'll be optimisitic
- kernel_supports_tls = true;
- }
- // TODO(csilvers): VLOG(1) the tls status once we support RAW_VLOG
- }
-# endif // HAVE_DECL_UNAME
-#endif // HAVE_TLS
-
-// __THROW is defined in glibc systems. It means, counter-intuitively,
-// "This function will never throw an exception." It's an optional
-// optimization tool, but we may need to use it to match glibc prototypes.
-#ifndef __THROW // I guess we're not on a glibc system
-# define __THROW // __THROW is just an optimization, so ok to make it ""
-#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 = 3;
-static const size_t kAlignment = 1 << kAlignShift;
-static const size_t kNumClasses = 68;
-
-// 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 kPageSize 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 = 512 * 1024;
-
-// 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.
-#ifdef NO_TCMALLOC_SAMPLES
-DEFINE_int64(tcmalloc_sample_parameter, 0,
- "Unused: code is compiled with NO_TCMALLOC_SAMPLES");
-static size_t sample_period = 0;
-#else
-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;
-#endif
-
-// Protects sample_period above
-static SpinLock sample_period_lock = SPINLOCK_INITIALIZER;
-
-// Parameters for controlling how fast memory is returned to the OS.
-
-DEFINE_double(tcmalloc_release_rate, 1,
- "Rate at which we release unused memory to the system. "
- "Zero means we never release memory back to the system. "
- "Increase this flag to return memory faster; decrease it "
- "to return memory slower. Reasonable rates are in the "
- "range [0,10]");
-
-//-------------------------------------------------------------------
-// Mapping from size to size_class and vice versa
-//-------------------------------------------------------------------
-
-// Sizes <= 1024 have an alignment >= 8. So for such sizes we have an
-// array indexed by ceil(size/8). Sizes > 1024 have an alignment >= 128.
-// So for these larger sizes we have an array indexed by ceil(size/128).
-//
-// We flatten both logical arrays into one physical array and use
-// arithmetic to compute an appropriate index. The constants used by
-// ClassIndex() were selected to make the flattening work.
-//
-// Examples:
-// Size Expression Index
-// -------------------------------------------------------
-// 0 (0 + 7) / 8 0
-// 1 (1 + 7) / 8 1
-// ...
-// 1024 (1024 + 7) / 8 128
-// 1025 (1025 + 127 + (120<<7)) / 128 129
-// ...
-// 32768 (32768 + 127 + (120<<7)) / 128 376
-static const size_t kMaxSmallSize = 1024;
-static const int shift_amount[2] = { 3, 7 }; // For divides by 8 or 128
-static const int add_amount[2] = { 7, 127 + (120 << 7) };
-static unsigned char class_array[377];
-
-// Compute index of the class_array[] entry for a given size
-static inline int ClassIndex(size_t s) {
- const int i = (s > kMaxSmallSize);
- return static_cast<int>((s + add_amount[i]) >> shift_amount[i]);
-}
-
-// Mapping from size class to max size storable in that class
-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;
-
-// 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;
-}
-
-// 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 ALWAYS_INLINE size_t SizeClass(size_t size) {
- return class_array[ClassIndex(size)];
-}
-
-// Get the byte-size for a specified class
-static ALWAYS_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() {
- // Do some sanity checking on add_amount[]/shift_amount[]/class_array[]
- if (ClassIndex(0) < 0) {
- MESSAGE("Invalid class index %d for size 0\n", ClassIndex(0));
- CRASH();
- }
- if (static_cast<size_t>(ClassIndex(kMaxSize)) >= sizeof(class_array)) {
- MESSAGE("Invalid class index %d for kMaxSize\n", ClassIndex(kMaxSize));
- CRASH();
- }
-
- // Compute the size classes we want to use
- size_t sc = 1; // Next size class to assign
- unsigned char 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++;
- }
- last_lg = lg;
- }
-
- // 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;
- while ((psize % size) > (psize >> 3)) {
- psize += kPageSize;
- }
- const size_t my_pages = psize >> kPageShift;
-
- if (sc > 1 && my_pages == class_to_pages[sc-1]) {
- // See if we can merge this into the previous class without
- // increasing the fragmentation of the previous class.
- const size_t my_objects = (my_pages << kPageShift) / size;
- const size_t prev_objects = (class_to_pages[sc-1] << kPageShift)
- / class_to_size[sc-1];
- if (my_objects == prev_objects) {
- // Adjust last class to include this size
- class_to_size[sc-1] = size;
- continue;
- }
- }
-
- // Add new class
- class_to_pages[sc] = my_pages;
- class_to_size[sc] = size;
- sc++;
- }
- if (sc != kNumClasses) {
- MESSAGE("wrong number of size classes: found %" PRIuS " instead of %d\n",
- sc, int(kNumClasses));
- CRASH();
- }
-
- // Initialize the mapping arrays
- int next_size = 0;
- for (unsigned char c = 1; c < kNumClasses; c++) {
- const size_t max_size_in_class = class_to_size[c];
- for (size_t s = next_size; s <= max_size_in_class; s += kAlignment) {
- class_array[ClassIndex(s)] = c;
- }
- next_size = static_cast<int>(max_size_in_class + kAlignment);
- }
-
- // Double-check sizes just to be safe
- for (size_t size = 0; size <= kMaxSize; size++) {
- const size_t sc = SizeClass(size);
- if (sc == 0) {
- MESSAGE("Bad size class %" PRIuS " for %" PRIuS "\n", sc, size);
- CRASH();
- }
- if (sc > 1 && size <= class_to_size[sc-1]) {
- MESSAGE("Allocating unnecessarily large class %" PRIuS " for %" PRIuS
- "\n", sc, size);
- CRASH();
- }
- if (sc >= kNumClasses) {
- MESSAGE("Bad size class %" PRIuS " for %" PRIuS "\n", sc, size);
- CRASH();
- }
- const size_t s = class_to_size[sc];
- if (size > s) {
- MESSAGE("Bad size %" PRIuS " for %" PRIuS " (sc = %" PRIuS ")\n", s, size, sc);
- CRASH();
- }
- if (s == 0) {
- MESSAGE("Bad size %" PRIuS " for %" PRIuS " (sc = %" PRIuS ")\n", s, size, sc);
- CRASH();
- }
- }
-
- // Initialize the num_objects_to_move array.
- for (size_t cl = 1; cl < kNumClasses; ++cl) {
- num_objects_to_move[cl] = NumMoveSize(ByteSizeForClass(cl));
- }
-
-#ifndef WTF_CHANGES
- if (false) {
- // Dump class sizes and maximum external wastage per size class
- for (size_t cl = 1; cl < kNumClasses; ++cl) {
- const int alloc_size = class_to_pages[cl] << kPageShift;
- const int alloc_objs = alloc_size / class_to_size[cl];
- const int min_used = (class_to_size[cl-1] + 1) * alloc_objs;
- const int max_waste = alloc_size - min_used;
- MESSAGE("SC %3d [ %8d .. %8d ] from %8d ; %2.0f%% maxwaste\n",
- int(cl),
- int(class_to_size[cl-1] + 1),
- int(class_to_size[cl]),
- int(class_to_pages[cl] << kPageShift),
- max_waste * 100.0 / alloc_size
- );
- }
- }
-#endif
-}
-
-// -------------------------------------------------------------------------
-// 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, 0);
- 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 size_t kAllocIncrement = 32 << 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_;
-
- // Linked list of all regions allocated by this allocator
- void* allocated_regions_;
-
- // 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;
- allocated_regions_ = 0;
- free_area_ = NULL;
- free_avail_ = 0;
- free_list_ = NULL;
- }
-
- 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
- char* new_allocation = reinterpret_cast<char*>(MetaDataAlloc(kAllocIncrement));
- if (!new_allocation)
- CRASH();
-
- *reinterpret_cast_ptr<void**>(new_allocation) = allocated_regions_;
- allocated_regions_ = new_allocation;
- free_area_ = new_allocation + kAlignedSize;
- free_avail_ = kAllocIncrement - kAlignedSize;
- }
- 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_; }
-
-#if defined(WTF_CHANGES) && OS(DARWIN)
- template <class Recorder>
- void recordAdministrativeRegions(Recorder& recorder, const RemoteMemoryReader& reader)
- {
- for (void* adminAllocation = allocated_regions_; adminAllocation; adminAllocation = reader.nextEntryInLinkedList(reinterpret_cast<void**>(adminAllocation)))
- recorder.recordRegion(reinterpret_cast<vm_address_t>(adminAllocation), kAllocIncrement);
- }
-#endif
-};
-
-// -------------------------------------------------------------------------
-// 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;
-
-static const Length kMaxValidPages = (~static_cast<Length>(0)) >> kPageShift;
-
-// Convert byte size into pages. This won't overflow, but may return
-// an unreasonably large value if bytes is huge enough.
-static inline Length pages(size_t bytes) {
- return (bytes >> kPageShift) +
- ((bytes & (kPageSize - 1)) > 0 ? 1 : 0);
-}
-
-// 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
- ASSERT(bytes <= (kMaxValidPages << kPageShift));
- 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
-#ifndef NO_TCMALLOC_SAMPLES
- unsigned int sample : 1; // Sampled object?
-#endif
- unsigned int sizeclass : 8; // Size-class for small objects (or 0)
- unsigned int refcount : 11; // Number of non-free objects
- bool decommitted : 1;
-
-#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
-};
-
-#define ASSERT_SPAN_COMMITTED(span) ASSERT(!span->decommitted)
-
-#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 inline 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 inline void DLL_Init(Span* list) {
- list->next = list;
- list->prev = list;
-}
-
-static inline void DLL_Remove(Span* span) {
- span->prev->next = span->next;
- span->next->prev = span->prev;
- span->prev = NULL;
- span->next = NULL;
-}
-
-static ALWAYS_INLINE bool DLL_IsEmpty(const Span* list) {
- return list->next == list;
-}
-
-static int DLL_Length(const Span* list) {
- 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 inline 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;
-}
-
-// -------------------------------------------------------------------------
-// Stack traces kept for sampled allocations
-// The following state is protected by pageheap_lock_.
-// -------------------------------------------------------------------------
-
-// size/depth are made the same size as a pointer so that some generic
-// code below can conveniently cast them back and forth to void*.
-static const int kMaxStackDepth = 31;
-struct StackTrace {
- uintptr_t size; // Size of object
- uintptr_t depth; // Number of PC values stored in array below
- void* stack[kMaxStackDepth];
-};
-static PageHeapAllocator<StackTrace> stacktrace_allocator;
-static Span sampled_objects;
-
-// -------------------------------------------------------------------------
-// Map from page-id to per-page data
-// -------------------------------------------------------------------------
-
-// We use PageMap2<> for 32-bit and PageMap3<> for 64-bit machines.
-// We also use a simple one-level cache for hot PageID-to-sizeclass mappings,
-// because sometimes the sizeclass is all the information we need.
-
-// Selector class -- general selector uses 3-level map
-template <int BITS> class MapSelector {
- public:
- typedef TCMalloc_PageMap3<BITS-kPageShift> Type;
- typedef PackedCache<BITS, uint64_t> CacheType;
-};
-
-#if defined(WTF_CHANGES)
-#if CPU(X86_64)
-// On all known X86-64 platforms, the upper 16 bits are always unused and therefore
-// can be excluded from the PageMap key.
-// See http://en.wikipedia.org/wiki/X86-64#Virtual_address_space_details
-
-static const size_t kBitsUnusedOn64Bit = 16;
-#else
-static const size_t kBitsUnusedOn64Bit = 0;
-#endif
-
-// A three-level map for 64-bit machines
-template <> class MapSelector<64> {
- public:
- typedef TCMalloc_PageMap3<64 - kPageShift - kBitsUnusedOn64Bit> Type;
- typedef PackedCache<64, uint64_t> CacheType;
-};
-#endif
-
-// A two-level map for 32-bit machines
-template <> class MapSelector<32> {
- public:
- typedef TCMalloc_PageMap2<32 - kPageShift> Type;
- typedef PackedCache<32 - kPageShift, uint16_t> CacheType;
-};
-
-// -------------------------------------------------------------------------
-// Page-level allocator
-// * Eager coalescing
-//
-// Heap for page-level allocation. We allow allocating and freeing a
-// contiguous runs of pages (called a "span").
-// -------------------------------------------------------------------------
-
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-// The page heap maintains a free list for spans that are no longer in use by
-// the central cache or any thread caches. We use a background thread to
-// periodically scan the free list and release a percentage of it back to the OS.
-
-// If free_committed_pages_ exceeds kMinimumFreeCommittedPageCount, the
-// background thread:
-// - wakes up
-// - pauses for kScavengeDelayInSeconds
-// - returns to the OS a percentage of the memory that remained unused during
-// that pause (kScavengePercentage * min_free_committed_pages_since_last_scavenge_)
-// The goal of this strategy is to reduce memory pressure in a timely fashion
-// while avoiding thrashing the OS allocator.
-
-// Time delay before the page heap scavenger will consider returning pages to
-// the OS.
-static const int kScavengeDelayInSeconds = 2;
-
-// Approximate percentage of free committed pages to return to the OS in one
-// scavenge.
-static const float kScavengePercentage = .5f;
-
-// number of span lists to keep spans in when memory is returned.
-static const int kMinSpanListsWithSpans = 32;
-
-// Number of free committed pages that we want to keep around. The minimum number of pages used when there
-// is 1 span in each of the first kMinSpanListsWithSpans spanlists. Currently 528 pages.
-static const size_t kMinimumFreeCommittedPageCount = kMinSpanListsWithSpans * ((1.0f+kMinSpanListsWithSpans) / 2.0f);
-
-#endif
-
-static SpinLock pageheap_lock = SPINLOCK_INITIALIZER;
-
-class TCMalloc_PageHeap {
- public:
- void init();
-
- // Allocate a run of "n" pages. Returns zero if out of memory.
- 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));
- }
-
-#ifdef WTF_CHANGES
- inline Span* GetDescriptorEnsureSafe(PageID p)
- {
- pagemap_.Ensure(p, 1);
- return GetDescriptor(p);
- }
-
- size_t ReturnedBytes() const;
-#endif
-
- // Dump state to stderr
-#ifndef WTF_CHANGES
- void Dump(TCMalloc_Printer* out);
-#endif
-
- // 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, bool decommitted);
-
- // Release all pages on the free list for reuse by the OS:
- void ReleaseFreePages();
-
- // Return 0 if we have no information, or else the correct sizeclass for p.
- // Reads and writes to pagemap_cache_ do not require locking.
- // The entries are 64 bits on 64-bit hardware and 16 bits on
- // 32-bit hardware, and we don't mind raciness as long as each read of
- // an entry yields a valid entry, not a partially updated entry.
- size_t GetSizeClassIfCached(PageID p) const {
- return pagemap_cache_.GetOrDefault(p, 0);
- }
- void CacheSizeClass(PageID p, size_t cl) const { pagemap_cache_.Put(p, cl); }
-
- private:
- // Pick the appropriate map and cache types based on pointer size
- typedef MapSelector<8*sizeof(uintptr_t)>::Type PageMap;
- typedef MapSelector<8*sizeof(uintptr_t)>::CacheType PageMapCache;
- PageMap pagemap_;
- mutable PageMapCache pagemap_cache_;
-
- // We segregate spans of a given size into two circular linked
- // lists: one for normal spans, and one for spans whose memory
- // has been returned to the system.
- struct SpanList {
- Span normal;
- Span returned;
- };
-
- // List of free spans of length >= kMaxPages
- SpanList large_;
-
- // Array mapping from span length to a doubly linked list of free spans
- SpanList free_[kMaxPages];
-
- // Number of pages kept in free lists
- uintptr_t free_pages_;
-
- // Bytes allocated from system
- uint64_t system_bytes_;
-
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
- // Number of pages kept in free lists that are still committed.
- Length free_committed_pages_;
-
- // Minimum number of free committed pages since last scavenge. (Can be 0 if
- // we've committed new pages since the last scavenge.)
- Length min_free_committed_pages_since_last_scavenge_;
-#endif
-
- 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.
- //
- // "released" is true iff "span" was found on a "returned" list.
- void Carve(Span* span, Length n, bool released);
-
- void RecordSpan(Span* span) {
- pagemap_.set(span->start, span);
- if (span->length > 1) {
- pagemap_.set(span->start + span->length - 1, span);
- }
- }
-
- // Allocate a large span of length == n. If successful, returns a
- // span of exactly the specified length. Else, returns NULL.
- Span* AllocLarge(Length n);
-
-#if !USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
- // Incrementally release some memory to the system.
- // IncrementalScavenge(n) is called whenever n pages are freed.
- void IncrementalScavenge(Length n);
-#endif
-
- // Number of pages to deallocate before doing more scavenging
- int64_t scavenge_counter_;
-
- // Index of last free list we scavenged
- size_t scavenge_index_;
-
-#if defined(WTF_CHANGES) && OS(DARWIN)
- friend class FastMallocZone;
-#endif
-
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
- void initializeScavenger();
- ALWAYS_INLINE void signalScavenger();
- void scavenge();
- ALWAYS_INLINE bool shouldScavenge() const;
-
-#if HAVE(DISPATCH_H) || OS(WINDOWS)
- void periodicScavenge();
- ALWAYS_INLINE bool isScavengerSuspended();
- ALWAYS_INLINE void scheduleScavenger();
- ALWAYS_INLINE void rescheduleScavenger();
- ALWAYS_INLINE void suspendScavenger();
-#endif
-
-#if HAVE(DISPATCH_H)
- dispatch_queue_t m_scavengeQueue;
- dispatch_source_t m_scavengeTimer;
- bool m_scavengingSuspended;
-#elif OS(WINDOWS)
- static void CALLBACK scavengerTimerFired(void*, BOOLEAN);
- HANDLE m_scavengeQueueTimer;
-#else
- static NO_RETURN_WITH_VALUE void* runScavengerThread(void*);
- NO_RETURN void scavengerThread();
-
- // Keeps track of whether the background thread is actively scavenging memory every kScavengeDelayInSeconds, or
- // it's blocked waiting for more pages to be deleted.
- bool m_scavengeThreadActive;
-
- pthread_mutex_t m_scavengeMutex;
- pthread_cond_t m_scavengeCondition;
-#endif
-
-#endif // USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-};
-
-void TCMalloc_PageHeap::init()
-{
- pagemap_.init(MetaDataAlloc);
- pagemap_cache_ = PageMapCache(0);
- free_pages_ = 0;
- system_bytes_ = 0;
-
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
- free_committed_pages_ = 0;
- min_free_committed_pages_since_last_scavenge_ = 0;
-#endif // USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-
- scavenge_counter_ = 0;
- // Start scavenging at kMaxPages list
- scavenge_index_ = kMaxPages-1;
- COMPILE_ASSERT(kNumClasses <= (1 << PageMapCache::kValuebits), valuebits);
- DLL_Init(&large_.normal);
- DLL_Init(&large_.returned);
- for (size_t i = 0; i < kMaxPages; i++) {
- DLL_Init(&free_[i].normal);
- DLL_Init(&free_[i].returned);
- }
-
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
- initializeScavenger();
-#endif // USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-}
-
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-
-#if HAVE(DISPATCH_H)
-
-void TCMalloc_PageHeap::initializeScavenger()
-{
- m_scavengeQueue = dispatch_queue_create("com.apple.JavaScriptCore.FastMallocSavenger", NULL);
- m_scavengeTimer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, m_scavengeQueue);
- dispatch_time_t startTime = dispatch_time(DISPATCH_TIME_NOW, kScavengeDelayInSeconds * NSEC_PER_SEC);
- dispatch_source_set_timer(m_scavengeTimer, startTime, kScavengeDelayInSeconds * NSEC_PER_SEC, 1000 * NSEC_PER_USEC);
- dispatch_source_set_event_handler(m_scavengeTimer, ^{ periodicScavenge(); });
- m_scavengingSuspended = true;
-}
-
-ALWAYS_INLINE bool TCMalloc_PageHeap::isScavengerSuspended()
-{
- ASSERT(pageheap_lock.IsHeld());
- return m_scavengingSuspended;
-}
-
-ALWAYS_INLINE void TCMalloc_PageHeap::scheduleScavenger()
-{
- ASSERT(pageheap_lock.IsHeld());
- m_scavengingSuspended = false;
- dispatch_resume(m_scavengeTimer);
-}
-
-ALWAYS_INLINE void TCMalloc_PageHeap::rescheduleScavenger()
-{
- // Nothing to do here for libdispatch.
-}
-
-ALWAYS_INLINE void TCMalloc_PageHeap::suspendScavenger()
-{
- ASSERT(pageheap_lock.IsHeld());
- m_scavengingSuspended = true;
- dispatch_suspend(m_scavengeTimer);
-}
-
-#elif OS(WINDOWS)
-
-void TCMalloc_PageHeap::scavengerTimerFired(void* context, BOOLEAN)
-{
- static_cast<TCMalloc_PageHeap*>(context)->periodicScavenge();
-}
-
-void TCMalloc_PageHeap::initializeScavenger()
-{
- m_scavengeQueueTimer = 0;
-}
-
-ALWAYS_INLINE bool TCMalloc_PageHeap::isScavengerSuspended()
-{
- ASSERT(IsHeld(pageheap_lock));
- return !m_scavengeQueueTimer;
-}
-
-ALWAYS_INLINE void TCMalloc_PageHeap::scheduleScavenger()
-{
- // We need to use WT_EXECUTEONLYONCE here and reschedule the timer, because
- // Windows will fire the timer event even when the function is already running.
- ASSERT(IsHeld(pageheap_lock));
- CreateTimerQueueTimer(&m_scavengeQueueTimer, 0, scavengerTimerFired, this, kScavengeDelayInSeconds * 1000, 0, WT_EXECUTEONLYONCE);
-}
-
-ALWAYS_INLINE void TCMalloc_PageHeap::rescheduleScavenger()
-{
- // We must delete the timer and create it again, because it is not possible to retrigger a timer on Windows.
- suspendScavenger();
- scheduleScavenger();
-}
-
-ALWAYS_INLINE void TCMalloc_PageHeap::suspendScavenger()
-{
- ASSERT(IsHeld(pageheap_lock));
- HANDLE scavengeQueueTimer = m_scavengeQueueTimer;
- m_scavengeQueueTimer = 0;
- DeleteTimerQueueTimer(0, scavengeQueueTimer, 0);
-}
-
-#else
-
-void TCMalloc_PageHeap::initializeScavenger()
-{
- // Create a non-recursive mutex.
-#if !defined(PTHREAD_MUTEX_NORMAL) || PTHREAD_MUTEX_NORMAL == PTHREAD_MUTEX_DEFAULT
- pthread_mutex_init(&m_scavengeMutex, 0);
-#else
- pthread_mutexattr_t attr;
- pthread_mutexattr_init(&attr);
- pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_NORMAL);
-
- pthread_mutex_init(&m_scavengeMutex, &attr);
-
- pthread_mutexattr_destroy(&attr);
-#endif
-
- pthread_cond_init(&m_scavengeCondition, 0);
- m_scavengeThreadActive = true;
- pthread_t thread;
- pthread_create(&thread, 0, runScavengerThread, this);
-}
-
-void* TCMalloc_PageHeap::runScavengerThread(void* context)
-{
- static_cast<TCMalloc_PageHeap*>(context)->scavengerThread();
-#if (COMPILER(MSVC) || COMPILER(SUNCC))
- // Without this, Visual Studio and Sun Studio will complain that this method does not return a value.
- return 0;
-#endif
-}
-
-ALWAYS_INLINE void TCMalloc_PageHeap::signalScavenger()
-{
- // m_scavengeMutex should be held before accessing m_scavengeThreadActive.
- ASSERT(pthread_mutex_trylock(m_scavengeMutex));
- if (!m_scavengeThreadActive && shouldScavenge())
- pthread_cond_signal(&m_scavengeCondition);
-}
-
-#endif
-
-void TCMalloc_PageHeap::scavenge()
-{
- size_t pagesToRelease = min_free_committed_pages_since_last_scavenge_ * kScavengePercentage;
- size_t targetPageCount = std::max<size_t>(kMinimumFreeCommittedPageCount, free_committed_pages_ - pagesToRelease);
-
- Length lastFreeCommittedPages = free_committed_pages_;
- while (free_committed_pages_ > targetPageCount) {
- ASSERT(Check());
- for (int i = kMaxPages; i > 0 && free_committed_pages_ >= targetPageCount; i--) {
- SpanList* slist = (static_cast<size_t>(i) == kMaxPages) ? &large_ : &free_[i];
- // If the span size is bigger than kMinSpanListsWithSpans pages return all the spans in the list, else return all but 1 span.
- // Return only 50% of a spanlist at a time so spans of size 1 are not the only ones left.
- size_t length = DLL_Length(&slist->normal);
- size_t numSpansToReturn = (i > kMinSpanListsWithSpans) ? length : length / 2;
- for (int j = 0; static_cast<size_t>(j) < numSpansToReturn && !DLL_IsEmpty(&slist->normal) && free_committed_pages_ > targetPageCount; j++) {
- Span* s = slist->normal.prev;
- DLL_Remove(s);
- ASSERT(!s->decommitted);
- if (!s->decommitted) {
- TCMalloc_SystemRelease(reinterpret_cast<void*>(s->start << kPageShift),
- static_cast<size_t>(s->length << kPageShift));
- ASSERT(free_committed_pages_ >= s->length);
- free_committed_pages_ -= s->length;
- s->decommitted = true;
- }
- DLL_Prepend(&slist->returned, s);
- }
- }
-
- if (lastFreeCommittedPages == free_committed_pages_)
- break;
- lastFreeCommittedPages = free_committed_pages_;
- }
-
- min_free_committed_pages_since_last_scavenge_ = free_committed_pages_;
-}
-
-ALWAYS_INLINE bool TCMalloc_PageHeap::shouldScavenge() const
-{
- return free_committed_pages_ > kMinimumFreeCommittedPageCount;
-}
-
-#endif // USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-
-inline Span* TCMalloc_PageHeap::New(Length n) {
- ASSERT(Check());
- ASSERT(n > 0);
-
- // Find first size >= n that has a non-empty list
- for (Length s = n; s < kMaxPages; s++) {
- Span* ll = NULL;
- bool released = false;
- if (!DLL_IsEmpty(&free_[s].normal)) {
- // Found normal span
- ll = &free_[s].normal;
- } else if (!DLL_IsEmpty(&free_[s].returned)) {
- // Found returned span; reallocate it
- ll = &free_[s].returned;
- released = true;
- } else {
- // Keep looking in larger classes
- continue;
- }
-
- Span* result = ll->next;
- Carve(result, n, released);
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
- // The newly allocated memory is from a span that's in the normal span list (already committed). Update the
- // free committed pages count.
- ASSERT(free_committed_pages_ >= n);
- free_committed_pages_ -= n;
- if (free_committed_pages_ < min_free_committed_pages_since_last_scavenge_)
- min_free_committed_pages_since_last_scavenge_ = free_committed_pages_;
-#endif // USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
- ASSERT(Check());
- free_pages_ -= n;
- return result;
- }
-
- Span* result = AllocLarge(n);
- if (result != NULL) {
- ASSERT_SPAN_COMMITTED(result);
- return result;
- }
-
- // Grow the heap and try again
- if (!GrowHeap(n)) {
- ASSERT(Check());
- return NULL;
- }
-
- return AllocLarge(n);
-}
-
-Span* TCMalloc_PageHeap::AllocLarge(Length n) {
- // find the best span (closest to n in size).
- // The following loops implements address-ordered best-fit.
- bool from_released = false;
- Span *best = NULL;
-
- // Search through normal list
- for (Span* span = large_.normal.next;
- span != &large_.normal;
- span = span->next) {
- if (span->length >= n) {
- if ((best == NULL)
- || (span->length < best->length)
- || ((span->length == best->length) && (span->start < best->start))) {
- best = span;
- from_released = false;
- }
- }
- }
-
- // Search through released list in case it has a better fit
- for (Span* span = large_.returned.next;
- span != &large_.returned;
- span = span->next) {
- if (span->length >= n) {
- if ((best == NULL)
- || (span->length < best->length)
- || ((span->length == best->length) && (span->start < best->start))) {
- best = span;
- from_released = true;
- }
- }
- }
-
- if (best != NULL) {
- Carve(best, n, from_released);
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
- // The newly allocated memory is from a span that's in the normal span list (already committed). Update the
- // free committed pages count.
- ASSERT(free_committed_pages_ >= n);
- free_committed_pages_ -= n;
- if (free_committed_pages_ < min_free_committed_pages_since_last_scavenge_)
- min_free_committed_pages_since_last_scavenge_ = free_committed_pages_;
-#endif // USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
- ASSERT(Check());
- free_pages_ -= n;
- return best;
- }
- 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 Length 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;
-}
-
-inline void TCMalloc_PageHeap::Carve(Span* span, Length n, bool released) {
- ASSERT(n > 0);
- DLL_Remove(span);
- span->free = 0;
- Event(span, 'A', n);
-
- if (released) {
- // If the span chosen to carve from is decommited, commit the entire span at once to avoid committing spans 1 page at a time.
- ASSERT(span->decommitted);
- TCMalloc_SystemCommit(reinterpret_cast<void*>(span->start << kPageShift), static_cast<size_t>(span->length << kPageShift));
- span->decommitted = false;
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
- free_committed_pages_ += span->length;
-#endif
- }
-
- const int extra = static_cast<int>(span->length - n);
- ASSERT(extra >= 0);
- if (extra > 0) {
- Span* leftover = NewSpan(span->start + n, extra);
- leftover->free = 1;
- leftover->decommitted = false;
- Event(leftover, 'S', extra);
- RecordSpan(leftover);
-
- // Place leftover span on appropriate free list
- SpanList* listpair = (static_cast<size_t>(extra) < kMaxPages) ? &free_[extra] : &large_;
- Span* dst = &listpair->normal;
- DLL_Prepend(dst, leftover);
-
- span->length = n;
- pagemap_.set(span->start + n - 1, span);
- }
-}
-
-static ALWAYS_INLINE void mergeDecommittedStates(Span* destination, Span* other)
-{
- if (destination->decommitted && !other->decommitted) {
- TCMalloc_SystemRelease(reinterpret_cast<void*>(other->start << kPageShift),
- static_cast<size_t>(other->length << kPageShift));
- } else if (other->decommitted && !destination->decommitted) {
- TCMalloc_SystemRelease(reinterpret_cast<void*>(destination->start << kPageShift),
- static_cast<size_t>(destination->length << kPageShift));
- destination->decommitted = true;
- }
-}
-
-inline 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;
-#ifndef NO_TCMALLOC_SAMPLES
- span->sample = 0;
-#endif
-
- // 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.
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
- // Track the total size of the neighboring free spans that are committed.
- Length neighboringCommittedSpansLength = 0;
-#endif
- 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;
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
- if (!prev->decommitted)
- neighboringCommittedSpansLength += len;
-#endif
- mergeDecommittedStates(span, prev);
- 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;
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
- if (!next->decommitted)
- neighboringCommittedSpansLength += len;
-#endif
- mergeDecommittedStates(span, next);
- 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->decommitted) {
- if (span->length < kMaxPages)
- DLL_Prepend(&free_[span->length].returned, span);
- else
- DLL_Prepend(&large_.returned, span);
- } else {
- if (span->length < kMaxPages)
- DLL_Prepend(&free_[span->length].normal, span);
- else
- DLL_Prepend(&large_.normal, span);
- }
- free_pages_ += n;
-
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
- if (span->decommitted) {
- // If the merged span is decommitted, that means we decommitted any neighboring spans that were
- // committed. Update the free committed pages count.
- free_committed_pages_ -= neighboringCommittedSpansLength;
- if (free_committed_pages_ < min_free_committed_pages_since_last_scavenge_)
- min_free_committed_pages_since_last_scavenge_ = free_committed_pages_;
- } else {
- // If the merged span remains committed, add the deleted span's size to the free committed pages count.
- free_committed_pages_ += n;
- }
-
- // Make sure the scavenge thread becomes active if we have enough freed pages to release some back to the system.
- signalScavenger();
-#else
- IncrementalScavenge(n);
-#endif
-
- ASSERT(Check());
-}
-
-#if !USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-void TCMalloc_PageHeap::IncrementalScavenge(Length n) {
- // Fast path; not yet time to release memory
- scavenge_counter_ -= n;
- if (scavenge_counter_ >= 0) return; // Not yet time to scavenge
-
- static const size_t kDefaultReleaseDelay = 64;
-
- // Find index of free list to scavenge
- size_t index = scavenge_index_ + 1;
- for (size_t i = 0; i < kMaxPages+1; i++) {
- if (index > kMaxPages) index = 0;
- SpanList* slist = (index == kMaxPages) ? &large_ : &free_[index];
- if (!DLL_IsEmpty(&slist->normal)) {
- // Release the last span on the normal portion of this list
- Span* s = slist->normal.prev;
- DLL_Remove(s);
- TCMalloc_SystemRelease(reinterpret_cast<void*>(s->start << kPageShift),
- static_cast<size_t>(s->length << kPageShift));
- s->decommitted = true;
- DLL_Prepend(&slist->returned, s);
-
- scavenge_counter_ = std::max<size_t>(16UL, std::min<size_t>(kDefaultReleaseDelay, kDefaultReleaseDelay - (free_pages_ / kDefaultReleaseDelay)));
-
- if (index == kMaxPages && !DLL_IsEmpty(&slist->normal))
- scavenge_index_ = index - 1;
- else
- scavenge_index_ = index;
- return;
- }
- index++;
- }
-
- // Nothing to scavenge, delay for a while
- scavenge_counter_ = kDefaultReleaseDelay;
-}
-#endif
-
-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 = static_cast<unsigned int>(sc);
- for (Length i = 1; i < span->length-1; i++) {
- pagemap_.set(span->start+i, span);
- }
-}
-
-#ifdef WTF_CHANGES
-size_t TCMalloc_PageHeap::ReturnedBytes() const {
- size_t result = 0;
- for (unsigned s = 0; s < kMaxPages; s++) {
- const int r_length = DLL_Length(&free_[s].returned);
- unsigned r_pages = s * r_length;
- result += r_pages << kPageShift;
- }
-
- for (Span* s = large_.returned.next; s != &large_.returned; s = s->next)
- result += s->length << kPageShift;
- return result;
-}
-#endif
-
-#ifndef WTF_CHANGES
-static double PagesToMB(uint64_t pages) {
- return (pages << kPageShift) / 1048576.0;
-}
-
-void TCMalloc_PageHeap::Dump(TCMalloc_Printer* out) {
- int nonempty_sizes = 0;
- for (int s = 0; s < kMaxPages; s++) {
- if (!DLL_IsEmpty(&free_[s].normal) || !DLL_IsEmpty(&free_[s].returned)) {
- nonempty_sizes++;
- }
- }
- out->printf("------------------------------------------------\n");
- out->printf("PageHeap: %d sizes; %6.1f MB free\n",
- nonempty_sizes, PagesToMB(free_pages_));
- out->printf("------------------------------------------------\n");
- uint64_t total_normal = 0;
- uint64_t total_returned = 0;
- for (int s = 0; s < kMaxPages; s++) {
- const int n_length = DLL_Length(&free_[s].normal);
- const int r_length = DLL_Length(&free_[s].returned);
- if (n_length + r_length > 0) {
- uint64_t n_pages = s * n_length;
- uint64_t r_pages = s * r_length;
- total_normal += n_pages;
- total_returned += r_pages;
- out->printf("%6u pages * %6u spans ~ %6.1f MB; %6.1f MB cum"
- "; unmapped: %6.1f MB; %6.1f MB cum\n",
- s,
- (n_length + r_length),
- PagesToMB(n_pages + r_pages),
- PagesToMB(total_normal + total_returned),
- PagesToMB(r_pages),
- PagesToMB(total_returned));
- }
- }
-
- uint64_t n_pages = 0;
- uint64_t r_pages = 0;
- int n_spans = 0;
- int r_spans = 0;
- out->printf("Normal large spans:\n");
- for (Span* s = large_.normal.next; s != &large_.normal; s = s->next) {
- out->printf(" [ %6" PRIuS " pages ] %6.1f MB\n",
- s->length, PagesToMB(s->length));
- n_pages += s->length;
- n_spans++;
- }
- out->printf("Unmapped large spans:\n");
- for (Span* s = large_.returned.next; s != &large_.returned; s = s->next) {
- out->printf(" [ %6" PRIuS " pages ] %6.1f MB\n",
- s->length, PagesToMB(s->length));
- r_pages += s->length;
- r_spans++;
- }
- total_normal += n_pages;
- total_returned += r_pages;
- out->printf(">255 large * %6u spans ~ %6.1f MB; %6.1f MB cum"
- "; unmapped: %6.1f MB; %6.1f MB cum\n",
- (n_spans + r_spans),
- PagesToMB(n_pages + r_pages),
- PagesToMB(total_normal + total_returned),
- PagesToMB(r_pages),
- PagesToMB(total_returned));
-}
-#endif
-
-bool TCMalloc_PageHeap::GrowHeap(Length n) {
- ASSERT(kMaxPages >= kMinSystemAlloc);
- if (n > kMaxValidPages) return false;
- Length ask = (n>kMinSystemAlloc) ? n : static_cast<Length>(kMinSystemAlloc);
- size_t actual_size;
- void* ptr = TCMalloc_SystemAlloc(ask << kPageShift, &actual_size, kPageSize);
- if (ptr == NULL) {
- if (n < ask) {
- // Try growing just "n" pages
- ask = n;
- ptr = TCMalloc_SystemAlloc(ask << kPageShift, &actual_size, kPageSize);
- }
- if (ptr == NULL) return false;
- }
- ask = actual_size >> 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].normal.next == &free_[0].normal);
- ASSERT(free_[0].returned.next == &free_[0].returned);
- CheckList(&large_.normal, kMaxPages, 1000000000, false);
- CheckList(&large_.returned, kMaxPages, 1000000000, true);
- for (Length s = 1; s < kMaxPages; s++) {
- CheckList(&free_[s].normal, s, s, false);
- CheckList(&free_[s].returned, s, s, true);
- }
- return true;
-}
-
-#if ASSERT_DISABLED
-bool TCMalloc_PageHeap::CheckList(Span*, Length, Length, bool) {
- return true;
-}
-#else
-bool TCMalloc_PageHeap::CheckList(Span* list, Length min_pages, Length max_pages, bool decommitted) {
- 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);
- CHECK_CONDITION(s->decommitted == decommitted);
- }
- return true;
-}
-#endif
-
-static void ReleaseFreeList(Span* list, Span* returned) {
- // Walk backwards through list so that when we push these
- // spans on the "returned" list, we preserve the order.
- while (!DLL_IsEmpty(list)) {
- Span* s = list->prev;
- DLL_Remove(s);
- s->decommitted = true;
- DLL_Prepend(returned, s);
- TCMalloc_SystemRelease(reinterpret_cast<void*>(s->start << kPageShift),
- static_cast<size_t>(s->length << kPageShift));
- }
-}
-
-void TCMalloc_PageHeap::ReleaseFreePages() {
- for (Length s = 0; s < kMaxPages; s++) {
- ReleaseFreeList(&free_[s].normal, &free_[s].returned);
- }
- ReleaseFreeList(&large_.normal, &large_.returned);
- ASSERT(Check());
-}
-
-//-------------------------------------------------------------------
-// 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_; }
-
- ALWAYS_INLINE void Push(void* ptr) {
- SLL_Push(&list_, ptr);
- length_++;
- }
-
- void PushRange(int N, void *start, void *end) {
- SLL_PushRange(&list_, start, end);
- length_ = length_ + static_cast<uint16_t>(N);
- }
-
- void PopRange(int N, void **start, void **end) {
- SLL_PopRange(&list_, N, start, end);
- ASSERT(length_ >= N);
- length_ = length_ - static_cast<uint16_t>(N);
- if (length_ < lowater_) lowater_ = length_;
- }
-
- ALWAYS_INLINE void* Pop() {
- ASSERT(list_ != NULL);
- length_--;
- if (length_ < lowater_) lowater_ = length_;
- return SLL_Pop(&list_);
- }
-
-#ifdef WTF_CHANGES
- template <class Finder, class Reader>
- void enumerateFreeObjects(Finder& finder, const Reader& reader)
- {
- for (void* nextObject = list_; nextObject; nextObject = reader.nextEntryInLinkedList(reinterpret_cast<void**>(nextObject)))
- finder.visit(nextObject);
- }
-#endif
-};
-
-//-------------------------------------------------------------------
-// Data kept per thread
-//-------------------------------------------------------------------
-
-class TCMalloc_ThreadCache {
- private:
- typedef TCMalloc_ThreadCache_FreeList FreeList;
-#if OS(WINDOWS)
- typedef DWORD ThreadIdentifier;
-#else
- typedef pthread_t ThreadIdentifier;
-#endif
-
- size_t size_; // Combined size of data
- ThreadIdentifier tid_; // Which thread owns it
- bool in_setspecific_; // Called 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
-
- // Allocate a new heap. REQUIRES: pageheap_lock is held.
- static inline TCMalloc_ThreadCache* NewHeap(ThreadIdentifier tid);
-
- // Use only as pthread thread-specific destructor function.
- static void DestroyThreadCache(void* ptr);
- public:
- // All ThreadCache objects are kept in a linked list (for stats collection)
- TCMalloc_ThreadCache* next_;
- TCMalloc_ThreadCache* prev_;
-
- void Init(ThreadIdentifier 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_; }
-
- ALWAYS_INLINE void* Allocate(size_t size);
- void Deallocate(void* ptr, size_t size_class);
-
- ALWAYS_INLINE void FetchFromCentralCache(size_t cl, size_t allocationSize);
- 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(size_t k);
-
- static void InitModule();
- static void InitTSD();
- static TCMalloc_ThreadCache* GetThreadHeap();
- static TCMalloc_ThreadCache* GetCache();
- static TCMalloc_ThreadCache* GetCacheIfPresent();
- static TCMalloc_ThreadCache* CreateCacheIfNecessary();
- static void DeleteCache(TCMalloc_ThreadCache* heap);
- static void BecomeIdle();
- static void RecomputeThreadCacheSize();
-
-#ifdef WTF_CHANGES
- template <class Finder, class Reader>
- void enumerateFreeObjects(Finder& finder, const Reader& reader)
- {
- for (unsigned sizeClass = 0; sizeClass < kNumClasses; sizeClass++)
- list_[sizeClass].enumerateFreeObjects(finder, reader);
- }
-#endif
-};
-
-//-------------------------------------------------------------------
-// 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.
- size_t 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_];
- }
-
-#ifdef WTF_CHANGES
- template <class Finder, class Reader>
- void enumerateFreeObjects(Finder& finder, const Reader& reader, TCMalloc_Central_FreeList* remoteCentralFreeList)
- {
- for (Span* span = &empty_; span && span != &empty_; span = (span->next ? reader(span->next) : 0))
- ASSERT(!span->objects);
-
- ASSERT(!nonempty_.objects);
- static const ptrdiff_t nonemptyOffset = reinterpret_cast<const char*>(&nonempty_) - reinterpret_cast<const char*>(this);
-
- Span* remoteNonempty = reinterpret_cast<Span*>(reinterpret_cast<char*>(remoteCentralFreeList) + nonemptyOffset);
- Span* remoteSpan = nonempty_.next;
-
- for (Span* span = reader(remoteSpan); span && remoteSpan != remoteNonempty; remoteSpan = span->next, span = (span->next ? reader(span->next) : 0)) {
- for (void* nextObject = span->objects; nextObject; nextObject = reader.nextEntryInLinkedList(reinterpret_cast<void**>(nextObject)))
- finder.visit(nextObject);
- }
- }
-#endif
-
- 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_.
- ALWAYS_INLINE void ReleaseToSpans(void* object);
-
- // REQUIRES: lock_ is held
- // Populate cache by fetching from the page heap.
- // May temporarily release lock_.
- ALWAYS_INLINE 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 ALWAYS_INLINE 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 AllocAlignmentInteger pageheap_memory[(sizeof(TCMalloc_PageHeap) + sizeof(AllocAlignmentInteger) - 1) / sizeof(AllocAlignmentInteger)];
-static bool phinited = false;
-
-// Avoid extra level of indirection by making "pageheap" be just an alias
-// of pageheap_memory.
-typedef union {
- void* m_memory;
- TCMalloc_PageHeap* m_pageHeap;
-} PageHeapUnion;
-
-static inline TCMalloc_PageHeap* getPageHeap()
-{
- PageHeapUnion u = { &pageheap_memory[0] };
- return u.m_pageHeap;
-}
-
-#define pageheap getPageHeap()
-
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-
-#if HAVE(DISPATCH_H) || OS(WINDOWS)
-
-void TCMalloc_PageHeap::periodicScavenge()
-{
- SpinLockHolder h(&pageheap_lock);
- pageheap->scavenge();
-
- if (shouldScavenge()) {
- rescheduleScavenger();
- return;
- }
-
- suspendScavenger();
-}
-
-ALWAYS_INLINE void TCMalloc_PageHeap::signalScavenger()
-{
- ASSERT(pageheap_lock.IsHeld());
- if (isScavengerSuspended() && shouldScavenge())
- scheduleScavenger();
-}
-
-#else
-
-void TCMalloc_PageHeap::scavengerThread()
-{
-#if HAVE(PTHREAD_SETNAME_NP)
- pthread_setname_np("JavaScriptCore: FastMalloc scavenger");
-#endif
-
- while (1) {
- if (!shouldScavenge()) {
- pthread_mutex_lock(&m_scavengeMutex);
- m_scavengeThreadActive = false;
- // Block until there are enough free committed pages to release back to the system.
- pthread_cond_wait(&m_scavengeCondition, &m_scavengeMutex);
- m_scavengeThreadActive = true;
- pthread_mutex_unlock(&m_scavengeMutex);
- }
- sleep(kScavengeDelayInSeconds);
- {
- SpinLockHolder h(&pageheap_lock);
- pageheap->scavenge();
- }
- }
-}
-
-#endif
-
-#endif
-
-// If TLS is available, we also store a copy
-// of the per-thread object in a __thread variable
-// since __thread variables are faster to read
-// than pthread_getspecific(). We still need
-// pthread_setspecific() because __thread
-// variables provide no way to run cleanup
-// code when a thread is destroyed.
-#ifdef HAVE_TLS
-static __thread TCMalloc_ThreadCache *threadlocal_heap;
-#endif
-// 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;
-#if USE(PTHREAD_GETSPECIFIC_DIRECT)
-static const pthread_key_t heap_key = __PTK_FRAMEWORK_JAVASCRIPTCORE_KEY0;
-#else
-static pthread_key_t heap_key;
-#endif
-#if OS(WINDOWS)
-DWORD tlsIndex = TLS_OUT_OF_INDEXES;
-#endif
-
-static ALWAYS_INLINE void setThreadHeap(TCMalloc_ThreadCache* heap)
-{
-#if USE(PTHREAD_GETSPECIFIC_DIRECT)
- // Can't have two libraries both doing this in the same process,
- // so check and make this crash right away.
- if (pthread_getspecific(heap_key))
- CRASH();
-#endif
-
- // Still do pthread_setspecific even if there's an alternate form
- // of thread-local storage in use, to benefit from the delete callback.
- pthread_setspecific(heap_key, heap);
-
-#if OS(WINDOWS)
- TlsSetValue(tlsIndex, heap);
-#endif
-}
-
-// 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;
- }
-}
-
-ALWAYS_INLINE 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
- unsigned 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;
- }
-}
-
-ALWAYS_INLINE bool TCMalloc_Central_FreeList::EvictRandomSizeClass(
- size_t locked_size_class, bool force) {
- static int race_counter = 0;
- int t = race_counter++; // Updated without a lock, but who cares.
- if (t >= static_cast<int>(kNumClasses)) {
- while (t >= static_cast<int>(kNumClasses)) {
- t -= kNumClasses;
- }
- race_counter = t;
- }
- ASSERT(t >= 0);
- ASSERT(t < static_cast<int>(kNumClasses));
- if (t == static_cast<int>(locked_size_class)) return false;
- return central_cache[t].ShrinkCache(static_cast<int>(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:
- SpinLock *held_, *temp_;
- public:
- inline explicit LockInverter(SpinLock* held, 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(¢ral_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);
- ASSERT_SPAN_COMMITTED(span);
- 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.
-ALWAYS_INLINE 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) {
-#if HAVE(ERRNO_H)
- MESSAGE("allocation failed: %d\n", errno);
-#elif OS(WINDOWS)
- MESSAGE("allocation failed: %d\n", ::GetLastError());
-#else
- MESSAGE("allocation failed\n");
-#endif
- lock_.Lock();
- return;
- }
- ASSERT_SPAN_COMMITTED(span);
- ASSERT(span->length == npages);
- // Cache sizeclass info eagerly. Locking is not necessary.
- // (Instead of being eager, we could just replace any stale info
- // about this span, but that seems to be no better in practice.)
- for (size_t i = 0; i < npages; i++) {
- pageheap->CacheSizeClass(span->start + i, size_class_);
- }
-
- // 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;
- char* nptr;
- while ((nptr = ptr + size) <= limit) {
- *tail = ptr;
- tail = reinterpret_cast_ptr<void**>(ptr);
- ptr = nptr;
- 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(k);
- return true;
- } else {
- bytes_until_sample_ -= k;
- return false;
- }
-}
-
-void TCMalloc_ThreadCache::Init(ThreadIdentifier 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
- bytes_until_sample_ = 0;
- rnd_ = static_cast<uint32_t>(reinterpret_cast<uintptr_t>(this));
- for (int i = 0; i < 100; i++) {
- PickNextSample(static_cast<size_t>(FLAGS_tcmalloc_sample_parameter * 2));
- }
-}
-
-void TCMalloc_ThreadCache::Cleanup() {
- // Put unused memory back into central cache
- for (size_t cl = 0; cl < kNumClasses; ++cl) {
- if (list_[cl].length() > 0) {
- ReleaseToCentralCache(cl, list_[cl].length());
- }
- }
-}
-
-ALWAYS_INLINE void* TCMalloc_ThreadCache::Allocate(size_t size) {
- ASSERT(size <= kMaxSize);
- const size_t cl = SizeClass(size);
- FreeList* list = &list_[cl];
- size_t allocationSize = ByteSizeForClass(cl);
- if (list->empty()) {
- FetchFromCentralCache(cl, allocationSize);
- if (list->empty()) return NULL;
- }
- size_ -= allocationSize;
- 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
-ALWAYS_INLINE void TCMalloc_ThreadCache::FetchFromCentralCache(size_t cl, size_t allocationSize) {
- 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_ += allocationSize * fetch_count;
-}
-
-// Remove some objects of class "cl" from thread heap and add to central cache
-inline 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
-inline 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 (size_t 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);
-}
-
-void TCMalloc_ThreadCache::PickNextSample(size_t k) {
- // 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 = static_cast<int>(FLAGS_tcmalloc_sample_parameter);
- static int last_flag_value = -1;
-
- if (flag_value != last_flag_value) {
- SpinLockHolder h(&sample_period_lock);
- int i;
- for (i = 0; i < (static_cast<int>(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;
-
- if (k > (static_cast<size_t>(-1) >> 2)) {
- // If the user has asked for a huge allocation then it is possible
- // for the code below to loop infinitely. Just return (note that
- // this throws off the sampling accuracy somewhat, but a user who
- // is allocating more than 1G of memory at a time can live with a
- // minor inaccuracy in profiling of small allocations, and also
- // would rather not wait for the loop below to terminate).
- return;
- }
-
- while (bytes_until_sample_ < k) {
- // Increase bytes_until_sample_ by enough average sampling periods
- // (sample_period >> 1) to allow us to sample past the current
- // allocation.
- bytes_until_sample_ += (sample_period >> 1);
- }
-
- bytes_until_sample_ -= k;
-}
-
-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) {
-#ifdef WTF_CHANGES
- InitTSD();
-#endif
- 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 (size_t i = 0; i < kNumClasses; ++i) {
- central_cache[i].Init(i);
- }
- pageheap->init();
- phinited = 1;
-#if defined(WTF_CHANGES) && OS(DARWIN)
- FastMallocZone::init();
-#endif
- }
-}
-
-inline TCMalloc_ThreadCache* TCMalloc_ThreadCache::NewHeap(ThreadIdentifier tid) {
- // Create the heap and add it to the linked list
- TCMalloc_ThreadCache *heap = threadheap_allocator.New();
- heap->Init(tid);
- heap->next_ = thread_heaps;
- heap->prev_ = NULL;
- if (thread_heaps != NULL) thread_heaps->prev_ = heap;
- thread_heaps = heap;
- thread_heap_count++;
- RecomputeThreadCacheSize();
- return heap;
-}
-
-inline TCMalloc_ThreadCache* TCMalloc_ThreadCache::GetThreadHeap() {
-#ifdef HAVE_TLS
- // __thread is faster, but only when the kernel supports it
- if (KernelSupportsTLS())
- return threadlocal_heap;
-#elif OS(WINDOWS)
- return static_cast<TCMalloc_ThreadCache*>(TlsGetValue(tlsIndex));
-#else
- return static_cast<TCMalloc_ThreadCache*>(pthread_getspecific(heap_key));
-#endif
-}
-
-inline TCMalloc_ThreadCache* TCMalloc_ThreadCache::GetCache() {
- TCMalloc_ThreadCache* ptr = NULL;
- if (!tsd_inited) {
- InitModule();
- } else {
- ptr = GetThreadHeap();
- }
- if (ptr == NULL) ptr = CreateCacheIfNecessary();
- return 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;
- void* const p = GetThreadHeap();
- return reinterpret_cast<TCMalloc_ThreadCache*>(p);
-}
-
-void TCMalloc_ThreadCache::InitTSD() {
- ASSERT(!tsd_inited);
-#if USE(PTHREAD_GETSPECIFIC_DIRECT)
- pthread_key_init_np(heap_key, DestroyThreadCache);
-#else
- pthread_key_create(&heap_key, DestroyThreadCache);
-#endif
-#if OS(WINDOWS)
- tlsIndex = TlsAlloc();
-#endif
- tsd_inited = true;
-
-#if !OS(WINDOWS)
- // We may have used a fake pthread_t for the main thread. Fix it.
- pthread_t zero;
- memset(&zero, 0, sizeof(zero));
-#endif
-#ifndef WTF_CHANGES
- SpinLockHolder h(&pageheap_lock);
-#else
- ASSERT(pageheap_lock.IsHeld());
-#endif
- for (TCMalloc_ThreadCache* h = thread_heaps; h != NULL; h = h->next_) {
-#if OS(WINDOWS)
- if (h->tid_ == 0) {
- h->tid_ = GetCurrentThreadId();
- }
-#else
- if (pthread_equal(h->tid_, zero)) {
- h->tid_ = pthread_self();
- }
-#endif
- }
-}
-
-TCMalloc_ThreadCache* TCMalloc_ThreadCache::CreateCacheIfNecessary() {
- // Initialize per-thread data if necessary
- TCMalloc_ThreadCache* heap = NULL;
- {
- SpinLockHolder h(&pageheap_lock);
-
-#if OS(WINDOWS)
- DWORD me;
- if (!tsd_inited) {
- me = 0;
- } else {
- me = GetCurrentThreadId();
- }
-#else
- // 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();
- }
-#endif
-
- // 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 OS(WINDOWS)
- if (h->tid_ == me) {
-#else
- if (pthread_equal(h->tid_, me)) {
-#endif
- heap = h;
- break;
- }
- }
-
- if (heap == NULL) heap = NewHeap(me);
- }
-
- // We call pthread_setspecific() outside the lock because it may
- // call malloc() recursively. The recursive call will never get
- // here again because it will find the already allocated heap in the
- // linked list of heaps.
- if (!heap->in_setspecific_ && tsd_inited) {
- heap->in_setspecific_ = true;
- setThreadHeap(heap);
- }
- return heap;
-}
-
-void TCMalloc_ThreadCache::BecomeIdle() {
- if (!tsd_inited) return; // No caches yet
- TCMalloc_ThreadCache* heap = GetThreadHeap();
- if (heap == NULL) return; // No thread cache to remove
- if (heap->in_setspecific_) return; // Do not disturb the active caller
-
- heap->in_setspecific_ = true;
- setThreadHeap(NULL);
-#ifdef HAVE_TLS
- // Also update the copy in __thread
- threadlocal_heap = NULL;
-#endif
- heap->in_setspecific_ = false;
- if (GetThreadHeap() == heap) {
- // Somehow heap got reinstated by a recursive call to malloc
- // from pthread_setspecific. We give up in this case.
- return;
- }
-
- // We can now get rid of the heap
- DeleteCache(heap);
-}
-
-void TCMalloc_ThreadCache::DestroyThreadCache(void* ptr) {
- // Note that "ptr" cannot be NULL since pthread promises not
- // to invoke the destructor on NULL values, but for safety,
- // we check anyway.
- if (ptr == NULL) return;
-#ifdef HAVE_TLS
- // Prevent fast path of GetThreadHeap() from returning heap.
- threadlocal_heap = NULL;
-#endif
- DeleteCache(reinterpret_cast<TCMalloc_ThreadCache*>(ptr));
-}
-
-void TCMalloc_ThreadCache::DeleteCache(TCMalloc_ThreadCache* heap) {
- // Remove all memory from heap
- 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 (size_t 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
-};
-
-#ifndef WTF_CHANGES
-// 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 (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 (size_t 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();
- }
-}
-#endif
-
-#ifndef WTF_CHANGES
-// 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 (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 %3d [ %8" PRIuS " bytes ] : "
- "%8" PRIu64 " 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" PRIu64 " Heap size\n"
- "MALLOC: %12" PRIu64 " Bytes in use by application\n"
- "MALLOC: %12" PRIu64 " Bytes free in page heap\n"
- "MALLOC: %12" PRIu64 " Bytes free in central cache\n"
- "MALLOC: %12" PRIu64 " Bytes free in transfer cache\n"
- "MALLOC: %12" PRIu64 " Bytes free in thread caches\n"
- "MALLOC: %12" PRIu64 " Spans in use\n"
- "MALLOC: %12" PRIu64 " Thread heaps in use\n"
- "MALLOC: %12" PRIu64 " 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*>(static_cast<uintptr_t>(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*>(static_cast<uintptr_t>(0));
- return result;
-}
-#endif
-
-#ifndef WTF_CHANGES
-
-// 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 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;
- }
-
- virtual void MarkThreadIdle() {
- TCMalloc_ThreadCache::BecomeIdle();
- }
-
- virtual void ReleaseFreeMemory() {
- SpinLockHolder h(&pageheap_lock);
- pageheap->ReleaseFreePages();
- }
-};
-#endif
-
-// 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() {
-#ifdef HAVE_TLS // this is true if the cc/ld/libc combo support TLS
- // Check whether the kernel also supports TLS (needs to happen at runtime)
- CheckIfKernelSupportsTLS();
-#endif
-#ifndef WTF_CHANGES
-#ifdef WIN32 // patch the windows VirtualAlloc, etc.
- PatchWindowsFunctions(); // defined in windows/patch_functions.cc
-#endif
-#endif
- free(malloc(1));
- TCMalloc_ThreadCache::InitTSD();
- free(malloc(1));
-#ifndef WTF_CHANGES
- MallocExtension::Register(new TCMallocImplementation);
-#endif
- }
-
-#ifndef WTF_CHANGES
- ~TCMallocGuard() {
- const char* env = getenv("MALLOCSTATS");
- if (env != NULL) {
- int level = atoi(env);
- if (level < 1) level = 1;
- PrintStats(level);
- }
-#ifdef WIN32
- UnpatchWindowsFunctions();
-#endif
- }
-#endif
-};
-
-#ifndef WTF_CHANGES
-static TCMallocGuard module_enter_exit_hook;
-#endif
-
-
-//-------------------------------------------------------------------
-// Helpers for the exported routines below
-//-------------------------------------------------------------------
-
-#ifndef WTF_CHANGES
-
-static Span* DoSampledAllocation(size_t size) {
-
- // Grab the stack trace outside the heap lock
- StackTrace tmp;
- tmp.depth = GetStackTrace(tmp.stack, kMaxStackDepth, 1);
- tmp.size = 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;
- }
-
- *stack = tmp;
- span->sample = 1;
- span->objects = stack;
- DLL_Prepend(&sampled_objects, span);
-
- return span;
-}
-#endif
-
-static inline bool CheckCachedSizeClass(void *ptr) {
- PageID p = reinterpret_cast<uintptr_t>(ptr) >> kPageShift;
- size_t cached_value = pageheap->GetSizeClassIfCached(p);
- return cached_value == 0 ||
- cached_value == pageheap->GetDescriptor(p)->sizeclass;
-}
-
-static inline void* CheckedMallocResult(void *result)
-{
- ASSERT(result == 0 || CheckCachedSizeClass(result));
- return result;
-}
-
-static inline void* SpanToMallocResult(Span *span) {
- ASSERT_SPAN_COMMITTED(span);
- pageheap->CacheSizeClass(span->start, 0);
- return
- CheckedMallocResult(reinterpret_cast<void*>(span->start << kPageShift));
-}
-
-#ifdef WTF_CHANGES
-template <bool crashOnFailure>
-#endif
-static ALWAYS_INLINE void* do_malloc(size_t size) {
- void* ret = NULL;
-
-#ifdef WTF_CHANGES
- ASSERT(!isForbidden());
-#endif
-
- // The following call forces module initialization
- TCMalloc_ThreadCache* heap = TCMalloc_ThreadCache::GetCache();
-#ifndef WTF_CHANGES
- if ((FLAGS_tcmalloc_sample_parameter > 0) && heap->SampleAllocation(size)) {
- Span* span = DoSampledAllocation(size);
- if (span != NULL) {
- ret = SpanToMallocResult(span);
- }
- } else
-#endif
- if (size > kMaxSize) {
- // Use page-level allocator
- SpinLockHolder h(&pageheap_lock);
- Span* span = pageheap->New(pages(size));
- if (span != NULL) {
- ret = SpanToMallocResult(span);
- }
- } else {
- // The common case, and also the simplest. This just pops the
- // size-appropriate freelist, afer replenishing it if it's empty.
- ret = CheckedMallocResult(heap->Allocate(size));
- }
- if (!ret) {
-#ifdef WTF_CHANGES
- if (crashOnFailure) // This branch should be optimized out by the compiler.
- CRASH();
-#else
- errno = ENOMEM;
-#endif
- }
- return ret;
-}
-
-static ALWAYS_INLINE void do_free(void* 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 = NULL;
- size_t cl = pageheap->GetSizeClassIfCached(p);
-
- if (cl == 0) {
- span = pageheap->GetDescriptor(p);
- cl = span->sizeclass;
- pageheap->CacheSizeClass(p, cl);
- }
- if (cl != 0) {
-#ifndef NO_TCMALLOC_SAMPLES
- ASSERT(!pageheap->GetDescriptor(p)->sample);
-#endif
- 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 != NULL && span->start == p);
-#ifndef NO_TCMALLOC_SAMPLES
- if (span->sample) {
- DLL_Remove(span);
- stacktrace_allocator.Delete(reinterpret_cast<StackTrace*>(span->objects));
- span->objects = NULL;
- }
-#endif
- pageheap->Delete(span);
- }
-}
-
-#ifndef WTF_CHANGES
-// 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 (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.
- size_t cl = SizeClass(size);
- while (cl < kNumClasses && ((class_to_size[cl] & (align - 1)) != 0)) {
- cl++;
- }
- if (cl < kNumClasses) {
- TCMalloc_ThreadCache* heap = TCMalloc_ThreadCache::GetCache();
- return CheckedMallocResult(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));
- return span == NULL ? NULL : SpanToMallocResult(span);
- }
-
- // Allocate extra pages and carve off an aligned portion
- const Length alloc = pages(size + align);
- Span* span = pageheap->New(alloc);
- if (span == NULL) return NULL;
-
- // Skip starting portion so that we end up aligned
- Length 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 Length needed = pages(size);
- ASSERT(span->length >= needed);
- if (span->length > needed) {
- Span* trailer = pageheap->Split(span, needed);
- pageheap->Delete(trailer);
- }
- return SpanToMallocResult(span);
-}
-#endif
-
-// Helpers for use by exported routines below:
-
-#ifndef WTF_CHANGES
-static inline void do_malloc_stats() {
- PrintStats(1);
-}
-#endif
-
-static inline int do_mallopt(int, int) {
- return 1; // Indicates error
-}
-
-#ifdef HAVE_STRUCT_MALLINFO // mallinfo isn't defined on freebsd, for instance
-static inline struct mallinfo do_mallinfo() {
- 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
-
-//-------------------------------------------------------------------
-// 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.
-
-#ifndef WTF_CHANGES
-extern "C"
-#else
-#define do_malloc do_malloc<crashOnFailure>
-
-template <bool crashOnFailure>
-ALWAYS_INLINE void* malloc(size_t);
-
-void* fastMalloc(size_t size)
-{
- return malloc<true>(size);
-}
-
-TryMallocReturnValue tryFastMalloc(size_t size)
-{
- return malloc<false>(size);
-}
-
-template <bool crashOnFailure>
-ALWAYS_INLINE
-#endif
-void* malloc(size_t size) {
-#if ENABLE(WTF_MALLOC_VALIDATION)
- if (std::numeric_limits<size_t>::max() - Internal::ValidationBufferSize <= size) // If overflow would occur...
- return 0;
- void* result = do_malloc(size + Internal::ValidationBufferSize);
- if (!result)
- return 0;
-
- Internal::ValidationHeader* header = static_cast<Internal::ValidationHeader*>(result);
- header->m_size = size;
- header->m_type = Internal::AllocTypeMalloc;
- header->m_prefix = static_cast<unsigned>(Internal::ValidationPrefix);
- result = header + 1;
- *Internal::fastMallocValidationSuffix(result) = Internal::ValidationSuffix;
- fastMallocValidate(result);
-#else
- void* result = do_malloc(size);
-#endif
-
-#ifndef WTF_CHANGES
- MallocHook::InvokeNewHook(result, size);
-#endif
- return result;
-}
-
-#ifndef WTF_CHANGES
-extern "C"
-#endif
-void free(void* ptr) {
-#ifndef WTF_CHANGES
- MallocHook::InvokeDeleteHook(ptr);
-#endif
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
- if (!ptr)
- return;
-
- fastMallocValidate(ptr);
- Internal::ValidationHeader* header = Internal::fastMallocValidationHeader(ptr);
- memset(ptr, 0xCC, header->m_size);
- do_free(header);
-#else
- do_free(ptr);
-#endif
-}
-
-#ifndef WTF_CHANGES
-extern "C"
-#else
-template <bool crashOnFailure>
-ALWAYS_INLINE void* calloc(size_t, size_t);
-
-void* fastCalloc(size_t n, size_t elem_size)
-{
- void* result = calloc<true>(n, elem_size);
-#if ENABLE(WTF_MALLOC_VALIDATION)
- fastMallocValidate(result);
-#endif
- return result;
-}
-
-TryMallocReturnValue tryFastCalloc(size_t n, size_t elem_size)
-{
- void* result = calloc<false>(n, elem_size);
-#if ENABLE(WTF_MALLOC_VALIDATION)
- fastMallocValidate(result);
-#endif
- return result;
-}
-
-template <bool crashOnFailure>
-ALWAYS_INLINE
-#endif
-void* calloc(size_t n, size_t elem_size) {
- size_t totalBytes = n * elem_size;
-
- // Protect against overflow
- if (n > 1 && elem_size && (totalBytes / elem_size) != n)
- return 0;
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
- void* result = malloc<crashOnFailure>(totalBytes);
- if (!result)
- return 0;
-
- memset(result, 0, totalBytes);
- fastMallocValidate(result);
-#else
- void* result = do_malloc(totalBytes);
- if (result != NULL) {
- memset(result, 0, totalBytes);
- }
-#endif
-
-#ifndef WTF_CHANGES
- MallocHook::InvokeNewHook(result, totalBytes);
-#endif
- return result;
-}
-
-// Since cfree isn't used anywhere, we don't compile it in.
-#ifndef WTF_CHANGES
-#ifndef WTF_CHANGES
-extern "C"
-#endif
-void cfree(void* ptr) {
-#ifndef WTF_CHANGES
- MallocHook::InvokeDeleteHook(ptr);
-#endif
- do_free(ptr);
-}
-#endif
-
-#ifndef WTF_CHANGES
-extern "C"
-#else
-template <bool crashOnFailure>
-ALWAYS_INLINE void* realloc(void*, size_t);
-
-void* fastRealloc(void* old_ptr, size_t new_size)
-{
-#if ENABLE(WTF_MALLOC_VALIDATION)
- fastMallocValidate(old_ptr);
-#endif
- void* result = realloc<true>(old_ptr, new_size);
-#if ENABLE(WTF_MALLOC_VALIDATION)
- fastMallocValidate(result);
-#endif
- return result;
-}
-
-TryMallocReturnValue tryFastRealloc(void* old_ptr, size_t new_size)
-{
-#if ENABLE(WTF_MALLOC_VALIDATION)
- fastMallocValidate(old_ptr);
-#endif
- void* result = realloc<false>(old_ptr, new_size);
-#if ENABLE(WTF_MALLOC_VALIDATION)
- fastMallocValidate(result);
-#endif
- return result;
-}
-
-template <bool crashOnFailure>
-ALWAYS_INLINE
-#endif
-void* realloc(void* old_ptr, size_t new_size) {
- if (old_ptr == NULL) {
-#if ENABLE(WTF_MALLOC_VALIDATION)
- void* result = malloc<crashOnFailure>(new_size);
-#else
- void* result = do_malloc(new_size);
-#ifndef WTF_CHANGES
- MallocHook::InvokeNewHook(result, new_size);
-#endif
-#endif
- return result;
- }
- if (new_size == 0) {
-#ifndef WTF_CHANGES
- MallocHook::InvokeDeleteHook(old_ptr);
-#endif
- free(old_ptr);
- return NULL;
- }
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
- if (std::numeric_limits<size_t>::max() - Internal::ValidationBufferSize <= new_size) // If overflow would occur...
- return 0;
- Internal::ValidationHeader* header = Internal::fastMallocValidationHeader(old_ptr);
- fastMallocValidate(old_ptr);
- old_ptr = header;
- header->m_size = new_size;
- new_size += Internal::ValidationBufferSize;
-#endif
-
- // Get the size of the old entry
- const PageID p = reinterpret_cast<uintptr_t>(old_ptr) >> kPageShift;
- size_t cl = pageheap->GetSizeClassIfCached(p);
- Span *span = NULL;
- size_t old_size;
- if (cl == 0) {
- span = pageheap->GetDescriptor(p);
- cl = span->sizeclass;
- pageheap->CacheSizeClass(p, cl);
- }
- if (cl != 0) {
- old_size = ByteSizeForClass(cl);
- } else {
- ASSERT(span != NULL);
- 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;
- }
-#ifndef WTF_CHANGES
- MallocHook::InvokeNewHook(new_ptr, new_size);
-#endif
- memcpy(new_ptr, old_ptr, ((old_size < new_size) ? old_size : new_size));
-#ifndef WTF_CHANGES
- MallocHook::InvokeDeleteHook(old_ptr);
-#endif
- // We could use a variant of do_free() that leverages the fact
- // that we already know the sizeclass of old_ptr. The benefit
- // would be small, so don't bother.
- do_free(old_ptr);
-#if ENABLE(WTF_MALLOC_VALIDATION)
- new_ptr = static_cast<Internal::ValidationHeader*>(new_ptr) + 1;
- *Internal::fastMallocValidationSuffix(new_ptr) = Internal::ValidationSuffix;
-#endif
- return new_ptr;
- } else {
-#if ENABLE(WTF_MALLOC_VALIDATION)
- old_ptr = static_cast<Internal::ValidationHeader*>(old_ptr) + 1; // Set old_ptr back to the user pointer.
- *Internal::fastMallocValidationSuffix(old_ptr) = Internal::ValidationSuffix;
-#endif
- return old_ptr;
- }
-}
-
-#ifdef WTF_CHANGES
-#undef do_malloc
-#else
-
-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
- 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;
- return p;
- }
- } else { // allocation success
- return p;
- }
-#endif
- }
-}
-
-#if ENABLE(GLOBAL_FASTMALLOC_NEW)
-
-void* operator new(size_t size) {
- void* p = cpp_alloc(size, false);
- // We keep this next instruction out of cpp_alloc for a reason: when
- // it's in, and new just calls cpp_alloc, the optimizer may fold the
- // new call into cpp_alloc, which messes up our whole section-based
- // stacktracing (see ATTRIBUTE_SECTION, above). This ensures cpp_alloc
- // isn't the last thing this fn calls, and prevents the folding.
- MallocHook::InvokeNewHook(p, size);
- return p;
-}
-
-void* operator new(size_t size, const std::nothrow_t&) __THROW {
- void* p = cpp_alloc(size, true);
- MallocHook::InvokeNewHook(p, size);
- return p;
-}
-
-void operator delete(void* p) __THROW {
- MallocHook::InvokeDeleteHook(p);
- do_free(p);
-}
-
-void operator delete(void* p, const std::nothrow_t&) __THROW {
- MallocHook::InvokeDeleteHook(p);
- do_free(p);
-}
-
-void* operator new[](size_t size) {
- void* p = cpp_alloc(size, false);
- // We keep this next instruction out of cpp_alloc for a reason: when
- // it's in, and new just calls cpp_alloc, the optimizer may fold the
- // new call into cpp_alloc, which messes up our whole section-based
- // stacktracing (see ATTRIBUTE_SECTION, above). This ensures cpp_alloc
- // isn't the last thing this fn calls, and prevents the folding.
- MallocHook::InvokeNewHook(p, size);
- return p;
-}
-
-void* operator new[](size_t size, const std::nothrow_t&) __THROW {
- void* p = cpp_alloc(size, true);
- MallocHook::InvokeNewHook(p, size);
- return p;
-}
-
-void operator delete[](void* p) __THROW {
- MallocHook::InvokeDeleteHook(p);
- do_free(p);
-}
-
-void operator delete[](void* p, const std::nothrow_t&) __THROW {
- MallocHook::InvokeDeleteHook(p);
- do_free(p);
-}
-
-#endif
-
-extern "C" void* memalign(size_t align, size_t size) __THROW {
- 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)
- __THROW {
- 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;
- }
-}
-
-static size_t pagesize = 0;
-
-extern "C" void* valloc(size_t size) __THROW {
- // 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) __THROW {
- // 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) {
- do_malloc_stats();
-}
-
-extern "C" int mallopt(int cmd, int value) {
- return do_mallopt(cmd, value);
-}
-
-#ifdef HAVE_STRUCT_MALLINFO
-extern "C" struct mallinfo mallinfo(void) {
- return do_mallinfo();
-}
-#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 (defined as part of glibc) also point to
-// the same implementations.
-//-------------------------------------------------------------------
-
-#if defined(__GLIBC__)
-extern "C" {
-#if COMPILER(GCC) && !defined(__MACH__) && defined(HAVE___ATTRIBUTE__)
- // Potentially faster variants that use the gcc alias extension.
- // Mach-O (Darwin) does not support weak aliases, hence the __MACH__ check.
-# 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 /* not __GNUC__ */
- // 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 /* __GNUC__ */
-}
-#endif /* __GLIBC__ */
-
-// 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)
- __THROW {
- void* result = do_memalign(align, size);
- MallocHook::InvokeNewHook(result, size);
- return result;
-}
-void *(*__memalign_hook)(size_t, size_t, const void *) = MemalignOverride;
-
-#endif
-
-#ifdef WTF_CHANGES
-void releaseFastMallocFreeMemory()
-{
- // Flush free pages in the current thread cache back to the page heap.
- // Low watermark mechanism in Scavenge() prevents full return on the first pass.
- // The second pass flushes everything.
- if (TCMalloc_ThreadCache* threadCache = TCMalloc_ThreadCache::GetCacheIfPresent()) {
- threadCache->Scavenge();
- threadCache->Scavenge();
- }
-
- SpinLockHolder h(&pageheap_lock);
- pageheap->ReleaseFreePages();
-}
-
-FastMallocStatistics fastMallocStatistics()
-{
- FastMallocStatistics statistics;
-
- SpinLockHolder lockHolder(&pageheap_lock);
- statistics.reservedVMBytes = static_cast<size_t>(pageheap->SystemBytes());
- statistics.committedVMBytes = statistics.reservedVMBytes - pageheap->ReturnedBytes();
-
- statistics.freeListBytes = 0;
- for (unsigned cl = 0; cl < kNumClasses; ++cl) {
- const int length = central_cache[cl].length();
- const int tc_length = central_cache[cl].tc_length();
-
- statistics.freeListBytes += ByteSizeForClass(cl) * (length + tc_length);
- }
- for (TCMalloc_ThreadCache* threadCache = thread_heaps; threadCache ; threadCache = threadCache->next_)
- statistics.freeListBytes += threadCache->Size();
-
- return statistics;
-}
-
-size_t fastMallocSize(const void* ptr)
-{
-#if ENABLE(WTF_MALLOC_VALIDATION)
- return Internal::fastMallocValidationHeader(const_cast<void*>(ptr))->m_size;
-#else
- const PageID p = reinterpret_cast<uintptr_t>(ptr) >> kPageShift;
- Span* span = pageheap->GetDescriptorEnsureSafe(p);
-
- if (!span || span->free)
- return 0;
-
- for (void* free = span->objects; free != NULL; free = *((void**) free)) {
- if (ptr == free)
- return 0;
- }
-
- if (size_t cl = span->sizeclass)
- return ByteSizeForClass(cl);
-
- return span->length << kPageShift;
-#endif
-}
-
-#if OS(DARWIN)
-
-class FreeObjectFinder {
- const RemoteMemoryReader& m_reader;
- HashSet<void*> m_freeObjects;
-
-public:
- FreeObjectFinder(const RemoteMemoryReader& reader) : m_reader(reader) { }
-
- void visit(void* ptr) { m_freeObjects.add(ptr); }
- bool isFreeObject(void* ptr) const { return m_freeObjects.contains(ptr); }
- bool isFreeObject(vm_address_t ptr) const { return isFreeObject(reinterpret_cast<void*>(ptr)); }
- size_t freeObjectCount() const { return m_freeObjects.size(); }
-
- void findFreeObjects(TCMalloc_ThreadCache* threadCache)
- {
- for (; threadCache; threadCache = (threadCache->next_ ? m_reader(threadCache->next_) : 0))
- threadCache->enumerateFreeObjects(*this, m_reader);
- }
-
- void findFreeObjects(TCMalloc_Central_FreeListPadded* centralFreeList, size_t numSizes, TCMalloc_Central_FreeListPadded* remoteCentralFreeList)
- {
- for (unsigned i = 0; i < numSizes; i++)
- centralFreeList[i].enumerateFreeObjects(*this, m_reader, remoteCentralFreeList + i);
- }
-};
-
-class PageMapFreeObjectFinder {
- const RemoteMemoryReader& m_reader;
- FreeObjectFinder& m_freeObjectFinder;
-
-public:
- PageMapFreeObjectFinder(const RemoteMemoryReader& reader, FreeObjectFinder& freeObjectFinder)
- : m_reader(reader)
- , m_freeObjectFinder(freeObjectFinder)
- { }
-
- int visit(void* ptr) const
- {
- if (!ptr)
- return 1;
-
- Span* span = m_reader(reinterpret_cast<Span*>(ptr));
- if (!span)
- return 1;
-
- if (span->free) {
- void* ptr = reinterpret_cast<void*>(span->start << kPageShift);
- m_freeObjectFinder.visit(ptr);
- } else if (span->sizeclass) {
- // Walk the free list of the small-object span, keeping track of each object seen
- for (void* nextObject = span->objects; nextObject; nextObject = m_reader.nextEntryInLinkedList(reinterpret_cast<void**>(nextObject)))
- m_freeObjectFinder.visit(nextObject);
- }
- return span->length;
- }
-};
-
-class PageMapMemoryUsageRecorder {
- task_t m_task;
- void* m_context;
- unsigned m_typeMask;
- vm_range_recorder_t* m_recorder;
- const RemoteMemoryReader& m_reader;
- const FreeObjectFinder& m_freeObjectFinder;
-
- HashSet<void*> m_seenPointers;
- Vector<Span*> m_coalescedSpans;
-
-public:
- PageMapMemoryUsageRecorder(task_t task, void* context, unsigned typeMask, vm_range_recorder_t* recorder, const RemoteMemoryReader& reader, const FreeObjectFinder& freeObjectFinder)
- : m_task(task)
- , m_context(context)
- , m_typeMask(typeMask)
- , m_recorder(recorder)
- , m_reader(reader)
- , m_freeObjectFinder(freeObjectFinder)
- { }
-
- ~PageMapMemoryUsageRecorder()
- {
- ASSERT(!m_coalescedSpans.size());
- }
-
- void recordPendingRegions()
- {
- Span* lastSpan = m_coalescedSpans[m_coalescedSpans.size() - 1];
- vm_range_t ptrRange = { m_coalescedSpans[0]->start << kPageShift, 0 };
- ptrRange.size = (lastSpan->start << kPageShift) - ptrRange.address + (lastSpan->length * kPageSize);
-
- // Mark the memory region the spans represent as a candidate for containing pointers
- if (m_typeMask & MALLOC_PTR_REGION_RANGE_TYPE)
- (*m_recorder)(m_task, m_context, MALLOC_PTR_REGION_RANGE_TYPE, &ptrRange, 1);
-
- if (!(m_typeMask & MALLOC_PTR_IN_USE_RANGE_TYPE)) {
- m_coalescedSpans.clear();
- return;
- }
-
- Vector<vm_range_t, 1024> allocatedPointers;
- for (size_t i = 0; i < m_coalescedSpans.size(); ++i) {
- Span *theSpan = m_coalescedSpans[i];
- if (theSpan->free)
- continue;
-
- vm_address_t spanStartAddress = theSpan->start << kPageShift;
- vm_size_t spanSizeInBytes = theSpan->length * kPageSize;
-
- if (!theSpan->sizeclass) {
- // If it's an allocated large object span, mark it as in use
- if (!m_freeObjectFinder.isFreeObject(spanStartAddress))
- allocatedPointers.append((vm_range_t){spanStartAddress, spanSizeInBytes});
- } else {
- const size_t objectSize = ByteSizeForClass(theSpan->sizeclass);
-
- // Mark each allocated small object within the span as in use
- const vm_address_t endOfSpan = spanStartAddress + spanSizeInBytes;
- for (vm_address_t object = spanStartAddress; object + objectSize <= endOfSpan; object += objectSize) {
- if (!m_freeObjectFinder.isFreeObject(object))
- allocatedPointers.append((vm_range_t){object, objectSize});
- }
- }
- }
-
- (*m_recorder)(m_task, m_context, MALLOC_PTR_IN_USE_RANGE_TYPE, allocatedPointers.data(), allocatedPointers.size());
-
- m_coalescedSpans.clear();
- }
-
- int visit(void* ptr)
- {
- if (!ptr)
- return 1;
-
- Span* span = m_reader(reinterpret_cast<Span*>(ptr));
- if (!span || !span->start)
- return 1;
-
- if (m_seenPointers.contains(ptr))
- return span->length;
- m_seenPointers.add(ptr);
-
- if (!m_coalescedSpans.size()) {
- m_coalescedSpans.append(span);
- return span->length;
- }
-
- Span* previousSpan = m_coalescedSpans[m_coalescedSpans.size() - 1];
- vm_address_t previousSpanStartAddress = previousSpan->start << kPageShift;
- vm_size_t previousSpanSizeInBytes = previousSpan->length * kPageSize;
-
- // If the new span is adjacent to the previous span, do nothing for now.
- vm_address_t spanStartAddress = span->start << kPageShift;
- if (spanStartAddress == previousSpanStartAddress + previousSpanSizeInBytes) {
- m_coalescedSpans.append(span);
- return span->length;
- }
-
- // New span is not adjacent to previous span, so record the spans coalesced so far.
- recordPendingRegions();
- m_coalescedSpans.append(span);
-
- return span->length;
- }
-};
-
-class AdminRegionRecorder {
- task_t m_task;
- void* m_context;
- unsigned m_typeMask;
- vm_range_recorder_t* m_recorder;
- const RemoteMemoryReader& m_reader;
-
- Vector<vm_range_t, 1024> m_pendingRegions;
-
-public:
- AdminRegionRecorder(task_t task, void* context, unsigned typeMask, vm_range_recorder_t* recorder, const RemoteMemoryReader& reader)
- : m_task(task)
- , m_context(context)
- , m_typeMask(typeMask)
- , m_recorder(recorder)
- , m_reader(reader)
- { }
-
- void recordRegion(vm_address_t ptr, size_t size)
- {
- if (m_typeMask & MALLOC_ADMIN_REGION_RANGE_TYPE)
- m_pendingRegions.append((vm_range_t){ ptr, size });
- }
-
- void visit(void *ptr, size_t size)
- {
- recordRegion(reinterpret_cast<vm_address_t>(ptr), size);
- }
-
- void recordPendingRegions()
- {
- if (m_pendingRegions.size()) {
- (*m_recorder)(m_task, m_context, MALLOC_ADMIN_REGION_RANGE_TYPE, m_pendingRegions.data(), m_pendingRegions.size());
- m_pendingRegions.clear();
- }
- }
-
- ~AdminRegionRecorder()
- {
- ASSERT(!m_pendingRegions.size());
- }
-};
-
-kern_return_t FastMallocZone::enumerate(task_t task, void* context, unsigned typeMask, vm_address_t zoneAddress, memory_reader_t reader, vm_range_recorder_t recorder)
-{
- RemoteMemoryReader memoryReader(task, reader);
-
- InitSizeClasses();
-
- FastMallocZone* mzone = memoryReader(reinterpret_cast<FastMallocZone*>(zoneAddress));
- TCMalloc_PageHeap* pageHeap = memoryReader(mzone->m_pageHeap);
- TCMalloc_ThreadCache** threadHeapsPointer = memoryReader(mzone->m_threadHeaps);
- TCMalloc_ThreadCache* threadHeaps = memoryReader(*threadHeapsPointer);
-
- TCMalloc_Central_FreeListPadded* centralCaches = memoryReader(mzone->m_centralCaches, sizeof(TCMalloc_Central_FreeListPadded) * kNumClasses);
-
- FreeObjectFinder finder(memoryReader);
- finder.findFreeObjects(threadHeaps);
- finder.findFreeObjects(centralCaches, kNumClasses, mzone->m_centralCaches);
-
- TCMalloc_PageHeap::PageMap* pageMap = &pageHeap->pagemap_;
- PageMapFreeObjectFinder pageMapFinder(memoryReader, finder);
- pageMap->visitValues(pageMapFinder, memoryReader);
-
- PageMapMemoryUsageRecorder usageRecorder(task, context, typeMask, recorder, memoryReader, finder);
- pageMap->visitValues(usageRecorder, memoryReader);
- usageRecorder.recordPendingRegions();
-
- AdminRegionRecorder adminRegionRecorder(task, context, typeMask, recorder, memoryReader);
- pageMap->visitAllocations(adminRegionRecorder, memoryReader);
-
- PageHeapAllocator<Span>* spanAllocator = memoryReader(mzone->m_spanAllocator);
- PageHeapAllocator<TCMalloc_ThreadCache>* pageHeapAllocator = memoryReader(mzone->m_pageHeapAllocator);
-
- spanAllocator->recordAdministrativeRegions(adminRegionRecorder, memoryReader);
- pageHeapAllocator->recordAdministrativeRegions(adminRegionRecorder, memoryReader);
-
- adminRegionRecorder.recordPendingRegions();
-
- return 0;
-}
-
-size_t FastMallocZone::size(malloc_zone_t*, const void*)
-{
- return 0;
-}
-
-void* FastMallocZone::zoneMalloc(malloc_zone_t*, size_t)
-{
- return 0;
-}
-
-void* FastMallocZone::zoneCalloc(malloc_zone_t*, size_t, size_t)
-{
- return 0;
-}
-
-void FastMallocZone::zoneFree(malloc_zone_t*, void* ptr)
-{
- // Due to <rdar://problem/5671357> zoneFree may be called by the system free even if the pointer
- // is not in this zone. When this happens, the pointer being freed was not allocated by any
- // zone so we need to print a useful error for the application developer.
- malloc_printf("*** error for object %p: pointer being freed was not allocated\n", ptr);
-}
-
-void* FastMallocZone::zoneRealloc(malloc_zone_t*, void*, size_t)
-{
- return 0;
-}
-
-
-#undef malloc
-#undef free
-#undef realloc
-#undef calloc
-
-extern "C" {
-malloc_introspection_t jscore_fastmalloc_introspection = { &FastMallocZone::enumerate, &FastMallocZone::goodSize, &FastMallocZone::check, &FastMallocZone::print,
- &FastMallocZone::log, &FastMallocZone::forceLock, &FastMallocZone::forceUnlock, &FastMallocZone::statistics
-
- , 0 // zone_locked will not be called on the zone unless it advertises itself as version five or higher.
- , 0, 0, 0, 0 // These members will not be used unless the zone advertises itself as version seven or higher.
-
- };
-}
-
-FastMallocZone::FastMallocZone(TCMalloc_PageHeap* pageHeap, TCMalloc_ThreadCache** threadHeaps, TCMalloc_Central_FreeListPadded* centralCaches, PageHeapAllocator<Span>* spanAllocator, PageHeapAllocator<TCMalloc_ThreadCache>* pageHeapAllocator)
- : m_pageHeap(pageHeap)
- , m_threadHeaps(threadHeaps)
- , m_centralCaches(centralCaches)
- , m_spanAllocator(spanAllocator)
- , m_pageHeapAllocator(pageHeapAllocator)
-{
- memset(&m_zone, 0, sizeof(m_zone));
- m_zone.version = 4;
- m_zone.zone_name = "JavaScriptCore FastMalloc";
- m_zone.size = &FastMallocZone::size;
- m_zone.malloc = &FastMallocZone::zoneMalloc;
- m_zone.calloc = &FastMallocZone::zoneCalloc;
- m_zone.realloc = &FastMallocZone::zoneRealloc;
- m_zone.free = &FastMallocZone::zoneFree;
- m_zone.valloc = &FastMallocZone::zoneValloc;
- m_zone.destroy = &FastMallocZone::zoneDestroy;
- m_zone.introspect = &jscore_fastmalloc_introspection;
- malloc_zone_register(&m_zone);
-}
-
-
-void FastMallocZone::init()
-{
- static FastMallocZone zone(pageheap, &thread_heaps, static_cast<TCMalloc_Central_FreeListPadded*>(central_cache), &span_allocator, &threadheap_allocator);
-}
-
-#endif // OS(DARWIN)
-
-} // namespace WTF
-#endif // WTF_CHANGES
-
-#endif // FORCE_SYSTEM_MALLOC
projects / apple / javascriptcore.git / blobdiff