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chromium / chromium / src / 7d5426fdb05ade9631fa3d9d0fe6135b272eb147 / . / third_party / tcmalloc / chromium / src / tcmalloc.cc
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// Copyright (c) 2005, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// ---
// Author: Sanjay Ghemawat <opensource@google.com>
//
// A malloc that uses a per-thread cache to satisfy small malloc requests.
// (The time for malloc/free of a small object drops from 300 ns to 50 ns.)
//
// See doc/tcmalloc.html for a high-level
// description of how this malloc works.
//
// SYNCHRONIZATION
// 1. The thread-specific lists are accessed without acquiring any locks.
// This is safe because each such list is only accessed by one thread.
// 2. We have a lock per central free-list, and hold it while manipulating
// the central free list for a particular size.
// 3. The central page allocator is protected by "pageheap_lock".
// 4. The pagemap (which maps from page-number to descriptor),
// can be read without holding any locks, and written while holding
// the "pageheap_lock".
// 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.
//
// PAGEMAP
// -------
// Page map contains a mapping from page id to Span.
//
// If Span s occupies pages [p..q],
// pagemap[p] == s
// pagemap[q] == s
// pagemap[p+1..q-1] are undefined
// pagemap[p-1] and pagemap[q+1] are defined:
// NULL if the corresponding page is not yet in the address space.
// Otherwise it points to a Span. This span may be free
// or allocated. If free, it is in one of pageheap's freelist.
//
// 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 <gperftools/tcmalloc.h>
#include <errno.h> // for ENOMEM, EINVAL, errno
#ifdef HAVE_SYS_CDEFS_H
#include <sys/cdefs.h> // for __THROW
#endif
#if defined HAVE_STDINT_H
#include <stdint.h>
#elif defined HAVE_INTTYPES_H
#include <inttypes.h>
#else
#include <sys/types.h>
#endif
#include <stddef.h> // for size_t, NULL
#include <stdlib.h> // for getenv
#include <string.h> // for strcmp, memset, strlen, etc
#ifdef HAVE_UNISTD_H
#include <unistd.h> // for getpagesize, write, etc
#endif
#include <algorithm> // for max, min
#include <limits> // for numeric_limits
#include <new> // for nothrow_t (ptr only), etc
#include <vector> // for vector
#include <gperftools/malloc_extension.h>
#include <gperftools/malloc_hook.h> // for MallocHook
#include "base/basictypes.h" // for int64
#include "base/commandlineflags.h" // for RegisterFlagValidator, etc
#include "base/dynamic_annotations.h" // for RunningOnValgrind
#include "base/spinlock.h" // for SpinLockHolder
#include "central_freelist.h" // for CentralFreeListPadded
#include "common.h" // for StackTrace, kPageShift, etc
#include "free_list.h" // for FL_Init
#include "internal_logging.h" // for ASSERT, TCMalloc_Printer, etc
#include "malloc_hook-inl.h" // for MallocHook::InvokeNewHook, etc
#include "page_heap.h" // for PageHeap, PageHeap::Stats
#include "page_heap_allocator.h" // for PageHeapAllocator
#include "span.h" // for Span, DLL_Prepend, etc
#include "stack_trace_table.h" // for StackTraceTable
#include "static_vars.h" // for Static
#include "system-alloc.h" // for DumpSystemAllocatorStats, etc
#include "tcmalloc_guard.h" // for TCMallocGuard
#include "thread_cache.h" // for ThreadCache
#if (defined(_WIN32) && !defined(__CYGWIN__) && !defined(__CYGWIN32__)) && !defined(WIN32_OVERRIDE_ALLOCATORS)
# define WIN32_DO_PATCHING 1
#endif
// Some windows file somewhere (at least on cygwin) #define's small (!)
// For instance, <windows.h> appears to have "#define small char".
#undef small
using STL_NAMESPACE::max;
using STL_NAMESPACE::min;
using STL_NAMESPACE::numeric_limits;
using STL_NAMESPACE::vector;
#include "libc_override.h"
// __THROW is defined in glibc (via <sys/cdefs.h>). 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
using tcmalloc::AlignmentForSize;
using tcmalloc::kLog;
using tcmalloc::kCrash;
using tcmalloc::kCrashWithStats;
using tcmalloc::Log;
using tcmalloc::PageHeap;
using tcmalloc::PageHeapAllocator;
using tcmalloc::SizeMap;
using tcmalloc::Span;
using tcmalloc::StackTrace;
using tcmalloc::Static;
using tcmalloc::ThreadCache;
// ---- Functions doing validation with an extra mark.
static size_t ExcludeSpaceForMark(size_t size);
static void AddRoomForMark(size_t* size);
static void ExcludeMarkFromSize(size_t* new_size);
static void MarkAllocatedRegion(void* ptr);
static void ValidateAllocatedRegion(void* ptr, size_t cl);
// ---- End validation functions.
DECLARE_int64(tcmalloc_sample_parameter);
DECLARE_double(tcmalloc_release_rate);
// For windows, the printf we use to report large allocs is
// potentially dangerous: it could cause a malloc that would cause an
// infinite loop. So by default we set the threshold to a huge number
// on windows, so this bad situation will never trigger. You can
// always set TCMALLOC_LARGE_ALLOC_REPORT_THRESHOLD manually if you
// want this functionality.
#ifdef _WIN32
const int64 kDefaultLargeAllocReportThreshold = static_cast<int64>(1) << 62;
#else
const int64 kDefaultLargeAllocReportThreshold = static_cast<int64>(1) << 30;
#endif
DEFINE_int64(tcmalloc_large_alloc_report_threshold,
EnvToInt64("TCMALLOC_LARGE_ALLOC_REPORT_THRESHOLD",
kDefaultLargeAllocReportThreshold),
"Allocations larger than this value cause a stack "
"trace to be dumped to stderr. The threshold for "
"dumping stack traces is increased by a factor of 1.125 "
"every time we print a message so that the threshold "
"automatically goes up by a factor of ~1000 every 60 "
"messages. This bounds the amount of extra logging "
"generated by this flag. Default value of this flag "
"is very large and therefore you should see no extra "
"logging unless the flag is overridden. Set to 0 to "
"disable reporting entirely.");
// We already declared these functions in tcmalloc.h, but we have to
// declare them again to give them an ATTRIBUTE_SECTION: we want to
// put all callers of MallocHook::Invoke* in this module into
// ATTRIBUTE_SECTION(google_malloc) section, so that
// MallocHook::GetCallerStackTrace can function accurately.
extern "C" {
void* tc_malloc(size_t size) __THROW
ATTRIBUTE_SECTION(google_malloc);
void tc_free(void* ptr) __THROW
ATTRIBUTE_SECTION(google_malloc);
void* tc_realloc(void* ptr, size_t size) __THROW
ATTRIBUTE_SECTION(google_malloc);
void* tc_calloc(size_t nmemb, size_t size) __THROW
ATTRIBUTE_SECTION(google_malloc);
void tc_cfree(void* ptr) __THROW
ATTRIBUTE_SECTION(google_malloc);
void* tc_memalign(size_t __alignment, size_t __size) __THROW
ATTRIBUTE_SECTION(google_malloc);
int tc_posix_memalign(void** ptr, size_t align, size_t size) __THROW
ATTRIBUTE_SECTION(google_malloc);
void* tc_valloc(size_t __size) __THROW
ATTRIBUTE_SECTION(google_malloc);
void* tc_pvalloc(size_t __size) __THROW
ATTRIBUTE_SECTION(google_malloc);
void tc_malloc_stats(void) __THROW
ATTRIBUTE_SECTION(google_malloc);
int tc_mallopt(int cmd, int value) __THROW
ATTRIBUTE_SECTION(google_malloc);
#ifdef HAVE_STRUCT_MALLINFO
struct mallinfo tc_mallinfo(void) __THROW
ATTRIBUTE_SECTION(google_malloc);
#endif
void* tc_new(size_t size)
ATTRIBUTE_SECTION(google_malloc);
void tc_delete(void* p) __THROW
ATTRIBUTE_SECTION(google_malloc);
void* tc_newarray(size_t size)
ATTRIBUTE_SECTION(google_malloc);
void tc_deletearray(void* p) __THROW
ATTRIBUTE_SECTION(google_malloc);
// And the nothrow variants of these:
void* tc_new_nothrow(size_t size, const std::nothrow_t&) __THROW
ATTRIBUTE_SECTION(google_malloc);
void* tc_newarray_nothrow(size_t size, const std::nothrow_t&) __THROW
ATTRIBUTE_SECTION(google_malloc);
// Surprisingly, standard C++ library implementations use a
// nothrow-delete internally. See, eg:
// http://www.dinkumware.com/manuals/?manual=compleat&page=new.html
void tc_delete_nothrow(void* ptr, const std::nothrow_t&) __THROW
ATTRIBUTE_SECTION(google_malloc);
void tc_deletearray_nothrow(void* ptr, const std::nothrow_t&) __THROW
ATTRIBUTE_SECTION(google_malloc);
// Some non-standard extensions that we support.
// This is equivalent to
// OS X: malloc_size()
// glibc: malloc_usable_size()
// Windows: _msize()
size_t tc_malloc_size(void* p) __THROW
ATTRIBUTE_SECTION(google_malloc);
void* tc_malloc_skip_new_handler(size_t size)
ATTRIBUTE_SECTION(google_malloc);
} // extern "C"
// ----------------------- IMPLEMENTATION -------------------------------
static int tc_new_mode = 0; // See tc_set_new_mode().
// Routines such as free() and realloc() catch some erroneous pointers
// passed to them, and invoke the below when they do. (An erroneous pointer
// won't be caught if it's within a valid span or a stale span for which
// the pagemap cache has a non-zero sizeclass.) This is a cheap (source-editing
// required) kind of exception handling for these routines.
namespace {
void InvalidFree(void* ptr) {
Log(kCrash, __FILE__, __LINE__, "Attempt to free invalid pointer", ptr);
}
size_t InvalidGetSizeForRealloc(const void* old_ptr) {
Log(kCrash, __FILE__, __LINE__,
"Attempt to realloc invalid pointer", old_ptr);
return 0;
}
size_t InvalidGetAllocatedSize(const void* ptr) {
Log(kCrash, __FILE__, __LINE__,
"Attempt to get the size of an invalid pointer", ptr);
return 0;
}
// For security reasons, we want to limit the size of allocations.
// See crbug.com/169327.
inline bool IsAllocSizePermitted(size_t alloc_size) {
// Never allow an allocation larger than what can be indexed via an int.
// Remove kPageSize to account for various rounding, padding and to have a
// small margin.
return alloc_size <= ((std::numeric_limits<int>::max)() - kPageSize);
}
} // unnamed namespace
// Extract interesting stats
struct TCMallocStats {
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 metadata_bytes; // Bytes alloced for metadata
uint64_t metadata_unmapped_bytes; // Address space reserved for metadata
// but is not committed.
PageHeap::Stats pageheap; // Stats from page heap
};
// Get stats into "r". Also get per-size-class counts if class_count != NULL
static void ExtractStats(TCMallocStats* r, uint64_t* class_count,
PageHeap::SmallSpanStats* small_spans,
PageHeap::LargeSpanStats* large_spans) {
r->central_bytes = 0;
r->transfer_bytes = 0;
for (int cl = 0; cl < kNumClasses; ++cl) {
const int length = Static::central_cache()[cl].length();
const int tc_length = Static::central_cache()[cl].tc_length();
const size_t cache_overhead = Static::central_cache()[cl].OverheadBytes();
const size_t size = static_cast<uint64_t>(
Static::sizemap()->ByteSizeForClass(cl));
r->central_bytes += (size * length) + cache_overhead;
r->transfer_bytes += (size * tc_length);
if (class_count) class_count[cl] = length + tc_length;
}
// Add stats from per-thread heaps
r->thread_bytes = 0;
{ // scope
SpinLockHolder h(Static::pageheap_lock());
ThreadCache::GetThreadStats(&r->thread_bytes, class_count);
r->metadata_bytes = tcmalloc::metadata_system_bytes();
r->metadata_unmapped_bytes = tcmalloc::metadata_unmapped_bytes();
r->pageheap = Static::pageheap()->stats();
if (small_spans != NULL) {
Static::pageheap()->GetSmallSpanStats(small_spans);
}
if (large_spans != NULL) {
Static::pageheap()->GetLargeSpanStats(large_spans);
}
}
}
static double PagesToMiB(uint64_t pages) {
return (pages << kPageShift) / 1048576.0;
}
// WRITE stats to "out"
static void DumpStats(TCMalloc_Printer* out, int level) {
TCMallocStats stats;
uint64_t class_count[kNumClasses];
PageHeap::SmallSpanStats small;
PageHeap::LargeSpanStats large;
if (level >= 2) {
ExtractStats(&stats, class_count, &small, &large);
} else {
ExtractStats(&stats, NULL, NULL, NULL);
}
static const double MiB = 1048576.0;
const uint64_t physical_memory_used_by_metadata =
stats.metadata_bytes - stats.metadata_unmapped_bytes;
const uint64_t unmapped_bytes =
stats.pageheap.unmapped_bytes + stats.metadata_unmapped_bytes;
const uint64_t virtual_memory_used = (stats.pageheap.system_bytes
+ stats.metadata_bytes);
const uint64_t physical_memory_used = virtual_memory_used - unmapped_bytes;
const uint64_t bytes_in_use_by_app = (physical_memory_used
- physical_memory_used_by_metadata
- stats.pageheap.free_bytes
- stats.central_bytes
- stats.transfer_bytes
- stats.thread_bytes);
out->printf(
"WASTE: %7.1f MiB bytes in use\n"
"WASTE: + %7.1f MiB committed but not used\n"
"WASTE: ------------\n"
"WASTE: = %7.1f MiB bytes committed\n"
"WASTE: committed/used ratio of %f\n",
bytes_in_use_by_app / MiB,
(stats.pageheap.committed_bytes - bytes_in_use_by_app) / MiB,
stats.pageheap.committed_bytes / MiB,
stats.pageheap.committed_bytes / static_cast<double>(bytes_in_use_by_app)
);
#ifdef TCMALLOC_SMALL_BUT_SLOW
out->printf(
"NOTE: SMALL MEMORY MODEL IS IN USE, PERFORMANCE MAY SUFFER.\n");
#endif
out->printf(
"------------------------------------------------\n"
"MALLOC: %12" PRIu64 " (%7.1f MiB) Bytes in use by application\n"
"MALLOC: + %12" PRIu64 " (%7.1f MiB) Bytes in page heap freelist\n"
"MALLOC: + %12" PRIu64 " (%7.1f MiB) Bytes in central cache freelist\n"
"MALLOC: + %12" PRIu64 " (%7.1f MiB) Bytes in transfer cache freelist\n"
"MALLOC: + %12" PRIu64 " (%7.1f MiB) Bytes in thread cache freelists\n"
"MALLOC: ------------\n"
"MALLOC: = %12" PRIu64 " (%7.1f MiB) Bytes committed\n"
"MALLOC: + %12" PRIu64 " (%7.1f MiB) Bytes in malloc metadata\n"
"MALLOC: ------------\n"
"MALLOC: = %12" PRIu64 " (%7.1f MiB) Actual memory used (physical + swap)\n"
"MALLOC: + %12" PRIu64 " (%7.1f MiB) Bytes released to OS (aka unmapped)\n"
"MALLOC: ------------\n"
"MALLOC: = %12" PRIu64 " (%7.1f MiB) Virtual address space used\n"
"MALLOC:\n"
"MALLOC: %12" PRIu64 " Spans in use\n"
"MALLOC: %12" PRIu64 " Thread heaps in use\n"
"MALLOC: %12" PRIu64 " Tcmalloc page size\n"
"------------------------------------------------\n"
"Call ReleaseFreeMemory() to release freelist memory to the OS"
" (via madvise()).\n"
"Bytes released to the OS take up virtual address space"
" but no physical memory.\n",
bytes_in_use_by_app, bytes_in_use_by_app / MiB,
stats.pageheap.free_bytes, stats.pageheap.free_bytes / MiB,
stats.central_bytes, stats.central_bytes / MiB,
stats.transfer_bytes, stats.transfer_bytes / MiB,
stats.thread_bytes, stats.thread_bytes / MiB,
stats.pageheap.committed_bytes, stats.pageheap.committed_bytes / MiB,
physical_memory_used_by_metadata , physical_memory_used_by_metadata / MiB,
physical_memory_used, physical_memory_used / MiB,
unmapped_bytes, unmapped_bytes / MiB,
virtual_memory_used, virtual_memory_used / MiB,
uint64_t(Static::span_allocator()->inuse()),
uint64_t(ThreadCache::HeapsInUse()),
uint64_t(kPageSize));
if (level >= 2) {
out->printf("------------------------------------------------\n");
out->printf("Size class breakdown\n");
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] * Static::sizemap()->ByteSizeForClass(cl);
cumulative += class_bytes;
out->printf("class %3d [ %8" PRIuS " bytes ] : "
"%8" PRIu64 " objs; %5.1f MiB; %5.1f cum MiB\n",
cl, Static::sizemap()->ByteSizeForClass(cl),
class_count[cl],
class_bytes / MiB,
cumulative / MiB);
}
}
// append page heap info
int nonempty_sizes = 0;
for (int s = 0; s < kMaxPages; s++) {
if (small.normal_length[s] + small.returned_length[s] > 0) {
nonempty_sizes++;
}
}
out->printf("------------------------------------------------\n");
out->printf("PageHeap: %d sizes; %6.1f MiB free; %6.1f MiB unmapped\n",
nonempty_sizes, stats.pageheap.free_bytes / MiB,
stats.pageheap.unmapped_bytes / MiB);
out->printf("------------------------------------------------\n");
uint64_t total_normal = 0;
uint64_t total_returned = 0;
for (int s = 0; s < kMaxPages; s++) {
const int n_length = small.normal_length[s];
const int r_length = small.returned_length[s];
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 MiB; %6.1f MiB cum"
"; unmapped: %6.1f MiB; %6.1f MiB cum\n",
s,
(n_length + r_length),
PagesToMiB(n_pages + r_pages),
PagesToMiB(total_normal + total_returned),
PagesToMiB(r_pages),
PagesToMiB(total_returned));
}
}
total_normal += large.normal_pages;
total_returned += large.returned_pages;
out->printf(">255 large * %6u spans ~ %6.1f MiB; %6.1f MiB cum"
"; unmapped: %6.1f MiB; %6.1f MiB cum\n",
static_cast<unsigned int>(large.spans),
PagesToMiB(large.normal_pages + large.returned_pages),
PagesToMiB(total_normal + total_returned),
PagesToMiB(large.returned_pages),
PagesToMiB(total_returned));
}
}
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** DumpHeapGrowthStackTraces() {
// Count how much space we need
int needed_slots = 0;
{
SpinLockHolder h(Static::pageheap_lock());
for (StackTrace* t = Static::growth_stacks();
t != NULL;
t = reinterpret_cast<StackTrace*>(
t->stack[tcmalloc::kMaxStackDepth-1])) {
needed_slots += 3 + t->depth;
}
needed_slots += 100; // Slop in case list grows
needed_slots += needed_slots/8; // An extra 12.5% slop
}
void** result = new void*[needed_slots];
if (result == NULL) {
Log(kLog, __FILE__, __LINE__,
"tcmalloc: allocation failed for stack trace slots",
needed_slots * sizeof(*result));
return NULL;
}
SpinLockHolder h(Static::pageheap_lock());
int used_slots = 0;
for (StackTrace* t = Static::growth_stacks();
t != NULL;
t = reinterpret_cast<StackTrace*>(
t->stack[tcmalloc::kMaxStackDepth-1])) {
ASSERT(used_slots < needed_slots); // Need to leave room for terminator
if (used_slots + 3 + t->depth >= needed_slots) {
// No more room
break;
}
result[used_slots+0] = reinterpret_cast<void*>(static_cast<uintptr_t>(1));
result[used_slots+1] = reinterpret_cast<void*>(t->size);
result[used_slots+2] = reinterpret_cast<void*>(t->depth);
for (int d = 0; d < t->depth; d++) {
result[used_slots+3+d] = t->stack[d];
}
used_slots += 3 + t->depth;
}
result[used_slots] = reinterpret_cast<void*>(static_cast<uintptr_t>(0));
return result;
}
static void IterateOverRanges(void* arg, MallocExtension::RangeFunction func) {
PageID page = 1; // Some code may assume that page==0 is never used
bool done = false;
while (!done) {
// Accumulate a small number of ranges in a local buffer
static const int kNumRanges = 16;
static base::MallocRange ranges[kNumRanges];
int n = 0;
{
SpinLockHolder h(Static::pageheap_lock());
while (n < kNumRanges) {
if (!Static::pageheap()->GetNextRange(page, &ranges[n])) {
done = true;
break;
} else {
uintptr_t limit = ranges[n].address + ranges[n].length;
page = (limit + kPageSize - 1) >> kPageShift;
n++;
}
}
}
for (int i = 0; i < n; i++) {
(*func)(arg, &ranges[i]);
}
}
}
// TCMalloc's support for extra malloc interfaces
class TCMallocImplementation : public MallocExtension {
private:
// ReleaseToSystem() might release more than the requested bytes because
// the page heap releases at the span granularity, and spans are of wildly
// different sizes. This member keeps track of the extra bytes bytes
// released so that the app can periodically call ReleaseToSystem() to
// release memory at a constant rate.
// NOTE: Protected by Static::pageheap_lock().
size_t extra_bytes_released_;
public:
TCMallocImplementation()
: extra_bytes_released_(0) {
}
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);
}
}
// We may print an extra, tcmalloc-specific warning message here.
virtual void GetHeapSample(MallocExtensionWriter* writer) {
if (FLAGS_tcmalloc_sample_parameter == 0) {
const char* const kWarningMsg =
"%warn\n"
"%warn This heap profile does not have any data in it, because\n"
"%warn the application was run with heap sampling turned off.\n"
"%warn To get useful data from GetHeapSample(), you must\n"
"%warn set the environment variable TCMALLOC_SAMPLE_PARAMETER to\n"
"%warn a positive sampling period, such as 524288.\n"
"%warn\n";
writer->append(kWarningMsg, strlen(kWarningMsg));
}
MallocExtension::GetHeapSample(writer);
}
virtual void** ReadStackTraces(int* sample_period) {
tcmalloc::StackTraceTable table;
{
SpinLockHolder h(Static::pageheap_lock());
Span* sampled = Static::sampled_objects();
for (Span* s = sampled->next; s != sampled; s = s->next) {
table.AddTrace(*reinterpret_cast<StackTrace*>(s->objects));
}
}
*sample_period = ThreadCache::GetCache()->GetSamplePeriod();
return table.ReadStackTracesAndClear(); // grabs and releases pageheap_lock
}
virtual void** ReadHeapGrowthStackTraces() {
return DumpHeapGrowthStackTraces();
}
virtual void Ranges(void* arg, RangeFunction func) {
IterateOverRanges(arg, func);
}
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, NULL, NULL);
*value = stats.pageheap.system_bytes
- stats.thread_bytes
- stats.central_bytes
- stats.transfer_bytes
- stats.pageheap.free_bytes
- stats.pageheap.unmapped_bytes;
return true;
}
if (strcmp(name, "generic.heap_size") == 0) {
TCMallocStats stats;
ExtractStats(&stats, NULL, NULL, NULL);
*value = stats.pageheap.system_bytes;
return true;
}
if (strcmp(name, "tcmalloc.slack_bytes") == 0) {
// Kept for backwards compatibility. Now defined externally as:
// pageheap_free_bytes + pageheap_unmapped_bytes.
SpinLockHolder l(Static::pageheap_lock());
PageHeap::Stats stats = Static::pageheap()->stats();
*value = stats.free_bytes + stats.unmapped_bytes;
return true;
}
if (strcmp(name, "tcmalloc.pageheap_free_bytes") == 0) {
SpinLockHolder l(Static::pageheap_lock());
*value = Static::pageheap()->stats().free_bytes;
return true;
}
if (strcmp(name, "tcmalloc.pageheap_unmapped_bytes") == 0) {
SpinLockHolder l(Static::pageheap_lock());
*value = Static::pageheap()->stats().unmapped_bytes;
return true;
}
if (strcmp(name, "tcmalloc.max_total_thread_cache_bytes") == 0) {
SpinLockHolder l(Static::pageheap_lock());
*value = ThreadCache::overall_thread_cache_size();
return true;
}
if (strcmp(name, "tcmalloc.current_total_thread_cache_bytes") == 0) {
TCMallocStats stats;
ExtractStats(&stats, NULL, NULL, 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) {
SpinLockHolder l(Static::pageheap_lock());
ThreadCache::set_overall_thread_cache_size(value);
return true;
}
return false;
}
virtual void MarkThreadIdle() {
ThreadCache::BecomeIdle();
}
virtual void MarkThreadBusy(); // Implemented below
virtual SysAllocator* GetSystemAllocator() {
SpinLockHolder h(Static::pageheap_lock());
return sys_alloc;
}
virtual void SetSystemAllocator(SysAllocator* alloc) {
SpinLockHolder h(Static::pageheap_lock());
sys_alloc = alloc;
}
virtual void ReleaseToSystem(size_t num_bytes) {
SpinLockHolder h(Static::pageheap_lock());
if (num_bytes <= extra_bytes_released_) {
// We released too much on a prior call, so don't release any
// more this time.
extra_bytes_released_ = extra_bytes_released_ - num_bytes;
return;
}
num_bytes = num_bytes - extra_bytes_released_;
// num_bytes might be less than one page. If we pass zero to
// ReleaseAtLeastNPages, it won't do anything, so we release a whole
// page now and let extra_bytes_released_ smooth it out over time.
Length num_pages = max<Length>(num_bytes >> kPageShift, 1);
size_t bytes_released = Static::pageheap()->ReleaseAtLeastNPages(
num_pages) << kPageShift;
if (bytes_released > num_bytes) {
extra_bytes_released_ = bytes_released - num_bytes;
} else {
// The PageHeap wasn't able to release num_bytes. Don't try to
// compensate with a big release next time. Specifically,
// ReleaseFreeMemory() calls ReleaseToSystem(LONG_MAX).
extra_bytes_released_ = 0;
}
}
virtual void SetMemoryReleaseRate(double rate) {
FLAGS_tcmalloc_release_rate = rate;
}
virtual double GetMemoryReleaseRate() {
return FLAGS_tcmalloc_release_rate;
}
virtual size_t GetEstimatedAllocatedSize(size_t size) {
if (size <= kMaxSize) {
const size_t cl = Static::sizemap()->SizeClass(size);
const size_t alloc_size = Static::sizemap()->ByteSizeForClass(cl);
return alloc_size;
} else {
return tcmalloc::pages(size) << kPageShift;
}
}
// This just calls GetSizeWithCallback, but because that's in an
// unnamed namespace, we need to move the definition below it in the
// file.
virtual size_t GetAllocatedSize(const void* ptr);
// This duplicates some of the logic in GetSizeWithCallback, but is
// faster. This is important on OS X, where this function is called
// on every allocation operation.
virtual Ownership GetOwnership(const void* ptr) {
const PageID p = reinterpret_cast<uintptr_t>(ptr) >> kPageShift;
// The rest of tcmalloc assumes that all allocated pointers use at
// most kAddressBits bits. If ptr doesn't, then it definitely
// wasn't alloacted by tcmalloc.
if ((p >> (kAddressBits - kPageShift)) > 0) {
return kNotOwned;
}
size_t cl = Static::pageheap()->GetSizeClassIfCached(p);
if (cl != 0) {
return kOwned;
}
const Span *span = Static::pageheap()->GetDescriptor(p);
return span ? kOwned : kNotOwned;
}
virtual void GetFreeListSizes(vector<MallocExtension::FreeListInfo>* v) {
static const char* kCentralCacheType = "tcmalloc.central";
static const char* kTransferCacheType = "tcmalloc.transfer";
static const char* kThreadCacheType = "tcmalloc.thread";
static const char* kPageHeapType = "tcmalloc.page";
static const char* kPageHeapUnmappedType = "tcmalloc.page_unmapped";
static const char* kLargeSpanType = "tcmalloc.large";
static const char* kLargeUnmappedSpanType = "tcmalloc.large_unmapped";
v->clear();
// central class information
int64 prev_class_size = 0;
for (int cl = 1; cl < kNumClasses; ++cl) {
size_t class_size = Static::sizemap()->ByteSizeForClass(cl);
MallocExtension::FreeListInfo i;
i.min_object_size = prev_class_size + 1;
i.max_object_size = class_size;
i.total_bytes_free =
Static::central_cache()[cl].length() * class_size;
i.type = kCentralCacheType;
v->push_back(i);
// transfer cache
i.total_bytes_free =
Static::central_cache()[cl].tc_length() * class_size;
i.type = kTransferCacheType;
v->push_back(i);
prev_class_size = Static::sizemap()->ByteSizeForClass(cl);
}
// Add stats from per-thread heaps
uint64_t class_count[kNumClasses];
memset(class_count, 0, sizeof(class_count));
{
SpinLockHolder h(Static::pageheap_lock());
uint64_t thread_bytes = 0;
ThreadCache::GetThreadStats(&thread_bytes, class_count);
}
prev_class_size = 0;
for (int cl = 1; cl < kNumClasses; ++cl) {
MallocExtension::FreeListInfo i;
i.min_object_size = prev_class_size + 1;
i.max_object_size = Static::sizemap()->ByteSizeForClass(cl);
i.total_bytes_free =
class_count[cl] * Static::sizemap()->ByteSizeForClass(cl);
i.type = kThreadCacheType;
v->push_back(i);
}
// append page heap info
PageHeap::SmallSpanStats small;
PageHeap::LargeSpanStats large;
{
SpinLockHolder h(Static::pageheap_lock());
Static::pageheap()->GetSmallSpanStats(&small);
Static::pageheap()->GetLargeSpanStats(&large);
}
// large spans: mapped
MallocExtension::FreeListInfo span_info;
span_info.type = kLargeSpanType;
span_info.max_object_size = (numeric_limits<size_t>::max)();
span_info.min_object_size = kMaxPages << kPageShift;
span_info.total_bytes_free = large.normal_pages << kPageShift;
v->push_back(span_info);
// large spans: unmapped
span_info.type = kLargeUnmappedSpanType;
span_info.total_bytes_free = large.returned_pages << kPageShift;
v->push_back(span_info);
// small spans
for (int s = 1; s < kMaxPages; s++) {
MallocExtension::FreeListInfo i;
i.max_object_size = (s << kPageShift);
i.min_object_size = ((s - 1) << kPageShift);
i.type = kPageHeapType;
i.total_bytes_free = (s << kPageShift) * small.normal_length[s];
v->push_back(i);
i.type = kPageHeapUnmappedType;
i.total_bytes_free = (s << kPageShift) * small.returned_length[s];
v->push_back(i);
}
}
};
// 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.
static int tcmallocguard_refcount = 0; // no lock needed: runs before main()
TCMallocGuard::TCMallocGuard() {
if (tcmallocguard_refcount++ == 0) {
#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)
tcmalloc::CheckIfKernelSupportsTLS();
#endif
ReplaceSystemAlloc(); // defined in libc_override_*.h
tc_free(tc_malloc(1));
ThreadCache::InitTSD();
tc_free(tc_malloc(1));
// Either we, or debugallocation.cc, or valgrind will control memory
// management. We register our extension if we're the winner.
#ifdef TCMALLOC_USING_DEBUGALLOCATION
// Let debugallocation register its extension.
#else
if (RunningOnValgrind()) {
// Let Valgrind uses its own malloc (so don't register our extension).
} else {
MallocExtension::Register(new TCMallocImplementation);
}
#endif
}
}
TCMallocGuard::~TCMallocGuard() {
if (--tcmallocguard_refcount == 0) {
const char* env = getenv("MALLOCSTATS");
if (env != NULL) {
int level = atoi(env);
if (level < 1) level = 1;
PrintStats(level);
}
}
}
#ifndef WIN32_OVERRIDE_ALLOCATORS
static TCMallocGuard module_enter_exit_hook;
#endif
//-------------------------------------------------------------------
// Helpers for the exported routines below
//-------------------------------------------------------------------
static inline bool CheckCachedSizeClass(void *ptr) {
PageID p = reinterpret_cast<uintptr_t>(ptr) >> kPageShift;
size_t cached_value = Static::pageheap()->GetSizeClassIfCached(p);
return cached_value == 0 ||
cached_value == Static::pageheap()->GetDescriptor(p)->sizeclass;
}
static inline void* CheckMallocResult(void *result) {
ASSERT(result == NULL || CheckCachedSizeClass(result));
MarkAllocatedRegion(result);
return result;
}
static inline void* SpanToMallocResult(Span *span) {
Static::pageheap()->CacheSizeClass(span->start, 0);
return
CheckMallocResult(reinterpret_cast<void*>(span->start << kPageShift));
}
static void* DoSampledAllocation(size_t size) {
// Grab the stack trace outside the heap lock
StackTrace tmp;
tmp.depth = GetStackTrace(tmp.stack, tcmalloc::kMaxStackDepth, 1);
tmp.size = size;
SpinLockHolder h(Static::pageheap_lock());
// Allocate span
Span *span = Static::pageheap()->New(tcmalloc::pages(size == 0 ? 1 : size));
if (span == NULL) {
return NULL;
}
// Allocate stack trace
StackTrace *stack = Static::stacktrace_allocator()->New();
if (stack == NULL) {
// Sampling failed because of lack of memory
return span;
}
*stack = tmp;
span->sample = 1;
span->objects = stack;
tcmalloc::DLL_Prepend(Static::sampled_objects(), span);
return SpanToMallocResult(span);
}
namespace {
// Copy of FLAGS_tcmalloc_large_alloc_report_threshold with
// automatic increases factored in.
static int64_t large_alloc_threshold =
(kPageSize > FLAGS_tcmalloc_large_alloc_report_threshold
? kPageSize : FLAGS_tcmalloc_large_alloc_report_threshold);
static void ReportLargeAlloc(Length num_pages, void* result) {
StackTrace stack;
stack.depth = GetStackTrace(stack.stack, tcmalloc::kMaxStackDepth, 1);
static const int N = 1000;
char buffer[N];
TCMalloc_Printer printer(buffer, N);
printer.printf("tcmalloc: large alloc %" PRIu64 " bytes == %p @ ",
static_cast<uint64>(num_pages) << kPageShift,
result);
for (int i = 0; i < stack.depth; i++) {
printer.printf(" %p", stack.stack[i]);
}
printer.printf("\n");
write(STDERR_FILENO, buffer, strlen(buffer));
}
inline void* cpp_alloc(size_t size, bool nothrow);
inline void* do_malloc(size_t size);
// TODO(willchan): Investigate whether or not inlining this much is harmful to
// performance.
// This is equivalent to do_malloc() except when tc_new_mode is set to true.
// Otherwise, it will run the std::new_handler if set.
inline void* do_malloc_or_cpp_alloc(size_t size) {
return tc_new_mode ? cpp_alloc(size, true) : do_malloc(size);
}
void* cpp_memalign(size_t align, size_t size);
void* do_memalign(size_t align, size_t size);
inline void* do_memalign_or_cpp_memalign(size_t align, size_t size) {
return tc_new_mode ? cpp_memalign(align, size) : do_memalign(align, size);
}
// Must be called with the page lock held.
inline bool should_report_large(Length num_pages) {
const int64 threshold = large_alloc_threshold;
if (threshold > 0 && num_pages >= (threshold >> kPageShift)) {
// Increase the threshold by 1/8 every time we generate a report.
// We cap the threshold at 8GiB to avoid overflow problems.
large_alloc_threshold = (threshold + threshold/8 < 8ll<<30
? threshold + threshold/8 : 8ll<<30);
return true;
}
return false;
}
// Helper for do_malloc().
inline void* do_malloc_pages(ThreadCache* heap, size_t size) {
void* result;
bool report_large;
Length num_pages = tcmalloc::pages(size);
size = num_pages << kPageShift;
// Chromium profiling. Measurements in March 2013 suggest this
// imposes a small enough runtime cost that there's no reason to
// try to optimize it.
heap->AddToByteAllocatedTotal(size);
if ((FLAGS_tcmalloc_sample_parameter > 0) && heap->SampleAllocation(size)) {
result = DoSampledAllocation(size);
SpinLockHolder h(Static::pageheap_lock());
report_large = should_report_large(num_pages);
} else {
SpinLockHolder h(Static::pageheap_lock());
Span* span = Static::pageheap()->New(num_pages);
result = (span == NULL ? NULL : SpanToMallocResult(span));
report_large = should_report_large(num_pages);
}
if (report_large) {
ReportLargeAlloc(num_pages, result);
}
return result;
}
inline void* do_malloc(size_t size) {
AddRoomForMark(&size);
void* ret = NULL;
// The following call forces module initialization
ThreadCache* heap = ThreadCache::GetCache();
if (size <= kMaxSize && IsAllocSizePermitted(size)) {
size_t cl = Static::sizemap()->SizeClass(size);
size = Static::sizemap()->class_to_size(cl);
// Chromium profiling. Measurements in March 2013 suggest this
// imposes a small enough runtime cost that there's no reason to
// try to optimize it.
heap->AddToByteAllocatedTotal(size);
if ((FLAGS_tcmalloc_sample_parameter > 0) &&
heap->SampleAllocation(size)) {
ret = DoSampledAllocation(size);
MarkAllocatedRegion(ret);
} else {
// The common case, and also the simplest. This just pops the
// size-appropriate freelist, after replenishing it if it's empty.
ret = CheckMallocResult(heap->Allocate(size, cl));
}
} else if (IsAllocSizePermitted(size)) {
ret = do_malloc_pages(heap, size);
MarkAllocatedRegion(ret);
}
if (ret == NULL) errno = ENOMEM;
ASSERT(IsAllocSizePermitted(size) || ret == NULL);
return ret;
}
inline void* do_calloc(size_t n, size_t elem_size) {
// Overflow check
const size_t size = n * elem_size;
if (elem_size != 0 && size / elem_size != n) return NULL;
void* result = do_malloc_or_cpp_alloc(size);
if (result != NULL) {
memset(result, 0, size);
}
return result;
}
static inline ThreadCache* GetCacheIfPresent() {
void* const p = ThreadCache::GetCacheIfPresent();
return reinterpret_cast<ThreadCache*>(p);
}
// This lets you call back to a given function pointer if ptr is invalid.
// It is used primarily by windows code which wants a specialized callback.
inline void do_free_with_callback(void* ptr, void (*invalid_free_fn)(void*)) {
if (ptr == NULL) return;
if (Static::pageheap() == NULL) {
// We called free() before malloc(). This can occur if the
// (system) malloc() is called before tcmalloc is loaded, and then
// free() is called after tcmalloc is loaded (and tc_free has
// replaced free), but before the global constructor has run that
// sets up the tcmalloc data structures.
(*invalid_free_fn)(ptr); // Decide how to handle the bad free request
return;
}
const PageID p = reinterpret_cast<uintptr_t>(ptr) >> kPageShift;
Span* span = NULL;
size_t cl = Static::pageheap()->GetSizeClassIfCached(p);
if (cl == 0) {
span = Static::pageheap()->GetDescriptor(p);
if (!span) {
// span can be NULL because the pointer passed in is invalid
// (not something returned by malloc or friends), or because the
// pointer was allocated with some other allocator besides
// tcmalloc. The latter can happen if tcmalloc is linked in via
// a dynamic library, but is not listed last on the link line.
// In that case, libraries after it on the link line will
// allocate with libc malloc, but free with tcmalloc's free.
(*invalid_free_fn)(ptr); // Decide how to handle the bad free request
return;
}
cl = span->sizeclass;
Static::pageheap()->CacheSizeClass(p, cl);
}
if (cl == 0) {
// Check to see if the object is in use.
CHECK_CONDITION_PRINT(span->location == Span::IN_USE,
"Object was not in-use");
CHECK_CONDITION_PRINT(
span->start << kPageShift == reinterpret_cast<uintptr_t>(ptr),
"Pointer is not pointing to the start of a span");
}
ValidateAllocatedRegion(ptr, cl);
if (cl != 0) {
ASSERT(!Static::pageheap()->GetDescriptor(p)->sample);
ThreadCache* heap = GetCacheIfPresent();
if (heap != NULL) {
heap->Deallocate(ptr, cl);
} else {
// Delete directly into central cache
tcmalloc::FL_Init(ptr);
Static::central_cache()[cl].InsertRange(ptr, ptr, 1);
}
} else {
SpinLockHolder h(Static::pageheap_lock());
ASSERT(reinterpret_cast<uintptr_t>(ptr) % kPageSize == 0);
ASSERT(span != NULL && span->start == p);
if (span->sample) {
StackTrace* st = reinterpret_cast<StackTrace*>(span->objects);
tcmalloc::DLL_Remove(span);
Static::stacktrace_allocator()->Delete(st);
span->objects = NULL;
}
Static::pageheap()->Delete(span);
}
}
// The default "do_free" that uses the default callback.
inline void do_free(void* ptr) {
return do_free_with_callback(ptr, &InvalidFree);
}
// NOTE: some logic here is duplicated in GetOwnership (above), for
// speed. If you change this function, look at that one too.
inline size_t GetSizeWithCallback(const void* ptr,
size_t (*invalid_getsize_fn)(const void*)) {
if (ptr == NULL)
return 0;
const PageID p = reinterpret_cast<uintptr_t>(ptr) >> kPageShift;
size_t cl = Static::pageheap()->GetSizeClassIfCached(p);
if (cl != 0) {
return Static::sizemap()->ByteSizeForClass(cl);
} else {
const Span *span = Static::pageheap()->GetDescriptor(p);
if (span == NULL) { // means we do not own this memory
return (*invalid_getsize_fn)(ptr);
} else if (span->sizeclass != 0) {
Static::pageheap()->CacheSizeClass(p, span->sizeclass);
return Static::sizemap()->ByteSizeForClass(span->sizeclass);
} else {
return span->length << kPageShift;
}
}
}
// This lets you call back to a given function pointer if ptr is invalid.
// It is used primarily by windows code which wants a specialized callback.
inline void* do_realloc_with_callback(
void* old_ptr, size_t new_size,
void (*invalid_free_fn)(void*),
size_t (*invalid_get_size_fn)(const void*)) {
AddRoomForMark(&new_size);
// Get the size of the old entry
const size_t old_size = GetSizeWithCallback(old_ptr, invalid_get_size_fn);
// Reallocate if the new size is larger than the old size,
// or if the new size is significantly smaller than the old size.
// We do hysteresis to avoid resizing ping-pongs:
// . If we need to grow, grow to max(new_size, old_size * 1.X)
// . Don't shrink unless new_size < old_size * 0.Y
// X and Y trade-off time for wasted space. For now we do 1.25 and 0.5.
const size_t min_growth = min(old_size / 4,
(std::numeric_limits<size_t>::max)() - old_size); // Avoid overflow.
const size_t lower_bound_to_grow = old_size + min_growth;
const size_t upper_bound_to_shrink = old_size / 2;
if ((new_size > old_size) || (new_size < upper_bound_to_shrink)) {
// Need to reallocate.
void* new_ptr = NULL;
if (new_size > old_size && new_size < lower_bound_to_grow) {
new_ptr = do_malloc_or_cpp_alloc(lower_bound_to_grow);
}
ExcludeMarkFromSize(&new_size); // do_malloc will add space if needed.
if (new_ptr == NULL) {
// Either new_size is not a tiny increment, or last do_malloc failed.
new_ptr = do_malloc_or_cpp_alloc(new_size);
}
if (new_ptr == NULL) {
return NULL;
}
MallocHook::InvokeNewHook(new_ptr, new_size);
memcpy(new_ptr, old_ptr, ((old_size < new_size) ? old_size : new_size));
MallocHook::InvokeDeleteHook(old_ptr);
// 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_with_callback(old_ptr, invalid_free_fn);
return new_ptr;
} else {
// We still need to call hooks to report the updated size:
MallocHook::InvokeDeleteHook(old_ptr);
ExcludeMarkFromSize(&new_size);
MallocHook::InvokeNewHook(old_ptr, new_size);
return old_ptr;
}
}
inline void* do_realloc(void* old_ptr, size_t new_size) {
return do_realloc_with_callback(old_ptr, new_size,
&InvalidFree, &InvalidGetSizeForRealloc);
}
// For use by exported routines below that want specific alignments
//
// Note: this code can be slow for alignments > 16, 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.
void* do_memalign(size_t align, size_t size) {
ASSERT((align & (align - 1)) == 0);
ASSERT(align > 0);
// Marked in CheckMallocResult(), which is also inside SpanToMallocResult().
AddRoomForMark(&size);
if (size + align < size) return NULL; // Overflow
// Fall back to malloc if we would already align this memory access properly.
if (align <= AlignmentForSize(size)) {
void* p = do_malloc(size);
ASSERT((reinterpret_cast<uintptr_t>(p) % align) == 0);
return p;
}
if (Static::pageheap() == NULL) 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.
int cl = Static::sizemap()->SizeClass(size);
while (cl < kNumClasses &&
((Static::sizemap()->class_to_size(cl) & (align - 1)) != 0)) {
cl++;
}
if (cl < kNumClasses) {
ThreadCache* heap = ThreadCache::GetCache();
size = Static::sizemap()->class_to_size(cl);
return CheckMallocResult(heap->Allocate(size, cl));
}
}
// We will allocate directly from the page heap
SpinLockHolder h(Static::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 = Static::pageheap()->New(tcmalloc::pages(size));
return span == NULL ? NULL : SpanToMallocResult(span);
}
// Allocate extra pages and carve off an aligned portion
const Length alloc = tcmalloc::pages(size + align);
Span* span = Static::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 = Static::pageheap()->Split(span, skip);
Static::pageheap()->Delete(span);
span = rest;
}
// Skip trailing portion that we do not need to return
const Length needed = tcmalloc::pages(size);
ASSERT(span->length >= needed);
if (span->length > needed) {
Span* trailer = Static::pageheap()->Split(span, needed);
Static::pageheap()->Delete(trailer);
}
return SpanToMallocResult(span);
}
// Helpers for use by exported routines below:
inline void do_malloc_stats() {
PrintStats(1);
}
inline int do_mallopt(int cmd, int value) {
return 1; // Indicates error
}
#ifdef HAVE_STRUCT_MALLINFO
inline struct mallinfo do_mallinfo() {
TCMallocStats stats;
ExtractStats(&stats, NULL, NULL, 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.pageheap.system_bytes);
info.fsmblks = static_cast<int>(stats.thread_bytes
+ stats.central_bytes
+ stats.transfer_bytes);
info.fordblks = static_cast<int>(stats.pageheap.free_bytes +
stats.pageheap.unmapped_bytes);
info.uordblks = static_cast<int>(stats.pageheap.system_bytes
- stats.thread_bytes
- stats.central_bytes
- stats.transfer_bytes
- stats.pageheap.free_bytes
- stats.pageheap.unmapped_bytes);
return info;
}
#endif // HAVE_STRUCT_MALLINFO
static SpinLock set_new_handler_lock(SpinLock::LINKER_INITIALIZED);
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 (defined(__GNUC__) && !defined(__EXCEPTIONS)) || (defined(_HAS_EXCEPTIONS) && !_HAS_EXCEPTIONS)
if (nh) {
// Since exceptions are disabled, we don't really know if new_handler
// failed. Assume it will abort if it fails.
(*nh)();
continue;
}
return 0;
#else
// 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;
}
#endif // (defined(__GNUC__) && !defined(__EXCEPTIONS)) || (defined(_HAS_EXCEPTIONS) && !_HAS_EXCEPTIONS)
} else { // allocation success
return p;
}
#endif // PREANSINEW
}
}
void* cpp_memalign(size_t align, size_t size) {
for (;;) {
void* p = do_memalign(align, 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 (defined(__GNUC__) && !defined(__EXCEPTIONS)) || (defined(_HAS_EXCEPTIONS) && !_HAS_EXCEPTIONS)
if (nh) {
// Since exceptions are disabled, we don't really know if new_handler
// failed. Assume it will abort if it fails.
(*nh)();
continue;
}
return 0;
#else
// If no new_handler is established, the allocation failed.
if (!nh)
return 0;
// 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&) {
return p;
}
#endif // (defined(__GNUC__) && !defined(__EXCEPTIONS)) || (defined(_HAS_EXCEPTIONS) && !_HAS_EXCEPTIONS)
} else { // allocation success
return p;
}
#endif // PREANSINEW
}
}
} // end unnamed namespace
// As promised, the definition of this function, declared above.
size_t TCMallocImplementation::GetAllocatedSize(const void* ptr) {
// Chromium workaround for third-party code calling tc_malloc_size(NULL), see
// http://code.google.com/p/chromium/issues/detail?id=118087
// Note: this is consistent with GLIBC's implementation of
// malloc_usable_size(NULL).
if (ptr == NULL)
return 0;
ASSERT(TCMallocImplementation::GetOwnership(ptr)
!= TCMallocImplementation::kNotOwned);
return ExcludeSpaceForMark(
GetSizeWithCallback(ptr, &InvalidGetAllocatedSize));
}
void TCMallocImplementation::MarkThreadBusy() {
// Allocate to force the creation of a thread cache, but avoid
// invoking any hooks.
do_free(do_malloc(0));
}
//-------------------------------------------------------------------
// Exported routines
//-------------------------------------------------------------------
extern "C" PERFTOOLS_DLL_DECL const char* tc_version(
int* major, int* minor, const char** patch) __THROW {
if (major) *major = TC_VERSION_MAJOR;
if (minor) *minor = TC_VERSION_MINOR;
if (patch) *patch = TC_VERSION_PATCH;
return TC_VERSION_STRING;
}
// This function behaves similarly to MSVC's _set_new_mode.
// If flag is 0 (default), calls to malloc will behave normally.
// If flag is 1, calls to malloc will behave like calls to new,
// and the std_new_handler will be invoked on failure.
// Returns the previous mode.
extern "C" PERFTOOLS_DLL_DECL int tc_set_new_mode(int flag) __THROW {
int old_mode = tc_new_mode;
tc_new_mode = flag;
return old_mode;
}
#ifndef TCMALLOC_USING_DEBUGALLOCATION // debugallocation.cc defines its own
// CAVEAT: The code structure below ensures that MallocHook methods are always
// called from the stack frame of the invoked allocation function.
// heap-checker.cc depends on this to start a stack trace from
// the call to the (de)allocation function.
extern "C" PERFTOOLS_DLL_DECL void* tc_malloc(size_t size) __THROW {
void* result = do_malloc_or_cpp_alloc(size);
MallocHook::InvokeNewHook(result, size);
return result;
}
extern "C" PERFTOOLS_DLL_DECL void tc_free(void* ptr) __THROW {
MallocHook::InvokeDeleteHook(ptr);
do_free(ptr);
}
extern "C" PERFTOOLS_DLL_DECL void* tc_calloc(size_t n,
size_t elem_size) __THROW {
void* result = do_calloc(n, elem_size);
MallocHook::InvokeNewHook(result, n * elem_size);
return result;
}
extern "C" PERFTOOLS_DLL_DECL void tc_cfree(void* ptr) __THROW {
MallocHook::InvokeDeleteHook(ptr);
do_free(ptr);
}
extern "C" PERFTOOLS_DLL_DECL void* tc_realloc(void* old_ptr,
size_t new_size) __THROW {
if (old_ptr == NULL) {
void* result = do_malloc_or_cpp_alloc(new_size);
MallocHook::InvokeNewHook(result, new_size);
return result;
}
if (new_size == 0) {
MallocHook::InvokeDeleteHook(old_ptr);
do_free(old_ptr);
return NULL;
}
return do_realloc(old_ptr, new_size);
}
extern "C" PERFTOOLS_DLL_DECL void* tc_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;
}
extern "C" PERFTOOLS_DLL_DECL void* tc_new_nothrow(size_t size, const std::nothrow_t&) __THROW {
void* p = cpp_alloc(size, true);
MallocHook::InvokeNewHook(p, size);
return p;
}
extern "C" PERFTOOLS_DLL_DECL void tc_delete(void* p) __THROW {
MallocHook::InvokeDeleteHook(p);
do_free(p);
}
// Standard C++ library implementations define and use this
// (via ::operator delete(ptr, nothrow)).
// But it's really the same as normal delete, so we just do the same thing.
extern "C" PERFTOOLS_DLL_DECL void tc_delete_nothrow(void* p, const std::nothrow_t&) __THROW {
MallocHook::InvokeDeleteHook(p);
do_free(p);
}
extern "C" PERFTOOLS_DLL_DECL void* tc_newarray(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;
}
extern "C" PERFTOOLS_DLL_DECL void* tc_newarray_nothrow(size_t size, const std::nothrow_t&)
__THROW {
void* p = cpp_alloc(size, true);
MallocHook::InvokeNewHook(p, size);
return p;
}
extern "C" PERFTOOLS_DLL_DECL void tc_deletearray(void* p) __THROW {
MallocHook::InvokeDeleteHook(p);
do_free(p);
}
extern "C" PERFTOOLS_DLL_DECL void tc_deletearray_nothrow(void* p, const std::nothrow_t&) __THROW {
MallocHook::InvokeDeleteHook(p);
do_free(p);
}
extern "C" PERFTOOLS_DLL_DECL void* tc_memalign(size_t align,
size_t size) __THROW {
void* result = do_memalign_or_cpp_memalign(align, size);
MallocHook::InvokeNewHook(result, size);
return result;
}
extern "C" PERFTOOLS_DLL_DECL int tc_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_or_cpp_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" PERFTOOLS_DLL_DECL void* tc_valloc(size_t size) __THROW {
// Allocate page-aligned object of length >= size bytes
if (pagesize == 0) pagesize = getpagesize();
void* result = do_memalign_or_cpp_memalign(pagesize, size);
MallocHook::InvokeNewHook(result, size);
return result;
}
extern "C" PERFTOOLS_DLL_DECL void* tc_pvalloc(size_t size) __THROW {
// Round up size to a multiple of pagesize
if (pagesize == 0) pagesize = getpagesize();
if (size == 0) { // pvalloc(0) should allocate one page, according to
size = pagesize; // http://man.free4web.biz/man3/libmpatrol.3.html
}
size = (size + pagesize - 1) & ~(pagesize - 1);
void* result = do_memalign_or_cpp_memalign(pagesize, size);
MallocHook::InvokeNewHook(result, size);
return result;
}
extern "C" PERFTOOLS_DLL_DECL void tc_malloc_stats(void) __THROW {
do_malloc_stats();
}
extern "C" PERFTOOLS_DLL_DECL int tc_mallopt(int cmd, int value) __THROW {
return do_mallopt(cmd, value);
}
#ifdef HAVE_STRUCT_MALLINFO
extern "C" PERFTOOLS_DLL_DECL struct mallinfo tc_mallinfo(void) __THROW {
return do_mallinfo();
}
#endif
extern "C" PERFTOOLS_DLL_DECL size_t tc_malloc_size(void* ptr) __THROW {
return MallocExtension::instance()->GetAllocatedSize(ptr);
}
#if defined(OS_LINUX)
extern "C" void* PERFTOOLS_DLL_DECL tc_malloc_skip_new_handler(size_t size) {
void* result = do_malloc(size);
MallocHook::InvokeNewHook(result, size);
return result;
}
#endif
#endif // TCMALLOC_USING_DEBUGALLOCATION
#if defined(OS_LINUX)
// Alias the weak symbol in chromium to our implementation.
extern "C" __attribute__((visibility("default"), alias("tc_malloc_skip_new_handler")))
void* tc_malloc_skip_new_handler_weak(size_t size);
#endif
// --- Validation implementation with an extra mark ----------------------------
// We will put a mark at the extreme end of each allocation block. We make
// sure that we always allocate enough "extra memory" that we can fit in the
// mark, and still provide the requested usable region. If ever that mark is
// not as expected, then we know that the user is corrupting memory beyond their
// request size, or that they have called free a second time without having
// the memory allocated (again). This allows us to spot most double free()s,
// but some can "slip by" or confuse our logic if the caller reallocates memory
// (for a second use) before performing an evil double-free of a first
// allocation
// This code can be optimized, but for now, it is written to be most easily
// understood, and flexible (since it is evolving a bit). Potential
// optimizations include using other calculated data, such as class size, or
// allocation size, which is known in the code above, but then is recalculated
// below. Another potential optimization would be careful manual inlining of
// code, but I *think* that the compile will probably do this for me, and I've
// been careful to avoid aliasing issues that might make a compiler back-off.
// Evolution includes experimenting with different marks, to minimize the chance
// that a mark would be misunderstood (missed corruption). The marks are meant
// to be hashed encoding of the location, so that they can't be copied over a
// different region (by accident) without being detected (most of the time).
// Enable the following define to turn on all the TCMalloc checking.
// It will cost about 2% in performance, but it will catch double frees (most of
// the time), and will often catch allocated-buffer overrun errors. This
// validation is only active when TCMalloc is used as the allocator.
#ifndef NDEBUG
#define TCMALLOC_VALIDATION
#endif
#if !defined(TCMALLOC_VALIDATION)
static size_t ExcludeSpaceForMark(size_t size) { return size; }
static void AddRoomForMark(size_t* size) {}
static void ExcludeMarkFromSize(size_t* new_size) {}
static void MarkAllocatedRegion(void* ptr) {}
static void ValidateAllocatedRegion(void* ptr, size_t cl) {}
#else // TCMALLOC_VALIDATION
static void DieFromDoubleFree() {
Log(kCrash, __FILE__, __LINE__, "Attempt to double free");
}
static void DieFromMemoryCorruption() {
Log(kCrash, __FILE__, __LINE__, "Memory corrupted");
}
// We can either do byte marking, or whole word marking based on the following
// define. char is as small as we can get, and word marking probably provides
// more than enough bits that we won't miss a corruption. Any sized integral
// type can be used, but we just define two examples.
// #define TCMALLOC_SMALL_VALIDATION
#if defined (TCMALLOC_SMALL_VALIDATION)
typedef char MarkType; // char saves memory... int is more complete.
static const MarkType kAllocationMarkMask = static_cast<MarkType>(0x36);
#else
typedef int MarkType; // char saves memory... int is more complete.
static const MarkType kAllocationMarkMask = static_cast<MarkType>(0xE1AB9536);
#endif
// TODO(jar): See if use of reference rather than pointer gets better inlining,
// or if macro is needed. My fear is that taking address map preclude register
// allocation :-(.
inline static void AddRoomForMark(size_t* size) {
*size += sizeof(kAllocationMarkMask);
}
inline static void ExcludeMarkFromSize(size_t* new_size) {
*new_size -= sizeof(kAllocationMarkMask);
}
inline static size_t ExcludeSpaceForMark(size_t size) {
return size - sizeof(kAllocationMarkMask); // Lie about size when asked.
}
inline static MarkType* GetMarkLocation(void* ptr) {
size_t size = GetSizeWithCallback(ptr, &InvalidGetAllocatedSize);
ASSERT(size % sizeof(kAllocationMarkMask) == 0);
size_t last_index = (size / sizeof(kAllocationMarkMask)) - 1;
return static_cast<MarkType*>(ptr) + last_index;
}
// We hash in the mark location plus the pointer so that we effectively mix in
// the size of the block. This means that if a span is used for different sizes
// that the mark will be different. It would be good to hash in the size (which
// we effectively get by using both mark location and pointer), but even better
// would be to also include the class, as it concisely contains the entropy
// found in the size (when we don't have large allocation), and there is less
// risk of losing those bits to truncation. It would probably be good to combine
// the high bits of size (capturing info about large blocks) with the class
// (which is a 6 bit number).
inline static MarkType GetMarkValue(void* ptr, MarkType* mark) {
void* ptr2 = static_cast<void*>(mark);
size_t offset1 = static_cast<char*>(ptr) - static_cast<char*>(NULL);
size_t offset2 = static_cast<char*>(ptr2) - static_cast<char*>(NULL);
static const int kInvariantBits = 2;
ASSERT((offset1 >> kInvariantBits) << kInvariantBits == offset1);
// Note: low bits of both offsets are invariants due to alignment. High bits
// of both offsets are the same (unless we have a large allocation). Avoid
// XORing high bits together, as they will cancel for most small allocations.
MarkType ret = kAllocationMarkMask;
// Using a little shift, we can safely XOR together both offsets.
ret ^= static_cast<MarkType>(offset1 >> kInvariantBits) ^
static_cast<MarkType>(offset2);
if (sizeof(ret) == 1) {
// Try to bring some high level bits into the mix.
ret += static_cast<MarkType>(offset1 >> 8) ^
static_cast<MarkType>(offset1 >> 16) ^
static_cast<MarkType>(offset1 >> 24) ;
}
// Hash in high bits on a 64 bit architecture.
if (sizeof(size_t) == 8 && sizeof(ret) == 4)
ret += offset1 >> 16;
if (ret == 0)
ret = kAllocationMarkMask; // Avoid common pattern of all zeros.
return ret;
}
// TODO(jar): Use the passed in TCmalloc Class Index to calculate mark location
// faster. The current implementation calls general functions, which have to
// recalculate this in order to get the Class Size. This is a slow and wasteful
// recomputation... but it is much more readable this way (for now).
static void ValidateAllocatedRegion(void* ptr, size_t cl) {
if (ptr == NULL) return;
MarkType* mark = GetMarkLocation(ptr);
MarkType allocated_mark = GetMarkValue(ptr, mark);
MarkType current_mark = *mark;
if (current_mark == ~allocated_mark)
DieFromDoubleFree();
if (current_mark != allocated_mark)
DieFromMemoryCorruption();
#ifndef NDEBUG
// In debug mode, copy the mark into all the free'd region.
size_t class_size = static_cast<size_t>(reinterpret_cast<char*>(mark) -
reinterpret_cast<char*>(ptr));
memset(ptr, static_cast<char>(0x36), class_size);
#endif
*mark = ~allocated_mark; // Distinctively not allocated.
}
static void MarkAllocatedRegion(void* ptr) {
if (ptr == NULL) return;
MarkType* mark = GetMarkLocation(ptr);
*mark = GetMarkValue(ptr, mark);
}
#endif // TCMALLOC_VALIDATION