diff options
Diffstat (limited to 'absl/base/internal/malloc_extension.h')
| -rw-r--r-- | absl/base/internal/malloc_extension.h | 426 |
1 files changed, 0 insertions, 426 deletions
diff --git a/absl/base/internal/malloc_extension.h b/absl/base/internal/malloc_extension.h deleted file mode 100644 index 75a00ce9..00000000 --- a/absl/base/internal/malloc_extension.h +++ /dev/null @@ -1,426 +0,0 @@ -// -// Copyright 2017 The Abseil Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. -// - -// Extra extensions exported by some malloc implementations. These -// extensions are accessed through a virtual base class so an -// application can link against a malloc that does not implement these -// extensions, and it will get default versions that do nothing. -// -// NOTE FOR C USERS: If you wish to use this functionality from within -// a C program, see malloc_extension_c.h. - -#ifndef ABSL_BASE_INTERNAL_MALLOC_EXTENSION_H_ -#define ABSL_BASE_INTERNAL_MALLOC_EXTENSION_H_ - -#include <stddef.h> -#include <stdint.h> -#include <atomic> -#include <map> -#include <memory> -#include <string> -#include <vector> - -#include "absl/base/attributes.h" -#include "absl/base/macros.h" -#include "absl/base/port.h" -namespace absl { -namespace base_internal { - -class MallocExtensionWriter; - -// Interface to a pluggable system allocator. -class SysAllocator { - public: - SysAllocator() { - } - virtual ~SysAllocator(); - - // Allocates "size"-byte of memory from system aligned with "alignment". - // Returns null if failed. Otherwise, the returned pointer p up to and - // including (p + actual_size -1) have been allocated. - virtual void* Alloc(size_t size, size_t *actual_size, size_t alignment) = 0; - - // Get a human-readable description of the current state of the - // allocator. The state is stored as a null-terminated std::string in - // a prefix of buffer. - virtual void GetStats(char* buffer, int length); -}; - -// The default implementations of the following routines do nothing. -// All implementations should be thread-safe; the current ones -// (DebugMallocImplementation and TCMallocImplementation) are. -class MallocExtension { - public: - virtual ~MallocExtension(); - - // Verifies that all blocks are valid. Returns true if all are; dumps - // core otherwise. A no-op except in debug mode. Even in debug mode, - // they may not do any checking except with certain malloc - // implementations. Thread-safe. - virtual bool VerifyAllMemory(); - - // Verifies that p was returned by new, has not been deleted, and is - // valid. Returns true if p is good; dumps core otherwise. A no-op - // except in debug mode. Even in debug mode, may not do any checking - // except with certain malloc implementations. Thread-safe. - virtual bool VerifyNewMemory(const void* p); - - // Verifies that p was returned by new[], has not been deleted, and is - // valid. Returns true if p is good; dumps core otherwise. A no-op - // except in debug mode. Even in debug mode, may not do any checking - // except with certain malloc implementations. Thread-safe. - virtual bool VerifyArrayNewMemory(const void* p); - - // Verifies that p was returned by malloc, has not been freed, and is - // valid. Returns true if p is good; dumps core otherwise. A no-op - // except in debug mode. Even in debug mode, may not do any checking - // except with certain malloc implementations. Thread-safe. - virtual bool VerifyMallocMemory(const void* p); - - // If statistics collection is enabled, sets *blocks to be the number of - // currently allocated blocks, sets *total to be the total size allocated - // over all blocks, sets histogram[n] to be the number of blocks with - // size between 2^n-1 and 2^(n+1), and returns true. Returns false, and - // does not change *blocks, *total, or *histogram, if statistics - // collection is disabled. - // - // Note that these statistics reflect memory allocated by new, new[], - // malloc(), and realloc(), but not mmap(). They may be larger (if not - // all pages have been written to) or smaller (if pages have been - // allocated by mmap()) than the total RSS size. They will always be - // smaller than the total virtual memory size. - static constexpr int kMallocHistogramSize = 64; - virtual bool MallocMemoryStats(int* blocks, size_t* total, - int histogram[kMallocHistogramSize]); - - // Get a human readable description of the current state of the malloc - // data structures. The state is stored as a null-terminated std::string - // in a prefix of "buffer[0,buffer_length-1]". - // REQUIRES: buffer_length > 0. - virtual void GetStats(char* buffer, int buffer_length); - - // Outputs to "writer" a sample of live objects and the stack traces - // that allocated these objects. The output can be passed to pprof. - virtual void GetHeapSample(MallocExtensionWriter* writer); - - // Outputs to "writer" the stack traces that caused growth in the - // address space size. The output can be passed to "pprof". - virtual void GetHeapGrowthStacks(MallocExtensionWriter* writer); - - // Outputs to "writer" a fragmentation profile. The output can be - // passed to "pprof". In particular, the result is a list of - // <n,total,stacktrace> tuples that says that "total" bytes in "n" - // objects are currently unusable because of fragmentation caused by - // an allocation with the specified "stacktrace". - virtual void GetFragmentationProfile(MallocExtensionWriter* writer); - - // ------------------------------------------------------------------- - // Control operations for getting and setting malloc implementation - // specific parameters. Some currently useful properties: - // - // generic - // ------- - // "generic.current_allocated_bytes" - // Number of bytes currently allocated by application - // This property is not writable. - // - // "generic.heap_size" - // Number of bytes in the heap == - // current_allocated_bytes + - // fragmentation + - // freed memory regions - // This property is not writable. - // - // tcmalloc - // -------- - // "tcmalloc.max_total_thread_cache_bytes" - // Upper limit on total number of bytes stored across all - // per-thread caches. Default: 16MB. - // - // "tcmalloc.current_total_thread_cache_bytes" - // Number of bytes used across all thread caches. - // This property is not writable. - // - // "tcmalloc.pageheap_free_bytes" - // Number of bytes in free, mapped pages in page heap. These - // bytes can be used to fulfill allocation requests. They - // always count towards virtual memory usage, and unless the - // underlying memory is swapped out by the OS, they also count - // towards physical memory usage. This property is not writable. - // - // "tcmalloc.pageheap_unmapped_bytes" - // Number of bytes in free, unmapped pages in page heap. - // These are bytes that have been released back to the OS, - // possibly by one of the MallocExtension "Release" calls. - // They can be used to fulfill allocation requests, but - // typically incur a page fault. They always count towards - // virtual memory usage, and depending on the OS, typically - // do not count towards physical memory usage. This property - // is not writable. - // - // "tcmalloc.per_cpu_caches_active" - // Whether tcmalloc is using per-CPU caches (1 or 0 respectively). - // This property is not writable. - // ------------------------------------------------------------------- - - // Get the named "property"'s value. Returns true if the property - // is known. Returns false if the property is not a valid property - // name for the current malloc implementation. - // REQUIRES: property != null; value != null - virtual bool GetNumericProperty(const char* property, size_t* value); - - // Set the named "property"'s value. Returns true if the property - // is known and writable. Returns false if the property is not a - // valid property name for the current malloc implementation, or - // is not writable. - // REQUIRES: property != null - virtual bool SetNumericProperty(const char* property, size_t value); - - // Mark the current thread as "idle". This routine may optionally - // be called by threads as a hint to the malloc implementation that - // any thread-specific resources should be released. Note: this may - // be an expensive routine, so it should not be called too often. - // - // Also, if the code that calls this routine will go to sleep for - // a while, it should take care to not allocate anything between - // the call to this routine and the beginning of the sleep. - // - // Most malloc implementations ignore this routine. - virtual void MarkThreadIdle(); - - // Mark the current thread as "busy". This routine should be - // called after MarkThreadIdle() if the thread will now do more - // work. If this method is not called, performance may suffer. - // - // Most malloc implementations ignore this routine. - virtual void MarkThreadBusy(); - - // Attempt to free any resources associated with cpu <cpu> (in the sense - // of only being usable from that CPU.) Returns the number of bytes - // previously assigned to "cpu" that were freed. Safe to call from - // any processor, not just <cpu>. - // - // Most malloc implementations ignore this routine (known exceptions: - // tcmalloc with --tcmalloc_per_cpu_caches=true.) - virtual size_t ReleaseCPUMemory(int cpu); - - // Gets the system allocator used by the malloc extension instance. Returns - // null for malloc implementations that do not support pluggable system - // allocators. - virtual SysAllocator* GetSystemAllocator(); - - // Sets the system allocator to the specified. - // - // Users could register their own system allocators for malloc implementation - // that supports pluggable system allocators, such as TCMalloc, by doing: - // alloc = new MyOwnSysAllocator(); - // MallocExtension::instance()->SetSystemAllocator(alloc); - // It's up to users whether to fall back (recommended) to the default - // system allocator (use GetSystemAllocator() above) or not. The caller is - // responsible to any necessary locking. - // See tcmalloc/system-alloc.h for the interface and - // tcmalloc/memfs_malloc.cc for the examples. - // - // It's a no-op for malloc implementations that do not support pluggable - // system allocators. - virtual void SetSystemAllocator(SysAllocator *a); - - // Try to release num_bytes of free memory back to the operating - // system for reuse. Use this extension with caution -- to get this - // memory back may require faulting pages back in by the OS, and - // that may be slow. (Currently only implemented in tcmalloc.) - virtual void ReleaseToSystem(size_t num_bytes); - - // Same as ReleaseToSystem() but release as much memory as possible. - virtual void ReleaseFreeMemory(); - - // Sets the 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]. (Currently - // only implemented in tcmalloc). - virtual void SetMemoryReleaseRate(double rate); - - // Gets the release rate. Returns a value < 0 if unknown. - virtual double GetMemoryReleaseRate(); - - // Returns the estimated number of bytes that will be allocated for - // a request of "size" bytes. This is an estimate: an allocation of - // SIZE bytes may reserve more bytes, but will never reserve less. - // (Currently only implemented in tcmalloc, other implementations - // always return SIZE.) - // This is equivalent to malloc_good_size() in OS X. - virtual size_t GetEstimatedAllocatedSize(size_t size); - - // Returns the actual number N of bytes reserved by tcmalloc for the - // pointer p. This number may be equal to or greater than the - // number of bytes requested when p was allocated. - // - // This routine is just useful for statistics collection. The - // client must *not* read or write from the extra bytes that are - // indicated by this call. - // - // Example, suppose the client gets memory by calling - // p = malloc(10) - // and GetAllocatedSize(p) returns 16. The client must only use the - // first 10 bytes p[0..9], and not attempt to read or write p[10..15]. - // - // p must have been allocated by this malloc implementation, must - // not be an interior pointer -- that is, must be exactly the - // pointer returned to by malloc() et al., not some offset from that - // -- and should not have been freed yet. p may be null. - // (Currently only implemented in tcmalloc; other implementations - // will return 0.) - virtual size_t GetAllocatedSize(const void* p); - - // Returns kOwned if this malloc implementation allocated the memory - // pointed to by p, or kNotOwned if some other malloc implementation - // allocated it or p is null. May also return kUnknownOwnership if - // the malloc implementation does not keep track of ownership. - // REQUIRES: p must be a value returned from a previous call to - // malloc(), calloc(), realloc(), memalign(), posix_memalign(), - // valloc(), pvalloc(), new, or new[], and must refer to memory that - // is currently allocated (so, for instance, you should not pass in - // a pointer after having called free() on it). - enum Ownership { - // NOTE: Enum values MUST be kept in sync with the version in - // malloc_extension_c.h - kUnknownOwnership = 0, - kOwned, - kNotOwned - }; - virtual Ownership GetOwnership(const void* p); - - // The current malloc implementation. Always non-null. - static MallocExtension* instance() { - InitModuleOnce(); - return current_instance_.load(std::memory_order_acquire); - } - - // Change the malloc implementation. Typically called by the - // malloc implementation during initialization. - static void Register(MallocExtension* implementation); - - // Type used by GetProperties. See comment on GetProperties. - struct Property { - size_t value; - // Stores breakdown of the property value bucketed by object size. - struct Bucket { - size_t min_object_size; - size_t max_object_size; - size_t size; - }; - // Empty unless detailed info was asked for and this type has buckets - std::vector<Bucket> buckets; - }; - - // Type used by GetProperties. See comment on GetProperties. - enum StatLevel { kSummary, kDetailed }; - - // Stores in *result detailed statistics about the malloc - // implementation. *result will be a map keyed by the name of - // the statistic. Each statistic has at least a "value" field. - // - // Some statistics may also contain an array of buckets if - // level==kDetailed and the "value" can be subdivided - // into different buckets for different object sizes. If - // such detailed statistics are not available, Property::buckets - // will be empty. Otherwise Property::buckets will contain - // potentially many entries. For each bucket b, b.value - // will count the value contributed by objects in the range - // [b.min_object_size, b.max_object_size]. - // - // Common across malloc implementations: - // generic.bytes_in_use_by_app -- Bytes currently in use by application - // generic.physical_memory_used -- Overall (including malloc internals) - // generic.virtual_memory_used -- Overall (including malloc internals) - // - // Tcmalloc specific properties - // tcmalloc.cpu_free -- Bytes in per-cpu free-lists - // tcmalloc.thread_cache_free -- Bytes in per-thread free-lists - // tcmalloc.transfer_cache -- Bytes in cross-thread transfer caches - // tcmalloc.central_cache_free -- Bytes in central cache - // tcmalloc.page_heap_free -- Bytes in page heap - // tcmalloc.page_heap_unmapped -- Bytes in page heap (no backing phys. mem) - // tcmalloc.metadata_bytes -- Used by internal data structures - // tcmalloc.thread_cache_count -- Number of thread caches in use - // - // Debug allocator - // debug.free_queue -- Recently freed objects - virtual void GetProperties(StatLevel level, - std::map<std::string, Property>* result); - private: - static MallocExtension* InitModule(); - - static void InitModuleOnce() { - // Pointer stored here so heap leak checker will consider the default - // instance reachable, even if current_instance_ is later overridden by - // MallocExtension::Register(). - ABSL_ATTRIBUTE_UNUSED static MallocExtension* default_instance = - InitModule(); - } - - static std::atomic<MallocExtension*> current_instance_; -}; - -// Base class than can handle output generated by GetHeapSample() and -// GetHeapGrowthStacks(). Use the available subclass or roll your -// own. Useful if you want explicit control over the type of output -// buffer used (e.g. IOBuffer, Cord, etc.) -class MallocExtensionWriter { - public: - virtual ~MallocExtensionWriter() {} - virtual void Write(const char* buf, int len) = 0; - protected: - MallocExtensionWriter() {} - MallocExtensionWriter(const MallocExtensionWriter&) = delete; - MallocExtensionWriter& operator=(const MallocExtensionWriter&) = delete; - - private: - virtual void UnusedKeyMethod(); // Dummy key method to avoid weak vtable. -}; - -// A subclass that writes to the std::string "out". NOTE: The generated -// data is *appended* to "*out". I.e., the old contents of "*out" are -// preserved. -class StringMallocExtensionWriter : public MallocExtensionWriter { - public: - explicit StringMallocExtensionWriter(std::string* out) : out_(out) {} - void Write(const char* buf, int len) override; - - private: - std::string* const out_; - StringMallocExtensionWriter(const StringMallocExtensionWriter&) = delete; - StringMallocExtensionWriter& operator=(const StringMallocExtensionWriter&) = - delete; -}; - -} // namespace base_internal -} // namespace absl - -// The nallocx function allocates no memory, but it performs the same size -// computation as the malloc function, and returns the real size of the -// allocation that would result from the equivalent malloc function call. -// Default weak implementation returns size unchanged, but tcmalloc overrides it -// and returns rounded up size. See the following link for details: -// http://www.unix.com/man-page/freebsd/3/nallocx/ -extern "C" size_t nallocx(size_t size, int flags); - -#ifndef MALLOCX_LG_ALIGN -#define MALLOCX_LG_ALIGN(la) (la) -#endif - -#endif // ABSL_BASE_INTERNAL_MALLOC_EXTENSION_H_ |